icu.lo insert.lo journal.lo legacy.lo loadext.lo \
         main.lo malloc.lo mem0.lo mem1.lo mem2.lo mem3.lo mem5.lo \
         memjournal.lo \
         mutex.lo mutex_noop.lo mutex_unix.lo mutex_w32.lo \
         notify.lo opcodes.lo os.lo os_unix.lo os_win.lo \
         pager.lo parse.lo pcache.lo pcache1.lo pragma.lo prepare.lo printf.lo \
         random.lo resolve.lo rowset.lo rtree.lo select.lo status.lo \
         table.lo tokenize.lo trigger.lo \
         update.lo util.lo vacuum.lo \
         vdbe.lo vdbeapi.lo vdbeaux.lo vdbeblob.lo vdbemem.lo vdbesort.lo \
         vdbetrace.lo wal.lo walker.lo where.lo utf.lo vtab.lo

# Object files for the amalgamation.
#
LIBOBJS1 = sqlite3.lo
................................................................................
  $(TOP)/src/status.c \
  $(TOP)/src/shell.c \
  $(TOP)/src/sqlite.h.in \
  $(TOP)/src/sqlite3ext.h \
  $(TOP)/src/sqliteInt.h \
  $(TOP)/src/sqliteLimit.h \
  $(TOP)/src/table.c \

  $(TOP)/src/tclsqlite.c \
  $(TOP)/src/tokenize.c \
  $(TOP)/src/trigger.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/update.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vacuum.c \
................................................................................
  $(TOP)/src/test6.c \
  $(TOP)/src/test7.c \
  $(TOP)/src/test8.c \
  $(TOP)/src/test9.c \
  $(TOP)/src/test_autoext.c \
  $(TOP)/src/test_async.c \
  $(TOP)/src/test_backup.c \

  $(TOP)/src/test_btree.c \
  $(TOP)/src/test_config.c \
  $(TOP)/src/test_demovfs.c \
  $(TOP)/src/test_devsym.c \
  $(TOP)/src/test_fs.c \
  $(TOP)/src/test_func.c \
  $(TOP)/src/test_hexio.c \
................................................................................
  $(TOP)/ext/fts3/fts3_test.c 

# Statically linked extensions
#
TESTSRC += \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/closure.c \

  $(TOP)/ext/misc/fileio.c \
  $(TOP)/ext/misc/fuzzer.c \
  $(TOP)/ext/misc/ieee754.c \
  $(TOP)/ext/misc/nextchar.c \
  $(TOP)/ext/misc/percentile.c \
  $(TOP)/ext/misc/regexp.c \
  $(TOP)/ext/misc/spellfix.c \
................................................................................

status.lo:	$(TOP)/src/status.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/status.c

table.lo:	$(TOP)/src/table.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/table.c




tokenize.lo:	$(TOP)/src/tokenize.c keywordhash.h $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/tokenize.c

trigger.lo:	$(TOP)/src/trigger.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/trigger.c

update.lo:	$(TOP)/src/update.c $(HDR)

         icu.lo insert.lo journal.lo legacy.lo loadext.lo \
         main.lo malloc.lo mem0.lo mem1.lo mem2.lo mem3.lo mem5.lo \
         memjournal.lo \
         mutex.lo mutex_noop.lo mutex_unix.lo mutex_w32.lo \
         notify.lo opcodes.lo os.lo os_unix.lo os_win.lo \
         pager.lo parse.lo pcache.lo pcache1.lo pragma.lo prepare.lo printf.lo \
         random.lo resolve.lo rowset.lo rtree.lo select.lo status.lo \
         table.lo threads.lo tokenize.lo trigger.lo \
         update.lo util.lo vacuum.lo \
         vdbe.lo vdbeapi.lo vdbeaux.lo vdbeblob.lo vdbemem.lo vdbesort.lo \
         vdbetrace.lo wal.lo walker.lo where.lo utf.lo vtab.lo

# Object files for the amalgamation.
#
LIBOBJS1 = sqlite3.lo
................................................................................
  $(TOP)/src/status.c \
  $(TOP)/src/shell.c \
  $(TOP)/src/sqlite.h.in \
  $(TOP)/src/sqlite3ext.h \
  $(TOP)/src/sqliteInt.h \
  $(TOP)/src/sqliteLimit.h \
  $(TOP)/src/table.c \
  $(TOP)/src/threads.c \
  $(TOP)/src/tclsqlite.c \
  $(TOP)/src/tokenize.c \
  $(TOP)/src/trigger.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/update.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vacuum.c \
................................................................................
  $(TOP)/src/test6.c \
  $(TOP)/src/test7.c \
  $(TOP)/src/test8.c \
  $(TOP)/src/test9.c \
  $(TOP)/src/test_autoext.c \
  $(TOP)/src/test_async.c \
  $(TOP)/src/test_backup.c \
  $(TOP)/src/test_blob.c \
  $(TOP)/src/test_btree.c \
  $(TOP)/src/test_config.c \
  $(TOP)/src/test_demovfs.c \
  $(TOP)/src/test_devsym.c \
  $(TOP)/src/test_fs.c \
  $(TOP)/src/test_func.c \
  $(TOP)/src/test_hexio.c \
................................................................................
  $(TOP)/ext/fts3/fts3_test.c 

# Statically linked extensions
#
TESTSRC += \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/closure.c \
  $(TOP)/ext/misc/eval.c \
  $(TOP)/ext/misc/fileio.c \
  $(TOP)/ext/misc/fuzzer.c \
  $(TOP)/ext/misc/ieee754.c \
  $(TOP)/ext/misc/nextchar.c \
  $(TOP)/ext/misc/percentile.c \
  $(TOP)/ext/misc/regexp.c \
  $(TOP)/ext/misc/spellfix.c \
................................................................................

status.lo:	$(TOP)/src/status.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/status.c

table.lo:	$(TOP)/src/table.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/table.c

threads.lo:	$(TOP)/src/threads.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/threads.c

tokenize.lo:	$(TOP)/src/tokenize.c keywordhash.h $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/tokenize.c

trigger.lo:	$(TOP)/src/trigger.c $(HDR)
	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/trigger.c

update.lo:	$(TOP)/src/update.c $(HDR)

         icu.lo insert.lo journal.lo legacy.lo loadext.lo \
         main.lo malloc.lo mem0.lo mem1.lo mem2.lo mem3.lo mem5.lo \
         memjournal.lo \
         mutex.lo mutex_noop.lo mutex_unix.lo mutex_w32.lo \
         notify.lo opcodes.lo os.lo os_unix.lo os_win.lo \
         pager.lo pcache.lo pcache1.lo pragma.lo prepare.lo printf.lo \
         random.lo resolve.lo rowset.lo rtree.lo select.lo status.lo \
         table.lo tokenize.lo trigger.lo \
         update.lo util.lo vacuum.lo \
         vdbeapi.lo vdbeaux.lo vdbeblob.lo vdbemem.lo vdbesort.lo \
         vdbetrace.lo wal.lo walker.lo where.lo utf.lo vtab.lo

# Object files for the amalgamation.
#
LIBOBJS1 = sqlite3.lo
................................................................................
  $(TOP)\src\status.c \
  $(TOP)\src\shell.c \
  $(TOP)\src\sqlite.h.in \
  $(TOP)\src\sqlite3ext.h \
  $(TOP)\src\sqliteInt.h \
  $(TOP)\src\sqliteLimit.h \
  $(TOP)\src\table.c \

  $(TOP)\src\tclsqlite.c \
  $(TOP)\src\tokenize.c \
  $(TOP)\src\trigger.c \
  $(TOP)\src\utf.c \
  $(TOP)\src\update.c \
  $(TOP)\src\util.c \
  $(TOP)\src\vacuum.c \
................................................................................
  $(TOP)\src\test6.c \
  $(TOP)\src\test7.c \
  $(TOP)\src\test8.c \
  $(TOP)\src\test9.c \
  $(TOP)\src\test_autoext.c \
  $(TOP)\src\test_async.c \
  $(TOP)\src\test_backup.c \

  $(TOP)\src\test_btree.c \
  $(TOP)\src\test_config.c \
  $(TOP)\src\test_demovfs.c \
  $(TOP)\src\test_devsym.c \
  $(TOP)\src\test_fs.c \
  $(TOP)\src\test_func.c \
  $(TOP)\src\test_hexio.c \
................................................................................
  $(TOP)\ext\fts3\fts3_test.c

# Statically linked extensions
#
TESTEXT = \
  $(TOP)\ext\misc\amatch.c \
  $(TOP)\ext\misc\closure.c \

  $(TOP)\ext\misc\fileio.c \
  $(TOP)\ext\misc\fuzzer.c \
  $(TOP)\ext\misc\ieee754.c \
  $(TOP)\ext\misc\nextchar.c \
  $(TOP)\ext\misc\percentile.c \
  $(TOP)\ext\misc\regexp.c \
  $(TOP)\ext\misc\spellfix.c \
................................................................................
	$(LTCOMPILE) -c $(TOP)\src\select.c

status.lo:	$(TOP)\src\status.c $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\status.c

table.lo:	$(TOP)\src\table.c $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\table.c




tokenize.lo:	$(TOP)\src\tokenize.c keywordhash.h $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\tokenize.c

trigger.lo:	$(TOP)\src\trigger.c $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\trigger.c

         icu.lo insert.lo journal.lo legacy.lo loadext.lo \
         main.lo malloc.lo mem0.lo mem1.lo mem2.lo mem3.lo mem5.lo \
         memjournal.lo \
         mutex.lo mutex_noop.lo mutex_unix.lo mutex_w32.lo \
         notify.lo opcodes.lo os.lo os_unix.lo os_win.lo \
         pager.lo pcache.lo pcache1.lo pragma.lo prepare.lo printf.lo \
         random.lo resolve.lo rowset.lo rtree.lo select.lo status.lo \
         table.lo threads.lo tokenize.lo trigger.lo \
         update.lo util.lo vacuum.lo \
         vdbeapi.lo vdbeaux.lo vdbeblob.lo vdbemem.lo vdbesort.lo \
         vdbetrace.lo wal.lo walker.lo where.lo utf.lo vtab.lo

# Object files for the amalgamation.
#
LIBOBJS1 = sqlite3.lo
................................................................................
  $(TOP)\src\status.c \
  $(TOP)\src\shell.c \
  $(TOP)\src\sqlite.h.in \
  $(TOP)\src\sqlite3ext.h \
  $(TOP)\src\sqliteInt.h \
  $(TOP)\src\sqliteLimit.h \
  $(TOP)\src\table.c \
  $(TOP)\src\threads.c \
  $(TOP)\src\tclsqlite.c \
  $(TOP)\src\tokenize.c \
  $(TOP)\src\trigger.c \
  $(TOP)\src\utf.c \
  $(TOP)\src\update.c \
  $(TOP)\src\util.c \
  $(TOP)\src\vacuum.c \
................................................................................
  $(TOP)\src\test6.c \
  $(TOP)\src\test7.c \
  $(TOP)\src\test8.c \
  $(TOP)\src\test9.c \
  $(TOP)\src\test_autoext.c \
  $(TOP)\src\test_async.c \
  $(TOP)\src\test_backup.c \
  $(TOP)\src\test_blob.c \
  $(TOP)\src\test_btree.c \
  $(TOP)\src\test_config.c \
  $(TOP)\src\test_demovfs.c \
  $(TOP)\src\test_devsym.c \
  $(TOP)\src\test_fs.c \
  $(TOP)\src\test_func.c \
  $(TOP)\src\test_hexio.c \
................................................................................
  $(TOP)\ext\fts3\fts3_test.c

# Statically linked extensions
#
TESTEXT = \
  $(TOP)\ext\misc\amatch.c \
  $(TOP)\ext\misc\closure.c \
  $(TOP)\ext\misc\eval.c \
  $(TOP)\ext\misc\fileio.c \
  $(TOP)\ext\misc\fuzzer.c \
  $(TOP)\ext\misc\ieee754.c \
  $(TOP)\ext\misc\nextchar.c \
  $(TOP)\ext\misc\percentile.c \
  $(TOP)\ext\misc\regexp.c \
  $(TOP)\ext\misc\spellfix.c \
................................................................................
	$(LTCOMPILE) -c $(TOP)\src\select.c

status.lo:	$(TOP)\src\status.c $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\status.c

table.lo:	$(TOP)\src\table.c $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\table.c

threads.lo:	$(TOP)\src\threads.c $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\threads.c

tokenize.lo:	$(TOP)\src\tokenize.c keywordhash.h $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\tokenize.c

trigger.lo:	$(TOP)\src\trigger.c $(HDR)
	$(LTCOMPILE) -c $(TOP)\src\trigger.c

3.8.7

3.8.8

#! /bin/sh
# Guess values for system-dependent variables and create Makefiles.
# Generated by GNU Autoconf 2.62 for sqlite 3.8.7.
#
# Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
# 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
# This configure script is free software; the Free Software Foundation
# gives unlimited permission to copy, distribute and modify it.
## --------------------- ##
## M4sh Initialization.  ##
................................................................................
MFLAGS=
MAKEFLAGS=
SHELL=${CONFIG_SHELL-/bin/sh}

# Identity of this package.
PACKAGE_NAME='sqlite'
PACKAGE_TARNAME='sqlite'
PACKAGE_VERSION='3.8.7'
PACKAGE_STRING='sqlite 3.8.7'
PACKAGE_BUGREPORT=''

# Factoring default headers for most tests.
ac_includes_default="\
#include <stdio.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
................................................................................
#
# Report the --help message.
#
if test "$ac_init_help" = "long"; then
  # Omit some internal or obsolete options to make the list less imposing.
  # This message is too long to be a string in the A/UX 3.1 sh.
  cat <<_ACEOF
\`configure' configures sqlite 3.8.7 to adapt to many kinds of systems.

Usage: $0 [OPTION]... [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.  See below for descriptions of some of the useful variables.

Defaults for the options are specified in brackets.
................................................................................
  --build=BUILD     configure for building on BUILD [guessed]
  --host=HOST       cross-compile to build programs to run on HOST [BUILD]
_ACEOF
fi

if test -n "$ac_init_help"; then
  case $ac_init_help in
     short | recursive ) echo "Configuration of sqlite 3.8.7:";;
   esac
  cat <<\_ACEOF

Optional Features:
  --disable-option-checking  ignore unrecognized --enable/--with options
  --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
  --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
................................................................................
    cd "$ac_pwd" || { ac_status=$?; break; }
  done
fi

test -n "$ac_init_help" && exit $ac_status
if $ac_init_version; then
  cat <<\_ACEOF
sqlite configure 3.8.7
generated by GNU Autoconf 2.62

Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
This configure script is free software; the Free Software Foundation
gives unlimited permission to copy, distribute and modify it.
_ACEOF
  exit
fi
cat >config.log <<_ACEOF
This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.

It was created by sqlite $as_me 3.8.7, which was
generated by GNU Autoconf 2.62.  Invocation command line was

  $ $0 $@

_ACEOF
exec 5>>config.log
{
................................................................................

exec 6>&1

# Save the log message, to keep $[0] and so on meaningful, and to
# report actual input values of CONFIG_FILES etc. instead of their
# values after options handling.
ac_log="
This file was extended by sqlite $as_me 3.8.7, which was
generated by GNU Autoconf 2.62.  Invocation command line was

  CONFIG_FILES    = $CONFIG_FILES
  CONFIG_HEADERS  = $CONFIG_HEADERS
  CONFIG_LINKS    = $CONFIG_LINKS
  CONFIG_COMMANDS = $CONFIG_COMMANDS
  $ $0 $@
................................................................................
$config_commands

Report bugs to <bug-autoconf@gnu.org>."

_ACEOF
cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
ac_cs_version="\\
sqlite config.status 3.8.7
configured by $0, generated by GNU Autoconf 2.62,
  with options \\"`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`\\"

Copyright (C) 2008 Free Software Foundation, Inc.
This config.status script is free software; the Free Software Foundation
gives unlimited permission to copy, distribute and modify it."

#! /bin/sh
# Guess values for system-dependent variables and create Makefiles.
# Generated by GNU Autoconf 2.62 for sqlite 3.8.8.
#
# Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
# 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
# This configure script is free software; the Free Software Foundation
# gives unlimited permission to copy, distribute and modify it.
## --------------------- ##
## M4sh Initialization.  ##
................................................................................
MFLAGS=
MAKEFLAGS=
SHELL=${CONFIG_SHELL-/bin/sh}

# Identity of this package.
PACKAGE_NAME='sqlite'
PACKAGE_TARNAME='sqlite'
PACKAGE_VERSION='3.8.8'
PACKAGE_STRING='sqlite 3.8.8'
PACKAGE_BUGREPORT=''

# Factoring default headers for most tests.
ac_includes_default="\
#include <stdio.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
................................................................................
#
# Report the --help message.
#
if test "$ac_init_help" = "long"; then
  # Omit some internal or obsolete options to make the list less imposing.
  # This message is too long to be a string in the A/UX 3.1 sh.
  cat <<_ACEOF
\`configure' configures sqlite 3.8.8 to adapt to many kinds of systems.

Usage: $0 [OPTION]... [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.  See below for descriptions of some of the useful variables.

Defaults for the options are specified in brackets.
................................................................................
  --build=BUILD     configure for building on BUILD [guessed]
  --host=HOST       cross-compile to build programs to run on HOST [BUILD]
_ACEOF
fi

if test -n "$ac_init_help"; then
  case $ac_init_help in
     short | recursive ) echo "Configuration of sqlite 3.8.8:";;
   esac
  cat <<\_ACEOF

Optional Features:
  --disable-option-checking  ignore unrecognized --enable/--with options
  --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
  --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
................................................................................
    cd "$ac_pwd" || { ac_status=$?; break; }
  done
fi

test -n "$ac_init_help" && exit $ac_status
if $ac_init_version; then
  cat <<\_ACEOF
sqlite configure 3.8.8
generated by GNU Autoconf 2.62

Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
This configure script is free software; the Free Software Foundation
gives unlimited permission to copy, distribute and modify it.
_ACEOF
  exit
fi
cat >config.log <<_ACEOF
This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.

It was created by sqlite $as_me 3.8.8, which was
generated by GNU Autoconf 2.62.  Invocation command line was

  $ $0 $@

_ACEOF
exec 5>>config.log
{
................................................................................

exec 6>&1

# Save the log message, to keep $[0] and so on meaningful, and to
# report actual input values of CONFIG_FILES etc. instead of their
# values after options handling.
ac_log="
This file was extended by sqlite $as_me 3.8.8, which was
generated by GNU Autoconf 2.62.  Invocation command line was

  CONFIG_FILES    = $CONFIG_FILES
  CONFIG_HEADERS  = $CONFIG_HEADERS
  CONFIG_LINKS    = $CONFIG_LINKS
  CONFIG_COMMANDS = $CONFIG_COMMANDS
  $ $0 $@
................................................................................
$config_commands

Report bugs to <bug-autoconf@gnu.org>."

_ACEOF
cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
ac_cs_version="\\
sqlite config.status 3.8.8
configured by $0, generated by GNU Autoconf 2.62,
  with options \\"`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`\\"

Copyright (C) 2008 Free Software Foundation, Inc.
This config.status script is free software; the Free Software Foundation
gives unlimited permission to copy, distribute and modify it."

  if( idxNum & FTS3_HAVE_DOCID_GE ) pDocidGe = apVal[iIdx++];
  if( idxNum & FTS3_HAVE_DOCID_LE ) pDocidLe = apVal[iIdx++];
  assert( iIdx==nVal );

  /* In case the cursor has been used before, clear it now. */
  sqlite3_finalize(pCsr->pStmt);
  sqlite3_free(pCsr->aDoclist);

  sqlite3Fts3ExprFree(pCsr->pExpr);
  memset(&pCursor[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));

  /* Set the lower and upper bounds on docids to return */
  pCsr->iMinDocid = fts3DocidRange(pDocidGe, SMALLEST_INT64);
  pCsr->iMaxDocid = fts3DocidRange(pDocidLe, LARGEST_INT64);

................................................................................
      for(i=0; rc==SQLITE_OK && i<p->nToken && bEof==0; i++){
        rc = incrPhraseTokenNext(pTab, p, i, &a[i], &bEof);
        if( a[i].bIgnore==0 && (bMaxSet==0 || DOCID_CMP(iMax, a[i].iDocid)<0) ){
          iMax = a[i].iDocid;
          bMaxSet = 1;
        }
      }
      assert( rc!=SQLITE_OK || a[p->nToken-1].bIgnore==0 );
      assert( rc!=SQLITE_OK || bMaxSet );

      /* Keep advancing iterators until they all point to the same document */
      for(i=0; i<p->nToken; i++){
        while( rc==SQLITE_OK && bEof==0 
            && a[i].bIgnore==0 && DOCID_CMP(a[i].iDocid, iMax)<0 
        ){

  if( idxNum & FTS3_HAVE_DOCID_GE ) pDocidGe = apVal[iIdx++];
  if( idxNum & FTS3_HAVE_DOCID_LE ) pDocidLe = apVal[iIdx++];
  assert( iIdx==nVal );

  /* In case the cursor has been used before, clear it now. */
  sqlite3_finalize(pCsr->pStmt);
  sqlite3_free(pCsr->aDoclist);
  sqlite3_free(pCsr->aMatchinfo);
  sqlite3Fts3ExprFree(pCsr->pExpr);
  memset(&pCursor[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));

  /* Set the lower and upper bounds on docids to return */
  pCsr->iMinDocid = fts3DocidRange(pDocidGe, SMALLEST_INT64);
  pCsr->iMaxDocid = fts3DocidRange(pDocidLe, LARGEST_INT64);

................................................................................
      for(i=0; rc==SQLITE_OK && i<p->nToken && bEof==0; i++){
        rc = incrPhraseTokenNext(pTab, p, i, &a[i], &bEof);
        if( a[i].bIgnore==0 && (bMaxSet==0 || DOCID_CMP(iMax, a[i].iDocid)<0) ){
          iMax = a[i].iDocid;
          bMaxSet = 1;
        }
      }
      assert( rc!=SQLITE_OK || (p->nToken>=1 && a[p->nToken-1].bIgnore==0) );
      assert( rc!=SQLITE_OK || bMaxSet );

      /* Keep advancing iterators until they all point to the same document */
      for(i=0; i<p->nToken; i++){
        while( rc==SQLITE_OK && bEof==0 
            && a[i].bIgnore==0 && DOCID_CMP(a[i].iDocid, iMax)<0 
        ){

  sqlite3_tokenizer_cursor *pCursor;
  Fts3Expr *pRet = 0;
  int i = 0;

  /* Set variable i to the maximum number of bytes of input to tokenize. */
  for(i=0; i<n; i++){
    if( sqlite3_fts3_enable_parentheses && (z[i]=='(' || z[i]==')') ) break;
    if( z[i]=='*' || z[i]=='"' ) break;
  }

  *pnConsumed = i;
  rc = sqlite3Fts3OpenTokenizer(pTokenizer, pParse->iLangid, z, i, &pCursor);
  if( rc==SQLITE_OK ){
    const char *zToken;
    int nToken = 0, iStart = 0, iEnd = 0, iPosition = 0;

  sqlite3_tokenizer_cursor *pCursor;
  Fts3Expr *pRet = 0;
  int i = 0;

  /* Set variable i to the maximum number of bytes of input to tokenize. */
  for(i=0; i<n; i++){
    if( sqlite3_fts3_enable_parentheses && (z[i]=='(' || z[i]==')') ) break;
    if( z[i]=='"' ) break;
  }

  *pnConsumed = i;
  rc = sqlite3Fts3OpenTokenizer(pTokenizer, pParse->iLangid, z, i, &pCursor);
  if( rc==SQLITE_OK ){
    const char *zToken;
    int nToken = 0, iStart = 0, iEnd = 0, iPosition = 0;

** of m for the first i bytes of a word.
**
** Return true if the m-value for z is 1 or more.  In other words,
** return true if z contains at least one vowel that is followed
** by a consonant.
**
** In this routine z[] is in reverse order.  So we are really looking
** for an instance of of a consonant followed by a vowel.
*/
static int m_gt_0(const char *z){
  while( isVowel(z) ){ z++; }
  if( *z==0 ) return 0;
  while( isConsonant(z) ){ z++; }
  return *z!=0;
}

** of m for the first i bytes of a word.
**
** Return true if the m-value for z is 1 or more.  In other words,
** return true if z contains at least one vowel that is followed
** by a consonant.
**
** In this routine z[] is in reverse order.  So we are really looking
** for an instance of a consonant followed by a vowel.
*/
static int m_gt_0(const char *z){
  while( isVowel(z) ){ z++; }
  if( *z==0 ) return 0;
  while( isConsonant(z) ){ z++; }
  return *z!=0;
}

/*
** 2014-11-10
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This SQLite extension implements SQL function eval() which runs
** SQL statements recursively.
*/
#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1
#include <string.h>

/*
** Structure used to accumulate the output
*/
struct EvalResult {
  char *z;               /* Accumulated output */
  const char *zSep;      /* Separator */
  int szSep;             /* Size of the separator string */
  sqlite3_int64 nAlloc;  /* Number of bytes allocated for z[] */
  sqlite3_int64 nUsed;   /* Number of bytes of z[] actually used */
};

/*
** Callback from sqlite_exec() for the eval() function.
*/
static int callback(void *pCtx, int argc, char **argv, char **colnames){
  struct EvalResult *p = (struct EvalResult*)pCtx;
  int i; 
  for(i=0; i<argc; i++){
    const char *z = argv[i] ? argv[i] : "";
    size_t sz = strlen(z);
    if( (sqlite3_int64)sz+p->nUsed+p->szSep+1 > p->nAlloc ){
      char *zNew;
      p->nAlloc = p->nAlloc*2 + sz + p->szSep + 1;
      /* Using sqlite3_realloc64() would be better, but it is a recent
      ** addition and will cause a segfault if loaded by an older version
      ** of SQLite.  */
      zNew = p->nAlloc<=0x7fffffff ? sqlite3_realloc(p->z, (int)p->nAlloc) : 0;
      if( zNew==0 ){
        sqlite3_free(p->z);
        memset(p, 0, sizeof(*p));
        return 1;
      }
      p->z = zNew;
    }
    if( p->nUsed>0 ){
      memcpy(&p->z[p->nUsed], p->zSep, p->szSep);
      p->nUsed += p->szSep;
    }
    memcpy(&p->z[p->nUsed], z, sz);
    p->nUsed += sz;
  }
  return 0;
}

/*
** Implementation of the eval(X) and eval(X,Y) SQL functions.
**
** Evaluate the SQL text in X.  Return the results, using string
** Y as the separator.  If Y is omitted, use a single space character.
*/
static void sqlEvalFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const char *zSql;
  sqlite3 *db;
  char *zErr = 0;
  int rc;
  struct EvalResult x;

  memset(&x, 0, sizeof(x));
  x.zSep = " ";
  zSql = (const char*)sqlite3_value_text(argv[0]);
  if( zSql==0 ) return;
  if( argc>1 ){
    x.zSep = (const char*)sqlite3_value_text(argv[1]);
    if( x.zSep==0 ) return;
  }
  x.szSep = (int)strlen(x.zSep);
  db = sqlite3_context_db_handle(context);
  rc = sqlite3_exec(db, zSql, callback, &x, &zErr);
  if( rc!=SQLITE_OK ){
    sqlite3_result_error(context, zErr, -1);
    sqlite3_free(zErr);
  }else if( x.zSep==0 ){
    sqlite3_result_error_nomem(context);
    sqlite3_free(x.z);
  }else{
    sqlite3_result_text(context, x.z, (int)x.nUsed, sqlite3_free);
  }
}


#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_eval_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
  (void)pzErrMsg;  /* Unused parameter */
  rc = sqlite3_create_function(db, "eval", 1, SQLITE_UTF8, 0,
                               sqlEvalFunc, 0, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "eval", 2, SQLITE_UTF8, 0,
                                 sqlEvalFunc, 0, 0);
  }
  return rc;
}

/*
** 2014-09-21
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This SQLite extension adds a debug "authorizer" callback to the database
** connection.  The callback merely writes the authorization request to
** standard output and returns SQLITE_OK.
**
** This extension can be used (for example) in the command-line shell to
** trace the operation of the authorizer.
*/
#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1
#include <stdio.h>

/*
** Display the authorization request
*/
static int authCallback(
  void *pClientData,
  int op,
  const char *z1,
  const char *z2,
  const char *z3,
  const char *z4
){
  const char *zOp;
  char zOpSpace[50];
  switch( op ){
    case SQLITE_CREATE_INDEX:        zOp = "CREATE_INDEX";        break;
    case SQLITE_CREATE_TABLE:        zOp = "CREATE_TABLE";        break;
    case SQLITE_CREATE_TEMP_INDEX:   zOp = "CREATE_TEMP_INDEX";   break;
    case SQLITE_CREATE_TEMP_TABLE:   zOp = "CREATE_TEMP_TABLE";   break;
    case SQLITE_CREATE_TEMP_TRIGGER: zOp = "CREATE_TEMP_TRIGGER"; break;
    case SQLITE_CREATE_TEMP_VIEW:    zOp = "CREATE_TEMP_VIEW";    break;
    case SQLITE_CREATE_TRIGGER:      zOp = "CREATE_TRIGGER";      break;
    case SQLITE_CREATE_VIEW:         zOp = "CREATE_VIEW";         break;
    case SQLITE_DELETE:              zOp = "DELETE";              break;
    case SQLITE_DROP_INDEX:          zOp = "DROP_INDEX";          break;
    case SQLITE_DROP_TABLE:          zOp = "DROP_TABLE";          break;
    case SQLITE_DROP_TEMP_INDEX:     zOp = "DROP_TEMP_INDEX";     break;
    case SQLITE_DROP_TEMP_TABLE:     zOp = "DROP_TEMP_TABLE";     break;
    case SQLITE_DROP_TEMP_TRIGGER:   zOp = "DROP_TEMP_TRIGGER";   break;
    case SQLITE_DROP_TEMP_VIEW:      zOp = "DROP_TEMP_VIEW";      break;
    case SQLITE_DROP_TRIGGER:        zOp = "DROP_TRIGGER";        break;
    case SQLITE_DROP_VIEW:           zOp = "DROP_VIEW";           break;
    case SQLITE_INSERT:              zOp = "INSERT";              break;
    case SQLITE_PRAGMA:              zOp = "PRAGMA";              break;
    case SQLITE_READ:                zOp = "READ";                break;
    case SQLITE_SELECT:              zOp = "SELECT";              break;
    case SQLITE_TRANSACTION:         zOp = "TRANSACTION";         break;
    case SQLITE_UPDATE:              zOp = "UPDATE";              break;
    case SQLITE_ATTACH:              zOp = "ATTACH";              break;
    case SQLITE_DETACH:              zOp = "DETACH";              break;
    case SQLITE_ALTER_TABLE:         zOp = "ALTER_TABLE";         break;
    case SQLITE_REINDEX:             zOp = "REINDEX";             break;
    case SQLITE_ANALYZE:             zOp = "ANALYZE";             break;
    case SQLITE_CREATE_VTABLE:       zOp = "CREATE_VTABLE";       break;
    case SQLITE_DROP_VTABLE:         zOp = "DROP_VTABLE";         break;
    case SQLITE_FUNCTION:            zOp = "FUNCTION";            break;
    case SQLITE_SAVEPOINT:           zOp = "SAVEPOINT";           break;
    case SQLITE_COPY:                zOp = "COPY";                break;
    case SQLITE_RECURSIVE:           zOp = "RECURSIVE";           break;


    default: {
      sqlite3_snprintf(sizeof(zOpSpace), zOpSpace, "%d", op);
      zOp = zOpSpace;
      break;
    }
  }
  if( z1==0 ) z1 = "NULL";
  if( z2==0 ) z2 = "NULL";
  if( z3==0 ) z3 = "NULL";
  if( z4==0 ) z4 = "NULL";
  printf("AUTH: %s,%s,%s,%s,%s\n", zOp, z1, z2, z3, z4);
  return SQLITE_OK;
}



#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_showauth_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
  (void)pzErrMsg;  /* Unused parameter */
  rc = sqlite3_set_authorizer(db, authCallback, 0);
  return rc;
}

  0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 2:C0E1} 
  0 1 1 {SEARCH TABLE t2 USING AUTOMATIC COVERING INDEX (v=?)}
}
do_eqp_test rtree6.2.4.2 {
  SELECT * FROM t1,t2 WHERE v=10 and x1<10 and x2>10
} {
  0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 2:C0E1} 
  0 1 1 {SEARCH TABLE t2 USING AUTOMATIC COVERING INDEX (v=?)}
}

do_eqp_test rtree6.2.5 {
  SELECT * FROM t1,t2 WHERE k=ii AND x1<v
} {
  0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 2:} 
  0 1 1 {SEARCH TABLE t2 USING INTEGER PRIMARY KEY (rowid=?)}

  0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 2:C0E1} 
  0 1 1 {SEARCH TABLE t2 USING AUTOMATIC COVERING INDEX (v=?)}
}
do_eqp_test rtree6.2.4.2 {
  SELECT * FROM t1,t2 WHERE v=10 and x1<10 and x2>10
} {
  0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 2:C0E1} 
  0 1 1 {SEARCH TABLE t2 USING AUTOMATIC PARTIAL COVERING INDEX (v=?)}
}

do_eqp_test rtree6.2.5 {
  SELECT * FROM t1,t2 WHERE k=ii AND x1<v
} {
  0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 2:} 
  0 1 1 {SEARCH TABLE t2 USING INTEGER PRIMARY KEY (rowid=?)}

/*
** 2014-09-08
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains the application interface definitions for the
** user-authentication extension feature.
**
** To compile with the user-authentication feature, append this file to
** end of an SQLite amalgamation header file ("sqlite3.h"), then add
** the SQLITE_USER_AUTHENTICATION compile-time option.  See the
** user-auth.txt file in the same source directory as this file for
** additional information.
*/
#ifdef SQLITE_USER_AUTHENTICATION

/*
** If a database contains the SQLITE_USER table, then the
** sqlite3_user_authenticate() interface must be invoked with an
** appropriate username and password prior to enable read and write
** access to the database.
**
** Return SQLITE_OK on success or SQLITE_ERROR if the username/password
** combination is incorrect or unknown.
**
** If the SQLITE_USER table is not present in the database file, then
** this interface is a harmless no-op returnning SQLITE_OK.
*/
int sqlite3_user_authenticate(
  sqlite3 *db,           /* The database connection */
  const char *zUsername, /* Username */
  const char *aPW,       /* Password or credentials */
  int nPW                /* Number of bytes in aPW[] */
);

/*
** The sqlite3_user_add() interface can be used (by an admin user only)
** to create a new user.  When called on a no-authentication-required
** database, this routine converts the database into an authentication-
** required database, automatically makes the added user an
** administrator, and logs in the current connection as that user.
** The sqlite3_user_add() interface only works for the "main" database, not
** for any ATTACH-ed databases.  Any call to sqlite3_user_add() by a
** non-admin user results in an error.
*/
int sqlite3_user_add(
  sqlite3 *db,           /* Database connection */
  const char *zUsername, /* Username to be added */
  const char *aPW,       /* Password or credentials */
  int nPW,               /* Number of bytes in aPW[] */
  int isAdmin            /* True to give new user admin privilege */
);

/*
** The sqlite3_user_change() interface can be used to change a users
** login credentials or admin privilege.  Any user can change their own
** login credentials.  Only an admin user can change another users login
** credentials or admin privilege setting.  No user may change their own 
** admin privilege setting.
*/
int sqlite3_user_change(
  sqlite3 *db,           /* Database connection */
  const char *zUsername, /* Username to change */
  const char *aPW,       /* New password or credentials */
  int nPW,               /* Number of bytes in aPW[] */
  int isAdmin            /* Modified admin privilege for the user */
);

/*
** The sqlite3_user_delete() interface can be used (by an admin user only)
** to delete a user.  The currently logged-in user cannot be deleted,
** which guarantees that there is always an admin user and hence that
** the database cannot be converted into a no-authentication-required
** database.
*/
int sqlite3_user_delete(
  sqlite3 *db,           /* Database connection */
  const char *zUsername  /* Username to remove */
);

#endif /* SQLITE_USER_AUTHENTICATION */

Activate the user authentication logic by including the
ext/userauth/userauth.c source code file in the build and
adding the -DSQLITE_USER_AUTHENTICATION compile-time option.
The ext/userauth/sqlite3userauth.h header file is available to
applications to define the interface.

When using the SQLite amalgamation, it is sufficient to append
the ext/userauth/userauth.c source file onto the end of the
amalgamation.

The following new APIs are available when user authentication is
activated:

   int sqlite3_user_authenticate(
     sqlite3 *db,           /* The database connection */
     const char *zUsername, /* Username */
     const char *aPW,       /* Password or credentials */
     int nPW                /* Number of bytes in aPW[] */
   );
   
   int sqlite3_user_add(
     sqlite3 *db,           /* Database connection */
     const char *zUsername, /* Username to be added */
     const char *aPW,       /* Password or credentials */
     int nPW,               /* Number of bytes in aPW[] */
     int isAdmin            /* True to give new user admin privilege */
   );
   
   int sqlite3_user_change(
     sqlite3 *db,           /* Database connection */
     const char *zUsername, /* Username to change */
     const void *aPW,       /* Modified password or credentials */
     int nPW,               /* Number of bytes in aPW[] */
     int isAdmin            /* Modified admin privilege for the user */
   );
   
   int sqlite3_user_delete(
     sqlite3 *db,           /* Database connection */
     const char *zUsername  /* Username to remove */
   );

With this extension, a database can be marked as requiring authentication.
By default a database does not require authentication.

The sqlite3_open(), sqlite3_open16(), and sqlite3_open_v2() interfaces
work as before: they open a new database connection.  However, if the
database being opened requires authentication, then attempts to read
or write from the database will fail with an SQLITE_AUTH error until 
after sqlite3_user_authenticate() has been called successfully.  The 
sqlite3_user_authenticate() call will return SQLITE_OK if the 
authentication credentials are accepted and SQLITE_ERROR if not.

Calling sqlite3_user_authenticate() on a no-authentication-required
database connection is a harmless no-op.  

If the database is encrypted, then sqlite3_key_v2() must be called first,
with the correct decryption key, prior to invoking sqlite3_user_authenticate().

To recapitulate: When opening an existing unencrypted authentication-
required database, the call sequence is:

    sqlite3_open_v2()
    sqlite3_user_authenticate();
    /* Database is now usable */

To open an existing, encrypted, authentication-required database, the
call sequence is:

    sqlite3_open_v2();
    sqlite3_key_v2();
    sqlite3_user_authenticate();
    /* Database is now usable */

When opening a no-authentication-required database, the database
connection is treated as if it was authenticated as an admin user.

When ATTACH-ing new database files to a connection, each newly attached
database that is an authentication-required database is checked using
the same username and password as supplied to the main database.  If that
check fails, then the ATTACH command fails with an SQLITE_AUTH error.

The sqlite3_user_add() interface can be used (by an admin user only)
to create a new user.  When called on a no-authentication-required
database and when A is true, the sqlite3_user_add(D,U,P,N,A) routine
converts the database into an authentication-required database and
logs in the database connection D as user U with password P,N.
To convert a no-authentication-required database into an authentication-
required database, the isAdmin parameter must be true.  If
sqlite3_user_add(D,U,P,N,A) is called on a no-authentication-required
database and A is false, then the call fails with an SQLITE_AUTH error.

Any call to sqlite3_user_add() by a non-admin user results in an error.

Hence, to create a new, unencrypted, authentication-required database,
the call sequence is:

    sqlite3_open_v2();
    sqlite3_user_add();

And to create a new, encrypted, authentication-required database, the call
sequence is:

    sqlite3_open_v2();
    sqlite3_key_v2();
    sqlite3_user_add();

The sqlite3_user_delete() interface can be used (by an admin user only)
to delete a user.  The currently logged-in user cannot be deleted,
which guarantees that there is always an admin user and hence that
the database cannot be converted into a no-authentication-required
database.

The sqlite3_user_change() interface can be used to change a users
login credentials or admin privilege.  Any user can change their own
password.  Only an admin user can change another users login
credentials or admin privilege setting.  No user may change their own 
admin privilege setting.

The sqlite3_set_authorizer() callback is modified to take a 7th parameter
which is the username of the currently logged in user, or NULL for a
no-authentication-required database.

-----------------------------------------------------------------------------
Implementation notes:

An authentication-required database is identified by the presence of a
new table:

    CREATE TABLE sqlite_user(
      uname TEXT PRIMARY KEY,
      isAdmin BOOLEAN,
      pw BLOB
    ) WITHOUT ROWID;

The sqlite_user table is inaccessible (unreadable and unwriteable) to
non-admin users and is read-only for admin users.  However, if the same
database file is opened by a version of SQLite that omits
the -DSQLITE_USER_AUTHENTICATION compile-time option, then the sqlite_user
table will be readable by anybody and writeable by anybody if
the "PRAGMA writable_schema=ON" statement is run first.

The sqlite_user.pw field is encoded by a built-in SQL function
"sqlite_crypt(X,Y)".  The two arguments are both BLOBs.  The first argument
is the plaintext password supplied to the sqlite3_user_authenticate()
interface.  The second argument is the sqlite_user.pw value and is supplied
so that the function can extract the "salt" used by the password encoder.
The result of sqlite_crypt(X,Y) is another blob which is the value that
ends up being stored in sqlite_user.pw.  To verify credentials X supplied
by the sqlite3_user_authenticate() routine, SQLite runs:

    sqlite_user.pw == sqlite_crypt(X, sqlite_user.pw)

To compute an appropriate sqlite_user.pw value from a new or modified
password X, sqlite_crypt(X,NULL) is run.  A new random salt is selected
when the second argument is NULL.

The built-in version of of sqlite_crypt() uses a simple Ceasar-cypher
which prevents passwords from being revealed by searching the raw database
for ASCII text, but is otherwise trivally broken.  For better password
security, the database should be encrypted using the SQLite Encryption
Extension or similar technology.  Or, the application can use the
sqlite3_create_function() interface to provide an alternative
implementation of sqlite_crypt() that computes a stronger password hash,
perhaps using a cryptographic hash function like SHA1.

/*
** 2014-09-08
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains the bulk of the implementation of the
** user-authentication extension feature.  Some parts of the user-
** authentication code are contained within the SQLite core (in the
** src/ subdirectory of the main source code tree) but those parts
** that could reasonable be separated out are moved into this file.
**
** To compile with the user-authentication feature, append this file to
** end of an SQLite amalgamation, then add the SQLITE_USER_AUTHENTICATION
** compile-time option.  See the user-auth.txt file in the same source
** directory as this file for additional information.
*/
#ifdef SQLITE_USER_AUTHENTICATION
#ifndef _SQLITEINT_H_
# include "sqliteInt.h"
#endif

/*
** Prepare an SQL statement for use by the user authentication logic.
** Return a pointer to the prepared statement on success.  Return a
** NULL pointer if there is an error of any kind.
*/
static sqlite3_stmt *sqlite3UserAuthPrepare(
  sqlite3 *db,
  const char *zFormat,
  ...
){
  sqlite3_stmt *pStmt;
  char *zSql;
  int rc;
  va_list ap;
  int savedFlags = db->flags;

  va_start(ap, zFormat);
  zSql = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
  if( zSql==0 ) return 0;
  db->flags |= SQLITE_WriteSchema;
  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
  db->flags = savedFlags;
  sqlite3_free(zSql);
  if( rc ){
    sqlite3_finalize(pStmt);
    pStmt = 0;
  }
  return pStmt;
}

/*
** Check to see if the sqlite_user table exists in database zDb.
*/
static int userTableExists(sqlite3 *db, const char *zDb){
  int rc;
  sqlite3_mutex_enter(db->mutex);
  sqlite3BtreeEnterAll(db);
  if( db->init.busy==0 ){
    char *zErr = 0;
    sqlite3Init(db, &zErr);
    sqlite3DbFree(db, zErr);
  }
  rc = sqlite3FindTable(db, "sqlite_user", zDb)!=0;
  sqlite3BtreeLeaveAll(db);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

/*
** Check to see if database zDb has a "sqlite_user" table and if it does
** whether that table can authenticate zUser with nPw,zPw.  Write one of
** the UAUTH_* user authorization level codes into *peAuth and return a
** result code.
*/
static int userAuthCheckLogin(
  sqlite3 *db,               /* The database connection to check */
  const char *zDb,           /* Name of specific database to check */
  u8 *peAuth                 /* OUT: One of UAUTH_* constants */
){
  sqlite3_stmt *pStmt;
  int rc;

  *peAuth = UAUTH_Unknown;
  if( !userTableExists(db, "main") ){
    *peAuth = UAUTH_Admin;  /* No sqlite_user table.  Everybody is admin. */
    return SQLITE_OK;
  }
  if( db->auth.zAuthUser==0 ){
    *peAuth = UAUTH_Fail;
    return SQLITE_OK;
  }
  pStmt = sqlite3UserAuthPrepare(db,
            "SELECT pw=sqlite_crypt(?1,pw), isAdmin FROM \"%w\".sqlite_user"
            " WHERE uname=?2", zDb);
  if( pStmt==0 ) return SQLITE_NOMEM;
  sqlite3_bind_blob(pStmt, 1, db->auth.zAuthPW, db->auth.nAuthPW,SQLITE_STATIC);
  sqlite3_bind_text(pStmt, 2, db->auth.zAuthUser, -1, SQLITE_STATIC);
  rc = sqlite3_step(pStmt);
  if( rc==SQLITE_ROW && sqlite3_column_int(pStmt,0) ){
    *peAuth = sqlite3_column_int(pStmt, 1) + UAUTH_User;
  }else{
    *peAuth = UAUTH_Fail;
  }
  return sqlite3_finalize(pStmt);
}
int sqlite3UserAuthCheckLogin(
  sqlite3 *db,               /* The database connection to check */
  const char *zDb,           /* Name of specific database to check */
  u8 *peAuth                 /* OUT: One of UAUTH_* constants */
){
  int rc;
  u8 savedAuthLevel;
  assert( zDb!=0 );
  assert( peAuth!=0 );
  savedAuthLevel = db->auth.authLevel;
  db->auth.authLevel = UAUTH_Admin;
  rc = userAuthCheckLogin(db, zDb, peAuth);
  db->auth.authLevel = savedAuthLevel;
  return rc;
}

/*
** If the current authLevel is UAUTH_Unknown, the take actions to figure
** out what authLevel should be
*/
void sqlite3UserAuthInit(sqlite3 *db){
  if( db->auth.authLevel==UAUTH_Unknown ){
    u8 authLevel = UAUTH_Fail;
    sqlite3UserAuthCheckLogin(db, "main", &authLevel);
    db->auth.authLevel = authLevel;
    if( authLevel<UAUTH_Admin ) db->flags &= ~SQLITE_WriteSchema;
  }
}

/*
** Implementation of the sqlite_crypt(X,Y) function.
**
** If Y is NULL then generate a new hash for password X and return that
** hash.  If Y is not null, then generate a hash for password X using the
** same salt as the previous hash Y and return the new hash.
*/
void sqlite3CryptFunc(
  sqlite3_context *context,
  int NotUsed,
  sqlite3_value **argv
){
  const char *zIn;
  int nIn, ii;
  u8 *zOut;
  char zSalt[8];
  zIn = sqlite3_value_blob(argv[0]);
  nIn = sqlite3_value_bytes(argv[0]);
  if( sqlite3_value_type(argv[1])==SQLITE_BLOB
   && sqlite3_value_bytes(argv[1])==nIn+sizeof(zSalt)
  ){
    memcpy(zSalt, sqlite3_value_blob(argv[1]), sizeof(zSalt));
  }else{
    sqlite3_randomness(sizeof(zSalt), zSalt);
  }
  zOut = sqlite3_malloc( nIn+sizeof(zSalt) );
  if( zOut==0 ){
    sqlite3_result_error_nomem(context);
  }else{
    memcpy(zOut, zSalt, sizeof(zSalt));
    for(ii=0; ii<nIn; ii++){
      zOut[ii+sizeof(zSalt)] = zIn[ii]^zSalt[ii&0x7];
    }
    sqlite3_result_blob(context, zOut, nIn+sizeof(zSalt), sqlite3_free);
  }
}

/*
** If a database contains the SQLITE_USER table, then the
** sqlite3_user_authenticate() interface must be invoked with an
** appropriate username and password prior to enable read and write
** access to the database.
**
** Return SQLITE_OK on success or SQLITE_ERROR if the username/password
** combination is incorrect or unknown.
**
** If the SQLITE_USER table is not present in the database file, then
** this interface is a harmless no-op returnning SQLITE_OK.
*/
int sqlite3_user_authenticate(
  sqlite3 *db,           /* The database connection */
  const char *zUsername, /* Username */
  const char *zPW,       /* Password or credentials */
  int nPW                /* Number of bytes in aPW[] */
){
  int rc;
  u8 authLevel = UAUTH_Fail;
  db->auth.authLevel = UAUTH_Unknown;
  sqlite3_free(db->auth.zAuthUser);
  sqlite3_free(db->auth.zAuthPW);
  memset(&db->auth, 0, sizeof(db->auth));
  db->auth.zAuthUser = sqlite3_mprintf("%s", zUsername);
  if( db->auth.zAuthUser==0 ) return SQLITE_NOMEM;
  db->auth.zAuthPW = sqlite3_malloc( nPW+1 );
  if( db->auth.zAuthPW==0 ) return SQLITE_NOMEM;
  memcpy(db->auth.zAuthPW,zPW,nPW);
  db->auth.nAuthPW = nPW;
  rc = sqlite3UserAuthCheckLogin(db, "main", &authLevel);
  db->auth.authLevel = authLevel;
  sqlite3ExpirePreparedStatements(db);
  if( rc ){
    return rc;           /* OOM error, I/O error, etc. */
  }
  if( authLevel<UAUTH_User ){
    return SQLITE_AUTH;  /* Incorrect username and/or password */
  }
  return SQLITE_OK;      /* Successful login */
}

/*
** The sqlite3_user_add() interface can be used (by an admin user only)
** to create a new user.  When called on a no-authentication-required
** database, this routine converts the database into an authentication-
** required database, automatically makes the added user an
** administrator, and logs in the current connection as that user.
** The sqlite3_user_add() interface only works for the "main" database, not
** for any ATTACH-ed databases.  Any call to sqlite3_user_add() by a
** non-admin user results in an error.
*/
int sqlite3_user_add(
  sqlite3 *db,           /* Database connection */
  const char *zUsername, /* Username to be added */
  const char *aPW,       /* Password or credentials */
  int nPW,               /* Number of bytes in aPW[] */
  int isAdmin            /* True to give new user admin privilege */
){
  sqlite3_stmt *pStmt;
  int rc;
  sqlite3UserAuthInit(db);
  if( db->auth.authLevel<UAUTH_Admin ) return SQLITE_AUTH;
  if( !userTableExists(db, "main") ){
    if( !isAdmin ) return SQLITE_AUTH;
    pStmt = sqlite3UserAuthPrepare(db, 
              "CREATE TABLE sqlite_user(\n"
              "  uname TEXT PRIMARY KEY,\n"
              "  isAdmin BOOLEAN,\n"
              "  pw BLOB\n"
              ") WITHOUT ROWID;");
    if( pStmt==0 ) return SQLITE_NOMEM;
    sqlite3_step(pStmt);
    rc = sqlite3_finalize(pStmt);
    if( rc ) return rc;
  }
  pStmt = sqlite3UserAuthPrepare(db, 
            "INSERT INTO sqlite_user(uname,isAdmin,pw)"
            " VALUES(%Q,%d,sqlite_crypt(?1,NULL))",
            zUsername, isAdmin!=0);
  if( pStmt==0 ) return SQLITE_NOMEM;
  sqlite3_bind_blob(pStmt, 1, aPW, nPW, SQLITE_STATIC);
  sqlite3_step(pStmt);
  rc = sqlite3_finalize(pStmt);
  if( rc ) return rc;
  if( db->auth.zAuthUser==0 ){
    assert( isAdmin!=0 );
    sqlite3_user_authenticate(db, zUsername, aPW, nPW);
  }
  return SQLITE_OK;
}

/*
** The sqlite3_user_change() interface can be used to change a users
** login credentials or admin privilege.  Any user can change their own
** login credentials.  Only an admin user can change another users login
** credentials or admin privilege setting.  No user may change their own 
** admin privilege setting.
*/
int sqlite3_user_change(
  sqlite3 *db,           /* Database connection */
  const char *zUsername, /* Username to change */
  const char *aPW,       /* Modified password or credentials */
  int nPW,               /* Number of bytes in aPW[] */
  int isAdmin            /* Modified admin privilege for the user */
){
  sqlite3_stmt *pStmt;
  int rc;
  u8 authLevel;

  authLevel = db->auth.authLevel;
  if( authLevel<UAUTH_User ){
    /* Must be logged in to make a change */
    return SQLITE_AUTH;
  }
  if( strcmp(db->auth.zAuthUser, zUsername)!=0 ){
    if( db->auth.authLevel<UAUTH_Admin ){
      /* Must be an administrator to change a different user */
      return SQLITE_AUTH;
    }
  }else if( isAdmin!=(authLevel==UAUTH_Admin) ){
    /* Cannot change the isAdmin setting for self */
    return SQLITE_AUTH;
  }
  db->auth.authLevel = UAUTH_Admin;
  if( !userTableExists(db, "main") ){
    /* This routine is a no-op if the user to be modified does not exist */
  }else{
    pStmt = sqlite3UserAuthPrepare(db,
              "UPDATE sqlite_user SET isAdmin=%d, pw=sqlite_crypt(?1,NULL)"
              " WHERE uname=%Q", isAdmin, zUsername);
    if( pStmt==0 ){
      rc = SQLITE_NOMEM;
    }else{
      sqlite3_bind_blob(pStmt, 1, aPW, nPW, SQLITE_STATIC);
      sqlite3_step(pStmt);
      rc = sqlite3_finalize(pStmt);
    }
  }
  db->auth.authLevel = authLevel;
  return rc;
}

/*
** The sqlite3_user_delete() interface can be used (by an admin user only)
** to delete a user.  The currently logged-in user cannot be deleted,
** which guarantees that there is always an admin user and hence that
** the database cannot be converted into a no-authentication-required
** database.
*/
int sqlite3_user_delete(
  sqlite3 *db,           /* Database connection */
  const char *zUsername  /* Username to remove */
){
  sqlite3_stmt *pStmt;
  if( db->auth.authLevel<UAUTH_Admin ){
    /* Must be an administrator to delete a user */
    return SQLITE_AUTH;
  }
  if( strcmp(db->auth.zAuthUser, zUsername)==0 ){
    /* Cannot delete self */
    return SQLITE_AUTH;
  }
  if( !userTableExists(db, "main") ){
    /* This routine is a no-op if the user to be deleted does not exist */
    return SQLITE_OK;
  }
  pStmt = sqlite3UserAuthPrepare(db,
              "DELETE FROM sqlite_user WHERE uname=%Q", zUsername);
  if( pStmt==0 ) return SQLITE_NOMEM;
  sqlite3_step(pStmt);
  return sqlite3_finalize(pStmt);
}

#endif /* SQLITE_USER_AUTHENTICATION */

# build the SQLite library and testing tools.
################################################################################

# This is how we compile
#
TCCX =  $(TCC) $(OPTS) -I. -I$(TOP)/src -I$(TOP) 
TCCX += -I$(TOP)/ext/rtree -I$(TOP)/ext/icu -I$(TOP)/ext/fts3
TCCX += -I$(TOP)/ext/async

# Object files for the SQLite library.
#
LIBOBJ+= vdbe.o parse.o \
         alter.o analyze.o attach.o auth.o \
         backup.o bitvec.o btmutex.o btree.o build.o \
         callback.o complete.o ctime.o date.o delete.o expr.o fault.o fkey.o \
................................................................................
         icu.o insert.o journal.o legacy.o loadext.o \
         main.o malloc.o mem0.o mem1.o mem2.o mem3.o mem5.o \
         memjournal.o \
         mutex.o mutex_noop.o mutex_unix.o mutex_w32.o \
         notify.o opcodes.o os.o os_unix.o os_win.o \
         pager.o pcache.o pcache1.o pragma.o prepare.o printf.o \
         random.o resolve.o rowset.o rtree.o select.o status.o \
         table.o tokenize.o trigger.o \
         update.o util.o vacuum.o \
         vdbeapi.o vdbeaux.o vdbeblob.o vdbemem.o vdbesort.o \
	 vdbetrace.o wal.o walker.o where.o utf.o vtab.o



# All of the source code files.
#
................................................................................
  $(TOP)/src/shell.c \
  $(TOP)/src/sqlite.h.in \
  $(TOP)/src/sqlite3ext.h \
  $(TOP)/src/sqliteInt.h \
  $(TOP)/src/sqliteLimit.h \
  $(TOP)/src/table.c \
  $(TOP)/src/tclsqlite.c \

  $(TOP)/src/tokenize.c \
  $(TOP)/src/trigger.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/update.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vacuum.c \
  $(TOP)/src/vdbe.c \
................................................................................
SRC += \
  $(TOP)/ext/icu/sqliteicu.h \
  $(TOP)/ext/icu/icu.c
SRC += \
  $(TOP)/ext/rtree/sqlite3rtree.h \
  $(TOP)/ext/rtree/rtree.h \
  $(TOP)/ext/rtree/rtree.c




# Generated source code files
#
SRC += \
  keywordhash.h \
  opcodes.c \
  opcodes.h \
................................................................................
  $(TOP)/src/test6.c \
  $(TOP)/src/test7.c \
  $(TOP)/src/test8.c \
  $(TOP)/src/test9.c \
  $(TOP)/src/test_autoext.c \
  $(TOP)/src/test_async.c \
  $(TOP)/src/test_backup.c \

  $(TOP)/src/test_btree.c \
  $(TOP)/src/test_config.c \
  $(TOP)/src/test_demovfs.c \
  $(TOP)/src/test_devsym.c \
  $(TOP)/src/test_fs.c \
  $(TOP)/src/test_func.c \
  $(TOP)/src/test_hexio.c \
................................................................................
  $(TOP)/src/test_wsd.c

# Extensions to be statically loaded.
#
TESTSRC += \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/closure.c \

  $(TOP)/ext/misc/fileio.c \
  $(TOP)/ext/misc/fuzzer.c \
  $(TOP)/ext/misc/ieee754.c \
  $(TOP)/ext/misc/nextchar.c \
  $(TOP)/ext/misc/percentile.c \
  $(TOP)/ext/misc/regexp.c \
  $(TOP)/ext/misc/spellfix.c \
................................................................................
  $(TOP)/src/pragma.c \
  $(TOP)/src/prepare.c \
  $(TOP)/src/printf.c \
  $(TOP)/src/random.c \
  $(TOP)/src/pcache.c \
  $(TOP)/src/pcache1.c \
  $(TOP)/src/select.c \

  $(TOP)/src/tokenize.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vdbeapi.c \
  $(TOP)/src/vdbeaux.c \
  $(TOP)/src/vdbe.c \
  $(TOP)/src/vdbemem.c \
................................................................................
  $(TOP)/ext/fts3/fts3Int.h \
  $(TOP)/ext/fts3/fts3_hash.h \
  $(TOP)/ext/fts3/fts3_tokenizer.h
EXTHDR += \
  $(TOP)/ext/rtree/rtree.h
EXTHDR += \
  $(TOP)/ext/icu/sqliteicu.h



# This is the default Makefile target.  The objects listed here
# are what get build when you type just "make" with no arguments.
#
all:	sqlite3.h libsqlite3.a sqlite3$(EXE)

libsqlite3.a:	$(LIBOBJ)
................................................................................
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts3/fts3_unicode2.c

fts3_write.o:	$(TOP)/ext/fts3/fts3_write.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts3/fts3_write.c

rtree.o:	$(TOP)/ext/rtree/rtree.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/rtree/rtree.c





# Rules for building test programs and for running tests
#
tclsqlite3:	$(TOP)/src/tclsqlite.c libsqlite3.a
	$(TCCX) $(TCL_FLAGS) -DTCLSH=1 -o tclsqlite3 \
		$(TOP)/src/tclsqlite.c libsqlite3.a $(LIBTCL) $(THREADLIB)

# build the SQLite library and testing tools.
################################################################################

# This is how we compile
#
TCCX =  $(TCC) $(OPTS) -I. -I$(TOP)/src -I$(TOP) 
TCCX += -I$(TOP)/ext/rtree -I$(TOP)/ext/icu -I$(TOP)/ext/fts3
TCCX += -I$(TOP)/ext/async -I$(TOP)/ext/userauth

# Object files for the SQLite library.
#
LIBOBJ+= vdbe.o parse.o \
         alter.o analyze.o attach.o auth.o \
         backup.o bitvec.o btmutex.o btree.o build.o \
         callback.o complete.o ctime.o date.o delete.o expr.o fault.o fkey.o \
................................................................................
         icu.o insert.o journal.o legacy.o loadext.o \
         main.o malloc.o mem0.o mem1.o mem2.o mem3.o mem5.o \
         memjournal.o \
         mutex.o mutex_noop.o mutex_unix.o mutex_w32.o \
         notify.o opcodes.o os.o os_unix.o os_win.o \
         pager.o pcache.o pcache1.o pragma.o prepare.o printf.o \
         random.o resolve.o rowset.o rtree.o select.o status.o \
         table.o threads.o tokenize.o trigger.o \
         update.o userauth.o util.o vacuum.o \
         vdbeapi.o vdbeaux.o vdbeblob.o vdbemem.o vdbesort.o \
	 vdbetrace.o wal.o walker.o where.o utf.o vtab.o



# All of the source code files.
#
................................................................................
  $(TOP)/src/shell.c \
  $(TOP)/src/sqlite.h.in \
  $(TOP)/src/sqlite3ext.h \
  $(TOP)/src/sqliteInt.h \
  $(TOP)/src/sqliteLimit.h \
  $(TOP)/src/table.c \
  $(TOP)/src/tclsqlite.c \
  $(TOP)/src/threads.c \
  $(TOP)/src/tokenize.c \
  $(TOP)/src/trigger.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/update.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vacuum.c \
  $(TOP)/src/vdbe.c \
................................................................................
SRC += \
  $(TOP)/ext/icu/sqliteicu.h \
  $(TOP)/ext/icu/icu.c
SRC += \
  $(TOP)/ext/rtree/sqlite3rtree.h \
  $(TOP)/ext/rtree/rtree.h \
  $(TOP)/ext/rtree/rtree.c
SRC += \
  $(TOP)/ext/userauth/userauth.c \
  $(TOP)/ext/userauth/sqlite3userauth.h

# Generated source code files
#
SRC += \
  keywordhash.h \
  opcodes.c \
  opcodes.h \
................................................................................
  $(TOP)/src/test6.c \
  $(TOP)/src/test7.c \
  $(TOP)/src/test8.c \
  $(TOP)/src/test9.c \
  $(TOP)/src/test_autoext.c \
  $(TOP)/src/test_async.c \
  $(TOP)/src/test_backup.c \
  $(TOP)/src/test_blob.c \
  $(TOP)/src/test_btree.c \
  $(TOP)/src/test_config.c \
  $(TOP)/src/test_demovfs.c \
  $(TOP)/src/test_devsym.c \
  $(TOP)/src/test_fs.c \
  $(TOP)/src/test_func.c \
  $(TOP)/src/test_hexio.c \
................................................................................
  $(TOP)/src/test_wsd.c

# Extensions to be statically loaded.
#
TESTSRC += \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/closure.c \
  $(TOP)/ext/misc/eval.c \
  $(TOP)/ext/misc/fileio.c \
  $(TOP)/ext/misc/fuzzer.c \
  $(TOP)/ext/misc/ieee754.c \
  $(TOP)/ext/misc/nextchar.c \
  $(TOP)/ext/misc/percentile.c \
  $(TOP)/ext/misc/regexp.c \
  $(TOP)/ext/misc/spellfix.c \
................................................................................
  $(TOP)/src/pragma.c \
  $(TOP)/src/prepare.c \
  $(TOP)/src/printf.c \
  $(TOP)/src/random.c \
  $(TOP)/src/pcache.c \
  $(TOP)/src/pcache1.c \
  $(TOP)/src/select.c \
  $(TOP)/src/threads.c \
  $(TOP)/src/tokenize.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vdbeapi.c \
  $(TOP)/src/vdbeaux.c \
  $(TOP)/src/vdbe.c \
  $(TOP)/src/vdbemem.c \
................................................................................
  $(TOP)/ext/fts3/fts3Int.h \
  $(TOP)/ext/fts3/fts3_hash.h \
  $(TOP)/ext/fts3/fts3_tokenizer.h
EXTHDR += \
  $(TOP)/ext/rtree/rtree.h
EXTHDR += \
  $(TOP)/ext/icu/sqliteicu.h
EXTHDR += \
  $(TOP)/ext/userauth/sqlite3userauth.h

# This is the default Makefile target.  The objects listed here
# are what get build when you type just "make" with no arguments.
#
all:	sqlite3.h libsqlite3.a sqlite3$(EXE)

libsqlite3.a:	$(LIBOBJ)
................................................................................
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts3/fts3_unicode2.c

fts3_write.o:	$(TOP)/ext/fts3/fts3_write.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts3/fts3_write.c

rtree.o:	$(TOP)/ext/rtree/rtree.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/rtree/rtree.c

userauth.o:	$(TOP)/ext/userauth/userauth.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/userauth/userauth.c


# Rules for building test programs and for running tests
#
tclsqlite3:	$(TOP)/src/tclsqlite.c libsqlite3.a
	$(TCCX) $(TCL_FLAGS) -DTCLSH=1 -o tclsqlite3 \
		$(TOP)/src/tclsqlite.c libsqlite3.a $(LIBTCL) $(THREADLIB)

.\"                                      Hey, EMACS: -*- nroff -*-
.\" First parameter, NAME, should be all caps
.\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
.\" other parameters are allowed: see man(7), man(1)
.TH SQLITE3 1 "Mon Jan 31 11:14:00 2014"
.\" Please adjust this date whenever revising the manpage.
.\"
.\" Some roff macros, for reference:
.\" .nh        disable hyphenation
.\" .hy        enable hyphenation
.\" .ad l      left justify
.\" .ad b      justify to both left and right margins
................................................................................

For example, to create a new database file named "mydata.db", create
a table named "memos" and insert a couple of records into that table:
.sp
$ 
.B sqlite3 mydata.db
.br
SQLite version 3.8.3
.br
Enter ".help" for instructions
.br
sqlite>
.B create table memos(text, priority INTEGER);
.br
sqlite>
................................................................................

A list of available meta-commands can be viewed at any time by issuing
the '.help' command.  For example:
.sp
sqlite>
.B .help
.nf
.cc |
.backup ?DB? FILE      Backup DB (default "main") to FILE
.bail ON|OFF           Stop after hitting an error.  Default OFF

.databases             List names and files of attached databases
.dump ?TABLE? ...      Dump the database in an SQL text format
                         If TABLE specified, only dump tables matching
                         LIKE pattern TABLE.
.echo ON|OFF           Turn command echo on or off

.exit                  Exit this program
.explain ?ON|OFF?      Turn output mode suitable for EXPLAIN on or off.
                         With no args, it turns EXPLAIN on.

.header(s) ON|OFF      Turn display of headers on or off
.help                  Show this message
.import FILE TABLE     Import data from FILE into TABLE
.indices ?TABLE?       Show names of all indices
                         If TABLE specified, only show indices for tables
                         matching LIKE pattern TABLE.
.load FILE ?ENTRY?     Load an extension library
.log FILE|off          Turn logging on or off.  FILE can be stderr/stdout
.mode MODE ?TABLE?     Set output mode where MODE is one of:
                         csv      Comma-separated values
                         column   Left-aligned columns.  (See .width)
                         html     HTML <table> code
                         insert   SQL insert statements for TABLE
                         line     One value per line
                         list     Values delimited by .separator string
                         tabs     Tab-separated values
                         tcl      TCL list elements
.nullvalue STRING      Use STRING in place of NULL values

.open ?FILENAME?       Close existing database and reopen FILENAME
.output FILENAME       Send output to FILENAME
.output stdout         Send output to the screen
.print STRING...       Print literal STRING
.prompt MAIN CONTINUE  Replace the standard prompts
.quit                  Exit this program
.read FILENAME         Execute SQL in FILENAME
.restore ?DB? FILE     Restore content of DB (default "main") from FILE

.schema ?TABLE?        Show the CREATE statements
                         If TABLE specified, only show tables matching
                         LIKE pattern TABLE.
.separator STRING      Change separator used by output mode and .import


.show                  Show the current values for various settings
.stats ON|OFF          Turn stats on or off

.tables ?TABLE?        List names of tables
                         If TABLE specified, only list tables matching
                         LIKE pattern TABLE.
.timeout MS            Try opening locked tables for MS milliseconds

.trace FILE|off        Output each SQL statement as it is run
.vfsname ?AUX?         Print the name of the VFS stack
.width NUM1 NUM2 ...   Set column widths for "column" mode
.timer ON|OFF          Turn the CPU timer measurement on or off

sqlite>
|cc .
.sp
.fi
.SH OPTIONS
.B sqlite3
has the following options:
.TP
.B \-bail
................................................................................
read and processed.  It should generally only contain meta-commands.

o If the -init option is present, the specified file is processed.

o All other command line options are processed.

.SH SEE ALSO
http://www.sqlite.org/
.br
The sqlite3-doc package.
.SH AUTHOR
This manual page was originally written by Andreas Rottmann
<rotty@debian.org>, for the Debian GNU/Linux system (but may be used
by others). It was subsequently revised by Bill Bumgarner <bbum@mac.com> and
further updated by Laszlo Boszormenyi <gcs@debian.hu> .

.\"                                      Hey, EMACS: -*- nroff -*-
.\" First parameter, NAME, should be all caps
.\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
.\" other parameters are allowed: see man(7), man(1)
.TH SQLITE3 1 "Fri Oct 31 10:41:31 EDT 2014"
.\" Please adjust this date whenever revising the manpage.
.\"
.\" Some roff macros, for reference:
.\" .nh        disable hyphenation
.\" .hy        enable hyphenation
.\" .ad l      left justify
.\" .ad b      justify to both left and right margins
................................................................................

For example, to create a new database file named "mydata.db", create
a table named "memos" and insert a couple of records into that table:
.sp
$ 
.B sqlite3 mydata.db
.br
SQLite version 3.8.8
.br
Enter ".help" for instructions
.br
sqlite>
.B create table memos(text, priority INTEGER);
.br
sqlite>
................................................................................

A list of available meta-commands can be viewed at any time by issuing
the '.help' command.  For example:
.sp
sqlite>
.B .help
.nf
.tr %.
%backup ?DB? FILE      Backup DB (default "main") to FILE
%bail on|off           Stop after hitting an error.  Default OFF
%clone NEWDB           Clone data into NEWDB from the existing database
%databases             List names and files of attached databases
%dump ?TABLE? ...      Dump the database in an SQL text format
                         If TABLE specified, only dump tables matching
                         LIKE pattern TABLE.
%echo on|off           Turn command echo on or off
%eqp on|off            Enable or disable automatic EXPLAIN QUERY PLAN
%exit                  Exit this program
%explain ?on|off?      Turn output mode suitable for EXPLAIN on or off.
                         With no args, it turns EXPLAIN on.
%fullschema            Show schema and the content of sqlite_stat tables
%headers on|off        Turn display of headers on or off
%help                  Show this message
%import FILE TABLE     Import data from FILE into TABLE
%indices ?TABLE?       Show names of all indices
                         If TABLE specified, only show indices for tables
                         matching LIKE pattern TABLE.
%load FILE ?ENTRY?     Load an extension library
%log FILE|off          Turn logging on or off.  FILE can be stderr/stdout
%mode MODE ?TABLE?     Set output mode where MODE is one of:
                         csv      Comma-separated values
                         column   Left-aligned columns.  (See .width)
                         html     HTML <table> code
                         insert   SQL insert statements for TABLE
                         line     One value per line
                         list     Values delimited by .separator string
                         tabs     Tab-separated values
                         tcl      TCL list elements
%nullvalue STRING      Use STRING in place of NULL values
%once FILENAME         Output for the next SQL command only to FILENAME
%open ?FILENAME?       Close existing database and reopen FILENAME
%output ?FILENAME?     Send output to FILENAME or stdout

%print STRING...       Print literal STRING
%prompt MAIN CONTINUE  Replace the standard prompts
%quit                  Exit this program
%read FILENAME         Execute SQL in FILENAME
%restore ?DB? FILE     Restore content of DB (default "main") from FILE
%save FILE             Write in-memory database into FILE
%schema ?TABLE?        Show the CREATE statements
                         If TABLE specified, only show tables matching
                         LIKE pattern TABLE.
%separator STRING ?NL? Change separator used by output mode and .import
                         NL is the end-of-line mark for CSV
%shell CMD ARGS...     Run CMD ARGS... in a system shell
%show                  Show the current values for various settings
%stats on|off          Turn stats on or off
%system CMD ARGS...    Run CMD ARGS... in a system shell
%tables ?TABLE?        List names of tables
                         If TABLE specified, only list tables matching
                         LIKE pattern TABLE.
%timeout MS            Try opening locked tables for MS milliseconds
%timer on|off          Turn SQL timer on or off
%trace FILE|off        Output each SQL statement as it is run
%vfsname ?AUX?         Print the name of the VFS stack
%width NUM1 NUM2 ...   Set column widths for "column" mode

                         Negative values right-justify
sqlite>

.sp
.fi
.SH OPTIONS
.B sqlite3
has the following options:
.TP
.B \-bail
................................................................................
read and processed.  It should generally only contain meta-commands.

o If the -init option is present, the specified file is processed.

o All other command line options are processed.

.SH SEE ALSO
http://www.sqlite.org/cli.html
.br
The sqlite3-doc package.
.SH AUTHOR
This manual page was originally written by Andreas Rottmann
<rotty@debian.org>, for the Debian GNU/Linux system (but may be used
by others). It was subsequently revised by Bill Bumgarner <bbum@mac.com> and
further updated by Laszlo Boszormenyi <gcs@debian.hu> .

  int len = 0;
  char *zRet;
  sqlite3 *db = sqlite3_context_db_handle(context);

  UNUSED_PARAMETER(NotUsed);

  /* The principle used to locate the table name in the CREATE TRIGGER 
  ** statement is that the table name is the first token that is immediatedly
  ** preceded by either TK_ON or TK_DOT and immediatedly followed by one
  ** of TK_WHEN, TK_BEGIN or TK_FOR.
  */
  if( zSql ){
    do {

      if( !*zCsr ){
        /* Ran out of input before finding the table name. Return NULL. */

  int len = 0;
  char *zRet;
  sqlite3 *db = sqlite3_context_db_handle(context);

  UNUSED_PARAMETER(NotUsed);

  /* The principle used to locate the table name in the CREATE TRIGGER 
  ** statement is that the table name is the first token that is immediately
  ** preceded by either TK_ON or TK_DOT and immediately followed by one
  ** of TK_WHEN, TK_BEGIN or TK_FOR.
  */
  if( zSql ){
    do {

      if( !*zCsr ){
        /* Ran out of input before finding the table name. Return NULL. */

** SQLITE_ENABLE_STAT3 defined.  The functionality of sqlite_stat3
** is a superset of sqlite_stat2.  The sqlite_stat4 is an enhanced
** version of sqlite_stat3 and is only available when compiled with
** SQLITE_ENABLE_STAT4 and in SQLite versions 3.8.1 and later.  It is
** not possible to enable both STAT3 and STAT4 at the same time.  If they
** are both enabled, then STAT4 takes precedence.
**
** For most applications, sqlite_stat1 provides all the statisics required
** for the query planner to make good choices.
**
** Format of sqlite_stat1:
**
** There is normally one row per index, with the index identified by the
** name in the idx column.  The tbl column is the name of the table to
** which the index belongs.  In each such row, the stat column will be
................................................................................
**
** For indexes on ordinary rowid tables, N==K+1.  But for indexes on
** WITHOUT ROWID tables, N=K+P where P is the number of columns in the
** PRIMARY KEY of the table.  The covering index that implements the
** original WITHOUT ROWID table as N==K as a special case.
**
** This routine allocates the Stat4Accum object in heap memory. The return 
** value is a pointer to the the Stat4Accum object encoded as a blob (i.e. 
** the size of the blob is sizeof(void*) bytes). 

*/
static void statInit(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  Stat4Accum *p;
................................................................................
  
    for(i=0; i<nCol; i++){
      p->aBest[i].iCol = i;
    }
  }
#endif

  /* Return a pointer to the allocated object to the caller */



  sqlite3_result_blob(context, p, sizeof(p), stat4Destructor);
}
static const FuncDef statInitFuncdef = {
  2+IsStat34,      /* nArg */
  SQLITE_UTF8,     /* funcFlags */
  0,               /* pUserData */
  0,               /* pNext */
  statInit,        /* xFunc */
................................................................................
#define STAT_GET_NLT   3          /* "nlt" column of stat[34] entry */
#define STAT_GET_NDLT  4          /* "ndlt" column of stat[34] entry */

/*
** Implementation of the stat_get(P,J) SQL function.  This routine is
** used to query statistical information that has been gathered into
** the Stat4Accum object by prior calls to stat_push().  The P parameter
** is a BLOB which is decoded into a pointer to the Stat4Accum objects.
** The content to returned is determined by the parameter J
** which is one of the STAT_GET_xxxx values defined above.
**
** If neither STAT3 nor STAT4 are enabled, then J is always
** STAT_GET_STAT1 and is hence omitted and this routine becomes
** a one-parameter function, stat_get(P), that always returns the
** stat1 table entry information.
................................................................................
    sqlite3VdbeAddOp3(v, OP_Function, 1, regStat4, regTemp);
    sqlite3VdbeChangeP4(v, -1, (char*)&statPushFuncdef, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, 2+IsStat34);
    sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);

    /* Add the entry to the stat1 table. */
    callStatGet(v, regStat4, STAT_GET_STAT1, regStat1);

    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "aaa", 0);
    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);

    /* Add the entries to the stat3 or stat4 table. */
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
    {
................................................................................
  ** name and the row count as the content.
  */
  if( pOnlyIdx==0 && needTableCnt ){
    VdbeComment((v, "%s", pTab->zName));
    sqlite3VdbeAddOp2(v, OP_Count, iTabCur, regStat1);
    jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1); VdbeCoverage(v);
    sqlite3VdbeAddOp2(v, OP_Null, 0, regIdxname);

    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "aaa", 0);
    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
    sqlite3VdbeJumpHere(v, jZeroRows);
  }
}

................................................................................
  int c;
  int i;
  tRowcnt v;

#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
  if( z==0 ) z = "";
#else
  if( NEVER(z==0) ) z = "";
#endif
  for(i=0; *z && i<nOut; i++){
    v = 0;
    while( (c=z[0])>='0' && c<='9' ){
      v = v*10 + c - '0';
      z++;
    }
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
    if( aOut ){
      aOut[i] = v;
    }else
#else
    assert( aOut==0 );
    UNUSED_PARAMETER(aOut);
#endif
    {
      aLog[i] = sqlite3LogEst(v);
    }

    if( *z==' ' ) z++;
  }
#ifndef SQLITE_ENABLE_STAT3_OR_STAT4
  assert( pIndex!=0 );
#else
  if( pIndex )
#endif


  while( z[0] ){
    if( sqlite3_strglob("unordered*", z)==0 ){
      pIndex->bUnordered = 1;
    }else if( sqlite3_strglob("sz=[0-9]*", z)==0 ){
      pIndex->szIdxRow = sqlite3LogEst(sqlite3Atoi(z+3));


    }
#ifdef SQLITE_ENABLE_COSTMULT
    else if( sqlite3_strglob("costmult=[0-9]*",z)==0 ){
      pIndex->pTable->costMult = sqlite3LogEst(sqlite3Atoi(z+9));
    }
#endif
    while( z[0]!=0 && z[0]!=' ' ) z++;
    while( z[0]==' ' ) z++;

  }
}

/*
** This callback is invoked once for each index when reading the
** sqlite_stat1 table.  
**
................................................................................
    pIndex = sqlite3PrimaryKeyIndex(pTable);
  }else{
    pIndex = sqlite3FindIndex(pInfo->db, argv[1], pInfo->zDatabase);
  }
  z = argv[2];

  if( pIndex ){









    pIndex->bUnordered = 0;
    decodeIntArray((char*)z, pIndex->nKeyCol+1, 0, pIndex->aiRowLogEst, pIndex);
    if( pIndex->pPartIdxWhere==0 ) pTable->nRowLogEst = pIndex->aiRowLogEst[0];
  }else{
    Index fakeIdx;
    fakeIdx.szIdxRow = pTable->szTabRow;
#ifdef SQLITE_ENABLE_COSTMULT
    fakeIdx.pTable = pTable;
#endif
................................................................................
      ** sample columns except the last. The last is always set to 1, as
      ** once the trailing PK fields are considered all index keys are
      ** unique.  */
      nCol = pIdx->nSampleCol-1;
      pIdx->aAvgEq[nCol] = 1;
    }
    for(iCol=0; iCol<nCol; iCol++){

      int i;                    /* Used to iterate through samples */
      tRowcnt sumEq = 0;        /* Sum of the nEq values */
      tRowcnt nSum = 0;         /* Number of terms contributing to sumEq */
      tRowcnt avgEq = 0;






      tRowcnt nDLt = pFinal->anDLt[iCol];







      /* Set nSum to the number of distinct (iCol+1) field prefixes that
      ** occur in the stat4 table for this index before pFinal. Set
      ** sumEq to the sum of the nEq values for column iCol for the same
      ** set (adding the value only once where there exist dupicate 
      ** prefixes).  */

      for(i=0; i<(pIdx->nSample-1); i++){
        if( aSample[i].anDLt[iCol]!=aSample[i+1].anDLt[iCol] ){

          sumEq += aSample[i].anEq[iCol];
          nSum++;
        }
      }
      if( nDLt>nSum ){
        avgEq = (pFinal->anLt[iCol] - sumEq)/(nDLt - nSum);



      }
      if( avgEq==0 ) avgEq = 1;
      pIdx->aAvgEq[iCol] = avgEq;
    }
  }
}

................................................................................
    rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
    sqlite3DbFree(db, zSql);
  }


  /* Load the statistics from the sqlite_stat4 table. */
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
  if( rc==SQLITE_OK ){
    int lookasideEnabled = db->lookaside.bEnabled;
    db->lookaside.bEnabled = 0;
    rc = loadStat4(db, sInfo.zDatabase);
    db->lookaside.bEnabled = lookasideEnabled;





  }
#endif

  if( rc==SQLITE_NOMEM ){
    db->mallocFailed = 1;
  }
  return rc;
}


#endif /* SQLITE_OMIT_ANALYZE */

** SQLITE_ENABLE_STAT3 defined.  The functionality of sqlite_stat3
** is a superset of sqlite_stat2.  The sqlite_stat4 is an enhanced
** version of sqlite_stat3 and is only available when compiled with
** SQLITE_ENABLE_STAT4 and in SQLite versions 3.8.1 and later.  It is
** not possible to enable both STAT3 and STAT4 at the same time.  If they
** are both enabled, then STAT4 takes precedence.
**
** For most applications, sqlite_stat1 provides all the statistics required
** for the query planner to make good choices.
**
** Format of sqlite_stat1:
**
** There is normally one row per index, with the index identified by the
** name in the idx column.  The tbl column is the name of the table to
** which the index belongs.  In each such row, the stat column will be
................................................................................
**
** For indexes on ordinary rowid tables, N==K+1.  But for indexes on
** WITHOUT ROWID tables, N=K+P where P is the number of columns in the
** PRIMARY KEY of the table.  The covering index that implements the
** original WITHOUT ROWID table as N==K as a special case.
**
** This routine allocates the Stat4Accum object in heap memory. The return 
** value is a pointer to the Stat4Accum object.  The datatype of the
** return value is BLOB, but it is really just a pointer to the Stat4Accum
** object.
*/
static void statInit(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  Stat4Accum *p;
................................................................................
  
    for(i=0; i<nCol; i++){
      p->aBest[i].iCol = i;
    }
  }
#endif

  /* Return a pointer to the allocated object to the caller.  Note that
  ** only the pointer (the 2nd parameter) matters.  The size of the object
  ** (given by the 3rd parameter) is never used and can be any positive
  ** value. */
  sqlite3_result_blob(context, p, sizeof(*p), stat4Destructor);
}
static const FuncDef statInitFuncdef = {
  2+IsStat34,      /* nArg */
  SQLITE_UTF8,     /* funcFlags */
  0,               /* pUserData */
  0,               /* pNext */
  statInit,        /* xFunc */
................................................................................
#define STAT_GET_NLT   3          /* "nlt" column of stat[34] entry */
#define STAT_GET_NDLT  4          /* "ndlt" column of stat[34] entry */

/*
** Implementation of the stat_get(P,J) SQL function.  This routine is
** used to query statistical information that has been gathered into
** the Stat4Accum object by prior calls to stat_push().  The P parameter
** has type BLOB but it is really just a pointer to the Stat4Accum object.
** The content to returned is determined by the parameter J
** which is one of the STAT_GET_xxxx values defined above.
**
** If neither STAT3 nor STAT4 are enabled, then J is always
** STAT_GET_STAT1 and is hence omitted and this routine becomes
** a one-parameter function, stat_get(P), that always returns the
** stat1 table entry information.
................................................................................
    sqlite3VdbeAddOp3(v, OP_Function, 1, regStat4, regTemp);
    sqlite3VdbeChangeP4(v, -1, (char*)&statPushFuncdef, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, 2+IsStat34);
    sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);

    /* Add the entry to the stat1 table. */
    callStatGet(v, regStat4, STAT_GET_STAT1, regStat1);
    assert( "BBB"[0]==SQLITE_AFF_TEXT );
    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);

    /* Add the entries to the stat3 or stat4 table. */
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
    {
................................................................................
  ** name and the row count as the content.
  */
  if( pOnlyIdx==0 && needTableCnt ){
    VdbeComment((v, "%s", pTab->zName));
    sqlite3VdbeAddOp2(v, OP_Count, iTabCur, regStat1);
    jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1); VdbeCoverage(v);
    sqlite3VdbeAddOp2(v, OP_Null, 0, regIdxname);
    assert( "BBB"[0]==SQLITE_AFF_TEXT );
    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
    sqlite3VdbeJumpHere(v, jZeroRows);
  }
}

................................................................................
  int c;
  int i;
  tRowcnt v;

#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
  if( z==0 ) z = "";
#else
  assert( z!=0 );
#endif
  for(i=0; *z && i<nOut; i++){
    v = 0;
    while( (c=z[0])>='0' && c<='9' ){
      v = v*10 + c - '0';
      z++;
    }
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
    if( aOut ) aOut[i] = v;
    if( aLog ) aLog[i] = sqlite3LogEst(v);

#else
    assert( aOut==0 );
    UNUSED_PARAMETER(aOut);
    assert( aLog!=0 );

    aLog[i] = sqlite3LogEst(v);

#endif
    if( *z==' ' ) z++;
  }
#ifndef SQLITE_ENABLE_STAT3_OR_STAT4
  assert( pIndex!=0 ); {
#else
  if( pIndex ){
#endif
    pIndex->bUnordered = 0;
    pIndex->noSkipScan = 0;
    while( z[0] ){
      if( sqlite3_strglob("unordered*", z)==0 ){
        pIndex->bUnordered = 1;
      }else if( sqlite3_strglob("sz=[0-9]*", z)==0 ){
        pIndex->szIdxRow = sqlite3LogEst(sqlite3Atoi(z+3));
      }else if( sqlite3_strglob("noskipscan*", z)==0 ){
        pIndex->noSkipScan = 1;
      }
#ifdef SQLITE_ENABLE_COSTMULT
      else if( sqlite3_strglob("costmult=[0-9]*",z)==0 ){
        pIndex->pTable->costMult = sqlite3LogEst(sqlite3Atoi(z+9));
      }
#endif
      while( z[0]!=0 && z[0]!=' ' ) z++;
      while( z[0]==' ' ) z++;
    }
  }
}

/*
** This callback is invoked once for each index when reading the
** sqlite_stat1 table.  
**
................................................................................
    pIndex = sqlite3PrimaryKeyIndex(pTable);
  }else{
    pIndex = sqlite3FindIndex(pInfo->db, argv[1], pInfo->zDatabase);
  }
  z = argv[2];

  if( pIndex ){
    int nCol = pIndex->nKeyCol+1;
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
    tRowcnt * const aiRowEst = pIndex->aiRowEst = (tRowcnt*)sqlite3MallocZero(
        sizeof(tRowcnt) * nCol
    );
    if( aiRowEst==0 ) pInfo->db->mallocFailed = 1;
#else
    tRowcnt * const aiRowEst = 0;
#endif
    pIndex->bUnordered = 0;
    decodeIntArray((char*)z, nCol, aiRowEst, pIndex->aiRowLogEst, pIndex);
    if( pIndex->pPartIdxWhere==0 ) pTable->nRowLogEst = pIndex->aiRowLogEst[0];
  }else{
    Index fakeIdx;
    fakeIdx.szIdxRow = pTable->szTabRow;
#ifdef SQLITE_ENABLE_COSTMULT
    fakeIdx.pTable = pTable;
#endif
................................................................................
      ** sample columns except the last. The last is always set to 1, as
      ** once the trailing PK fields are considered all index keys are
      ** unique.  */
      nCol = pIdx->nSampleCol-1;
      pIdx->aAvgEq[nCol] = 1;
    }
    for(iCol=0; iCol<nCol; iCol++){
      int nSample = pIdx->nSample;
      int i;                    /* Used to iterate through samples */
      tRowcnt sumEq = 0;        /* Sum of the nEq values */

      tRowcnt avgEq = 0;
      tRowcnt nRow;             /* Number of rows in index */
      i64 nSum100 = 0;          /* Number of terms contributing to sumEq */
      i64 nDist100;             /* Number of distinct values in index */

      if( !pIdx->aiRowEst || iCol>=pIdx->nKeyCol || pIdx->aiRowEst[iCol+1]==0 ){
        nRow = pFinal->anLt[iCol];
        nDist100 = (i64)100 * pFinal->anDLt[iCol];
        nSample--;
      }else{
        nRow = pIdx->aiRowEst[0];
        nDist100 = ((i64)100 * pIdx->aiRowEst[0]) / pIdx->aiRowEst[iCol+1];
      }
      pIdx->nRowEst0 = nRow;

      /* Set nSum to the number of distinct (iCol+1) field prefixes that
      ** occur in the stat4 table for this index. Set sumEq to the sum of 
      ** the nEq values for column iCol for the same set (adding the value 
      ** only once where there exist duplicate prefixes).  */

      for(i=0; i<nSample; i++){
        if( i==(pIdx->nSample-1)
         || aSample[i].anDLt[iCol]!=aSample[i+1].anDLt[iCol] 
        ){
          sumEq += aSample[i].anEq[iCol];
          nSum100 += 100;
        }
      }



      if( nDist100>nSum100 ){
        avgEq = ((i64)100 * (nRow - sumEq))/(nDist100 - nSum100);
      }
      if( avgEq==0 ) avgEq = 1;
      pIdx->aAvgEq[iCol] = avgEq;
    }
  }
}

................................................................................
    rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
    sqlite3DbFree(db, zSql);
  }


  /* Load the statistics from the sqlite_stat4 table. */
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
  if( rc==SQLITE_OK && OptimizationEnabled(db, SQLITE_Stat34) ){
    int lookasideEnabled = db->lookaside.bEnabled;
    db->lookaside.bEnabled = 0;
    rc = loadStat4(db, sInfo.zDatabase);
    db->lookaside.bEnabled = lookasideEnabled;
  }
  for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
    Index *pIdx = sqliteHashData(i);
    sqlite3_free(pIdx->aiRowEst);
    pIdx->aiRowEst = 0;
  }
#endif

  if( rc==SQLITE_NOMEM ){
    db->mallocFailed = 1;
  }
  return rc;
}


#endif /* SQLITE_OMIT_ANALYZE */

  ** we found it.
  */
  if( rc==SQLITE_OK ){
    sqlite3BtreeEnterAll(db);
    rc = sqlite3Init(db, &zErrDyn);
    sqlite3BtreeLeaveAll(db);
  }









  if( rc ){
    int iDb = db->nDb - 1;
    assert( iDb>=2 );
    if( db->aDb[iDb].pBt ){
      sqlite3BtreeClose(db->aDb[iDb].pBt);
      db->aDb[iDb].pBt = 0;
      db->aDb[iDb].pSchema = 0;

  ** we found it.
  */
  if( rc==SQLITE_OK ){
    sqlite3BtreeEnterAll(db);
    rc = sqlite3Init(db, &zErrDyn);
    sqlite3BtreeLeaveAll(db);
  }
#ifdef SQLITE_USER_AUTHENTICATION
  if( rc==SQLITE_OK ){
    u8 newAuth = 0;
    rc = sqlite3UserAuthCheckLogin(db, zName, &newAuth);
    if( newAuth<db->auth.authLevel ){
      rc = SQLITE_AUTH_USER;
    }
  }
#endif
  if( rc ){
    int iDb = db->nDb - 1;
    assert( iDb>=2 );
    if( db->aDb[iDb].pBt ){
      sqlite3BtreeClose(db->aDb[iDb].pBt);
      db->aDb[iDb].pBt = 0;
      db->aDb[iDb].pSchema = 0;

** setting of the auth function is NULL.
*/
int sqlite3_set_authorizer(
  sqlite3 *db,
  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
  void *pArg
){



  sqlite3_mutex_enter(db->mutex);
  db->xAuth = xAuth;
  db->pAuthArg = pArg;
  sqlite3ExpirePreparedStatements(db);
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}

/*
................................................................................
  const char *zCol,               /* Column name */
  int iDb                         /* Index of containing database. */
){
  sqlite3 *db = pParse->db;       /* Database handle */
  char *zDb = db->aDb[iDb].zName; /* Name of attached database */
  int rc;                         /* Auth callback return code */

  rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext);




  if( rc==SQLITE_DENY ){
    if( db->nDb>2 || iDb!=0 ){
      sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited",zDb,zTab,zCol);
    }else{
      sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited", zTab, zCol);
    }
    pParse->rc = SQLITE_AUTH;
................................................................................
  if( db->init.busy || IN_DECLARE_VTAB ){
    return SQLITE_OK;
  }

  if( db->xAuth==0 ){
    return SQLITE_OK;
  }
  rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext);




  if( rc==SQLITE_DENY ){
    sqlite3ErrorMsg(pParse, "not authorized");
    pParse->rc = SQLITE_AUTH;
  }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
    rc = SQLITE_DENY;
    sqliteAuthBadReturnCode(pParse);
  }

** setting of the auth function is NULL.
*/
int sqlite3_set_authorizer(
  sqlite3 *db,
  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
  void *pArg
){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  db->xAuth = (sqlite3_xauth)xAuth;
  db->pAuthArg = pArg;
  sqlite3ExpirePreparedStatements(db);
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}

/*
................................................................................
  const char *zCol,               /* Column name */
  int iDb                         /* Index of containing database. */
){
  sqlite3 *db = pParse->db;       /* Database handle */
  char *zDb = db->aDb[iDb].zName; /* Name of attached database */
  int rc;                         /* Auth callback return code */

  rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext
#ifdef SQLITE_USER_AUTHENTICATION
                 ,db->auth.zAuthUser
#endif
                );
  if( rc==SQLITE_DENY ){
    if( db->nDb>2 || iDb!=0 ){
      sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited",zDb,zTab,zCol);
    }else{
      sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited", zTab, zCol);
    }
    pParse->rc = SQLITE_AUTH;
................................................................................
  if( db->init.busy || IN_DECLARE_VTAB ){
    return SQLITE_OK;
  }

  if( db->xAuth==0 ){
    return SQLITE_OK;
  }
  rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext
#ifdef SQLITE_USER_AUTHENTICATION
                 ,db->auth.zAuthUser
#endif
                );
  if( rc==SQLITE_DENY ){
    sqlite3ErrorMsg(pParse, "not authorized");
    pParse->rc = SQLITE_AUTH;
  }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
    rc = SQLITE_DENY;
    sqliteAuthBadReturnCode(pParse);
  }

** of the source.
*/
static int setDestPgsz(sqlite3_backup *p){
  int rc;
  rc = sqlite3BtreeSetPageSize(p->pDest,sqlite3BtreeGetPageSize(p->pSrc),-1,0);
  return rc;
}















/*
** Create an sqlite3_backup process to copy the contents of zSrcDb from
** connection handle pSrcDb to zDestDb in pDestDb. If successful, return
** a pointer to the new sqlite3_backup object.
**
** If an error occurs, NULL is returned and an error code and error message
................................................................................
sqlite3_backup *sqlite3_backup_init(
  sqlite3* pDestDb,                     /* Database to write to */
  const char *zDestDb,                  /* Name of database within pDestDb */
  sqlite3* pSrcDb,                      /* Database connection to read from */
  const char *zSrcDb                    /* Name of database within pSrcDb */
){
  sqlite3_backup *p;                    /* Value to return */








  /* Lock the source database handle. The destination database
  ** handle is not locked in this routine, but it is locked in
  ** sqlite3_backup_step(). The user is required to ensure that no
  ** other thread accesses the destination handle for the duration
  ** of the backup operation.  Any attempt to use the destination
  ** database connection while a backup is in progress may cause
................................................................................
    p->pSrc = findBtree(pDestDb, pSrcDb, zSrcDb);
    p->pDest = findBtree(pDestDb, pDestDb, zDestDb);
    p->pDestDb = pDestDb;
    p->pSrcDb = pSrcDb;
    p->iNext = 1;
    p->isAttached = 0;


    if( 0==p->pSrc || 0==p->pDest || setDestPgsz(p)==SQLITE_NOMEM ){


      /* One (or both) of the named databases did not exist or an OOM

      ** error was hit.  The error has already been written into the
      ** pDestDb handle.  All that is left to do here is free the
      ** sqlite3_backup structure.
      */
      sqlite3_free(p);
      p = 0;
    }
  }
  if( p ){
    p->pSrc->nBackup++;
  }
................................................................................
*/
int sqlite3_backup_step(sqlite3_backup *p, int nPage){
  int rc;
  int destMode;       /* Destination journal mode */
  int pgszSrc = 0;    /* Source page size */
  int pgszDest = 0;   /* Destination page size */




  sqlite3_mutex_enter(p->pSrcDb->mutex);
  sqlite3BtreeEnter(p->pSrc);
  if( p->pDestDb ){
    sqlite3_mutex_enter(p->pDestDb->mutex);
  }

  rc = p->rc;
................................................................................
    while( *pp!=p ){
      pp = &(*pp)->pNext;
    }
    *pp = p->pNext;
  }

  /* If a transaction is still open on the Btree, roll it back. */
  sqlite3BtreeRollback(p->pDest, SQLITE_OK);

  /* Set the error code of the destination database handle. */
  rc = (p->rc==SQLITE_DONE) ? SQLITE_OK : p->rc;
  if( p->pDestDb ){
    sqlite3Error(p->pDestDb, rc);

    /* Exit the mutexes and free the backup context structure. */
................................................................................
}

/*
** Return the number of pages still to be backed up as of the most recent
** call to sqlite3_backup_step().
*/
int sqlite3_backup_remaining(sqlite3_backup *p){






  return p->nRemaining;
}

/*
** Return the total number of pages in the source database as of the most 
** recent call to sqlite3_backup_step().
*/
int sqlite3_backup_pagecount(sqlite3_backup *p){






  return p->nPagecount;
}

/*
** This function is called after the contents of page iPage of the
** source database have been modified. If page iPage has already been 
** copied into the destination database, then the data written to the

** of the source.
*/
static int setDestPgsz(sqlite3_backup *p){
  int rc;
  rc = sqlite3BtreeSetPageSize(p->pDest,sqlite3BtreeGetPageSize(p->pSrc),-1,0);
  return rc;
}

/*
** Check that there is no open read-transaction on the b-tree passed as the
** second argument. If there is not, return SQLITE_OK. Otherwise, if there
** is an open read-transaction, return SQLITE_ERROR and leave an error 
** message in database handle db.
*/
static int checkReadTransaction(sqlite3 *db, Btree *p){
  if( sqlite3BtreeIsInReadTrans(p) ){
    sqlite3ErrorWithMsg(db, SQLITE_ERROR, "destination database is in use");
    return SQLITE_ERROR;
  }
  return SQLITE_OK;
}

/*
** Create an sqlite3_backup process to copy the contents of zSrcDb from
** connection handle pSrcDb to zDestDb in pDestDb. If successful, return
** a pointer to the new sqlite3_backup object.
**
** If an error occurs, NULL is returned and an error code and error message
................................................................................
sqlite3_backup *sqlite3_backup_init(
  sqlite3* pDestDb,                     /* Database to write to */
  const char *zDestDb,                  /* Name of database within pDestDb */
  sqlite3* pSrcDb,                      /* Database connection to read from */
  const char *zSrcDb                    /* Name of database within pSrcDb */
){
  sqlite3_backup *p;                    /* Value to return */

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(pSrcDb)||!sqlite3SafetyCheckOk(pDestDb) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif

  /* Lock the source database handle. The destination database
  ** handle is not locked in this routine, but it is locked in
  ** sqlite3_backup_step(). The user is required to ensure that no
  ** other thread accesses the destination handle for the duration
  ** of the backup operation.  Any attempt to use the destination
  ** database connection while a backup is in progress may cause
................................................................................
    p->pSrc = findBtree(pDestDb, pSrcDb, zSrcDb);
    p->pDest = findBtree(pDestDb, pDestDb, zDestDb);
    p->pDestDb = pDestDb;
    p->pSrcDb = pSrcDb;
    p->iNext = 1;
    p->isAttached = 0;

    if( 0==p->pSrc || 0==p->pDest 
     || setDestPgsz(p)==SQLITE_NOMEM 
     || checkReadTransaction(pDestDb, p->pDest)!=SQLITE_OK 
     ){
      /* One (or both) of the named databases did not exist or an OOM
      ** error was hit. Or there is a transaction open on the destination
      ** database. The error has already been written into the pDestDb 
      ** handle. All that is left to do here is free the sqlite3_backup 
      ** structure.  */

      sqlite3_free(p);
      p = 0;
    }
  }
  if( p ){
    p->pSrc->nBackup++;
  }
................................................................................
*/
int sqlite3_backup_step(sqlite3_backup *p, int nPage){
  int rc;
  int destMode;       /* Destination journal mode */
  int pgszSrc = 0;    /* Source page size */
  int pgszDest = 0;   /* Destination page size */

#ifdef SQLITE_ENABLE_API_ARMOR
  if( p==0 ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(p->pSrcDb->mutex);
  sqlite3BtreeEnter(p->pSrc);
  if( p->pDestDb ){
    sqlite3_mutex_enter(p->pDestDb->mutex);
  }

  rc = p->rc;
................................................................................
    while( *pp!=p ){
      pp = &(*pp)->pNext;
    }
    *pp = p->pNext;
  }

  /* If a transaction is still open on the Btree, roll it back. */
  sqlite3BtreeRollback(p->pDest, SQLITE_OK, 0);

  /* Set the error code of the destination database handle. */
  rc = (p->rc==SQLITE_DONE) ? SQLITE_OK : p->rc;
  if( p->pDestDb ){
    sqlite3Error(p->pDestDb, rc);

    /* Exit the mutexes and free the backup context structure. */
................................................................................
}

/*
** Return the number of pages still to be backed up as of the most recent
** call to sqlite3_backup_step().
*/
int sqlite3_backup_remaining(sqlite3_backup *p){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( p==0 ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  return p->nRemaining;
}

/*
** Return the total number of pages in the source database as of the most 
** recent call to sqlite3_backup_step().
*/
int sqlite3_backup_pagecount(sqlite3_backup *p){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( p==0 ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  return p->nPagecount;
}

/*
** This function is called after the contents of page iPage of the
** source database have been modified. If page iPage has already been 
** copied into the destination database, then the data written to the

** and thus help the sqlite3BtreeLock() routine to run much faster
** in the common case.
*/
static void SQLITE_NOINLINE btreeLockCarefully(Btree *p){
  Btree *pLater;

  /* In most cases, we should be able to acquire the lock we
  ** want without having to go throught the ascending lock
  ** procedure that follows.  Just be sure not to block.
  */
  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
    p->pBt->db = p->db;
    p->locked = 1;
    return;
  }

** and thus help the sqlite3BtreeLock() routine to run much faster
** in the common case.
*/
static void SQLITE_NOINLINE btreeLockCarefully(Btree *p){
  Btree *pLater;

  /* In most cases, we should be able to acquire the lock we
  ** want without having to go through the ascending lock
  ** procedure that follows.  Just be sure not to block.
  */
  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
    p->pBt->db = p->db;
    p->locked = 1;
    return;
  }

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

/*
** The header string that appears at the beginning of every
................................................................................
  i64 iRow,               /* The rowid that might be changing */
  int isClearTable        /* True if all rows are being deleted */
){
  BtCursor *p;
  BtShared *pBt = pBtree->pBt;
  assert( sqlite3BtreeHoldsMutex(pBtree) );
  for(p=pBt->pCursor; p; p=p->pNext){

    if( (p->curFlags & BTCF_Incrblob)!=0 && (isClearTable || p->info.nKey==iRow) ){

      p->eState = CURSOR_INVALID;
    }
  }
}

#else
  /* Stub function when INCRBLOB is omitted */
................................................................................
  /* If this is an intKey table, then the above call to BtreeKeySize()
  ** stores the integer key in pCur->nKey. In this case this value is
  ** all that is required. Otherwise, if pCur is not open on an intKey
  ** table, then malloc space for and store the pCur->nKey bytes of key 
  ** data.
  */
  if( 0==pCur->apPage[0]->intKey ){
    void *pKey = sqlite3Malloc( (int)pCur->nKey );
    if( pKey ){
      rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
      if( rc==SQLITE_OK ){
        pCur->pKey = pKey;
      }else{
        sqlite3_free(pKey);
      }
................................................................................

/* This helper routine to saveAllCursors does the actual work of saving
** the cursors if and when a cursor is found that actually requires saving.
** The common case is that no cursors need to be saved, so this routine is
** broken out from its caller to avoid unnecessary stack pointer movement.
*/
static int SQLITE_NOINLINE saveCursorsOnList(
  BtCursor *p,           /* The first cursor that needs saving */
  Pgno iRoot,            /* Only save cursor with this iRoot.  Save all if zero */
  BtCursor *pExcept      /* Do not save this cursor */
){
  do{
    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ){
      if( p->eState==CURSOR_VALID ){
        int rc = saveCursorPosition(p);
        if( SQLITE_OK!=rc ){
          return rc;
................................................................................
**
** Calling this routine with a NULL cursor pointer returns false.
**
** Use the separate sqlite3BtreeCursorRestore() routine to restore a cursor
** back to where it ought to be if this routine returns true.
*/
int sqlite3BtreeCursorHasMoved(BtCursor *pCur){
  return pCur && pCur->eState!=CURSOR_VALID;
}

/*
** This routine restores a cursor back to its original position after it
** has been moved by some outside activity (such as a btree rebalance or
** a row having been deleted out from under the cursor).  
**
................................................................................
}

/*
** Parse a cell content block and fill in the CellInfo structure.  There
** are two versions of this function.  btreeParseCell() takes a 
** cell index as the second argument and btreeParseCellPtr() 
** takes a pointer to the body of the cell as its second argument.
**
** Within this file, the parseCell() macro can be called instead of
** btreeParseCellPtr(). Using some compilers, this will be faster.
*/
static void btreeParseCellPtr(
  MemPage *pPage,         /* Page containing the cell */
  u8 *pCell,              /* Pointer to the cell text. */
  CellInfo *pInfo         /* Fill in this structure */
){
  u16 n;                  /* Number bytes in cell content header */
  u32 nPayload;           /* Number of bytes of cell payload */

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );

  pInfo->pCell = pCell;
  assert( pPage->leaf==0 || pPage->leaf==1 );
  n = pPage->childPtrSize;
  assert( n==4-4*pPage->leaf );
  if( pPage->intKey ){
    if( pPage->hasData ){
      assert( n==0 );
      n = getVarint32(pCell, nPayload);
    }else{
      nPayload = 0;
    }
    n += getVarint(&pCell[n], (u64*)&pInfo->nKey);
    pInfo->nData = nPayload;
  }else{
    pInfo->nData = 0;
    n += getVarint32(&pCell[n], nPayload);
    pInfo->nKey = nPayload;
  }
  pInfo->nPayload = nPayload;
  pInfo->nHeader = n;
  testcase( nPayload==pPage->maxLocal );
  testcase( nPayload==pPage->maxLocal+1 );
  if( likely(nPayload<=pPage->maxLocal) ){
    /* This is the (easy) common case where the entire payload fits
    ** on the local page.  No overflow is required.
    */

    if( (pInfo->nSize = (u16)(n+nPayload))<4 ) pInfo->nSize = 4;
    pInfo->nLocal = (u16)nPayload;
    pInfo->iOverflow = 0;
  }else{
    /* If the payload will not fit completely on the local page, we have
    ** to decide how much to store locally and how much to spill onto
    ** overflow pages.  The strategy is to minimize the amount of unused
    ** space on overflow pages while keeping the amount of local storage
................................................................................
    testcase( surplus==maxLocal );
    testcase( surplus==maxLocal+1 );
    if( surplus <= maxLocal ){
      pInfo->nLocal = (u16)surplus;
    }else{
      pInfo->nLocal = (u16)minLocal;
    }
    pInfo->iOverflow = (u16)(pInfo->nLocal + n);
    pInfo->nSize = pInfo->iOverflow + 4;
  }
}
#define parseCell(pPage, iCell, pInfo) \
  btreeParseCellPtr((pPage), findCell((pPage), (iCell)), (pInfo))
static void btreeParseCell(
  MemPage *pPage,         /* Page containing the cell */
  int iCell,              /* The cell index.  First cell is 0 */
  CellInfo *pInfo         /* Fill in this structure */
){
  parseCell(pPage, iCell, pInfo);
}

/*
** Compute the total number of bytes that a Cell needs in the cell
** data area of the btree-page.  The return number includes the cell
** data header and the local payload, but not any overflow page or
** the space used by the cell pointer.
*/
static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
  u8 *pIter = &pCell[pPage->childPtrSize];
  u32 nSize;


#ifdef SQLITE_DEBUG
  /* The value returned by this function should always be the same as
  ** the (CellInfo.nSize) value found by doing a full parse of the
  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
  ** this function verifies that this invariant is not violated. */
  CellInfo debuginfo;
  btreeParseCellPtr(pPage, pCell, &debuginfo);
#endif

  if( pPage->intKey ){
    u8 *pEnd;
    if( pPage->hasData ){
      pIter += getVarint32(pIter, nSize);
    }else{
      nSize = 0;
    }










    /* pIter now points at the 64-bit integer key value, a variable length 
    ** integer. The following block moves pIter to point at the first byte
    ** past the end of the key value. */
    pEnd = &pIter[9];
    while( (*pIter++)&0x80 && pIter<pEnd );
  }else{
    pIter += getVarint32(pIter, nSize);
  }

  testcase( nSize==pPage->maxLocal );
  testcase( nSize==pPage->maxLocal+1 );
  if( nSize>pPage->maxLocal ){



    int minLocal = pPage->minLocal;
    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
    testcase( nSize==pPage->maxLocal );
    testcase( nSize==pPage->maxLocal+1 );
    if( nSize>pPage->maxLocal ){
      nSize = minLocal;
    }
    nSize += 4;
  }
  nSize += (u32)(pIter - pCell);

  /* The minimum size of any cell is 4 bytes. */
  if( nSize<4 ){
    nSize = 4;
  }

  assert( nSize==debuginfo.nSize );
  return (u16)nSize;
}

#ifdef SQLITE_DEBUG
/* This variation on cellSizePtr() is used inside of assert() statements
** only. */
static u16 cellSize(MemPage *pPage, int iCell){
................................................................................
** for the overflow page.
*/
static void ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell, int *pRC){
  CellInfo info;
  if( *pRC ) return;
  assert( pCell!=0 );
  btreeParseCellPtr(pPage, pCell, &info);
  assert( (info.nData+(pPage->intKey?0:info.nKey))==info.nPayload );
  if( info.iOverflow ){
    Pgno ovfl = get4byte(&pCell[info.iOverflow]);
    ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
  }
}
#endif


/*
** Defragment the page given.  All Cells are moved to the
** end of the page and all free space is collected into one
** big FreeBlk that occurs in between the header and cell
** pointer array and the cell content area.





*/
static int defragmentPage(MemPage *pPage){
  int i;                     /* Loop counter */
  int pc;                    /* Address of a i-th cell */
  int hdr;                   /* Offset to the page header */
  int size;                  /* Size of a cell */
  int usableSize;            /* Number of usable bytes on a page */
  int cellOffset;            /* Offset to the cell pointer array */
  int cbrk;                  /* Offset to the cell content area */
  int nCell;                 /* Number of cells on the page */
  unsigned char *data;       /* The page data */
  unsigned char *temp;       /* Temp area for cell content */

  int iCellFirst;            /* First allowable cell index */
  int iCellLast;             /* Last possible cell index */


  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( pPage->pBt!=0 );
  assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE );
  assert( pPage->nOverflow==0 );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
  data = pPage->aData;
  hdr = pPage->hdrOffset;
  cellOffset = pPage->cellOffset;
  nCell = pPage->nCell;
  assert( nCell==get2byte(&data[hdr+3]) );
  usableSize = pPage->pBt->usableSize;
  cbrk = get2byte(&data[hdr+5]);
  memcpy(&temp[cbrk], &data[cbrk], usableSize - cbrk);
  cbrk = usableSize;
  iCellFirst = cellOffset + 2*nCell;
  iCellLast = usableSize - 4;
  for(i=0; i<nCell; i++){
    u8 *pAddr;     /* The i-th cell pointer */
    pAddr = &data[cellOffset + i*2];
    pc = get2byte(pAddr);
................................................................................
    ** if SQLITE_ENABLE_OVERSIZE_CELL_CHECK is defined 
    */
    if( pc<iCellFirst || pc>iCellLast ){
      return SQLITE_CORRUPT_BKPT;
    }
#endif
    assert( pc>=iCellFirst && pc<=iCellLast );
    size = cellSizePtr(pPage, &temp[pc]);
    cbrk -= size;
#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
    if( cbrk<iCellFirst ){
      return SQLITE_CORRUPT_BKPT;
    }
#else
    if( cbrk<iCellFirst || pc+size>usableSize ){
      return SQLITE_CORRUPT_BKPT;
    }
#endif
    assert( cbrk+size<=usableSize && cbrk>=iCellFirst );
    testcase( cbrk+size==usableSize );
    testcase( pc+size==usableSize );
    memcpy(&data[cbrk], &temp[pc], size);
    put2byte(pAddr, cbrk);









  }
  assert( cbrk>=iCellFirst );
  put2byte(&data[hdr+5], cbrk);
  data[hdr+1] = 0;
  data[hdr+2] = 0;
  data[hdr+7] = 0;
  memset(&data[iCellFirst], 0, cbrk-iCellFirst);
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  if( cbrk-iCellFirst!=pPage->nFree ){
    return SQLITE_CORRUPT_BKPT;
  }
  return SQLITE_OK;
}
































































/*
** Allocate nByte bytes of space from within the B-Tree page passed
** as the first argument. Write into *pIdx the index into pPage->aData[]
** of the first byte of allocated space. Return either SQLITE_OK or
** an error code (usually SQLITE_CORRUPT).
**
................................................................................
** allocation is being made in order to insert a new cell, so we will
** also end up needing a new cell pointer.
*/
static int allocateSpace(MemPage *pPage, int nByte, int *pIdx){
  const int hdr = pPage->hdrOffset;    /* Local cache of pPage->hdrOffset */
  u8 * const data = pPage->aData;      /* Local cache of pPage->aData */
  int top;                             /* First byte of cell content area */

  int gap;        /* First byte of gap between cell pointers and cell content */
  int rc;         /* Integer return code */
  int usableSize; /* Usable size of the page */
  
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( pPage->pBt );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( nByte>=0 );  /* Minimum cell size is 4 */
  assert( pPage->nFree>=nByte );
  assert( pPage->nOverflow==0 );
  usableSize = pPage->pBt->usableSize;
  assert( nByte < usableSize-8 );

  assert( pPage->cellOffset == hdr + 12 - 4*pPage->leaf );
  gap = pPage->cellOffset + 2*pPage->nCell;
  assert( gap<=65536 );
  top = get2byte(&data[hdr+5]);
  if( gap>top ){
    if( top==0 ){
      top = 65536;
    }else{
      return SQLITE_CORRUPT_BKPT;
    }
  }

  /* If there is enough space between gap and top for one more cell pointer
  ** array entry offset, and if the freelist is not empty, then search the
  ** freelist looking for a free slot big enough to satisfy the request.
  */
  testcase( gap+2==top );
  testcase( gap+1==top );
  testcase( gap==top );
  if( gap+2<=top && (data[hdr+1] || data[hdr+2]) ){
    int pc, addr;
    for(addr=hdr+1; (pc = get2byte(&data[addr]))>0; addr=pc){
      int size;            /* Size of the free slot */
      if( pc>usableSize-4 || pc<addr+4 ){
        return SQLITE_CORRUPT_BKPT;
      }
      size = get2byte(&data[pc+2]);
      if( size>=nByte ){
        int x = size - nByte;
        testcase( x==4 );
        testcase( x==3 );
        if( x<4 ){
          if( data[hdr+7]>=60 ) goto defragment_page;
          /* Remove the slot from the free-list. Update the number of
          ** fragmented bytes within the page. */
          memcpy(&data[addr], &data[pc], 2);
          data[hdr+7] += (u8)x;
        }else if( size+pc > usableSize ){
          return SQLITE_CORRUPT_BKPT;
        }else{
          /* The slot remains on the free-list. Reduce its size to account
          ** for the portion used by the new allocation. */
          put2byte(&data[pc+2], x);
        }


        *pIdx = pc + x;
        return SQLITE_OK;
      }
    }
  }

  /* The request could not be fulfilled using a freelist slot.  Check
  ** to see if defragmentation is necessary.
  */
  testcase( gap+2+nByte==top );
  if( gap+2+nByte>top ){
defragment_page:
    testcase( pPage->nCell==0 );
    rc = defragmentPage(pPage);
    if( rc ) return rc;
    top = get2byteNotZero(&data[hdr+5]);
    assert( gap+nByte<=top );
  }


................................................................................
** Note that even though the freeblock list was checked by btreeInitPage(),
** that routine will not detect overlap between cells or freeblocks.  Nor
** does it detect cells or freeblocks that encrouch into the reserved bytes
** at the end of the page.  So do additional corruption checks inside this
** routine and return SQLITE_CORRUPT if any problems are found.
*/
static int freeSpace(MemPage *pPage, u16 iStart, u16 iSize){
  u16 iPtr;                             /* Address of pointer to next freeblock */
  u16 iFreeBlk;                         /* Address of the next freeblock */
  u8 hdr;                               /* Page header size.  0 or 100 */
  u8 nFrag = 0;                         /* Reduction in fragmentation */
  u16 iOrigSize = iSize;                /* Original value of iSize */
  u32 iLast = pPage->pBt->usableSize-4; /* Largest possible freeblock offset */
  u32 iEnd = iStart + iSize;            /* First byte past the iStart buffer */
  unsigned char *data = pPage->aData;   /* Page content */

  assert( pPage->pBt!=0 );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( iStart>=pPage->hdrOffset+6+pPage->childPtrSize );
  assert( iEnd <= pPage->pBt->usableSize );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( iSize>=4 );   /* Minimum cell size is 4 */
  assert( iStart<=iLast );

  /* Overwrite deleted information with zeros when the secure_delete
  ** option is enabled */
  if( pPage->pBt->btsFlags & BTS_SECURE_DELETE ){
................................................................................
      nFrag = iFreeBlk - iEnd;
      if( iEnd>iFreeBlk ) return SQLITE_CORRUPT_BKPT;
      iEnd = iFreeBlk + get2byte(&data[iFreeBlk+2]);
      iSize = iEnd - iStart;
      iFreeBlk = get2byte(&data[iFreeBlk]);
    }
  
    /* If iPtr is another freeblock (that is, if iPtr is not the freelist pointer
    ** in the page header) then check to see if iStart should be coalesced 
    ** onto the end of iPtr.
    */
    if( iPtr>hdr+1 ){
      int iPtrEnd = iPtr + get2byte(&data[iPtr+2]);
      if( iPtrEnd+3>=iStart ){
        if( iPtrEnd>iStart ) return SQLITE_CORRUPT_BKPT;
        nFrag += iStart - iPtrEnd;
        iSize = iEnd - iPtr;
................................................................................
  assert( pPage->hdrOffset==(pPage->pgno==1 ? 100 : 0) );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  pPage->leaf = (u8)(flagByte>>3);  assert( PTF_LEAF == 1<<3 );
  flagByte &= ~PTF_LEAF;
  pPage->childPtrSize = 4-4*pPage->leaf;
  pBt = pPage->pBt;
  if( flagByte==(PTF_LEAFDATA | PTF_INTKEY) ){






    pPage->intKey = 1;
    pPage->hasData = pPage->leaf;

    pPage->maxLocal = pBt->maxLeaf;
    pPage->minLocal = pBt->minLeaf;
  }else if( flagByte==PTF_ZERODATA ){






    pPage->intKey = 0;
    pPage->hasData = 0;


    pPage->maxLocal = pBt->maxLocal;
    pPage->minLocal = pBt->minLocal;
  }else{


    return SQLITE_CORRUPT_BKPT;
  }
  pPage->max1bytePayload = pBt->max1bytePayload;
  return SQLITE_OK;
}

/*
................................................................................
    int iCellFirst;    /* First allowable cell or freeblock offset */
    int iCellLast;     /* Last possible cell or freeblock offset */

    pBt = pPage->pBt;

    hdr = pPage->hdrOffset;
    data = pPage->aData;


    if( decodeFlags(pPage, data[hdr]) ) return SQLITE_CORRUPT_BKPT;
    assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
    pPage->maskPage = (u16)(pBt->pageSize - 1);
    pPage->nOverflow = 0;
    usableSize = pBt->usableSize;
    pPage->cellOffset = cellOffset = hdr + 12 - 4*pPage->leaf;
    pPage->aDataEnd = &data[usableSize];
    pPage->aCellIdx = &data[cellOffset];



    top = get2byteNotZero(&data[hdr+5]);


    pPage->nCell = get2byte(&data[hdr+3]);
    if( pPage->nCell>MX_CELL(pBt) ){
      /* To many cells for a single page.  The page must be corrupt */
      return SQLITE_CORRUPT_BKPT;
    }
    testcase( pPage->nCell==MX_CELL(pBt) );






    /* A malformed database page might cause us to read past the end
    ** of page when parsing a cell.  
    **
    ** The following block of code checks early to see if a cell extends
    ** past the end of a page boundary and causes SQLITE_CORRUPT to be 
    ** returned if it does.
................................................................................
          return SQLITE_CORRUPT_BKPT;
        }
      }
      if( !pPage->leaf ) iCellLast++;
    }  
#endif

    /* Compute the total free space on the page */



    pc = get2byte(&data[hdr+1]);
    nFree = data[hdr+7] + top;
    while( pc>0 ){
      u16 next, size;
      if( pc<iCellFirst || pc>iCellLast ){



        /* Start of free block is off the page */

        return SQLITE_CORRUPT_BKPT; 
      }
      next = get2byte(&data[pc]);
      size = get2byte(&data[pc+2]);
      if( (next>0 && next<=pc+size+3) || pc+size>usableSize ){
        /* Free blocks must be in ascending order. And the last byte of
        ** the free-block must lie on the database page.  */
................................................................................
  
    pBt->pCursor = 0;
    pBt->pPage1 = 0;
    if( sqlite3PagerIsreadonly(pBt->pPager) ) pBt->btsFlags |= BTS_READ_ONLY;
#ifdef SQLITE_SECURE_DELETE
    pBt->btsFlags |= BTS_SECURE_DELETE;
#endif



    pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
    if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
         || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
      pBt->pageSize = 0;
#ifndef SQLITE_OMIT_AUTOVACUUM
      /* If the magic name ":memory:" will create an in-memory database, then
      ** leave the autoVacuum mode at 0 (do not auto-vacuum), even if
................................................................................
      if( zFilename && !isMemdb ){
        pBt->autoVacuum = (SQLITE_DEFAULT_AUTOVACUUM ? 1 : 0);
        pBt->incrVacuum = (SQLITE_DEFAULT_AUTOVACUUM==2 ? 1 : 0);
      }
#endif
      nReserve = 0;
    }else{



      nReserve = zDbHeader[20];
      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
#ifndef SQLITE_OMIT_AUTOVACUUM
      pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
      pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
#endif
    }
................................................................................
#else
  return 1;
#endif
}

/*
** Make sure pBt->pTmpSpace points to an allocation of 
** MX_CELL_SIZE(pBt) bytes.

*/
static void allocateTempSpace(BtShared *pBt){
  if( !pBt->pTmpSpace ){
    pBt->pTmpSpace = sqlite3PageMalloc( pBt->pageSize );

    /* One of the uses of pBt->pTmpSpace is to format cells before
    ** inserting them into a leaf page (function fillInCell()). If
................................................................................
    ** a cell is less than 4 bytes in size, it is rounded up to 4 bytes
    ** by the various routines that manipulate binary cells. Which
    ** can mean that fillInCell() only initializes the first 2 or 3
    ** bytes of pTmpSpace, but that the first 4 bytes are copied from
    ** it into a database page. This is not actually a problem, but it
    ** does cause a valgrind error when the 1 or 2 bytes of unitialized 
    ** data is passed to system call write(). So to avoid this error,
    ** zero the first 4 bytes of temp space here.  */






    if( pBt->pTmpSpace ) memset(pBt->pTmpSpace, 0, 4);


  }
}

/*
** Free the pBt->pTmpSpace allocation
*/
static void freeTempSpace(BtShared *pBt){
  sqlite3PageFree( pBt->pTmpSpace);


  pBt->pTmpSpace = 0;

}

/*
** Close an open database and invalidate all cursors.
*/
int sqlite3BtreeClose(Btree *p){
  BtShared *pBt = p->pBt;
................................................................................
    }
  }

  /* Rollback any active transaction and free the handle structure.
  ** The call to sqlite3BtreeRollback() drops any table-locks held by
  ** this handle.
  */
  sqlite3BtreeRollback(p, SQLITE_OK);
  sqlite3BtreeLeave(p);

  /* If there are still other outstanding references to the shared-btree
  ** structure, return now. The remainder of this procedure cleans 
  ** up the shared-btree.
  */
  assert( p->wantToLock==0 && p->locked==0 );
................................................................................
    nPage = nPageFile;
  }
  if( nPage>0 ){
    u32 pageSize;
    u32 usableSize;
    u8 *page1 = pPage1->aData;
    rc = SQLITE_NOTADB;



    if( memcmp(page1, zMagicHeader, 16)!=0 ){
      goto page1_init_failed;
    }

#ifdef SQLITE_OMIT_WAL
    if( page1[18]>1 ){
      pBt->btsFlags |= BTS_READ_ONLY;
................................................................................
        releasePage(pPage1);
        return SQLITE_OK;
      }
      rc = SQLITE_NOTADB;
    }
#endif

    /* The maximum embedded fraction must be exactly 25%.  And the minimum
    ** embedded fraction must be 12.5% for both leaf-data and non-leaf-data.

    ** The original design allowed these amounts to vary, but as of
    ** version 3.6.0, we require them to be fixed.
    */
    if( memcmp(&page1[21], "\100\040\040",3)!=0 ){
      goto page1_init_failed;
    }



    pageSize = (page1[16]<<8) | (page1[17]<<16);


    if( ((pageSize-1)&pageSize)!=0
     || pageSize>SQLITE_MAX_PAGE_SIZE 
     || pageSize<=256 
    ){
      goto page1_init_failed;
    }
    assert( (pageSize & 7)==0 );







    usableSize = pageSize - page1[20];
    if( (u32)pageSize!=pBt->pageSize ){
      /* After reading the first page of the database assuming a page size
      ** of BtShared.pageSize, we have discovered that the page-size is
      ** actually pageSize. Unlock the database, leave pBt->pPage1 at
      ** zero and return SQLITE_OK. The caller will call this function
      ** again with the correct page-size.
................................................................................
                                   pageSize-usableSize);
      return rc;
    }
    if( (pBt->db->flags & SQLITE_RecoveryMode)==0 && nPage>nPageFile ){
      rc = SQLITE_CORRUPT_BKPT;
      goto page1_init_failed;
    }



    if( usableSize<480 ){
      goto page1_init_failed;
    }
    pBt->pageSize = pageSize;
    pBt->usableSize = usableSize;
#ifndef SQLITE_OMIT_AUTOVACUUM
    pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
................................................................................
** in assert() expressions, so it is only compiled if NDEBUG is not
** defined.
**
** Only write cursors are counted if wrOnly is true.  If wrOnly is
** false then all cursors are counted.
**
** For the purposes of this routine, a cursor is any cursor that
** is capable of reading or writing to the databse.  Cursors that
** have been tripped into the CURSOR_FAULT state are not counted.
*/
static int countValidCursors(BtShared *pBt, int wrOnly){
  BtCursor *pCur;
  int r = 0;
  for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
    if( (wrOnly==0 || (pCur->curFlags & BTCF_WriteFlag)!=0)
................................................................................
**
** If there is a transaction in progress, this routine is a no-op.
*/
static void unlockBtreeIfUnused(BtShared *pBt){
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE );
  if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){

    assert( pBt->pPage1->aData );
    assert( sqlite3PagerRefcount(pBt->pPager)==1 );
    assert( pBt->pPage1->aData );
    releasePage(pBt->pPage1);
    pBt->pPage1 = 0;
  }
}

/*
** If pBt points to an empty file then convert that empty file
** into a new empty database by initializing the first page of
** the database.
................................................................................

/*
** Perform a single step of an incremental-vacuum. If successful, return
** SQLITE_OK. If there is no work to do (and therefore no point in 
** calling this function again), return SQLITE_DONE. Or, if an error 
** occurs, return some other error code.
**
** More specificly, this function attempts to re-organize the database so 
** that the last page of the file currently in use is no longer in use.
**
** Parameter nFin is the number of pages that this database would contain
** were this function called until it returns SQLITE_DONE.
**
** If the bCommit parameter is non-zero, this function assumes that the 
** caller will keep calling incrVacuumStep() until it returns SQLITE_DONE 
** or an error. bCommit is passed true for an auto-vacuum-on-commmit 
** operation, or false for an incremental vacuum.
*/
static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg, int bCommit){
  Pgno nFreeList;           /* Number of pages still on the free-list */
  int rc;

  assert( sqlite3_mutex_held(pBt->mutex) );
................................................................................
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** This routine sets the state to CURSOR_FAULT and the error
** code to errCode for every cursor on BtShared that pBtree
** references.

**
** Every cursor is tripped, including cursors that belong
** to other database connections that happen to be sharing
** the cache with pBtree.
**
** This routine gets called when a rollback occurs.
** All cursors using the same cache must be tripped
** to prevent them from trying to use the btree after
** the rollback.  The rollback may have deleted tables
** or moved root pages, so it is not sufficient to
** save the state of the cursor.  The cursor must be
** invalidated.









*/
void sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode){
  BtCursor *p;



  if( pBtree==0 ) return;
  sqlite3BtreeEnter(pBtree);
  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
    int i;









    sqlite3BtreeClearCursor(p);
    p->eState = CURSOR_FAULT;
    p->skipNext = errCode;

    for(i=0; i<=p->iPage; i++){
      releasePage(p->apPage[i]);
      p->apPage[i] = 0;
    }
  }
  sqlite3BtreeLeave(pBtree);
}



/*
** Rollback the transaction in progress.  All cursors will be



** invalided by this operation.  Any attempt to use a cursor
** that was open at the beginning of this operation will result
** in an error.
**
** This will release the write lock on the database file.  If there
** are no active cursors, it also releases the read lock.
*/
int sqlite3BtreeRollback(Btree *p, int tripCode){
  int rc;
  BtShared *pBt = p->pBt;
  MemPage *pPage1;



  sqlite3BtreeEnter(p);
  if( tripCode==SQLITE_OK ){
    rc = tripCode = saveAllCursors(pBt, 0, 0);

  }else{
    rc = SQLITE_OK;
  }
  if( tripCode ){
    sqlite3BtreeTripAllCursors(p, tripCode);


  }
  btreeIntegrity(p);

  if( p->inTrans==TRANS_WRITE ){
    int rc2;

    assert( TRANS_WRITE==pBt->inTransaction );
................................................................................

  btreeEndTransaction(p);
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** Start a statement subtransaction. The subtransaction can can be rolled
** back independently of the main transaction. You must start a transaction 
** before starting a subtransaction. The subtransaction is ended automatically 
** if the main transaction commits or rolls back.
**
** Statement subtransactions are used around individual SQL statements
** that are contained within a BEGIN...COMMIT block.  If a constraint
** error occurs within the statement, the effect of that one statement
................................................................................
  assert( p->inTrans>TRANS_NONE );
  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
  assert( pBt->pPage1 && pBt->pPage1->aData );

  if( NEVER(wrFlag && (pBt->btsFlags & BTS_READ_ONLY)!=0) ){
    return SQLITE_READONLY;
  }




  if( iTable==1 && btreePagecount(pBt)==0 ){
    assert( wrFlag==0 );
    iTable = 0;
  }

  /* Now that no other errors can occur, finish filling in the BtCursor
  ** variables and link the cursor into the BtShared list.  */
................................................................................
** BtCursor.info is a cache of the information in the current cell.
** Using this cache reduces the number of calls to btreeParseCell().
**
** 2007-06-25:  There is a bug in some versions of MSVC that cause the
** compiler to crash when getCellInfo() is implemented as a macro.
** But there is a measureable speed advantage to using the macro on gcc
** (when less compiler optimizations like -Os or -O0 are used and the
** compiler is not doing agressive inlining.)  So we use a real function
** for MSVC and a macro for everything else.  Ticket #2457.
*/
#ifndef NDEBUG
  static void assertCellInfo(BtCursor *pCur){
    CellInfo info;
    int iPage = pCur->iPage;
    memset(&info, 0, sizeof(info));
................................................................................
**
** The caller must position the cursor prior to invoking this routine.
** 
** This routine cannot fail.  It always returns SQLITE_OK.  
*/
int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
  if( pCur->eState!=CURSOR_VALID ){
    *pSize = 0;
  }else{
    getCellInfo(pCur);
    *pSize = pCur->info.nKey;
  }
  return SQLITE_OK;
}

/*
** Set *pSize to the number of bytes of data in the entry the
** cursor currently points to.
**
................................................................................
** Failure is not possible.  This function always returns SQLITE_OK.
** It might just as well be a procedure (returning void) but we continue
** to return an integer result code for historical reasons.
*/
int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );

  getCellInfo(pCur);
  *pSize = pCur->info.nData;
  return SQLITE_OK;
}

/*
** Given the page number of an overflow page in the database (parameter
** ovfl), this function finds the page number of the next page in the 
** linked list of overflow pages. If possible, it uses the auto-vacuum
................................................................................
** Data is read to or from the buffer pBuf.
**
** The content being read or written might appear on the main page
** or be scattered out on multiple overflow pages.
**
** If the current cursor entry uses one or more overflow pages and the
** eOp argument is not 2, this function may allocate space for and lazily 
** popluates the overflow page-list cache array (BtCursor.aOverflow). 
** Subsequent calls use this cache to make seeking to the supplied offset 
** more efficient.
**
** Once an overflow page-list cache has been allocated, it may be
** invalidated if some other cursor writes to the same table, or if
** the cursor is moved to a different row. Additionally, in auto-vacuum
** mode, the following events may invalidate an overflow page-list cache.
................................................................................
  u32 offset,          /* Begin reading this far into payload */
  u32 amt,             /* Read this many bytes */
  unsigned char *pBuf, /* Write the bytes into this buffer */ 
  int eOp              /* zero to read. non-zero to write. */
){
  unsigned char *aPayload;
  int rc = SQLITE_OK;
  u32 nKey;
  int iIdx = 0;
  MemPage *pPage = pCur->apPage[pCur->iPage]; /* Btree page of current entry */
  BtShared *pBt = pCur->pBt;                  /* Btree this cursor belongs to */
#ifdef SQLITE_DIRECT_OVERFLOW_READ

  int bEnd;                                   /* True if reading to end of data */
#endif

  assert( pPage );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
  assert( cursorHoldsMutex(pCur) );
  assert( eOp!=2 || offset==0 );      /* Always start from beginning for eOp==2 */

  getCellInfo(pCur);
  aPayload = pCur->info.pCell + pCur->info.nHeader;
  nKey = (pPage->intKey ? 0 : (int)pCur->info.nKey);
#ifdef SQLITE_DIRECT_OVERFLOW_READ
  bEnd = (offset+amt==nKey+pCur->info.nData);

#endif


  if( NEVER(offset+amt > nKey+pCur->info.nData) 
   || &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
  ){
    /* Trying to read or write past the end of the data is an error */
    return SQLITE_CORRUPT_BKPT;
  }

  /* Check if data must be read/written to/from the btree page itself. */
  if( offset<pCur->info.nLocal ){
    int a = amt;
................................................................................
      }
    }

    /* If the overflow page-list cache has been allocated and the
    ** entry for the first required overflow page is valid, skip
    ** directly to it.
    */
    if( (pCur->curFlags & BTCF_ValidOvfl)!=0 && pCur->aOverflow[offset/ovflSize] ){


      iIdx = (offset/ovflSize);
      nextPage = pCur->aOverflow[iIdx];
      offset = (offset%ovflSize);
    }

    for( ; rc==SQLITE_OK && amt>0 && nextPage; iIdx++){

................................................................................
        **
        **   1) this is a read operation, and 
        **   2) data is required from the start of this overflow page, and
        **   3) the database is file-backed, and
        **   4) there is no open write-transaction, and
        **   5) the database is not a WAL database,
        **   6) all data from the page is being read.

        **
        ** then data can be read directly from the database file into the
        ** output buffer, bypassing the page-cache altogether. This speeds
        ** up loading large records that span many overflow pages.
        */
        if( (eOp&0x01)==0                                      /* (1) */
         && offset==0                                          /* (2) */
         && (bEnd || a==ovflSize)                              /* (6) */
         && pBt->inTransaction==TRANS_READ                     /* (4) */
         && (fd = sqlite3PagerFile(pBt->pPager))->pMethods     /* (3) */
         && pBt->pPage1->aData[19]==0x01                       /* (5) */

        ){
          u8 aSave[4];
          u8 *aWrite = &pBuf[-4];

          memcpy(aSave, aWrite, 4);
          rc = sqlite3OsRead(fd, aWrite, a+4, (i64)pBt->pageSize*(nextPage-1));
          nextPage = get4byte(aWrite);
          memcpy(aWrite, aSave, 4);
        }else
#endif

................................................................................
    return SQLITE_CORRUPT_BKPT;
  }
  return rc;
}

/*
** Read part of the key associated with cursor pCur.  Exactly
** "amt" bytes will be transfered into pBuf[].  The transfer
** begins at "offset".
**
** The caller must ensure that pCur is pointing to a valid row
** in the table.
**
** Return SQLITE_OK on success or an error code if anything goes
** wrong.  An error is returned if "offset+amt" is larger than
................................................................................
  assert( pCur!=0 && pCur->iPage>=0 && pCur->apPage[pCur->iPage]);
  assert( pCur->eState==CURSOR_VALID );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
  assert( pCur->info.nSize>0 );
  *pAmt = pCur->info.nLocal;
  return (void*)(pCur->info.pCell + pCur->info.nHeader);
}


/*
** For the entry that cursor pCur is point to, return as
** many bytes of the key or data as are available on the local
** b-tree page.  Write the number of available bytes into *pAmt.
................................................................................
static int moveToRightmost(BtCursor *pCur){
  Pgno pgno;
  int rc = SQLITE_OK;
  MemPage *pPage = 0;

  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  while( rc==SQLITE_OK && !(pPage = pCur->apPage[pCur->iPage])->leaf ){
    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    pCur->aiIdx[pCur->iPage] = pPage->nCell;
    rc = moveToChild(pCur, pgno);

  }
  if( rc==SQLITE_OK ){
    pCur->aiIdx[pCur->iPage] = pPage->nCell-1;
    pCur->info.nSize = 0;
    pCur->curFlags &= ~BTCF_ValidNKey;
  }
  return rc;
}

/* Move the cursor to the first entry in the table.  Return SQLITE_OK
** on success.  Set *pRes to 0 if the cursor actually points to something
** or set *pRes to 1 if the table is empty.
*/
int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
................................................................................
      *pRes = -1;
      return SQLITE_OK;
    }
  }

  if( pIdxKey ){
    xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);
    pIdxKey->isCorrupt = 0;
    assert( pIdxKey->default_rc==1 
         || pIdxKey->default_rc==0 
         || pIdxKey->default_rc==-1
    );
  }else{
    xRecordCompare = 0; /* All keys are integers */
  }
................................................................................
    assert( biasRight==0 || biasRight==1 );
    idx = upr>>(1-biasRight); /* idx = biasRight ? upr : (lwr+upr)/2; */
    pCur->aiIdx[pCur->iPage] = (u16)idx;
    if( xRecordCompare==0 ){
      for(;;){
        i64 nCellKey;
        pCell = findCell(pPage, idx) + pPage->childPtrSize;
        if( pPage->hasData ){
          while( 0x80 <= *(pCell++) ){
            if( pCell>=pPage->aDataEnd ) return SQLITE_CORRUPT_BKPT;
          }
        }
        getVarint(pCell, (u64*)&nCellKey);
        if( nCellKey<intKey ){
          lwr = idx+1;
................................................................................
        */
        nCell = pCell[0];
        if( nCell<=pPage->max1bytePayload ){
          /* This branch runs if the record-size field of the cell is a
          ** single byte varint and the record fits entirely on the main
          ** b-tree page.  */
          testcase( pCell+nCell+1==pPage->aDataEnd );
          c = xRecordCompare(nCell, (void*)&pCell[1], pIdxKey, 0);
        }else if( !(pCell[1] & 0x80) 
          && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
        ){
          /* The record-size field is a 2 byte varint and the record 
          ** fits entirely on the main b-tree page.  */
          testcase( pCell+nCell+2==pPage->aDataEnd );
          c = xRecordCompare(nCell, (void*)&pCell[2], pIdxKey, 0);
        }else{
          /* The record flows over onto one or more overflow pages. In
          ** this case the whole cell needs to be parsed, a buffer allocated
          ** and accessPayload() used to retrieve the record into the
          ** buffer before VdbeRecordCompare() can be called. */
          void *pCellKey;
          u8 * const pCellBody = pCell - pPage->childPtrSize;
................................................................................
          }
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          rc = accessPayload(pCur, 0, nCell, (unsigned char*)pCellKey, 2);
          if( rc ){
            sqlite3_free(pCellKey);
            goto moveto_finish;
          }
          c = xRecordCompare(nCell, pCellKey, pIdxKey, 0);
          sqlite3_free(pCellKey);
        }
        assert( pIdxKey->isCorrupt==0 || c==0 );



        if( c<0 ){
          lwr = idx+1;
        }else if( c>0 ){
          upr = idx-1;
        }else{
          assert( c==0 );
          *pRes = 0;
          rc = SQLITE_OK;
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          if( pIdxKey->isCorrupt ) rc = SQLITE_CORRUPT;
          goto moveto_finish;
        }
        if( lwr>upr ) break;
        assert( lwr+upr>=0 );
        idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2 */
      }
    }
................................................................................
}

/*
** Advance the cursor to the next entry in the database.  If
** successful then set *pRes=0.  If the cursor
** was already pointing to the last entry in the database before
** this routine was called, then set *pRes=1.






**
** The calling function will set *pRes to 0 or 1.  The initial *pRes value
** will be 1 if the cursor being stepped corresponds to an SQL index and
** if this routine could have been skipped if that SQL index had been
** a unique index.  Otherwise the caller will have set *pRes to zero.
** Zero is the common case. The btree implementation is free to use the
** initial *pRes value as a hint to improve performance, but the current
** SQLite btree implementation does not. (Note that the comdb2 btree
** implementation does use this hint, however.)
*/
int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
  int rc;
  int idx;
  MemPage *pPage;

  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 || *pRes==1 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );

  if( pCur->eState!=CURSOR_VALID ){
    invalidateOverflowCache(pCur);

    rc = restoreCursorPosition(pCur);
    if( rc!=SQLITE_OK ){
      *pRes = 0;
      return rc;
    }
    if( CURSOR_INVALID==pCur->eState ){
      *pRes = 1;
      return SQLITE_OK;
    }
    if( pCur->skipNext ){
      assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_SKIPNEXT );
      pCur->eState = CURSOR_VALID;
      if( pCur->skipNext>0 ){
        pCur->skipNext = 0;
        *pRes = 0;
        return SQLITE_OK;
      }
      pCur->skipNext = 0;
    }
  }

  pPage = pCur->apPage[pCur->iPage];
................................................................................
  /* If the database file is corrupt, it is possible for the value of idx 
  ** to be invalid here. This can only occur if a second cursor modifies
  ** the page while cursor pCur is holding a reference to it. Which can
  ** only happen if the database is corrupt in such a way as to link the
  ** page into more than one b-tree structure. */
  testcase( idx>pPage->nCell );

  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  if( idx>=pPage->nCell ){
    if( !pPage->leaf ){
      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
      if( rc ){
        *pRes = 0;
        return rc;
      }
      rc = moveToLeftmost(pCur);
      *pRes = 0;
      return rc;
    }
    do{
      if( pCur->iPage==0 ){
        *pRes = 1;
        pCur->eState = CURSOR_INVALID;
        return SQLITE_OK;
      }
      moveToParent(pCur);
      pPage = pCur->apPage[pCur->iPage];
    }while( pCur->aiIdx[pCur->iPage]>=pPage->nCell );
    *pRes = 0;
    if( pPage->intKey ){
      rc = sqlite3BtreeNext(pCur, pRes);
    }else{
      rc = SQLITE_OK;
    }


    return rc;


  }









  *pRes = 0;






  if( pPage->leaf ){
    return SQLITE_OK;
  }

  rc = moveToLeftmost(pCur);
  return rc;
}


/*
** Step the cursor to the back to the previous entry in the database.  If
** successful then set *pRes=0.  If the cursor
** was already pointing to the first entry in the database before
** this routine was called, then set *pRes=1.






**
** The calling function will set *pRes to 0 or 1.  The initial *pRes value
** will be 1 if the cursor being stepped corresponds to an SQL index and
** if this routine could have been skipped if that SQL index had been
** a unique index.  Otherwise the caller will have set *pRes to zero.
** Zero is the common case. The btree implementation is free to use the
** initial *pRes value as a hint to improve performance, but the current
** SQLite btree implementation does not. (Note that the comdb2 btree
** implementation does use this hint, however.)
*/
int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
  int rc;
  MemPage *pPage;

  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 || *pRes==1 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidOvfl);

  if( pCur->eState!=CURSOR_VALID ){
    if( ALWAYS(pCur->eState>=CURSOR_REQUIRESEEK) ){
      rc = btreeRestoreCursorPosition(pCur);
      if( rc!=SQLITE_OK ){
        *pRes = 0;
        return rc;
      }
    }
    if( CURSOR_INVALID==pCur->eState ){
      *pRes = 1;
      return SQLITE_OK;
    }
    if( pCur->skipNext ){
      assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_SKIPNEXT );
      pCur->eState = CURSOR_VALID;
      if( pCur->skipNext<0 ){
        pCur->skipNext = 0;
        *pRes = 0;
        return SQLITE_OK;
      }
      pCur->skipNext = 0;
    }
  }

  pPage = pCur->apPage[pCur->iPage];
  assert( pPage->isInit );
  if( !pPage->leaf ){
    int idx = pCur->aiIdx[pCur->iPage];
    rc = moveToChild(pCur, get4byte(findCell(pPage, idx)));
    if( rc ){
      *pRes = 0;
      return rc;
    }
    rc = moveToRightmost(pCur);
  }else{
    while( pCur->aiIdx[pCur->iPage]==0 ){
      if( pCur->iPage==0 ){
        pCur->eState = CURSOR_INVALID;
        *pRes = 1;
        return SQLITE_OK;
      }
      moveToParent(pCur);
    }
    pCur->info.nSize = 0;
    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);

    pCur->aiIdx[pCur->iPage]--;
    pPage = pCur->apPage[pCur->iPage];
    if( pPage->intKey && !pPage->leaf ){
      rc = sqlite3BtreePrevious(pCur, pRes);
    }else{
      rc = SQLITE_OK;
    }
  }







  *pRes = 0;









  return rc;
}

/*
** Allocate a new page from the database file.
**
** The new page is marked as dirty.  (In other words, sqlite3PagerWrite()
** has already been called on the new page.)  The new page has also
................................................................................
  MemPage *pPrevTrunk = 0;
  Pgno mxPage;     /* Total size of the database file */

  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( eMode==BTALLOC_ANY || (nearby>0 && IfNotOmitAV(pBt->autoVacuum)) );
  pPage1 = pBt->pPage1;
  mxPage = btreePagecount(pBt);


  n = get4byte(&pPage1->aData[36]);
  testcase( n==mxPage-1 );
  if( n>=mxPage ){
    return SQLITE_CORRUPT_BKPT;
  }
  if( n>0 ){
    /* There are pages on the freelist.  Reuse one of those pages. */
................................................................................
    ** is not true. Otherwise, it runs once for each trunk-page on the
    ** free-list until the page 'nearby' is located (eMode==BTALLOC_EXACT)
    ** or until a page less than 'nearby' is located (eMode==BTALLOC_LT)
    */
    do {
      pPrevTrunk = pTrunk;
      if( pPrevTrunk ){



        iTrunk = get4byte(&pPrevTrunk->aData[0]);
      }else{



        iTrunk = get4byte(&pPage1->aData[32]);
      }
      testcase( iTrunk==mxPage );
      if( iTrunk>mxPage ){
        rc = SQLITE_CORRUPT_BKPT;
      }else{
        rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
................................................................................
      }
      if( rc ){
        pTrunk = 0;
        goto end_allocate_page;
      }
      assert( pTrunk!=0 );
      assert( pTrunk->aData!=0 );

      k = get4byte(&pTrunk->aData[4]); /* # of leaves on this trunk page */

      if( k==0 && !searchList ){
        /* The trunk has no leaves and the list is not being searched. 
        ** So extract the trunk page itself and use it as the newly 
        ** allocated page */
        assert( pPrevTrunk==0 );
        rc = sqlite3PagerWrite(pTrunk->pDbPage);
        if( rc ){
................................................................................
                 *pPgno, closest+1, k, pTrunk->pgno, n-1));
          rc = sqlite3PagerWrite(pTrunk->pDbPage);
          if( rc ) goto end_allocate_page;
          if( closest<k-1 ){
            memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
          }
          put4byte(&aData[4], k-1);
          noContent = !btreeGetHasContent(pBt, *pPgno) ? PAGER_GET_NOCONTENT : 0;
          rc = btreeGetPage(pBt, *pPgno, ppPage, noContent);
          if( rc==SQLITE_OK ){
            rc = sqlite3PagerWrite((*ppPage)->pDbPage);
            if( rc!=SQLITE_OK ){
              releasePage(*ppPage);
            }
          }
................................................................................
    **
    ** Note that the pager will not actually attempt to load or journal 
    ** content for any page that really does lie past the end of the database
    ** file on disk. So the effects of disabling the no-content optimization
    ** here are confined to those pages that lie between the end of the
    ** database image and the end of the database file.
    */
    int bNoContent = (0==IfNotOmitAV(pBt->bDoTruncate)) ? PAGER_GET_NOCONTENT : 0;

    rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
    if( rc ) return rc;
    pBt->nPage++;
    if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ) pBt->nPage++;

#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
      ** 3.6.0, databases with freelist trunk pages holding more than
      ** usableSize/4 - 8 entries will be reported as corrupt.  In order
      ** to maintain backwards compatibility with older versions of SQLite,
      ** we will continue to restrict the number of entries to usableSize/4 - 8
      ** for now.  At some point in the future (once everyone has upgraded
      ** to 3.6.0 or later) we should consider fixing the conditional above
      ** to read "usableSize/4-2" instead of "usableSize/4-8".





      */
      rc = sqlite3PagerWrite(pTrunk->pDbPage);
      if( rc==SQLITE_OK ){
        put4byte(&pTrunk->aData[4], nLeaf+1);
        put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
        if( pPage && (pBt->btsFlags & BTS_SECURE_DELETE)==0 ){
          sqlite3PagerDontWrite(pPage->pDbPage);
................................................................................
static void freePage(MemPage *pPage, int *pRC){
  if( (*pRC)==SQLITE_OK ){
    *pRC = freePage2(pPage->pBt, pPage, pPage->pgno);
  }
}

/*
** Free any overflow pages associated with the given Cell.


*/
static int clearCell(MemPage *pPage, unsigned char *pCell){




  BtShared *pBt = pPage->pBt;
  CellInfo info;
  Pgno ovflPgno;
  int rc;
  int nOvfl;
  u32 ovflPageSize;

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  btreeParseCellPtr(pPage, pCell, &info);

  if( info.iOverflow==0 ){
    return SQLITE_OK;  /* No overflow pages. Return without doing anything */
  }
  if( pCell+info.iOverflow+3 > pPage->aData+pPage->maskPage ){
    return SQLITE_CORRUPT_BKPT;  /* Cell extends past end of page */
  }
  ovflPgno = get4byte(&pCell[info.iOverflow]);
................................................................................
  MemPage *pOvfl = 0;
  MemPage *pToRelease = 0;
  unsigned char *pPrior;
  unsigned char *pPayload;
  BtShared *pBt = pPage->pBt;
  Pgno pgnoOvfl = 0;
  int nHeader;
  CellInfo info;

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );

  /* pPage is not necessarily writeable since pCell might be auxiliary
  ** buffer space that is separate from the pPage buffer area */
  assert( pCell<pPage->aData || pCell>=&pPage->aData[pBt->pageSize]
            || sqlite3PagerIswriteable(pPage->pDbPage) );

  /* Fill in the header. */
  nHeader = 0;
  if( !pPage->leaf ){
    nHeader += 4;
  }
  if( pPage->hasData ){
    nHeader += putVarint32(&pCell[nHeader], nData+nZero);
  }else{
    nData = nZero = 0;


  }
  nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);
  btreeParseCellPtr(pPage, pCell, &info);
  assert( info.nHeader==nHeader );
  assert( info.nKey==nKey );
  assert( info.nData==(u32)(nData+nZero) );
  
  /* Fill in the payload */
  nPayload = nData + nZero;
  if( pPage->intKey ){
    pSrc = pData;
    nSrc = nData;
    nData = 0;
  }else{ 
    if( NEVER(nKey>0x7fffffff || pKey==0) ){
      return SQLITE_CORRUPT_BKPT;
    }
    nPayload += (int)nKey;
    pSrc = pKey;
    nSrc = (int)nKey;
  }





  *pnSize = info.nSize;








  spaceLeft = info.nLocal;



  pPayload = &pCell[nHeader];





















  pPrior = &pCell[info.iOverflow];




  while( nPayload>0 ){
    if( spaceLeft==0 ){
#ifndef SQLITE_OMIT_AUTOVACUUM
      Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
      if( pBt->autoVacuum ){
        do{
          pgnoOvfl++;
................................................................................
  }
  rc = freeSpace(pPage, pc, sz);
  if( rc ){
    *pRC = rc;
    return;
  }
  pPage->nCell--;







  memmove(ptr, ptr+2, 2*(pPage->nCell - idx));
  put2byte(&data[hdr+3], pPage->nCell);
  pPage->nFree += 2;

}

/*
** Insert a new cell on pPage at cell index "i".  pCell points to the
** content of the cell.
**
** If the cell content will fit on the page, then put it there.  If it
** will not fit, then make a copy of the cell content into pTemp if
** pTemp is not null.  Regardless of pTemp, allocate a new entry
** in pPage->apOvfl[] and make it point to the cell content (either
** in pTemp or the original pCell) and also record its index. 
** Allocating a new entry in pPage->aCell[] implies that 
** pPage->nOverflow is incremented.
**
** If nSkip is non-zero, then do not copy the first nSkip bytes of the
** cell. The caller will overwrite them after this function returns. If
** nSkip is non-zero, then pCell may not point to an invalid memory location 
** (but pCell+nSkip is always valid).
*/
static void insertCell(
  MemPage *pPage,   /* Page into which we are copying */
  int i,            /* New cell becomes the i-th cell of the page */
  u8 *pCell,        /* Content of the new cell */
  int sz,           /* Bytes of content in pCell */
  u8 *pTemp,        /* Temp storage space for pCell, if needed */
................................................................................
){
  int idx = 0;      /* Where to write new cell content in data[] */
  int j;            /* Loop counter */
  int end;          /* First byte past the last cell pointer in data[] */
  int ins;          /* Index in data[] where new cell pointer is inserted */
  int cellOffset;   /* Address of first cell pointer in data[] */
  u8 *data;         /* The content of the whole page */
  int nSkip = (iChild ? 4 : 0);

  if( *pRC ) return;

  assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
  assert( MX_CELL(pPage->pBt)<=10921 );
  assert( pPage->nCell<=MX_CELL(pPage->pBt) || CORRUPT_DB );
  assert( pPage->nOverflow<=ArraySize(pPage->apOvfl) );
................................................................................
  ** malformed cell from a leaf page to an interior page, if the cell size
  ** wanted to be less than 4 but got rounded up to 4 on the leaf, then size
  ** might be less than 8 (leaf-size + pointer) on the interior node.  Hence
  ** the term after the || in the following assert(). */
  assert( sz==cellSizePtr(pPage, pCell) || (sz==8 && iChild>0) );
  if( pPage->nOverflow || sz+2>pPage->nFree ){
    if( pTemp ){
      memcpy(pTemp+nSkip, pCell+nSkip, sz-nSkip);
      pCell = pTemp;
    }
    if( iChild ){
      put4byte(pCell, iChild);
    }
    j = pPage->nOverflow++;
    assert( j<(int)(sizeof(pPage->apOvfl)/sizeof(pPage->apOvfl[0])) );
................................................................................
    if( rc ){ *pRC = rc; return; }
    /* The allocateSpace() routine guarantees the following two properties
    ** if it returns success */
    assert( idx >= end+2 );
    assert( idx+sz <= (int)pPage->pBt->usableSize );
    pPage->nCell++;
    pPage->nFree -= (u16)(2 + sz);
    memcpy(&data[idx+nSkip], pCell+nSkip, sz-nSkip);
    if( iChild ){
      put4byte(&data[idx], iChild);
    }
    memmove(&data[ins+2], &data[ins], end-ins);
    put2byte(&data[ins], idx);
    put2byte(&data[pPage->hdrOffset+3], pPage->nCell);
#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
      ptrmapPutOvflPtr(pPage, pCell, pRC);
    }
#endif
  }
}

/*
** Add a list of cells to a page.  The page should be initially empty.
** The cells are guaranteed to fit on the page.









*/
static void assemblePage(
  MemPage *pPage,   /* The page to be assemblied */
  int nCell,        /* The number of cells to add to this page */


  u8 **apCell,      /* Pointers to cell bodies */
  u16 *aSize        /* Sizes of the cells */

){
  int i;            /* Loop counter */
  u8 *pCellptr;     /* Address of next cell pointer */
  int cellbody;     /* Address of next cell body */
  u8 * const data = pPage->aData;             /* Pointer to data for pPage */
  const int hdr = pPage->hdrOffset;           /* Offset of header on pPage */
  const int nUsable = pPage->pBt->usableSize; /* Usable size of page */



























  assert( pPage->nOverflow==0 );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( nCell>=0 && nCell<=(int)MX_CELL(pPage->pBt)
            && (int)MX_CELL(pPage->pBt)<=10921);
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );

  /* Check that the page has just been zeroed by zeroPage() */
  assert( pPage->nCell==0 );
  assert( get2byteNotZero(&data[hdr+5])==nUsable );





  pCellptr = &pPage->aCellIdx[nCell*2];
  cellbody = nUsable;
  for(i=nCell-1; i>=0; i--){
    u16 sz = aSize[i];



















































    pCellptr -= 2;






































    cellbody -= sz;








































    put2byte(pCellptr, cellbody);
    memcpy(&data[cellbody], apCell[i], sz);



  }
  put2byte(&data[hdr+3], nCell);
  put2byte(&data[hdr+5], cellbody);
  pPage->nFree -= (nCell*2 + nUsable - cellbody);
























































  pPage->nCell = (u16)nCell;




















}

/*
** The following parameters determine how many adjacent pages get involved
** in a balancing operation.  NN is the number of neighbors on either side
** of the page that participate in the balancing operation.  NB is the
** total number of pages that participate, including the target page and
................................................................................
  Pgno pgnoNew;                        /* Page number of pNew */

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
  assert( pPage->nOverflow==1 );

  /* This error condition is now caught prior to reaching this function */
  if( pPage->nCell==0 ) return SQLITE_CORRUPT_BKPT;

  /* Allocate a new page. This page will become the right-sibling of 
  ** pPage. Make the parent page writable, so that the new divider cell
  ** may be inserted. If both these operations are successful, proceed.
  */
  rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);

................................................................................
    u8 *pCell = pPage->apOvfl[0];
    u16 szCell = cellSizePtr(pPage, pCell);
    u8 *pStop;

    assert( sqlite3PagerIswriteable(pNew->pDbPage) );
    assert( pPage->aData[0]==(PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF) );
    zeroPage(pNew, PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF);
    assemblePage(pNew, 1, &pCell, &szCell);


    /* If this is an auto-vacuum database, update the pointer map
    ** with entries for the new page, and any pointer from the 
    ** cell on the page to an overflow page. If either of these
    ** operations fails, the return code is set, but the contents
    ** of the parent page are still manipulated by thh code below.
    ** That is Ok, at this point the parent page is guaranteed to
................................................................................
  int usableSpace;             /* Bytes in pPage beyond the header */
  int pageFlags;               /* Value of pPage->aData[0] */
  int subtotal;                /* Subtotal of bytes in cells on one page */
  int iSpace1 = 0;             /* First unused byte of aSpace1[] */
  int iOvflSpace = 0;          /* First unused byte of aOvflSpace[] */
  int szScratch;               /* Size of scratch memory requested */
  MemPage *apOld[NB];          /* pPage and up to two siblings */
  MemPage *apCopy[NB];         /* Private copies of apOld[] pages */
  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
  u8 *pRight;                  /* Location in parent of right-sibling pointer */
  u8 *apDiv[NB-1];             /* Divider cells in pParent */
  int cntNew[NB+2];            /* Index in aCell[] of cell after i-th page */

  int szNew[NB+2];             /* Combined size of cells place on i-th page */
  u8 **apCell = 0;             /* All cells begin balanced */
  u16 *szCell;                 /* Local size of all cells in apCell[] */
  u8 *aSpace1;                 /* Space for copies of dividers cells */
  Pgno pgno;                   /* Temp var to store a page number in */






  pBt = pParent->pBt;
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( sqlite3PagerIswriteable(pParent->pDbPage) );

#if 0
  TRACE(("BALANCE: begin page %d child of %d\n", pPage->pgno, pParent->pgno));
#endif
................................................................................
  /* Make nMaxCells a multiple of 4 in order to preserve 8-byte
  ** alignment */
  nMaxCells = (nMaxCells + 3)&~3;

  /*
  ** Allocate space for memory structures
  */
  k = pBt->pageSize + ROUND8(sizeof(MemPage));
  szScratch =
       nMaxCells*sizeof(u8*)                       /* apCell */
     + nMaxCells*sizeof(u16)                       /* szCell */
     + pBt->pageSize                               /* aSpace1 */
     + k*nOld;                                     /* Page copies (apCopy) */




  apCell = sqlite3ScratchMalloc( szScratch ); 
  if( apCell==0 ){
    rc = SQLITE_NOMEM;
    goto balance_cleanup;
  }
  szCell = (u16*)&apCell[nMaxCells];
  aSpace1 = (u8*)&szCell[nMaxCells];
  assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );

  /*
  ** Load pointers to all cells on sibling pages and the divider cells
  ** into the local apCell[] array.  Make copies of the divider cells
  ** into space obtained from aSpace1[] and remove the divider cells
  ** from pParent.
  **
  ** If the siblings are on leaf pages, then the child pointers of the
  ** divider cells are stripped from the cells before they are copied
  ** into aSpace1[].  In this way, all cells in apCell[] are without
  ** child pointers.  If siblings are not leaves, then all cell in
  ** apCell[] include child pointers.  Either way, all cells in apCell[]
  ** are alike.
  **
  ** leafCorrection:  4 if pPage is a leaf.  0 if pPage is not a leaf.
  **       leafData:  1 if pPage holds key+data and pParent holds only keys.
  */
  leafCorrection = apOld[0]->leaf*4;
  leafData = apOld[0]->hasData;
  for(i=0; i<nOld; i++){
    int limit;
    
    /* Before doing anything else, take a copy of the i'th original sibling
    ** The rest of this function will use data from the copies rather
    ** that the original pages since the original pages will be in the
    ** process of being overwritten.  */
    MemPage *pOld = apCopy[i] = (MemPage*)&aSpace1[pBt->pageSize + k*i];
    memcpy(pOld, apOld[i], sizeof(MemPage));
    pOld->aData = (void*)&pOld[1];
    memcpy(pOld->aData, apOld[i]->aData, pBt->pageSize);

    limit = pOld->nCell+pOld->nOverflow;
    if( pOld->nOverflow>0 ){
      for(j=0; j<limit; j++){
        assert( nCell<nMaxCells );
        apCell[nCell] = findOverflowCell(pOld, j);
        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
................................................................................
      for(j=0; j<limit; j++){
        assert( nCell<nMaxCells );
        apCell[nCell] = findCellv2(aData, maskPage, cellOffset, j);
        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
        nCell++;
      }
    }       

    if( i<nOld-1 && !leafData){
      u16 sz = (u16)szNew[i];
      u8 *pTemp;
      assert( nCell<nMaxCells );
      szCell[nCell] = sz;
      pTemp = &aSpace1[iSpace1];
      iSpace1 += sz;
................................................................................
        assert( pOld->hdrOffset==0 );
        /* The right pointer of the child page pOld becomes the left
        ** pointer of the divider cell */
        memcpy(apCell[nCell], &pOld->aData[8], 4);
      }else{
        assert( leafCorrection==4 );
        if( szCell[nCell]<4 ){
          /* Do not allow any cells smaller than 4 bytes. */




          szCell[nCell] = 4;
        }
      }
      nCell++;
    }
  }

................................................................................
  ** 
  */
  usableSpace = pBt->usableSize - 12 + leafCorrection;
  for(subtotal=k=i=0; i<nCell; i++){
    assert( i<nMaxCells );
    subtotal += szCell[i] + 2;
    if( subtotal > usableSpace ){
      szNew[k] = subtotal - szCell[i];
      cntNew[k] = i;
      if( leafData ){ i--; }
      subtotal = 0;
      k++;
      if( k>NB+1 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
    }
  }
  szNew[k] = subtotal;
  cntNew[k] = nCell;
  k++;

  /*
  ** The packing computed by the previous block is biased toward the siblings
  ** on the left side.  The left siblings are always nearly full, while the
  ** right-most sibling might be nearly empty.  This block of code attempts

  ** to adjust the packing of siblings to get a better balance.
  **
  ** This adjustment is more than an optimization.  The packing above might
  ** be so out of balance as to be illegal.  For example, the right-most
  ** sibling might be completely empty.  This adjustment is not optional.
  */
  for(i=k-1; i>0; i--){
    int szRight = szNew[i];  /* Size of sibling on the right */
................................................................................
      r = cntNew[i-1] - 1;
      d = r + 1 - leafData;
    }
    szNew[i] = szRight;
    szNew[i-1] = szLeft;
  }



  /* Either we found one or more cells (cntnew[0])>0) or pPage is
  ** a virtual root page.  A virtual root page is when the real root
  ** page is page 1 and we are the only child of that page.
  **
  ** UPDATE:  The assert() below is not necessarily true if the database
  ** file is corrupt.  The corruption will be detected and reported later
  ** in this procedure so there is no need to act upon it now.
  */
#if 0
  assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) );
#endif

  TRACE(("BALANCE: old: %d %d %d  ",
    apOld[0]->pgno, 
    nOld>=2 ? apOld[1]->pgno : 0,
    nOld>=3 ? apOld[2]->pgno : 0
  ));

  /*
  ** Allocate k new pages.  Reuse old pages where possible.
  */
  if( apOld[0]->pgno<=1 ){
    rc = SQLITE_CORRUPT_BKPT;
................................................................................
      rc = sqlite3PagerWrite(pNew->pDbPage);
      nNew++;
      if( rc ) goto balance_cleanup;
    }else{
      assert( i>0 );
      rc = allocateBtreePage(pBt, &pNew, &pgno, (bBulk ? 1 : pgno), 0);
      if( rc ) goto balance_cleanup;

      apNew[i] = pNew;
      nNew++;


      /* Set the pointer-map entry for the new sibling page. */
      if( ISAUTOVACUUM ){
        ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno, &rc);
        if( rc!=SQLITE_OK ){
          goto balance_cleanup;
        }
      }
    }
  }

  /* Free any old pages that were not reused as new pages.
  */
  while( i<nOld ){
    freePage(apOld[i], &rc);
    if( rc ) goto balance_cleanup;
    releasePage(apOld[i]);
    apOld[i] = 0;
    i++;
  }

  /*
  ** Put the new pages in accending order.  This helps to

  ** keep entries in the disk file in order so that a scan
  ** of the table is a linear scan through the file.  That
  ** in turn helps the operating system to deliver pages
  ** from the disk more rapidly.
  **
  ** An O(n^2) insertion sort algorithm is used, but since
  ** n is never more than NB (a small constant), that should
  ** not be a problem.
  **
  ** When NB==3, this one optimization makes the database
  ** about 25% faster for large insertions and deletions.
  */
  for(i=0; i<k-1; i++){

    int minV = apNew[i]->pgno;
    int minI = i;
    for(j=i+1; j<k; j++){
      if( apNew[j]->pgno<(unsigned)minV ){














        minI = j;
        minV = apNew[j]->pgno;


      }





    }
    if( minI>i ){
      MemPage *pT;

      pT = apNew[i];
      apNew[i] = apNew[minI];
      apNew[minI] = pT;
    }
  }
  TRACE(("new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",



    apNew[0]->pgno, szNew[0],
    nNew>=2 ? apNew[1]->pgno : 0, nNew>=2 ? szNew[1] : 0,

    nNew>=3 ? apNew[2]->pgno : 0, nNew>=3 ? szNew[2] : 0,

    nNew>=4 ? apNew[3]->pgno : 0, nNew>=4 ? szNew[3] : 0,

    nNew>=5 ? apNew[4]->pgno : 0, nNew>=5 ? szNew[4] : 0));



  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
  put4byte(pRight, apNew[nNew-1]->pgno);













  /*
  ** Evenly distribute the data in apCell[] across the new pages.
  ** Insert divider cells into pParent as necessary.










  */
  j = 0;
  for(i=0; i<nNew; i++){
    /* Assemble the new sibling page. */

    MemPage *pNew = apNew[i];
    assert( j<nMaxCells );
    zeroPage(pNew, pageFlags);
    assemblePage(pNew, cntNew[i]-j, &apCell[j], &szCell[j]);
    assert( pNew->nCell>0 || (nNew==1 && cntNew[0]==0) );

    assert( pNew->nOverflow==0 );











    j = cntNew[i];



    /* If the sibling page assembled above was not the right-most sibling,
    ** insert a divider cell into the parent page.
    */
    assert( i<nNew-1 || j==nCell );
    if( j<nCell ){
























      u8 *pCell;
      u8 *pTemp;
      int sz;



      assert( j<nMaxCells );
      pCell = apCell[j];
      sz = szCell[j] + leafCorrection;
      pTemp = &aOvflSpace[iOvflSpace];
      if( !pNew->leaf ){
        memcpy(&pNew->aData[8], pCell, 4);
      }else if( leafData ){
        /* If the tree is a leaf-data tree, and the siblings are leaves, 
        ** then there is no divider cell in apCell[]. Instead, the divider 
        ** cell consists of the integer key for the right-most cell of 
        ** the sibling-page assembled above only.
        */
        CellInfo info;
        j--;
        btreeParseCellPtr(pNew, apCell[j], &info);
        pCell = pTemp;
        sz = 4 + putVarint(&pCell[4], info.nKey);
        pTemp = 0;
      }else{
        pCell -= 4;
        /* Obscure case for non-leaf-data trees: If the cell at pCell was
        ** previously stored on a leaf node, and its reported size was 4
        ** bytes, then it may actually be smaller than this 
        ** (see btreeParseCellPtr(), 4 bytes is the minimum size of
        ** any cell). But it is important to pass the correct size to 
        ** insertCell(), so reparse the cell now.
        **
        ** Note that this can never happen in an SQLite data file, as all
        ** cells are at least 4 bytes. It only happens in b-trees used
        ** to evaluate "IN (SELECT ...)" and similar clauses.
        */
        if( szCell[j]==4 ){
          assert(leafCorrection==4);
          sz = cellSizePtr(pParent, pCell);
        }
      }
      iOvflSpace += sz;
      assert( sz<=pBt->maxLocal+23 );
      assert( iOvflSpace <= (int)pBt->pageSize );
      insertCell(pParent, nxDiv, pCell, sz, pTemp, pNew->pgno, &rc);
      if( rc!=SQLITE_OK ) goto balance_cleanup;
      assert( sqlite3PagerIswriteable(pParent->pDbPage) );

      j++;
      nxDiv++;
    }
































  }
  assert( j==nCell );




























  assert( nOld>0 );
  assert( nNew>0 );
  if( (pageFlags & PTF_LEAF)==0 ){
    u8 *zChild = &apCopy[nOld-1]->aData[8];
    memcpy(&apNew[nNew-1]->aData[8], zChild, 4);
  }

  if( isRoot && pParent->nCell==0 && pParent->hdrOffset<=apNew[0]->nFree ){
    /* The root page of the b-tree now contains no cells. The only sibling
    ** page is the right-child of the parent. Copy the contents of the
    ** child page into the parent, decreasing the overall height of the
    ** b-tree structure by one. This is described as the "balance-shallower"
    ** sub-algorithm in some documentation.
    **
    ** If this is an auto-vacuum database, the call to copyNodeContent() 
    ** sets all pointer-map entries corresponding to database image pages 
    ** for which the pointer is stored within the content being copied.
    **
    ** The second assert below verifies that the child page is defragmented
    ** (it must be, as it was just reconstructed using assemblePage()). This
    ** is important if the parent page happens to be page 1 of the database
    ** image.  */

    assert( nNew==1 );


    assert( apNew[0]->nFree == 
        (get2byte(&apNew[0]->aData[5])-apNew[0]->cellOffset-apNew[0]->nCell*2) 

    );
    copyNodeContent(apNew[0], pParent, &rc);
    freePage(apNew[0], &rc);
  }else if( ISAUTOVACUUM ){
    /* Fix the pointer-map entries for all the cells that were shifted around. 
    ** There are several different types of pointer-map entries that need to
    ** be dealt with by this routine. Some of these have been set already, but
    ** many have not. The following is a summary:
    **
    **   1) The entries associated with new sibling pages that were not
    **      siblings when this function was called. These have already
    **      been set. We don't need to worry about old siblings that were
    **      moved to the free-list - the freePage() code has taken care
    **      of those.
    **
    **   2) The pointer-map entries associated with the first overflow
    **      page in any overflow chains used by new divider cells. These 
    **      have also already been taken care of by the insertCell() code.
    **
    **   3) If the sibling pages are not leaves, then the child pages of
    **      cells stored on the sibling pages may need to be updated.
    **
    **   4) If the sibling pages are not internal intkey nodes, then any
    **      overflow pages used by these cells may need to be updated
    **      (internal intkey nodes never contain pointers to overflow pages).
    **
    **   5) If the sibling pages are not leaves, then the pointer-map
    **      entries for the right-child pages of each sibling may need
    **      to be updated.
    **
    ** Cases 1 and 2 are dealt with above by other code. The next
    ** block deals with cases 3 and 4 and the one after that, case 5. Since
    ** setting a pointer map entry is a relatively expensive operation, this
    ** code only sets pointer map entries for child or overflow pages that have
    ** actually moved between pages.  */
    MemPage *pNew = apNew[0];
    MemPage *pOld = apCopy[0];
    int nOverflow = pOld->nOverflow;
    int iNextOld = pOld->nCell + nOverflow;
    int iOverflow = (nOverflow ? pOld->aiOvfl[0] : -1);
    j = 0;                             /* Current 'old' sibling page */
    k = 0;                             /* Current 'new' sibling page */


    for(i=0; i<nCell; i++){
      int isDivider = 0;
      while( i==iNextOld ){
        /* Cell i is the cell immediately following the last cell on old
        ** sibling page j. If the siblings are not leaf pages of an
        ** intkey b-tree, then cell i was a divider cell. */
        assert( j+1 < ArraySize(apCopy) );
        assert( j+1 < nOld );
        pOld = apCopy[++j];
        iNextOld = i + !leafData + pOld->nCell + pOld->nOverflow;
        if( pOld->nOverflow ){
          nOverflow = pOld->nOverflow;
          iOverflow = i + !leafData + pOld->aiOvfl[0];


        }
        isDivider = !leafData;  
      }

      assert(nOverflow>0 || iOverflow<i );
      assert(nOverflow<2 || pOld->aiOvfl[0]==pOld->aiOvfl[1]-1);
      assert(nOverflow<3 || pOld->aiOvfl[1]==pOld->aiOvfl[2]-1);
      if( i==iOverflow ){
        isDivider = 1;
        if( (--nOverflow)>0 ){
          iOverflow++;
        }
      }

      if( i==cntNew[k] ){
        /* Cell i is the cell immediately following the last cell on new
        ** sibling page k. If the siblings are not leaf pages of an
        ** intkey b-tree, then cell i is a divider cell.  */
        pNew = apNew[++k];
        if( !leafData ) continue;
      }
      assert( j<nOld );
      assert( k<nNew );



      /* If the cell was originally divider cell (and is not now) or
      ** an overflow cell, or if the cell was located on a different sibling
      ** page before the balancing, then the pointer map entries associated
      ** with any child or overflow pages need to be updated.  */
      if( isDivider || pOld->pgno!=pNew->pgno ){
        if( !leafCorrection ){
          ptrmapPut(pBt, get4byte(apCell[i]), PTRMAP_BTREE, pNew->pgno, &rc);




        }
        if( szCell[i]>pNew->minLocal ){
          ptrmapPutOvflPtr(pNew, apCell[i], &rc);
        }
      }
    }

    if( !leafCorrection ){
      for(i=0; i<nNew; i++){
        u32 key = get4byte(&apNew[i]->aData[8]);
        ptrmapPut(pBt, key, PTRMAP_BTREE, apNew[i]->pgno, &rc);
      }
    }

#if 0

    /* The ptrmapCheckPages() contains assert() statements that verify that
    ** all pointer map pages are set correctly. This is helpful while 
    ** debugging. This is usually disabled because a corrupt database may
    ** cause an assert() statement to fail.  */
    ptrmapCheckPages(apNew, nNew);
    ptrmapCheckPages(&pParent, 1);
#endif
  }

  assert( pParent->isInit );
  TRACE(("BALANCE: finished: old=%d new=%d cells=%d\n",
          nOld, nNew, nCell));


  /*
  ** Cleanup before returning.
  */
balance_cleanup:
  sqlite3ScratchFree(apCell);
  for(i=0; i<nOld; i++){
................................................................................
    }else{
      MemPage * const pParent = pCur->apPage[iPage-1];
      int const iIdx = pCur->aiIdx[iPage-1];

      rc = sqlite3PagerWrite(pParent->pDbPage);
      if( rc==SQLITE_OK ){
#ifndef SQLITE_OMIT_QUICKBALANCE
        if( pPage->hasData
         && pPage->nOverflow==1
         && pPage->aiOvfl[0]==pPage->nCell
         && pParent->pgno!=1
         && pParent->nCell==iIdx
        ){
          /* Call balance_quick() to create a new sibling of pPage on which
          ** to store the overflow cell. balance_quick() inserts a new cell
          ** into pParent, which may cause pParent overflow. If this
          ** happens, the next interation of the do-loop will balance pParent 
          ** use either balance_nonroot() or balance_deeper(). Until this
          ** happens, the overflow cell is stored in the aBalanceQuickSpace[]
          ** buffer. 
          **
          ** The purpose of the following assert() is to check that only a
          ** single call to balance_quick() is made for each call to this
          ** function. If this were not verified, a subtle bug involving reuse
................................................................................
** For an INTKEY table, only the nKey value of the key is used.  pKey is
** ignored.  For a ZERODATA table, the pData and nData are both ignored.
**
** If the seekResult parameter is non-zero, then a successful call to
** MovetoUnpacked() to seek cursor pCur to (pKey, nKey) has already
** been performed. seekResult is the search result returned (a negative
** number if pCur points at an entry that is smaller than (pKey, nKey), or
** a positive value if pCur points at an etry that is larger than 
** (pKey, nKey)). 
**
** If the seekResult parameter is non-zero, then the caller guarantees that
** cursor pCur is pointing at the existing copy of a row that is to be
** overwritten.  If the seekResult parameter is 0, then cursor pCur may
** point to any entry or to no entry at all and so this function has to seek
** the cursor before the new key can be inserted.
................................................................................

  if( pCur->eState==CURSOR_FAULT ){
    assert( pCur->skipNext!=SQLITE_OK );
    return pCur->skipNext;
  }

  assert( cursorHoldsMutex(pCur) );
  assert( (pCur->curFlags & BTCF_WriteFlag)!=0 && pBt->inTransaction==TRANS_WRITE

              && (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );

  /* Assert that the caller has been consistent. If this cursor was opened
  ** expecting an index b-tree, then the caller should be inserting blob
  ** keys with no associated data. If the cursor was opened expecting an
  ** intkey table, the caller should be inserting integer keys with a
................................................................................
    /* If this is an insert into a table b-tree, invalidate any incrblob 
    ** cursors open on the row being replaced */
    invalidateIncrblobCursors(p, nKey, 0);

    /* If the cursor is currently on the last row and we are appending a
    ** new row onto the end, set the "loc" to avoid an unnecessary btreeMoveto()
    ** call */
    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && nKey>0 && pCur->info.nKey==nKey-1 ){

      loc = -1;
    }
  }

  if( !loc ){
    rc = btreeMoveto(pCur, pKey, nKey, appendBias, &loc);
    if( rc ) return rc;
................................................................................
  assert( pPage->intKey || nKey>=0 );
  assert( pPage->leaf || !pPage->intKey );

  TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
          pCur->pgnoRoot, nKey, nData, pPage->pgno,
          loc==0 ? "overwrite" : "new entry"));
  assert( pPage->isInit );
  allocateTempSpace(pBt);
  newCell = pBt->pTmpSpace;
  if( newCell==0 ) return SQLITE_NOMEM;

  rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
  if( rc ) goto end_insert;
  assert( szNew==cellSizePtr(pPage, newCell) );
  assert( szNew <= MX_CELL_SIZE(pBt) );
  idx = pCur->aiIdx[pCur->iPage];
  if( loc==0 ){
    u16 szOld;
................................................................................
    if( rc ){
      goto end_insert;
    }
    oldCell = findCell(pPage, idx);
    if( !pPage->leaf ){
      memcpy(newCell, oldCell, 4);
    }
    szOld = cellSizePtr(pPage, oldCell);
    rc = clearCell(pPage, oldCell);
    dropCell(pPage, idx, szOld, &rc);
    if( rc ) goto end_insert;
  }else if( loc<0 && pPage->nCell>0 ){
    assert( pPage->leaf );
    idx = ++pCur->aiIdx[pCur->iPage];
  }else{
    assert( pPage->leaf );
................................................................................

end_insert:
  return rc;
}

/*
** Delete the entry that the cursor is pointing to.  The cursor
** is left pointing at a arbitrary location.
*/
int sqlite3BtreeDelete(BtCursor *pCur){
  Btree *p = pCur->pBtree;
  BtShared *pBt = p->pBt;              
  int rc;                              /* Return code */
  MemPage *pPage;                      /* Page to delete cell from */
  unsigned char *pCell;                /* Pointer to cell to delete */
  int iCellIdx;                        /* Index of cell to delete */
  int iCellDepth;                      /* Depth of node containing pCell */ 


  assert( cursorHoldsMutex(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( pCur->curFlags & BTCF_WriteFlag );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
  assert( !hasReadConflicts(p, pCur->pgnoRoot) );
................................................................................
  ** invalidate any incrblob cursors open on the row being deleted.  */
  if( pCur->pKeyInfo==0 ){
    invalidateIncrblobCursors(p, pCur->info.nKey, 0);
  }

  rc = sqlite3PagerWrite(pPage->pDbPage);
  if( rc ) return rc;
  rc = clearCell(pPage, pCell);
  dropCell(pPage, iCellIdx, cellSizePtr(pPage, pCell), &rc);
  if( rc ) return rc;

  /* If the cell deleted was not located on a leaf page, then the cursor
  ** is currently pointing to the largest entry in the sub-tree headed
  ** by the child-page of the cell that was just deleted from an internal
  ** node. The cell from the leaf node needs to be moved to the internal
  ** node to replace the deleted cell.  */
................................................................................
    int nCell;
    Pgno n = pCur->apPage[iCellDepth+1]->pgno;
    unsigned char *pTmp;

    pCell = findCell(pLeaf, pLeaf->nCell-1);
    nCell = cellSizePtr(pLeaf, pCell);
    assert( MX_CELL_SIZE(pBt) >= nCell );

    allocateTempSpace(pBt);
    pTmp = pBt->pTmpSpace;


    rc = sqlite3PagerWrite(pLeaf->pDbPage);
    insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n, &rc);
    dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
    if( rc ) return rc;
  }

  /* Balance the tree. If the entry deleted was located on a leaf page,
................................................................................
  int *pnChange            /* Add number of Cells freed to this counter */
){
  MemPage *pPage;
  int rc;
  unsigned char *pCell;
  int i;
  int hdr;


  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pgno>btreePagecount(pBt) ){
    return SQLITE_CORRUPT_BKPT;
  }

  rc = getAndInitPage(pBt, pgno, &pPage, 0);
................................................................................
  hdr = pPage->hdrOffset;
  for(i=0; i<pPage->nCell; i++){
    pCell = findCell(pPage, i);
    if( !pPage->leaf ){
      rc = clearDatabasePage(pBt, get4byte(pCell), 1, pnChange);
      if( rc ) goto cleardatabasepage_out;
    }
    rc = clearCell(pPage, pCell);
    if( rc ) goto cleardatabasepage_out;
  }
  if( !pPage->leaf ){
    rc = clearDatabasePage(pBt, get4byte(&pPage->aData[hdr+8]), 1, pnChange);
    if( rc ) goto cleardatabasepage_out;
  }else if( pnChange ){
    assert( pPage->intKey );
................................................................................

#ifndef SQLITE_OMIT_INTEGRITY_CHECK
/*
** Append a message to the error message string.
*/
static void checkAppendMsg(
  IntegrityCk *pCheck,
  char *zMsg1,
  const char *zFormat,
  ...
){
  va_list ap;

  if( !pCheck->mxErr ) return;
  pCheck->mxErr--;
  pCheck->nErr++;
  va_start(ap, zFormat);
  if( pCheck->errMsg.nChar ){
    sqlite3StrAccumAppend(&pCheck->errMsg, "\n", 1);
  }
  if( zMsg1 ){

    sqlite3StrAccumAppendAll(&pCheck->errMsg, zMsg1);
  }
  sqlite3VXPrintf(&pCheck->errMsg, 1, zFormat, ap);
  va_end(ap);
  if( pCheck->errMsg.accError==STRACCUM_NOMEM ){
    pCheck->mallocFailed = 1;
  }
}
................................................................................
  pCheck->aPgRef[iPg/8] |= (1 << (iPg & 0x07));
}


/*
** Add 1 to the reference count for page iPage.  If this is the second
** reference to the page, add an error message to pCheck->zErrMsg.
** Return 1 if there are 2 ore more references to the page and 0 if
** if this is the first reference to the page.
**
** Also check that the page number is in bounds.
*/
static int checkRef(IntegrityCk *pCheck, Pgno iPage, char *zContext){
  if( iPage==0 ) return 1;
  if( iPage>pCheck->nPage ){
    checkAppendMsg(pCheck, zContext, "invalid page number %d", iPage);
    return 1;
  }
  if( getPageReferenced(pCheck, iPage) ){
    checkAppendMsg(pCheck, zContext, "2nd reference to page %d", iPage);
    return 1;
  }
  setPageReferenced(pCheck, iPage);
  return 0;
}

#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
** page iParent, pointer type ptrType. If not, append an error message
** to pCheck.
*/
static void checkPtrmap(
  IntegrityCk *pCheck,   /* Integrity check context */
  Pgno iChild,           /* Child page number */
  u8 eType,              /* Expected pointer map type */
  Pgno iParent,          /* Expected pointer map parent page number */
  char *zContext         /* Context description (used for error msg) */
){
  int rc;
  u8 ePtrmapType;
  Pgno iPtrmapParent;

  rc = ptrmapGet(pCheck->pBt, iChild, &ePtrmapType, &iPtrmapParent);
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ) pCheck->mallocFailed = 1;
    checkAppendMsg(pCheck, zContext, "Failed to read ptrmap key=%d", iChild);
    return;
  }

  if( ePtrmapType!=eType || iPtrmapParent!=iParent ){
    checkAppendMsg(pCheck, zContext, 
      "Bad ptr map entry key=%d expected=(%d,%d) got=(%d,%d)", 
      iChild, eType, iParent, ePtrmapType, iPtrmapParent);
  }
}
#endif

/*
................................................................................
** Check the integrity of the freelist or of an overflow page list.
** Verify that the number of pages on the list is N.
*/
static void checkList(
  IntegrityCk *pCheck,  /* Integrity checking context */
  int isFreeList,       /* True for a freelist.  False for overflow page list */
  int iPage,            /* Page number for first page in the list */
  int N,                /* Expected number of pages in the list */
  char *zContext        /* Context for error messages */
){
  int i;
  int expected = N;
  int iFirst = iPage;
  while( N-- > 0 && pCheck->mxErr ){
    DbPage *pOvflPage;
    unsigned char *pOvflData;
    if( iPage<1 ){
      checkAppendMsg(pCheck, zContext,
         "%d of %d pages missing from overflow list starting at %d",
          N+1, expected, iFirst);
      break;
    }
    if( checkRef(pCheck, iPage, zContext) ) break;
    if( sqlite3PagerGet(pCheck->pPager, (Pgno)iPage, &pOvflPage) ){
      checkAppendMsg(pCheck, zContext, "failed to get page %d", iPage);
      break;
    }
    pOvflData = (unsigned char *)sqlite3PagerGetData(pOvflPage);
    if( isFreeList ){
      int n = get4byte(&pOvflData[4]);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pCheck->pBt->autoVacuum ){
        checkPtrmap(pCheck, iPage, PTRMAP_FREEPAGE, 0, zContext);
      }
#endif
      if( n>(int)pCheck->pBt->usableSize/4-2 ){
        checkAppendMsg(pCheck, zContext,
           "freelist leaf count too big on page %d", iPage);
        N--;
      }else{
        for(i=0; i<n; i++){
          Pgno iFreePage = get4byte(&pOvflData[8+i*4]);
#ifndef SQLITE_OMIT_AUTOVACUUM
          if( pCheck->pBt->autoVacuum ){
            checkPtrmap(pCheck, iFreePage, PTRMAP_FREEPAGE, 0, zContext);
          }
#endif
          checkRef(pCheck, iFreePage, zContext);
        }
        N -= n;
      }
    }
#ifndef SQLITE_OMIT_AUTOVACUUM
    else{
      /* If this database supports auto-vacuum and iPage is not the last
      ** page in this overflow list, check that the pointer-map entry for
      ** the following page matches iPage.
      */
      if( pCheck->pBt->autoVacuum && N>0 ){
        i = get4byte(pOvflData);
        checkPtrmap(pCheck, i, PTRMAP_OVERFLOW2, iPage, zContext);
      }
    }
#endif
    iPage = get4byte(pOvflData);
    sqlite3PagerUnref(pOvflPage);
  }
}
................................................................................
**      7.  Verify that the depth of all children is the same.
**      8.  Make sure this page is at least 33% full or else it is
**          the root of the tree.
*/
static int checkTreePage(
  IntegrityCk *pCheck,  /* Context for the sanity check */
  int iPage,            /* Page number of the page to check */
  char *zParentContext, /* Parent context */
  i64 *pnParentMinKey, 
  i64 *pnParentMaxKey
){
  MemPage *pPage;
  int i, rc, depth, d2, pgno, cnt;
  int hdr, cellStart;
  int nCell;
  u8 *data;
  BtShared *pBt;
  int usableSize;
  char zContext[100];
  char *hit = 0;
  i64 nMinKey = 0;
  i64 nMaxKey = 0;

  sqlite3_snprintf(sizeof(zContext), zContext, "Page %d: ", iPage);


  /* Check that the page exists
  */
  pBt = pCheck->pBt;
  usableSize = pBt->usableSize;
  if( iPage==0 ) return 0;
  if( checkRef(pCheck, iPage, zParentContext) ) return 0;


  if( (rc = btreeGetPage(pBt, (Pgno)iPage, &pPage, 0))!=0 ){
    checkAppendMsg(pCheck, zContext,
       "unable to get the page. error code=%d", rc);
    return 0;


  }

  /* Clear MemPage.isInit to make sure the corruption detection code in
  ** btreeInitPage() is executed.  */
  pPage->isInit = 0;
  if( (rc = btreeInitPage(pPage))!=0 ){
    assert( rc==SQLITE_CORRUPT );  /* The only possible error from InitPage */
    checkAppendMsg(pCheck, zContext, 
                   "btreeInitPage() returns error code %d", rc);
    releasePage(pPage);
    return 0;

  }

  /* Check out all the cells.
  */
  depth = 0;
  for(i=0; i<pPage->nCell && pCheck->mxErr; i++){
    u8 *pCell;
    u32 sz;
    CellInfo info;

    /* Check payload overflow pages
    */
    sqlite3_snprintf(sizeof(zContext), zContext,
             "On tree page %d cell %d: ", iPage, i);


    pCell = findCell(pPage,i);
    btreeParseCellPtr(pPage, pCell, &info);
    sz = info.nData;
    if( !pPage->intKey ) sz += (int)info.nKey;
    /* For intKey pages, check that the keys are in order.
    */


    else if( i==0 ) nMinKey = nMaxKey = info.nKey;
    else{
      if( info.nKey <= nMaxKey ){
        checkAppendMsg(pCheck, zContext, 
            "Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
      }
      nMaxKey = info.nKey;
    }
    assert( sz==info.nPayload );
    if( (sz>info.nLocal) 
     && (&pCell[info.iOverflow]<=&pPage->aData[pBt->usableSize])
    ){
      int nPage = (sz - info.nLocal + usableSize - 5)/(usableSize - 4);
      Pgno pgnoOvfl = get4byte(&pCell[info.iOverflow]);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pBt->autoVacuum ){
        checkPtrmap(pCheck, pgnoOvfl, PTRMAP_OVERFLOW1, iPage, zContext);
      }
#endif
      checkList(pCheck, 0, pgnoOvfl, nPage, zContext);
    }

    /* Check sanity of left child page.
    */
    if( !pPage->leaf ){
      pgno = get4byte(pCell);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pBt->autoVacuum ){
        checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
      }
#endif
      d2 = checkTreePage(pCheck, pgno, zContext, &nMinKey, i==0 ? NULL : &nMaxKey);
      if( i>0 && d2!=depth ){
        checkAppendMsg(pCheck, zContext, "Child page depth differs");
      }
      depth = d2;
    }
  }

  if( !pPage->leaf ){
    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    sqlite3_snprintf(sizeof(zContext), zContext, 
                     "On page %d at right child: ", iPage);

#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pBt->autoVacuum ){
      checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
    }
#endif
    checkTreePage(pCheck, pgno, zContext, NULL, !pPage->nCell ? NULL : &nMaxKey);
  }
 
  /* For intKey leaf pages, check that the min/max keys are in order
  ** with any left/parent/right pages.
  */


  if( pPage->leaf && pPage->intKey ){
    /* if we are a left child page */
    if( pnParentMinKey ){
      /* if we are the left most child page */
      if( !pnParentMaxKey ){
        if( nMaxKey > *pnParentMinKey ){
          checkAppendMsg(pCheck, zContext, 
              "Rowid %lld out of order (max larger than parent min of %lld)",
              nMaxKey, *pnParentMinKey);
        }
      }else{
        if( nMinKey <= *pnParentMinKey ){
          checkAppendMsg(pCheck, zContext, 
              "Rowid %lld out of order (min less than parent min of %lld)",
              nMinKey, *pnParentMinKey);
        }
        if( nMaxKey > *pnParentMaxKey ){
          checkAppendMsg(pCheck, zContext, 
              "Rowid %lld out of order (max larger than parent max of %lld)",
              nMaxKey, *pnParentMaxKey);
        }
        *pnParentMinKey = nMaxKey;
      }
    /* else if we're a right child page */
    } else if( pnParentMaxKey ){
      if( nMinKey <= *pnParentMaxKey ){
        checkAppendMsg(pCheck, zContext, 
            "Rowid %lld out of order (min less than parent max of %lld)",
            nMinKey, *pnParentMaxKey);
      }
    }
  }

  /* Check for complete coverage of the page
  */
  data = pPage->aData;
  hdr = pPage->hdrOffset;
  hit = sqlite3PageMalloc( pBt->pageSize );

  if( hit==0 ){
    pCheck->mallocFailed = 1;
  }else{
    int contentOffset = get2byteNotZero(&data[hdr+5]);
    assert( contentOffset<=usableSize );  /* Enforced by btreeInitPage() */
    memset(hit+contentOffset, 0, usableSize-contentOffset);
    memset(hit, 1, contentOffset);


    nCell = get2byte(&data[hdr+3]);


    cellStart = hdr + 12 - 4*pPage->leaf;


    for(i=0; i<nCell; i++){
      int pc = get2byte(&data[cellStart+i*2]);
      u32 size = 65536;
      int j;
      if( pc<=usableSize-4 ){
        size = cellSizePtr(pPage, &data[pc]);
      }
      if( (int)(pc+size-1)>=usableSize ){

        checkAppendMsg(pCheck, 0, 
            "Corruption detected in cell %d on page %d",i,iPage);
      }else{
        for(j=pc+size-1; j>=pc; j--) hit[j]++;
      }
    }



    i = get2byte(&data[hdr+1]);
    while( i>0 ){
      int size, j;
      assert( i<=usableSize-4 );     /* Enforced by btreeInitPage() */
      size = get2byte(&data[i+2]);
      assert( i+size<=usableSize );  /* Enforced by btreeInitPage() */
      for(j=i+size-1; j>=i; j--) hit[j]++;




      j = get2byte(&data[i]);


      assert( j==0 || j>i+size );  /* Enforced by btreeInitPage() */
      assert( j<=usableSize-4 );   /* Enforced by btreeInitPage() */
      i = j;
    }
    for(i=cnt=0; i<usableSize; i++){
      if( hit[i]==0 ){
        cnt++;
      }else if( hit[i]>1 ){
        checkAppendMsg(pCheck, 0,
          "Multiple uses for byte %d of page %d", i, iPage);
        break;
      }
    }





    if( cnt!=data[hdr+7] ){
      checkAppendMsg(pCheck, 0, 
          "Fragmentation of %d bytes reported as %d on page %d",
          cnt, data[hdr+7], iPage);
    }
  }
  sqlite3PageFree(hit);
  releasePage(pPage);





  return depth+1;
}
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */

#ifndef SQLITE_OMIT_INTEGRITY_CHECK
/*
** This routine does a complete check of the given BTree file.  aRoot[] is
................................................................................
  nRef = sqlite3PagerRefcount(pBt->pPager);
  sCheck.pBt = pBt;
  sCheck.pPager = pBt->pPager;
  sCheck.nPage = btreePagecount(sCheck.pBt);
  sCheck.mxErr = mxErr;
  sCheck.nErr = 0;
  sCheck.mallocFailed = 0;



  *pnErr = 0;
  if( sCheck.nPage==0 ){
    sqlite3BtreeLeave(p);
    return 0;
  }

  sCheck.aPgRef = sqlite3MallocZero((sCheck.nPage / 8)+ 1);
................................................................................
  i = PENDING_BYTE_PAGE(pBt);
  if( i<=sCheck.nPage ) setPageReferenced(&sCheck, i);
  sqlite3StrAccumInit(&sCheck.errMsg, zErr, sizeof(zErr), SQLITE_MAX_LENGTH);
  sCheck.errMsg.useMalloc = 2;

  /* Check the integrity of the freelist
  */

  checkList(&sCheck, 1, get4byte(&pBt->pPage1->aData[32]),
            get4byte(&pBt->pPage1->aData[36]), "Main freelist: ");


  /* Check all the tables.
  */
  for(i=0; (int)i<nRoot && sCheck.mxErr; i++){
    if( aRoot[i]==0 ) continue;
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pBt->autoVacuum && aRoot[i]>1 ){
      checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0, 0);
    }
#endif

    checkTreePage(&sCheck, aRoot[i], "List of tree roots: ", NULL, NULL);

  }

  /* Make sure every page in the file is referenced
  */
  for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
#ifdef SQLITE_OMIT_AUTOVACUUM
    if( getPageReferenced(&sCheck, i)==0 ){
      checkAppendMsg(&sCheck, 0, "Page %d is never used", i);
    }
#else
    /* If the database supports auto-vacuum, make sure no tables contain
    ** references to pointer-map pages.
    */
    if( getPageReferenced(&sCheck, i)==0 && 
       (PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
      checkAppendMsg(&sCheck, 0, "Page %d is never used", i);
    }
    if( getPageReferenced(&sCheck, i)!=0 && 
       (PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
      checkAppendMsg(&sCheck, 0, "Pointer map page %d is referenced", i);
    }
#endif
  }

  /* Make sure this analysis did not leave any unref() pages.
  ** This is an internal consistency check; an integrity check
  ** of the integrity check.
  */
  if( NEVER(nRef != sqlite3PagerRefcount(pBt->pPager)) ){
    checkAppendMsg(&sCheck, 0, 
      "Outstanding page count goes from %d to %d during this analysis",
      nRef, sqlite3PagerRefcount(pBt->pPager)
    );
  }

  /* Clean  up and report errors.
  */
................................................................................
    return SQLITE_ABORT;
  }

  /* Save the positions of all other cursors open on this table. This is
  ** required in case any of them are holding references to an xFetch
  ** version of the b-tree page modified by the accessPayload call below.
  **
  ** Note that pCsr must be open on a BTREE_INTKEY table and saveCursorPosition()
  ** and hence saveAllCursors() cannot fail on a BTREE_INTKEY table, hence
  ** saveAllCursors can only return SQLITE_OK.
  */
  VVA_ONLY(rc =) saveAllCursors(pCsr->pBt, pCsr->pgnoRoot, pCsr);
  assert( rc==SQLITE_OK );

  /* Check some assumptions: 
................................................................................

/*
** Return true if the given Btree is read-only.
*/
int sqlite3BtreeIsReadonly(Btree *p){
  return (p->pBt->btsFlags & BTS_READ_ONLY)!=0;
}

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements an external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

/*
** The header string that appears at the beginning of every
................................................................................
  i64 iRow,               /* The rowid that might be changing */
  int isClearTable        /* True if all rows are being deleted */
){
  BtCursor *p;
  BtShared *pBt = pBtree->pBt;
  assert( sqlite3BtreeHoldsMutex(pBtree) );
  for(p=pBt->pCursor; p; p=p->pNext){
    if( (p->curFlags & BTCF_Incrblob)!=0
     && (isClearTable || p->info.nKey==iRow)
    ){
      p->eState = CURSOR_INVALID;
    }
  }
}

#else
  /* Stub function when INCRBLOB is omitted */
................................................................................
  /* If this is an intKey table, then the above call to BtreeKeySize()
  ** stores the integer key in pCur->nKey. In this case this value is
  ** all that is required. Otherwise, if pCur is not open on an intKey
  ** table, then malloc space for and store the pCur->nKey bytes of key 
  ** data.
  */
  if( 0==pCur->apPage[0]->intKey ){
    void *pKey = sqlite3Malloc( pCur->nKey );
    if( pKey ){
      rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
      if( rc==SQLITE_OK ){
        pCur->pKey = pKey;
      }else{
        sqlite3_free(pKey);
      }
................................................................................

/* This helper routine to saveAllCursors does the actual work of saving
** the cursors if and when a cursor is found that actually requires saving.
** The common case is that no cursors need to be saved, so this routine is
** broken out from its caller to avoid unnecessary stack pointer movement.
*/
static int SQLITE_NOINLINE saveCursorsOnList(
  BtCursor *p,         /* The first cursor that needs saving */
  Pgno iRoot,          /* Only save cursor with this iRoot. Save all if zero */
  BtCursor *pExcept    /* Do not save this cursor */
){
  do{
    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ){
      if( p->eState==CURSOR_VALID ){
        int rc = saveCursorPosition(p);
        if( SQLITE_OK!=rc ){
          return rc;
................................................................................
**
** Calling this routine with a NULL cursor pointer returns false.
**
** Use the separate sqlite3BtreeCursorRestore() routine to restore a cursor
** back to where it ought to be if this routine returns true.
*/
int sqlite3BtreeCursorHasMoved(BtCursor *pCur){
  return pCur->eState!=CURSOR_VALID;
}

/*
** This routine restores a cursor back to its original position after it
** has been moved by some outside activity (such as a btree rebalance or
** a row having been deleted out from under the cursor).  
**
................................................................................
}

/*
** Parse a cell content block and fill in the CellInfo structure.  There
** are two versions of this function.  btreeParseCell() takes a 
** cell index as the second argument and btreeParseCellPtr() 
** takes a pointer to the body of the cell as its second argument.



*/
static void btreeParseCellPtr(
  MemPage *pPage,         /* Page containing the cell */
  u8 *pCell,              /* Pointer to the cell text. */
  CellInfo *pInfo         /* Fill in this structure */
){
  u8 *pIter;              /* For scanning through pCell */
  u32 nPayload;           /* Number of bytes of cell payload */

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( pPage->leaf==0 || pPage->leaf==1 );
  if( pPage->intKeyLeaf ){
    assert( pPage->childPtrSize==0 );
    pIter = pCell + getVarint32(pCell, nPayload);
    pIter += getVarint(pIter, (u64*)&pInfo->nKey);
  }else if( pPage->noPayload ){
    assert( pPage->childPtrSize==4 );
    pInfo->nSize = 4 + getVarint(&pCell[4], (u64*)&pInfo->nKey);
    pInfo->nPayload = 0;
    pInfo->nLocal = 0;
    pInfo->iOverflow = 0;
    pInfo->pPayload = 0;
    return;
  }else{
    pIter = pCell + pPage->childPtrSize;
    pIter += getVarint32(pIter, nPayload);

    pInfo->nKey = nPayload;
  }
  pInfo->nPayload = nPayload;
  pInfo->pPayload = pIter;
  testcase( nPayload==pPage->maxLocal );
  testcase( nPayload==pPage->maxLocal+1 );
  if( nPayload<=pPage->maxLocal ){
    /* This is the (easy) common case where the entire payload fits
    ** on the local page.  No overflow is required.
    */
    pInfo->nSize = nPayload + (u16)(pIter - pCell);
    if( pInfo->nSize<4 ) pInfo->nSize = 4;
    pInfo->nLocal = (u16)nPayload;
    pInfo->iOverflow = 0;
  }else{
    /* If the payload will not fit completely on the local page, we have
    ** to decide how much to store locally and how much to spill onto
    ** overflow pages.  The strategy is to minimize the amount of unused
    ** space on overflow pages while keeping the amount of local storage
................................................................................
    testcase( surplus==maxLocal );
    testcase( surplus==maxLocal+1 );
    if( surplus <= maxLocal ){
      pInfo->nLocal = (u16)surplus;
    }else{
      pInfo->nLocal = (u16)minLocal;
    }
    pInfo->iOverflow = (u16)(&pInfo->pPayload[pInfo->nLocal] - pCell);
    pInfo->nSize = pInfo->iOverflow + 4;
  }
}


static void btreeParseCell(
  MemPage *pPage,         /* Page containing the cell */
  int iCell,              /* The cell index.  First cell is 0 */
  CellInfo *pInfo         /* Fill in this structure */
){
  btreeParseCellPtr(pPage, findCell(pPage, iCell), pInfo);
}

/*
** Compute the total number of bytes that a Cell needs in the cell
** data area of the btree-page.  The return number includes the cell
** data header and the local payload, but not any overflow page or
** the space used by the cell pointer.
*/
static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
  u8 *pIter = pCell + pPage->childPtrSize; /* For looping over bytes of pCell */
  u8 *pEnd;                                /* End mark for a varint */
  u32 nSize;                               /* Size value to return */

#ifdef SQLITE_DEBUG
  /* The value returned by this function should always be the same as
  ** the (CellInfo.nSize) value found by doing a full parse of the
  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
  ** this function verifies that this invariant is not violated. */
  CellInfo debuginfo;
  btreeParseCellPtr(pPage, pCell, &debuginfo);
#endif

  if( pPage->noPayload ){
    pEnd = &pIter[9];
    while( (*pIter++)&0x80 && pIter<pEnd );
    assert( pPage->childPtrSize==4 );
    return (u16)(pIter - pCell);

  }
  nSize = *pIter;
  if( nSize>=0x80 ){
    pEnd = &pIter[9];
    nSize &= 0x7f;
    do{
      nSize = (nSize<<7) | (*++pIter & 0x7f);
    }while( *(pIter)>=0x80 && pIter<pEnd );
  }
  pIter++;
  if( pPage->intKey ){
    /* pIter now points at the 64-bit integer key value, a variable length 
    ** integer. The following block moves pIter to point at the first byte
    ** past the end of the key value. */
    pEnd = &pIter[9];
    while( (*pIter++)&0x80 && pIter<pEnd );


  }

  testcase( nSize==pPage->maxLocal );
  testcase( nSize==pPage->maxLocal+1 );
  if( nSize<=pPage->maxLocal ){
    nSize += (u32)(pIter - pCell);
    if( nSize<4 ) nSize = 4;
  }else{
    int minLocal = pPage->minLocal;
    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
    testcase( nSize==pPage->maxLocal );
    testcase( nSize==pPage->maxLocal+1 );
    if( nSize>pPage->maxLocal ){
      nSize = minLocal;
    }


    nSize += 4 + (u16)(pIter - pCell);
  }





  assert( nSize==debuginfo.nSize || CORRUPT_DB );
  return (u16)nSize;
}

#ifdef SQLITE_DEBUG
/* This variation on cellSizePtr() is used inside of assert() statements
** only. */
static u16 cellSize(MemPage *pPage, int iCell){
................................................................................
** for the overflow page.
*/
static void ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell, int *pRC){
  CellInfo info;
  if( *pRC ) return;
  assert( pCell!=0 );
  btreeParseCellPtr(pPage, pCell, &info);

  if( info.iOverflow ){
    Pgno ovfl = get4byte(&pCell[info.iOverflow]);
    ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
  }
}
#endif


/*
** Defragment the page given.  All Cells are moved to the
** end of the page and all free space is collected into one
** big FreeBlk that occurs in between the header and cell
** pointer array and the cell content area.
**
** EVIDENCE-OF: R-44582-60138 SQLite may from time to time reorganize a
** b-tree page so that there are no freeblocks or fragment bytes, all
** unused bytes are contained in the unallocated space region, and all
** cells are packed tightly at the end of the page.
*/
static int defragmentPage(MemPage *pPage){
  int i;                     /* Loop counter */
  int pc;                    /* Address of the i-th cell */
  int hdr;                   /* Offset to the page header */
  int size;                  /* Size of a cell */
  int usableSize;            /* Number of usable bytes on a page */
  int cellOffset;            /* Offset to the cell pointer array */
  int cbrk;                  /* Offset to the cell content area */
  int nCell;                 /* Number of cells on the page */
  unsigned char *data;       /* The page data */
  unsigned char *temp;       /* Temp area for cell content */
  unsigned char *src;        /* Source of content */
  int iCellFirst;            /* First allowable cell index */
  int iCellLast;             /* Last possible cell index */


  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( pPage->pBt!=0 );
  assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE );
  assert( pPage->nOverflow==0 );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  temp = 0;
  src = data = pPage->aData;
  hdr = pPage->hdrOffset;
  cellOffset = pPage->cellOffset;
  nCell = pPage->nCell;
  assert( nCell==get2byte(&data[hdr+3]) );
  usableSize = pPage->pBt->usableSize;


  cbrk = usableSize;
  iCellFirst = cellOffset + 2*nCell;
  iCellLast = usableSize - 4;
  for(i=0; i<nCell; i++){
    u8 *pAddr;     /* The i-th cell pointer */
    pAddr = &data[cellOffset + i*2];
    pc = get2byte(pAddr);
................................................................................
    ** if SQLITE_ENABLE_OVERSIZE_CELL_CHECK is defined 
    */
    if( pc<iCellFirst || pc>iCellLast ){
      return SQLITE_CORRUPT_BKPT;
    }
#endif
    assert( pc>=iCellFirst && pc<=iCellLast );
    size = cellSizePtr(pPage, &src[pc]);
    cbrk -= size;
#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
    if( cbrk<iCellFirst ){
      return SQLITE_CORRUPT_BKPT;
    }
#else
    if( cbrk<iCellFirst || pc+size>usableSize ){
      return SQLITE_CORRUPT_BKPT;
    }
#endif
    assert( cbrk+size<=usableSize && cbrk>=iCellFirst );
    testcase( cbrk+size==usableSize );
    testcase( pc+size==usableSize );

    put2byte(pAddr, cbrk);
    if( temp==0 ){
      int x;
      if( cbrk==pc ) continue;
      temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
      x = get2byte(&data[hdr+5]);
      memcpy(&temp[x], &data[x], (cbrk+size) - x);
      src = temp;
    }
    memcpy(&data[cbrk], &src[pc], size);
  }
  assert( cbrk>=iCellFirst );
  put2byte(&data[hdr+5], cbrk);
  data[hdr+1] = 0;
  data[hdr+2] = 0;
  data[hdr+7] = 0;
  memset(&data[iCellFirst], 0, cbrk-iCellFirst);
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  if( cbrk-iCellFirst!=pPage->nFree ){
    return SQLITE_CORRUPT_BKPT;
  }
  return SQLITE_OK;
}

/*
** Search the free-list on page pPg for space to store a cell nByte bytes in
** size. If one can be found, return a pointer to the space and remove it
** from the free-list.
**
** If no suitable space can be found on the free-list, return NULL.
**
** This function may detect corruption within pPg.  If corruption is
** detected then *pRc is set to SQLITE_CORRUPT and NULL is returned.
**
** If a slot of at least nByte bytes is found but cannot be used because 
** there are already at least 60 fragmented bytes on the page, return NULL.
** In this case, if pbDefrag parameter is not NULL, set *pbDefrag to true.
*/
static u8 *pageFindSlot(MemPage *pPg, int nByte, int *pRc, int *pbDefrag){
  const int hdr = pPg->hdrOffset;
  u8 * const aData = pPg->aData;
  int iAddr;
  int pc;
  int usableSize = pPg->pBt->usableSize;

  for(iAddr=hdr+1; (pc = get2byte(&aData[iAddr]))>0; iAddr=pc){
    int size;            /* Size of the free slot */
    /* EVIDENCE-OF: R-06866-39125 Freeblocks are always connected in order of
    ** increasing offset. */
    if( pc>usableSize-4 || pc<iAddr+4 ){
      *pRc = SQLITE_CORRUPT_BKPT;
      return 0;
    }
    /* EVIDENCE-OF: R-22710-53328 The third and fourth bytes of each
    ** freeblock form a big-endian integer which is the size of the freeblock
    ** in bytes, including the 4-byte header. */
    size = get2byte(&aData[pc+2]);
    if( size>=nByte ){
      int x = size - nByte;
      testcase( x==4 );
      testcase( x==3 );
      if( x<4 ){
        /* EVIDENCE-OF: R-11498-58022 In a well-formed b-tree page, the total
        ** number of bytes in fragments may not exceed 60. */
        if( aData[hdr+7]>=60 ){
          if( pbDefrag ) *pbDefrag = 1;
          return 0;
        }
        /* Remove the slot from the free-list. Update the number of
        ** fragmented bytes within the page. */
        memcpy(&aData[iAddr], &aData[pc], 2);
        aData[hdr+7] += (u8)x;
      }else if( size+pc > usableSize ){
        *pRc = SQLITE_CORRUPT_BKPT;
        return 0;
      }else{
        /* The slot remains on the free-list. Reduce its size to account
         ** for the portion used by the new allocation. */
        put2byte(&aData[pc+2], x);
      }
      return &aData[pc + x];
    }
  }

  return 0;
}

/*
** Allocate nByte bytes of space from within the B-Tree page passed
** as the first argument. Write into *pIdx the index into pPage->aData[]
** of the first byte of allocated space. Return either SQLITE_OK or
** an error code (usually SQLITE_CORRUPT).
**
................................................................................
** allocation is being made in order to insert a new cell, so we will
** also end up needing a new cell pointer.
*/
static int allocateSpace(MemPage *pPage, int nByte, int *pIdx){
  const int hdr = pPage->hdrOffset;    /* Local cache of pPage->hdrOffset */
  u8 * const data = pPage->aData;      /* Local cache of pPage->aData */
  int top;                             /* First byte of cell content area */
  int rc = SQLITE_OK;                  /* Integer return code */
  int gap;        /* First byte of gap between cell pointers and cell content */


  
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( pPage->pBt );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( nByte>=0 );  /* Minimum cell size is 4 */
  assert( pPage->nFree>=nByte );
  assert( pPage->nOverflow==0 );
  assert( nByte < (int)(pPage->pBt->usableSize-8) );


  assert( pPage->cellOffset == hdr + 12 - 4*pPage->leaf );
  gap = pPage->cellOffset + 2*pPage->nCell;
  assert( gap<=65536 );
  /* EVIDENCE-OF: R-29356-02391 If the database uses a 65536-byte page size
  ** and the reserved space is zero (the usual value for reserved space)
  ** then the cell content offset of an empty page wants to be 65536.
  ** However, that integer is too large to be stored in a 2-byte unsigned
  ** integer, so a value of 0 is used in its place. */
  top = get2byteNotZero(&data[hdr+5]);
  if( gap>top ) return SQLITE_CORRUPT_BKPT;


  /* If there is enough space between gap and top for one more cell pointer
  ** array entry offset, and if the freelist is not empty, then search the
  ** freelist looking for a free slot big enough to satisfy the request.
  */
  testcase( gap+2==top );
  testcase( gap+1==top );
  testcase( gap==top );
  if( gap+2<=top && (data[hdr+1] || data[hdr+2]) ){
    int bDefrag = 0;
    u8 *pSpace = pageFindSlot(pPage, nByte, &rc, &bDefrag);
    if( rc ) return rc;









    if( bDefrag ) goto defragment_page;











    if( pSpace ){
      assert( pSpace>=data && (pSpace - data)<65536 );
      *pIdx = (int)(pSpace - data);
      return SQLITE_OK;

    }
  }

  /* The request could not be fulfilled using a freelist slot.  Check
  ** to see if defragmentation is necessary.
  */
  testcase( gap+2+nByte==top );
  if( gap+2+nByte>top ){
 defragment_page:
    assert( pPage->nCell>0 || CORRUPT_DB );
    rc = defragmentPage(pPage);
    if( rc ) return rc;
    top = get2byteNotZero(&data[hdr+5]);
    assert( gap+nByte<=top );
  }


................................................................................
** Note that even though the freeblock list was checked by btreeInitPage(),
** that routine will not detect overlap between cells or freeblocks.  Nor
** does it detect cells or freeblocks that encrouch into the reserved bytes
** at the end of the page.  So do additional corruption checks inside this
** routine and return SQLITE_CORRUPT if any problems are found.
*/
static int freeSpace(MemPage *pPage, u16 iStart, u16 iSize){
  u16 iPtr;                             /* Address of ptr to next freeblock */
  u16 iFreeBlk;                         /* Address of the next freeblock */
  u8 hdr;                               /* Page header size.  0 or 100 */
  u8 nFrag = 0;                         /* Reduction in fragmentation */
  u16 iOrigSize = iSize;                /* Original value of iSize */
  u32 iLast = pPage->pBt->usableSize-4; /* Largest possible freeblock offset */
  u32 iEnd = iStart + iSize;            /* First byte past the iStart buffer */
  unsigned char *data = pPage->aData;   /* Page content */

  assert( pPage->pBt!=0 );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( iStart>=pPage->hdrOffset+6+pPage->childPtrSize );
  assert( CORRUPT_DB || iEnd <= pPage->pBt->usableSize );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( iSize>=4 );   /* Minimum cell size is 4 */
  assert( iStart<=iLast );

  /* Overwrite deleted information with zeros when the secure_delete
  ** option is enabled */
  if( pPage->pBt->btsFlags & BTS_SECURE_DELETE ){
................................................................................
      nFrag = iFreeBlk - iEnd;
      if( iEnd>iFreeBlk ) return SQLITE_CORRUPT_BKPT;
      iEnd = iFreeBlk + get2byte(&data[iFreeBlk+2]);
      iSize = iEnd - iStart;
      iFreeBlk = get2byte(&data[iFreeBlk]);
    }
  
    /* If iPtr is another freeblock (that is, if iPtr is not the freelist
    ** pointer in the page header) then check to see if iStart should be
    ** coalesced onto the end of iPtr.
    */
    if( iPtr>hdr+1 ){
      int iPtrEnd = iPtr + get2byte(&data[iPtr+2]);
      if( iPtrEnd+3>=iStart ){
        if( iPtrEnd>iStart ) return SQLITE_CORRUPT_BKPT;
        nFrag += iStart - iPtrEnd;
        iSize = iEnd - iPtr;
................................................................................
  assert( pPage->hdrOffset==(pPage->pgno==1 ? 100 : 0) );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  pPage->leaf = (u8)(flagByte>>3);  assert( PTF_LEAF == 1<<3 );
  flagByte &= ~PTF_LEAF;
  pPage->childPtrSize = 4-4*pPage->leaf;
  pBt = pPage->pBt;
  if( flagByte==(PTF_LEAFDATA | PTF_INTKEY) ){
    /* EVIDENCE-OF: R-03640-13415 A value of 5 means the page is an interior
    ** table b-tree page. */
    assert( (PTF_LEAFDATA|PTF_INTKEY)==5 );
    /* EVIDENCE-OF: R-20501-61796 A value of 13 means the page is a leaf
    ** table b-tree page. */
    assert( (PTF_LEAFDATA|PTF_INTKEY|PTF_LEAF)==13 );
    pPage->intKey = 1;
    pPage->intKeyLeaf = pPage->leaf;
    pPage->noPayload = !pPage->leaf;
    pPage->maxLocal = pBt->maxLeaf;
    pPage->minLocal = pBt->minLeaf;
  }else if( flagByte==PTF_ZERODATA ){
    /* EVIDENCE-OF: R-27225-53936 A value of 2 means the page is an interior
    ** index b-tree page. */
    assert( (PTF_ZERODATA)==2 );
    /* EVIDENCE-OF: R-16571-11615 A value of 10 means the page is a leaf
    ** index b-tree page. */
    assert( (PTF_ZERODATA|PTF_LEAF)==10 );
    pPage->intKey = 0;

    pPage->intKeyLeaf = 0;
    pPage->noPayload = 0;
    pPage->maxLocal = pBt->maxLocal;
    pPage->minLocal = pBt->minLocal;
  }else{
    /* EVIDENCE-OF: R-47608-56469 Any other value for the b-tree page type is
    ** an error. */
    return SQLITE_CORRUPT_BKPT;
  }
  pPage->max1bytePayload = pBt->max1bytePayload;
  return SQLITE_OK;
}

/*
................................................................................
    int iCellFirst;    /* First allowable cell or freeblock offset */
    int iCellLast;     /* Last possible cell or freeblock offset */

    pBt = pPage->pBt;

    hdr = pPage->hdrOffset;
    data = pPage->aData;
    /* EVIDENCE-OF: R-28594-02890 The one-byte flag at offset 0 indicating
    ** the b-tree page type. */
    if( decodeFlags(pPage, data[hdr]) ) return SQLITE_CORRUPT_BKPT;
    assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
    pPage->maskPage = (u16)(pBt->pageSize - 1);
    pPage->nOverflow = 0;
    usableSize = pBt->usableSize;
    pPage->cellOffset = cellOffset = hdr + 8 + pPage->childPtrSize;
    pPage->aDataEnd = &data[usableSize];
    pPage->aCellIdx = &data[cellOffset];
    /* EVIDENCE-OF: R-58015-48175 The two-byte integer at offset 5 designates
    ** the start of the cell content area. A zero value for this integer is
    ** interpreted as 65536. */
    top = get2byteNotZero(&data[hdr+5]);
    /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
    ** number of cells on the page. */
    pPage->nCell = get2byte(&data[hdr+3]);
    if( pPage->nCell>MX_CELL(pBt) ){
      /* To many cells for a single page.  The page must be corrupt */
      return SQLITE_CORRUPT_BKPT;
    }
    testcase( pPage->nCell==MX_CELL(pBt) );
    /* EVIDENCE-OF: R-24089-57979 If a page contains no cells (which is only
    ** possible for a root page of a table that contains no rows) then the
    ** offset to the cell content area will equal the page size minus the
    ** bytes of reserved space. */
    assert( pPage->nCell>0 || top==usableSize || CORRUPT_DB );

    /* A malformed database page might cause us to read past the end
    ** of page when parsing a cell.  
    **
    ** The following block of code checks early to see if a cell extends
    ** past the end of a page boundary and causes SQLITE_CORRUPT to be 
    ** returned if it does.
................................................................................
          return SQLITE_CORRUPT_BKPT;
        }
      }
      if( !pPage->leaf ) iCellLast++;
    }  
#endif

    /* Compute the total free space on the page
    ** EVIDENCE-OF: R-23588-34450 The two-byte integer at offset 1 gives the
    ** start of the first freeblock on the page, or is zero if there are no
    ** freeblocks. */
    pc = get2byte(&data[hdr+1]);
    nFree = data[hdr+7] + top;  /* Init nFree to non-freeblock free space */
    while( pc>0 ){
      u16 next, size;
      if( pc<iCellFirst || pc>iCellLast ){
        /* EVIDENCE-OF: R-55530-52930 In a well-formed b-tree page, there will
        ** always be at least one cell before the first freeblock.
        **
        ** Or, the freeblock is off the end of the page
        */
        return SQLITE_CORRUPT_BKPT; 
      }
      next = get2byte(&data[pc]);
      size = get2byte(&data[pc+2]);
      if( (next>0 && next<=pc+size+3) || pc+size>usableSize ){
        /* Free blocks must be in ascending order. And the last byte of
        ** the free-block must lie on the database page.  */
................................................................................
  
    pBt->pCursor = 0;
    pBt->pPage1 = 0;
    if( sqlite3PagerIsreadonly(pBt->pPager) ) pBt->btsFlags |= BTS_READ_ONLY;
#ifdef SQLITE_SECURE_DELETE
    pBt->btsFlags |= BTS_SECURE_DELETE;
#endif
    /* EVIDENCE-OF: R-51873-39618 The page size for a database file is
    ** determined by the 2-byte integer located at an offset of 16 bytes from
    ** the beginning of the database file. */
    pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
    if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
         || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
      pBt->pageSize = 0;
#ifndef SQLITE_OMIT_AUTOVACUUM
      /* If the magic name ":memory:" will create an in-memory database, then
      ** leave the autoVacuum mode at 0 (do not auto-vacuum), even if
................................................................................
      if( zFilename && !isMemdb ){
        pBt->autoVacuum = (SQLITE_DEFAULT_AUTOVACUUM ? 1 : 0);
        pBt->incrVacuum = (SQLITE_DEFAULT_AUTOVACUUM==2 ? 1 : 0);
      }
#endif
      nReserve = 0;
    }else{
      /* EVIDENCE-OF: R-37497-42412 The size of the reserved region is
      ** determined by the one-byte unsigned integer found at an offset of 20
      ** into the database file header. */
      nReserve = zDbHeader[20];
      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
#ifndef SQLITE_OMIT_AUTOVACUUM
      pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
      pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
#endif
    }
................................................................................
#else
  return 1;
#endif
}

/*
** Make sure pBt->pTmpSpace points to an allocation of 
** MX_CELL_SIZE(pBt) bytes with a 4-byte prefix for a left-child
** pointer.
*/
static void allocateTempSpace(BtShared *pBt){
  if( !pBt->pTmpSpace ){
    pBt->pTmpSpace = sqlite3PageMalloc( pBt->pageSize );

    /* One of the uses of pBt->pTmpSpace is to format cells before
    ** inserting them into a leaf page (function fillInCell()). If
................................................................................
    ** a cell is less than 4 bytes in size, it is rounded up to 4 bytes
    ** by the various routines that manipulate binary cells. Which
    ** can mean that fillInCell() only initializes the first 2 or 3
    ** bytes of pTmpSpace, but that the first 4 bytes are copied from
    ** it into a database page. This is not actually a problem, but it
    ** does cause a valgrind error when the 1 or 2 bytes of unitialized 
    ** data is passed to system call write(). So to avoid this error,
    ** zero the first 4 bytes of temp space here.
    **
    ** Also:  Provide four bytes of initialized space before the
    ** beginning of pTmpSpace as an area available to prepend the
    ** left-child pointer to the beginning of a cell.
    */
    if( pBt->pTmpSpace ){
      memset(pBt->pTmpSpace, 0, 8);
      pBt->pTmpSpace += 4;
    }
  }
}

/*
** Free the pBt->pTmpSpace allocation
*/
static void freeTempSpace(BtShared *pBt){
  if( pBt->pTmpSpace ){
    pBt->pTmpSpace -= 4;
    sqlite3PageFree(pBt->pTmpSpace);
    pBt->pTmpSpace = 0;
  }
}

/*
** Close an open database and invalidate all cursors.
*/
int sqlite3BtreeClose(Btree *p){
  BtShared *pBt = p->pBt;
................................................................................
    }
  }

  /* Rollback any active transaction and free the handle structure.
  ** The call to sqlite3BtreeRollback() drops any table-locks held by
  ** this handle.
  */
  sqlite3BtreeRollback(p, SQLITE_OK, 0);
  sqlite3BtreeLeave(p);

  /* If there are still other outstanding references to the shared-btree
  ** structure, return now. The remainder of this procedure cleans 
  ** up the shared-btree.
  */
  assert( p->wantToLock==0 && p->locked==0 );
................................................................................
    nPage = nPageFile;
  }
  if( nPage>0 ){
    u32 pageSize;
    u32 usableSize;
    u8 *page1 = pPage1->aData;
    rc = SQLITE_NOTADB;
    /* EVIDENCE-OF: R-43737-39999 Every valid SQLite database file begins
    ** with the following 16 bytes (in hex): 53 51 4c 69 74 65 20 66 6f 72 6d
    ** 61 74 20 33 00. */
    if( memcmp(page1, zMagicHeader, 16)!=0 ){
      goto page1_init_failed;
    }

#ifdef SQLITE_OMIT_WAL
    if( page1[18]>1 ){
      pBt->btsFlags |= BTS_READ_ONLY;
................................................................................
        releasePage(pPage1);
        return SQLITE_OK;
      }
      rc = SQLITE_NOTADB;
    }
#endif

    /* EVIDENCE-OF: R-15465-20813 The maximum and minimum embedded payload
    ** fractions and the leaf payload fraction values must be 64, 32, and 32.
    **
    ** The original design allowed these amounts to vary, but as of
    ** version 3.6.0, we require them to be fixed.
    */
    if( memcmp(&page1[21], "\100\040\040",3)!=0 ){
      goto page1_init_failed;
    }
    /* EVIDENCE-OF: R-51873-39618 The page size for a database file is
    ** determined by the 2-byte integer located at an offset of 16 bytes from
    ** the beginning of the database file. */
    pageSize = (page1[16]<<8) | (page1[17]<<16);
    /* EVIDENCE-OF: R-25008-21688 The size of a page is a power of two
    ** between 512 and 65536 inclusive. */
    if( ((pageSize-1)&pageSize)!=0
     || pageSize>SQLITE_MAX_PAGE_SIZE 
     || pageSize<=256 
    ){
      goto page1_init_failed;
    }
    assert( (pageSize & 7)==0 );
    /* EVIDENCE-OF: R-59310-51205 The "reserved space" size in the 1-byte
    ** integer at offset 20 is the number of bytes of space at the end of
    ** each page to reserve for extensions. 
    **
    ** EVIDENCE-OF: R-37497-42412 The size of the reserved region is
    ** determined by the one-byte unsigned integer found at an offset of 20
    ** into the database file header. */
    usableSize = pageSize - page1[20];
    if( (u32)pageSize!=pBt->pageSize ){
      /* After reading the first page of the database assuming a page size
      ** of BtShared.pageSize, we have discovered that the page-size is
      ** actually pageSize. Unlock the database, leave pBt->pPage1 at
      ** zero and return SQLITE_OK. The caller will call this function
      ** again with the correct page-size.
................................................................................
                                   pageSize-usableSize);
      return rc;
    }
    if( (pBt->db->flags & SQLITE_RecoveryMode)==0 && nPage>nPageFile ){
      rc = SQLITE_CORRUPT_BKPT;
      goto page1_init_failed;
    }
    /* EVIDENCE-OF: R-28312-64704 However, the usable size is not allowed to
    ** be less than 480. In other words, if the page size is 512, then the
    ** reserved space size cannot exceed 32. */
    if( usableSize<480 ){
      goto page1_init_failed;
    }
    pBt->pageSize = pageSize;
    pBt->usableSize = usableSize;
#ifndef SQLITE_OMIT_AUTOVACUUM
    pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
................................................................................
** in assert() expressions, so it is only compiled if NDEBUG is not
** defined.
**
** Only write cursors are counted if wrOnly is true.  If wrOnly is
** false then all cursors are counted.
**
** For the purposes of this routine, a cursor is any cursor that
** is capable of reading or writing to the database.  Cursors that
** have been tripped into the CURSOR_FAULT state are not counted.
*/
static int countValidCursors(BtShared *pBt, int wrOnly){
  BtCursor *pCur;
  int r = 0;
  for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
    if( (wrOnly==0 || (pCur->curFlags & BTCF_WriteFlag)!=0)
................................................................................
**
** If there is a transaction in progress, this routine is a no-op.
*/
static void unlockBtreeIfUnused(BtShared *pBt){
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE );
  if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){
    MemPage *pPage1 = pBt->pPage1;
    assert( pPage1->aData );
    assert( sqlite3PagerRefcount(pBt->pPager)==1 );
    pBt->pPage1 = 0;
    releasePage(pPage1);

  }
}

/*
** If pBt points to an empty file then convert that empty file
** into a new empty database by initializing the first page of
** the database.
................................................................................

/*
** Perform a single step of an incremental-vacuum. If successful, return
** SQLITE_OK. If there is no work to do (and therefore no point in 
** calling this function again), return SQLITE_DONE. Or, if an error 
** occurs, return some other error code.
**
** More specifically, this function attempts to re-organize the database so 
** that the last page of the file currently in use is no longer in use.
**
** Parameter nFin is the number of pages that this database would contain
** were this function called until it returns SQLITE_DONE.
**
** If the bCommit parameter is non-zero, this function assumes that the 
** caller will keep calling incrVacuumStep() until it returns SQLITE_DONE 
** or an error. bCommit is passed true for an auto-vacuum-on-commit 
** operation, or false for an incremental vacuum.
*/
static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg, int bCommit){
  Pgno nFreeList;           /* Number of pages still on the free-list */
  int rc;

  assert( sqlite3_mutex_held(pBt->mutex) );
................................................................................
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** This routine sets the state to CURSOR_FAULT and the error
** code to errCode for every cursor on any BtShared that pBtree
** references.  Or if the writeOnly flag is set to 1, then only
** trip write cursors and leave read cursors unchanged.
**
** Every cursor is a candidate to be tripped, including cursors
** that belong to other database connections that happen to be
** sharing the cache with pBtree.
**
** This routine gets called when a rollback occurs. If the writeOnly

** flag is true, then only write-cursors need be tripped - read-only
** cursors save their current positions so that they may continue 
** following the rollback. Or, if writeOnly is false, all cursors are 
** tripped. In general, writeOnly is false if the transaction being
** rolled back modified the database schema. In this case b-tree root
** pages may be moved or deleted from the database altogether, making
** it unsafe for read cursors to continue.
**
** If the writeOnly flag is true and an error is encountered while 
** saving the current position of a read-only cursor, all cursors, 
** including all read-cursors are tripped.
**
** SQLITE_OK is returned if successful, or if an error occurs while
** saving a cursor position, an SQLite error code.
*/
int sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode, int writeOnly){
  BtCursor *p;
  int rc = SQLITE_OK;

  assert( (writeOnly==0 || writeOnly==1) && BTCF_WriteFlag==1 );
  if( pBtree ){
    sqlite3BtreeEnter(pBtree);
    for(p=pBtree->pBt->pCursor; p; p=p->pNext){
      int i;
      if( writeOnly && (p->curFlags & BTCF_WriteFlag)==0 ){
        if( p->eState==CURSOR_VALID ){
          rc = saveCursorPosition(p);
          if( rc!=SQLITE_OK ){
            (void)sqlite3BtreeTripAllCursors(pBtree, rc, 0);
            break;
          }
        }
      }else{
        sqlite3BtreeClearCursor(p);
        p->eState = CURSOR_FAULT;
        p->skipNext = errCode;
      }
      for(i=0; i<=p->iPage; i++){
        releasePage(p->apPage[i]);
        p->apPage[i] = 0;
      }
    }
    sqlite3BtreeLeave(pBtree);
  }
  return rc;
}

/*
** Rollback the transaction in progress.
**
** If tripCode is not SQLITE_OK then cursors will be invalidated (tripped).
** Only write cursors are tripped if writeOnly is true but all cursors are
** tripped if writeOnly is false.  Any attempt to use

** a tripped cursor will result in an error.
**
** This will release the write lock on the database file.  If there
** are no active cursors, it also releases the read lock.
*/
int sqlite3BtreeRollback(Btree *p, int tripCode, int writeOnly){
  int rc;
  BtShared *pBt = p->pBt;
  MemPage *pPage1;

  assert( writeOnly==1 || writeOnly==0 );
  assert( tripCode==SQLITE_ABORT_ROLLBACK || tripCode==SQLITE_OK );
  sqlite3BtreeEnter(p);
  if( tripCode==SQLITE_OK ){
    rc = tripCode = saveAllCursors(pBt, 0, 0);
    if( rc ) writeOnly = 0;
  }else{
    rc = SQLITE_OK;
  }
  if( tripCode ){
    int rc2 = sqlite3BtreeTripAllCursors(p, tripCode, writeOnly);
    assert( rc==SQLITE_OK || (writeOnly==0 && rc2==SQLITE_OK) );
    if( rc2!=SQLITE_OK ) rc = rc2;
  }
  btreeIntegrity(p);

  if( p->inTrans==TRANS_WRITE ){
    int rc2;

    assert( TRANS_WRITE==pBt->inTransaction );
................................................................................

  btreeEndTransaction(p);
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** Start a statement subtransaction. The subtransaction can be rolled
** back independently of the main transaction. You must start a transaction 
** before starting a subtransaction. The subtransaction is ended automatically 
** if the main transaction commits or rolls back.
**
** Statement subtransactions are used around individual SQL statements
** that are contained within a BEGIN...COMMIT block.  If a constraint
** error occurs within the statement, the effect of that one statement
................................................................................
  assert( p->inTrans>TRANS_NONE );
  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
  assert( pBt->pPage1 && pBt->pPage1->aData );

  if( NEVER(wrFlag && (pBt->btsFlags & BTS_READ_ONLY)!=0) ){
    return SQLITE_READONLY;
  }
  if( wrFlag ){
    allocateTempSpace(pBt);
    if( pBt->pTmpSpace==0 ) return SQLITE_NOMEM;
  }
  if( iTable==1 && btreePagecount(pBt)==0 ){
    assert( wrFlag==0 );
    iTable = 0;
  }

  /* Now that no other errors can occur, finish filling in the BtCursor
  ** variables and link the cursor into the BtShared list.  */
................................................................................
** BtCursor.info is a cache of the information in the current cell.
** Using this cache reduces the number of calls to btreeParseCell().
**
** 2007-06-25:  There is a bug in some versions of MSVC that cause the
** compiler to crash when getCellInfo() is implemented as a macro.
** But there is a measureable speed advantage to using the macro on gcc
** (when less compiler optimizations like -Os or -O0 are used and the
** compiler is not doing aggressive inlining.)  So we use a real function
** for MSVC and a macro for everything else.  Ticket #2457.
*/
#ifndef NDEBUG
  static void assertCellInfo(BtCursor *pCur){
    CellInfo info;
    int iPage = pCur->iPage;
    memset(&info, 0, sizeof(info));
................................................................................
**
** The caller must position the cursor prior to invoking this routine.
** 
** This routine cannot fail.  It always returns SQLITE_OK.  
*/
int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );



  getCellInfo(pCur);
  *pSize = pCur->info.nKey;

  return SQLITE_OK;
}

/*
** Set *pSize to the number of bytes of data in the entry the
** cursor currently points to.
**
................................................................................
** Failure is not possible.  This function always returns SQLITE_OK.
** It might just as well be a procedure (returning void) but we continue
** to return an integer result code for historical reasons.
*/
int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->apPage[pCur->iPage]->intKeyLeaf==1 );
  getCellInfo(pCur);
  *pSize = pCur->info.nPayload;
  return SQLITE_OK;
}

/*
** Given the page number of an overflow page in the database (parameter
** ovfl), this function finds the page number of the next page in the 
** linked list of overflow pages. If possible, it uses the auto-vacuum
................................................................................
** Data is read to or from the buffer pBuf.
**
** The content being read or written might appear on the main page
** or be scattered out on multiple overflow pages.
**
** If the current cursor entry uses one or more overflow pages and the
** eOp argument is not 2, this function may allocate space for and lazily 
** populates the overflow page-list cache array (BtCursor.aOverflow). 
** Subsequent calls use this cache to make seeking to the supplied offset 
** more efficient.
**
** Once an overflow page-list cache has been allocated, it may be
** invalidated if some other cursor writes to the same table, or if
** the cursor is moved to a different row. Additionally, in auto-vacuum
** mode, the following events may invalidate an overflow page-list cache.
................................................................................
  u32 offset,          /* Begin reading this far into payload */
  u32 amt,             /* Read this many bytes */
  unsigned char *pBuf, /* Write the bytes into this buffer */ 
  int eOp              /* zero to read. non-zero to write. */
){
  unsigned char *aPayload;
  int rc = SQLITE_OK;

  int iIdx = 0;
  MemPage *pPage = pCur->apPage[pCur->iPage]; /* Btree page of current entry */
  BtShared *pBt = pCur->pBt;                  /* Btree this cursor belongs to */
#ifdef SQLITE_DIRECT_OVERFLOW_READ
  unsigned char * const pBufStart = pBuf;
  int bEnd;                                 /* True if reading to end of data */
#endif

  assert( pPage );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
  assert( cursorHoldsMutex(pCur) );
  assert( eOp!=2 || offset==0 );    /* Always start from beginning for eOp==2 */

  getCellInfo(pCur);
  aPayload = pCur->info.pPayload;

#ifdef SQLITE_DIRECT_OVERFLOW_READ

  bEnd = offset+amt==pCur->info.nPayload;
#endif
  assert( offset+amt <= pCur->info.nPayload );


  if( &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize] ){

    /* Trying to read or write past the end of the data is an error */
    return SQLITE_CORRUPT_BKPT;
  }

  /* Check if data must be read/written to/from the btree page itself. */
  if( offset<pCur->info.nLocal ){
    int a = amt;
................................................................................
      }
    }

    /* If the overflow page-list cache has been allocated and the
    ** entry for the first required overflow page is valid, skip
    ** directly to it.
    */
    if( (pCur->curFlags & BTCF_ValidOvfl)!=0
     && pCur->aOverflow[offset/ovflSize]
    ){
      iIdx = (offset/ovflSize);
      nextPage = pCur->aOverflow[iIdx];
      offset = (offset%ovflSize);
    }

    for( ; rc==SQLITE_OK && amt>0 && nextPage; iIdx++){

................................................................................
        **
        **   1) this is a read operation, and 
        **   2) data is required from the start of this overflow page, and
        **   3) the database is file-backed, and
        **   4) there is no open write-transaction, and
        **   5) the database is not a WAL database,
        **   6) all data from the page is being read.
        **   7) at least 4 bytes have already been read into the output buffer 
        **
        ** then data can be read directly from the database file into the
        ** output buffer, bypassing the page-cache altogether. This speeds
        ** up loading large records that span many overflow pages.
        */
        if( (eOp&0x01)==0                                      /* (1) */
         && offset==0                                          /* (2) */
         && (bEnd || a==ovflSize)                              /* (6) */
         && pBt->inTransaction==TRANS_READ                     /* (4) */
         && (fd = sqlite3PagerFile(pBt->pPager))->pMethods     /* (3) */
         && pBt->pPage1->aData[19]==0x01                       /* (5) */
         && &pBuf[-4]>=pBufStart                               /* (7) */
        ){
          u8 aSave[4];
          u8 *aWrite = &pBuf[-4];
          assert( aWrite>=pBufStart );                         /* hence (7) */
          memcpy(aSave, aWrite, 4);
          rc = sqlite3OsRead(fd, aWrite, a+4, (i64)pBt->pageSize*(nextPage-1));
          nextPage = get4byte(aWrite);
          memcpy(aWrite, aSave, 4);
        }else
#endif

................................................................................
    return SQLITE_CORRUPT_BKPT;
  }
  return rc;
}

/*
** Read part of the key associated with cursor pCur.  Exactly
** "amt" bytes will be transferred into pBuf[].  The transfer
** begins at "offset".
**
** The caller must ensure that pCur is pointing to a valid row
** in the table.
**
** Return SQLITE_OK on success or an error code if anything goes
** wrong.  An error is returned if "offset+amt" is larger than
................................................................................
  assert( pCur!=0 && pCur->iPage>=0 && pCur->apPage[pCur->iPage]);
  assert( pCur->eState==CURSOR_VALID );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
  assert( pCur->info.nSize>0 );
  *pAmt = pCur->info.nLocal;
  return (void*)pCur->info.pPayload;
}


/*
** For the entry that cursor pCur is point to, return as
** many bytes of the key or data as are available on the local
** b-tree page.  Write the number of available bytes into *pAmt.
................................................................................
static int moveToRightmost(BtCursor *pCur){
  Pgno pgno;
  int rc = SQLITE_OK;
  MemPage *pPage = 0;

  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  while( !(pPage = pCur->apPage[pCur->iPage])->leaf ){
    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    pCur->aiIdx[pCur->iPage] = pPage->nCell;
    rc = moveToChild(pCur, pgno);
    if( rc ) return rc;
  }

  pCur->aiIdx[pCur->iPage] = pPage->nCell-1;
  assert( pCur->info.nSize==0 );
  assert( (pCur->curFlags & BTCF_ValidNKey)==0 );

  return SQLITE_OK;
}

/* Move the cursor to the first entry in the table.  Return SQLITE_OK
** on success.  Set *pRes to 0 if the cursor actually points to something
** or set *pRes to 1 if the table is empty.
*/
int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
................................................................................
      *pRes = -1;
      return SQLITE_OK;
    }
  }

  if( pIdxKey ){
    xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);
    pIdxKey->errCode = 0;
    assert( pIdxKey->default_rc==1 
         || pIdxKey->default_rc==0 
         || pIdxKey->default_rc==-1
    );
  }else{
    xRecordCompare = 0; /* All keys are integers */
  }
................................................................................
    assert( biasRight==0 || biasRight==1 );
    idx = upr>>(1-biasRight); /* idx = biasRight ? upr : (lwr+upr)/2; */
    pCur->aiIdx[pCur->iPage] = (u16)idx;
    if( xRecordCompare==0 ){
      for(;;){
        i64 nCellKey;
        pCell = findCell(pPage, idx) + pPage->childPtrSize;
        if( pPage->intKeyLeaf ){
          while( 0x80 <= *(pCell++) ){
            if( pCell>=pPage->aDataEnd ) return SQLITE_CORRUPT_BKPT;
          }
        }
        getVarint(pCell, (u64*)&nCellKey);
        if( nCellKey<intKey ){
          lwr = idx+1;
................................................................................
        */
        nCell = pCell[0];
        if( nCell<=pPage->max1bytePayload ){
          /* This branch runs if the record-size field of the cell is a
          ** single byte varint and the record fits entirely on the main
          ** b-tree page.  */
          testcase( pCell+nCell+1==pPage->aDataEnd );
          c = xRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
        }else if( !(pCell[1] & 0x80) 
          && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
        ){
          /* The record-size field is a 2 byte varint and the record 
          ** fits entirely on the main b-tree page.  */
          testcase( pCell+nCell+2==pPage->aDataEnd );
          c = xRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
        }else{
          /* The record flows over onto one or more overflow pages. In
          ** this case the whole cell needs to be parsed, a buffer allocated
          ** and accessPayload() used to retrieve the record into the
          ** buffer before VdbeRecordCompare() can be called. */
          void *pCellKey;
          u8 * const pCellBody = pCell - pPage->childPtrSize;
................................................................................
          }
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          rc = accessPayload(pCur, 0, nCell, (unsigned char*)pCellKey, 2);
          if( rc ){
            sqlite3_free(pCellKey);
            goto moveto_finish;
          }
          c = xRecordCompare(nCell, pCellKey, pIdxKey);
          sqlite3_free(pCellKey);
        }
        assert( 
            (pIdxKey->errCode!=SQLITE_CORRUPT || c==0)
         && (pIdxKey->errCode!=SQLITE_NOMEM || pCur->pBtree->db->mallocFailed)
        );
        if( c<0 ){
          lwr = idx+1;
        }else if( c>0 ){
          upr = idx-1;
        }else{
          assert( c==0 );
          *pRes = 0;
          rc = SQLITE_OK;
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          if( pIdxKey->errCode ) rc = SQLITE_CORRUPT;
          goto moveto_finish;
        }
        if( lwr>upr ) break;
        assert( lwr+upr>=0 );
        idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2 */
      }
    }
................................................................................
}

/*
** Advance the cursor to the next entry in the database.  If
** successful then set *pRes=0.  If the cursor
** was already pointing to the last entry in the database before
** this routine was called, then set *pRes=1.
**
** The main entry point is sqlite3BtreeNext().  That routine is optimized
** for the common case of merely incrementing the cell counter BtCursor.aiIdx
** to the next cell on the current page.  The (slower) btreeNext() helper
** routine is called when it is necessary to move to a different page or
** to restore the cursor.
**
** The calling function will set *pRes to 0 or 1.  The initial *pRes value
** will be 1 if the cursor being stepped corresponds to an SQL index and
** if this routine could have been skipped if that SQL index had been
** a unique index.  Otherwise the caller will have set *pRes to zero.
** Zero is the common case. The btree implementation is free to use the
** initial *pRes value as a hint to improve performance, but the current
** SQLite btree implementation does not. (Note that the comdb2 btree
** implementation does use this hint, however.)
*/
static SQLITE_NOINLINE int btreeNext(BtCursor *pCur, int *pRes){
  int rc;
  int idx;
  MemPage *pPage;

  assert( cursorHoldsMutex(pCur) );


  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  assert( *pRes==0 );
  if( pCur->eState!=CURSOR_VALID ){

    assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
    rc = restoreCursorPosition(pCur);
    if( rc!=SQLITE_OK ){

      return rc;
    }
    if( CURSOR_INVALID==pCur->eState ){
      *pRes = 1;
      return SQLITE_OK;
    }
    if( pCur->skipNext ){
      assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_SKIPNEXT );
      pCur->eState = CURSOR_VALID;
      if( pCur->skipNext>0 ){
        pCur->skipNext = 0;

        return SQLITE_OK;
      }
      pCur->skipNext = 0;
    }
  }

  pPage = pCur->apPage[pCur->iPage];
................................................................................
  /* If the database file is corrupt, it is possible for the value of idx 
  ** to be invalid here. This can only occur if a second cursor modifies
  ** the page while cursor pCur is holding a reference to it. Which can
  ** only happen if the database is corrupt in such a way as to link the
  ** page into more than one b-tree structure. */
  testcase( idx>pPage->nCell );



  if( idx>=pPage->nCell ){
    if( !pPage->leaf ){
      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));


      if( rc ) return rc;

      return moveToLeftmost(pCur);


    }
    do{
      if( pCur->iPage==0 ){
        *pRes = 1;
        pCur->eState = CURSOR_INVALID;
        return SQLITE_OK;
      }
      moveToParent(pCur);
      pPage = pCur->apPage[pCur->iPage];
    }while( pCur->aiIdx[pCur->iPage]>=pPage->nCell );

    if( pPage->intKey ){
      return sqlite3BtreeNext(pCur, pRes);
    }else{
      return SQLITE_OK;
    }
  }
  if( pPage->leaf ){
    return SQLITE_OK;
  }else{
    return moveToLeftmost(pCur);
  }
}
int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
  MemPage *pPage;
  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 || *pRes==1 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  *pRes = 0;
  if( pCur->eState!=CURSOR_VALID ) return btreeNext(pCur, pRes);
  pPage = pCur->apPage[pCur->iPage];
  if( (++pCur->aiIdx[pCur->iPage])>=pPage->nCell ){
    pCur->aiIdx[pCur->iPage]--;
    return btreeNext(pCur, pRes);
  }
  if( pPage->leaf ){
    return SQLITE_OK;

  }else{
    return moveToLeftmost(pCur);

  }
}

/*
** Step the cursor to the back to the previous entry in the database.  If
** successful then set *pRes=0.  If the cursor
** was already pointing to the first entry in the database before
** this routine was called, then set *pRes=1.
**
** The main entry point is sqlite3BtreePrevious().  That routine is optimized
** for the common case of merely decrementing the cell counter BtCursor.aiIdx
** to the previous cell on the current page.  The (slower) btreePrevious()
** helper routine is called when it is necessary to move to a different page
** or to restore the cursor.
**
** The calling function will set *pRes to 0 or 1.  The initial *pRes value
** will be 1 if the cursor being stepped corresponds to an SQL index and
** if this routine could have been skipped if that SQL index had been
** a unique index.  Otherwise the caller will have set *pRes to zero.
** Zero is the common case. The btree implementation is free to use the
** initial *pRes value as a hint to improve performance, but the current
** SQLite btree implementation does not. (Note that the comdb2 btree
** implementation does use this hint, however.)
*/
static SQLITE_NOINLINE int btreePrevious(BtCursor *pCur, int *pRes){
  int rc;
  MemPage *pPage;

  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  assert( (pCur->curFlags & (BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey))==0 );
  assert( pCur->info.nSize==0 );
  if( pCur->eState!=CURSOR_VALID ){

    rc = restoreCursorPosition(pCur);
    if( rc!=SQLITE_OK ){

      return rc;

    }
    if( CURSOR_INVALID==pCur->eState ){
      *pRes = 1;
      return SQLITE_OK;
    }
    if( pCur->skipNext ){
      assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_SKIPNEXT );
      pCur->eState = CURSOR_VALID;
      if( pCur->skipNext<0 ){
        pCur->skipNext = 0;

        return SQLITE_OK;
      }
      pCur->skipNext = 0;
    }
  }

  pPage = pCur->apPage[pCur->iPage];
  assert( pPage->isInit );
  if( !pPage->leaf ){
    int idx = pCur->aiIdx[pCur->iPage];
    rc = moveToChild(pCur, get4byte(findCell(pPage, idx)));


    if( rc ) return rc;

    rc = moveToRightmost(pCur);
  }else{
    while( pCur->aiIdx[pCur->iPage]==0 ){
      if( pCur->iPage==0 ){
        pCur->eState = CURSOR_INVALID;
        *pRes = 1;
        return SQLITE_OK;
      }
      moveToParent(pCur);
    }
    assert( pCur->info.nSize==0 );
    assert( (pCur->curFlags & (BTCF_ValidNKey|BTCF_ValidOvfl))==0 );

    pCur->aiIdx[pCur->iPage]--;
    pPage = pCur->apPage[pCur->iPage];
    if( pPage->intKey && !pPage->leaf ){
      rc = sqlite3BtreePrevious(pCur, pRes);
    }else{
      rc = SQLITE_OK;
    }
  }
  return rc;
}
int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 || *pRes==1 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  *pRes = 0;
  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey);
  pCur->info.nSize = 0;
  if( pCur->eState!=CURSOR_VALID
   || pCur->aiIdx[pCur->iPage]==0
   || pCur->apPage[pCur->iPage]->leaf==0
  ){
    return btreePrevious(pCur, pRes);
  }
  pCur->aiIdx[pCur->iPage]--;
  return SQLITE_OK;
}

/*
** Allocate a new page from the database file.
**
** The new page is marked as dirty.  (In other words, sqlite3PagerWrite()
** has already been called on the new page.)  The new page has also
................................................................................
  MemPage *pPrevTrunk = 0;
  Pgno mxPage;     /* Total size of the database file */

  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( eMode==BTALLOC_ANY || (nearby>0 && IfNotOmitAV(pBt->autoVacuum)) );
  pPage1 = pBt->pPage1;
  mxPage = btreePagecount(pBt);
  /* EVIDENCE-OF: R-05119-02637 The 4-byte big-endian integer at offset 36
  ** stores stores the total number of pages on the freelist. */
  n = get4byte(&pPage1->aData[36]);
  testcase( n==mxPage-1 );
  if( n>=mxPage ){
    return SQLITE_CORRUPT_BKPT;
  }
  if( n>0 ){
    /* There are pages on the freelist.  Reuse one of those pages. */
................................................................................
    ** is not true. Otherwise, it runs once for each trunk-page on the
    ** free-list until the page 'nearby' is located (eMode==BTALLOC_EXACT)
    ** or until a page less than 'nearby' is located (eMode==BTALLOC_LT)
    */
    do {
      pPrevTrunk = pTrunk;
      if( pPrevTrunk ){
        /* EVIDENCE-OF: R-01506-11053 The first integer on a freelist trunk page
        ** is the page number of the next freelist trunk page in the list or
        ** zero if this is the last freelist trunk page. */
        iTrunk = get4byte(&pPrevTrunk->aData[0]);
      }else{
        /* EVIDENCE-OF: R-59841-13798 The 4-byte big-endian integer at offset 32
        ** stores the page number of the first page of the freelist, or zero if
        ** the freelist is empty. */
        iTrunk = get4byte(&pPage1->aData[32]);
      }
      testcase( iTrunk==mxPage );
      if( iTrunk>mxPage ){
        rc = SQLITE_CORRUPT_BKPT;
      }else{
        rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
................................................................................
      }
      if( rc ){
        pTrunk = 0;
        goto end_allocate_page;
      }
      assert( pTrunk!=0 );
      assert( pTrunk->aData!=0 );
      /* EVIDENCE-OF: R-13523-04394 The second integer on a freelist trunk page
      ** is the number of leaf page pointers to follow. */
      k = get4byte(&pTrunk->aData[4]);
      if( k==0 && !searchList ){
        /* The trunk has no leaves and the list is not being searched. 
        ** So extract the trunk page itself and use it as the newly 
        ** allocated page */
        assert( pPrevTrunk==0 );
        rc = sqlite3PagerWrite(pTrunk->pDbPage);
        if( rc ){
................................................................................
                 *pPgno, closest+1, k, pTrunk->pgno, n-1));
          rc = sqlite3PagerWrite(pTrunk->pDbPage);
          if( rc ) goto end_allocate_page;
          if( closest<k-1 ){
            memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
          }
          put4byte(&aData[4], k-1);
          noContent = !btreeGetHasContent(pBt, *pPgno)? PAGER_GET_NOCONTENT : 0;
          rc = btreeGetPage(pBt, *pPgno, ppPage, noContent);
          if( rc==SQLITE_OK ){
            rc = sqlite3PagerWrite((*ppPage)->pDbPage);
            if( rc!=SQLITE_OK ){
              releasePage(*ppPage);
            }
          }
................................................................................
    **
    ** Note that the pager will not actually attempt to load or journal 
    ** content for any page that really does lie past the end of the database
    ** file on disk. So the effects of disabling the no-content optimization
    ** here are confined to those pages that lie between the end of the
    ** database image and the end of the database file.
    */
    int bNoContent = (0==IfNotOmitAV(pBt->bDoTruncate))? PAGER_GET_NOCONTENT:0;

    rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
    if( rc ) return rc;
    pBt->nPage++;
    if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ) pBt->nPage++;

#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
      ** 3.6.0, databases with freelist trunk pages holding more than
      ** usableSize/4 - 8 entries will be reported as corrupt.  In order
      ** to maintain backwards compatibility with older versions of SQLite,
      ** we will continue to restrict the number of entries to usableSize/4 - 8
      ** for now.  At some point in the future (once everyone has upgraded
      ** to 3.6.0 or later) we should consider fixing the conditional above
      ** to read "usableSize/4-2" instead of "usableSize/4-8".
      **
      ** EVIDENCE-OF: R-19920-11576 However, newer versions of SQLite still
      ** avoid using the last six entries in the freelist trunk page array in
      ** order that database files created by newer versions of SQLite can be
      ** read by older versions of SQLite.
      */
      rc = sqlite3PagerWrite(pTrunk->pDbPage);
      if( rc==SQLITE_OK ){
        put4byte(&pTrunk->aData[4], nLeaf+1);
        put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
        if( pPage && (pBt->btsFlags & BTS_SECURE_DELETE)==0 ){
          sqlite3PagerDontWrite(pPage->pDbPage);
................................................................................
static void freePage(MemPage *pPage, int *pRC){
  if( (*pRC)==SQLITE_OK ){
    *pRC = freePage2(pPage->pBt, pPage, pPage->pgno);
  }
}

/*
** Free any overflow pages associated with the given Cell.  Write the
** local Cell size (the number of bytes on the original page, omitting
** overflow) into *pnSize.
*/
static int clearCell(
  MemPage *pPage,          /* The page that contains the Cell */
  unsigned char *pCell,    /* First byte of the Cell */
  u16 *pnSize              /* Write the size of the Cell here */
){
  BtShared *pBt = pPage->pBt;
  CellInfo info;
  Pgno ovflPgno;
  int rc;
  int nOvfl;
  u32 ovflPageSize;

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  btreeParseCellPtr(pPage, pCell, &info);
  *pnSize = info.nSize;
  if( info.iOverflow==0 ){
    return SQLITE_OK;  /* No overflow pages. Return without doing anything */
  }
  if( pCell+info.iOverflow+3 > pPage->aData+pPage->maskPage ){
    return SQLITE_CORRUPT_BKPT;  /* Cell extends past end of page */
  }
  ovflPgno = get4byte(&pCell[info.iOverflow]);
................................................................................
  MemPage *pOvfl = 0;
  MemPage *pToRelease = 0;
  unsigned char *pPrior;
  unsigned char *pPayload;
  BtShared *pBt = pPage->pBt;
  Pgno pgnoOvfl = 0;
  int nHeader;


  assert( sqlite3_mutex_held(pPage->pBt->mutex) );

  /* pPage is not necessarily writeable since pCell might be auxiliary
  ** buffer space that is separate from the pPage buffer area */
  assert( pCell<pPage->aData || pCell>=&pPage->aData[pBt->pageSize]
            || sqlite3PagerIswriteable(pPage->pDbPage) );

  /* Fill in the header. */
  nHeader = pPage->childPtrSize;
  nPayload = nData + nZero;


  if( pPage->intKeyLeaf ){
    nHeader += putVarint32(&pCell[nHeader], nPayload);
  }else{

    assert( nData==0 );
    assert( nZero==0 );
  }
  nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);




  
  /* Fill in the payload size */

  if( pPage->intKey ){
    pSrc = pData;
    nSrc = nData;
    nData = 0;
  }else{ 
    if( NEVER(nKey>0x7fffffff || pKey==0) ){
      return SQLITE_CORRUPT_BKPT;
    }
    nPayload = (int)nKey;
    pSrc = pKey;
    nSrc = (int)nKey;
  }
  if( nPayload<=pPage->maxLocal ){
    n = nHeader + nPayload;
    testcase( n==3 );
    testcase( n==4 );
    if( n<4 ) n = 4;
    *pnSize = n;
    spaceLeft = nPayload;
    pPrior = pCell;
  }else{
    int mn = pPage->minLocal;
    n = mn + (nPayload - mn) % (pPage->pBt->usableSize - 4);
    testcase( n==pPage->maxLocal );
    testcase( n==pPage->maxLocal+1 );
    if( n > pPage->maxLocal ) n = mn;
    spaceLeft = n;
    *pnSize = n + nHeader + 4;
    pPrior = &pCell[nHeader+n];
  }
  pPayload = &pCell[nHeader];

  /* At this point variables should be set as follows:
  **
  **   nPayload           Total payload size in bytes
  **   pPayload           Begin writing payload here
  **   spaceLeft          Space available at pPayload.  If nPayload>spaceLeft,
  **                      that means content must spill into overflow pages.
  **   *pnSize            Size of the local cell (not counting overflow pages)
  **   pPrior             Where to write the pgno of the first overflow page
  **
  ** Use a call to btreeParseCellPtr() to verify that the values above
  ** were computed correctly.
  */
#if SQLITE_DEBUG
  {
    CellInfo info;
    btreeParseCellPtr(pPage, pCell, &info);
    assert( nHeader=(int)(info.pPayload - pCell) );
    assert( info.nKey==nKey );
    assert( *pnSize == info.nSize );
    assert( spaceLeft == info.nLocal );
    assert( pPrior == &pCell[info.iOverflow] );
  }
#endif

  /* Write the payload into the local Cell and any extra into overflow pages */
  while( nPayload>0 ){
    if( spaceLeft==0 ){
#ifndef SQLITE_OMIT_AUTOVACUUM
      Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
      if( pBt->autoVacuum ){
        do{
          pgnoOvfl++;
................................................................................
  }
  rc = freeSpace(pPage, pc, sz);
  if( rc ){
    *pRC = rc;
    return;
  }
  pPage->nCell--;
  if( pPage->nCell==0 ){
    memset(&data[hdr+1], 0, 4);
    data[hdr+7] = 0;
    put2byte(&data[hdr+5], pPage->pBt->usableSize);
    pPage->nFree = pPage->pBt->usableSize - pPage->hdrOffset
                       - pPage->childPtrSize - 8;
  }else{
    memmove(ptr, ptr+2, 2*(pPage->nCell - idx));
    put2byte(&data[hdr+3], pPage->nCell);
    pPage->nFree += 2;
  }
}

/*
** Insert a new cell on pPage at cell index "i".  pCell points to the
** content of the cell.
**
** If the cell content will fit on the page, then put it there.  If it
** will not fit, then make a copy of the cell content into pTemp if
** pTemp is not null.  Regardless of pTemp, allocate a new entry
** in pPage->apOvfl[] and make it point to the cell content (either
** in pTemp or the original pCell) and also record its index. 
** Allocating a new entry in pPage->aCell[] implies that 
** pPage->nOverflow is incremented.





*/
static void insertCell(
  MemPage *pPage,   /* Page into which we are copying */
  int i,            /* New cell becomes the i-th cell of the page */
  u8 *pCell,        /* Content of the new cell */
  int sz,           /* Bytes of content in pCell */
  u8 *pTemp,        /* Temp storage space for pCell, if needed */
................................................................................
){
  int idx = 0;      /* Where to write new cell content in data[] */
  int j;            /* Loop counter */
  int end;          /* First byte past the last cell pointer in data[] */
  int ins;          /* Index in data[] where new cell pointer is inserted */
  int cellOffset;   /* Address of first cell pointer in data[] */
  u8 *data;         /* The content of the whole page */


  if( *pRC ) return;

  assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
  assert( MX_CELL(pPage->pBt)<=10921 );
  assert( pPage->nCell<=MX_CELL(pPage->pBt) || CORRUPT_DB );
  assert( pPage->nOverflow<=ArraySize(pPage->apOvfl) );
................................................................................
  ** malformed cell from a leaf page to an interior page, if the cell size
  ** wanted to be less than 4 but got rounded up to 4 on the leaf, then size
  ** might be less than 8 (leaf-size + pointer) on the interior node.  Hence
  ** the term after the || in the following assert(). */
  assert( sz==cellSizePtr(pPage, pCell) || (sz==8 && iChild>0) );
  if( pPage->nOverflow || sz+2>pPage->nFree ){
    if( pTemp ){
      memcpy(pTemp, pCell, sz);
      pCell = pTemp;
    }
    if( iChild ){
      put4byte(pCell, iChild);
    }
    j = pPage->nOverflow++;
    assert( j<(int)(sizeof(pPage->apOvfl)/sizeof(pPage->apOvfl[0])) );
................................................................................
    if( rc ){ *pRC = rc; return; }
    /* The allocateSpace() routine guarantees the following two properties
    ** if it returns success */
    assert( idx >= end+2 );
    assert( idx+sz <= (int)pPage->pBt->usableSize );
    pPage->nCell++;
    pPage->nFree -= (u16)(2 + sz);
    memcpy(&data[idx], pCell, sz);
    if( iChild ){
      put4byte(&data[idx], iChild);
    }
    memmove(&data[ins+2], &data[ins], end-ins);
    put2byte(&data[ins], idx);
    put2byte(&data[pPage->hdrOffset+3], pPage->nCell);
#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
      ptrmapPutOvflPtr(pPage, pCell, pRC);
    }
#endif
  }
}

/*
** Array apCell[] contains pointers to nCell b-tree page cells. The 
** szCell[] array contains the size in bytes of each cell. This function
** replaces the current contents of page pPg with the contents of the cell
** array.
**
** Some of the cells in apCell[] may currently be stored in pPg. This
** function works around problems caused by this by making a copy of any 
** such cells before overwriting the page data.
**
** The MemPage.nFree field is invalidated by this function. It is the 
** responsibility of the caller to set it correctly.
*/
static void rebuildPage(


  MemPage *pPg,                   /* Edit this page */
  int nCell,                      /* Final number of cells on page */
  u8 **apCell,                    /* Array of cells */

  u16 *szCell                     /* Array of cell sizes */
){






  const int hdr = pPg->hdrOffset;          /* Offset of header on pPg */
  u8 * const aData = pPg->aData;           /* Pointer to data for pPg */
  const int usableSize = pPg->pBt->usableSize;
  u8 * const pEnd = &aData[usableSize];
  int i;
  u8 *pCellptr = pPg->aCellIdx;
  u8 *pTmp = sqlite3PagerTempSpace(pPg->pBt->pPager);
  u8 *pData;

  i = get2byte(&aData[hdr+5]);
  memcpy(&pTmp[i], &aData[i], usableSize - i);

  pData = pEnd;
  for(i=0; i<nCell; i++){
    u8 *pCell = apCell[i];
    if( pCell>aData && pCell<pEnd ){
      pCell = &pTmp[pCell - aData];
    }
    pData -= szCell[i];
    memcpy(pData, pCell, szCell[i]);
    put2byte(pCellptr, (pData - aData));
    pCellptr += 2;
    assert( szCell[i]==cellSizePtr(pPg, pCell) );
  }

  /* The pPg->nFree field is now set incorrectly. The caller will fix it. */
  pPg->nCell = nCell;
  pPg->nOverflow = 0;








  put2byte(&aData[hdr+1], 0);
  put2byte(&aData[hdr+3], pPg->nCell);
  put2byte(&aData[hdr+5], pData - aData);
  aData[hdr+7] = 0x00;
}





/*
** Array apCell[] contains nCell pointers to b-tree cells. Array szCell
** contains the size in bytes of each such cell. This function attempts to 
** add the cells stored in the array to page pPg. If it cannot (because 
** the page needs to be defragmented before the cells will fit), non-zero
** is returned. Otherwise, if the cells are added successfully, zero is
** returned.
**
** Argument pCellptr points to the first entry in the cell-pointer array
** (part of page pPg) to populate. After cell apCell[0] is written to the
** page body, a 16-bit offset is written to pCellptr. And so on, for each
** cell in the array. It is the responsibility of the caller to ensure
** that it is safe to overwrite this part of the cell-pointer array.
**
** When this function is called, *ppData points to the start of the 
** content area on page pPg. If the size of the content area is extended,
** *ppData is updated to point to the new start of the content area
** before returning.
**
** Finally, argument pBegin points to the byte immediately following the
** end of the space required by this page for the cell-pointer area (for
** all cells - not just those inserted by the current call). If the content
** area must be extended to before this point in order to accomodate all
** cells in apCell[], then the cells do not fit and non-zero is returned.
*/
static int pageInsertArray(
  MemPage *pPg,                   /* Page to add cells to */
  u8 *pBegin,                     /* End of cell-pointer array */
  u8 **ppData,                    /* IN/OUT: Page content -area pointer */
  u8 *pCellptr,                   /* Pointer to cell-pointer area */
  int nCell,                      /* Number of cells to add to pPg */
  u8 **apCell,                    /* Array of cells */
  u16 *szCell                     /* Array of cell sizes */
){
  int i;
  u8 *aData = pPg->aData;
  u8 *pData = *ppData;
  const int bFreelist = aData[1] || aData[2];
  assert( CORRUPT_DB || pPg->hdrOffset==0 );    /* Never called on page 1 */
  for(i=0; i<nCell; i++){
    int sz = szCell[i];
    int rc;
    u8 *pSlot;
    if( bFreelist==0 || (pSlot = pageFindSlot(pPg, sz, &rc, 0))==0 ){
      pData -= sz;
      if( pData<pBegin ) return 1;
      pSlot = pData;
    }
    memcpy(pSlot, apCell[i], sz);
    put2byte(pCellptr, (pSlot - aData));
    pCellptr += 2;
  }
  *ppData = pData;
  return 0;
}

/*
** Array apCell[] contains nCell pointers to b-tree cells. Array szCell 
** contains the size in bytes of each such cell. This function adds the
** space associated with each cell in the array that is currently stored 
** within the body of pPg to the pPg free-list. The cell-pointers and other
** fields of the page are not updated.
**
** This function returns the total number of cells added to the free-list.
*/
static int pageFreeArray(
  MemPage *pPg,                   /* Page to edit */
  int nCell,                      /* Cells to delete */
  u8 **apCell,                    /* Array of cells */
  u16 *szCell                     /* Array of cell sizes */
){
  u8 * const aData = pPg->aData;
  u8 * const pEnd = &aData[pPg->pBt->usableSize];
  u8 * const pStart = &aData[pPg->hdrOffset + 8 + pPg->childPtrSize];
  int nRet = 0;
  int i;
  u8 *pFree = 0;
  int szFree = 0;

  for(i=0; i<nCell; i++){
    u8 *pCell = apCell[i];
    if( pCell>=pStart && pCell<pEnd ){
      int sz = szCell[i];
      if( pFree!=(pCell + sz) ){
        if( pFree ){
          assert( pFree>aData && (pFree - aData)<65536 );
          freeSpace(pPg, (u16)(pFree - aData), szFree);
        }
        pFree = pCell;
        szFree = sz;
        if( pFree+sz>pEnd ) return 0;
      }else{
        pFree = pCell;
        szFree += sz;
      }
      nRet++;
    }
  }
  if( pFree ){
    assert( pFree>aData && (pFree - aData)<65536 );
    freeSpace(pPg, (u16)(pFree - aData), szFree);
  }
  return nRet;
}

/*
** apCell[] and szCell[] contains pointers to and sizes of all cells in the
** pages being balanced.  The current page, pPg, has pPg->nCell cells starting
** with apCell[iOld].  After balancing, this page should hold nNew cells
** starting at apCell[iNew].
**
** This routine makes the necessary adjustments to pPg so that it contains
** the correct cells after being balanced.
**
** The pPg->nFree field is invalid when this function returns. It is the
** responsibility of the caller to set it correctly.
*/
static void editPage(
  MemPage *pPg,                   /* Edit this page */
  int iOld,                       /* Index of first cell currently on page */
  int iNew,                       /* Index of new first cell on page */
  int nNew,                       /* Final number of cells on page */
  u8 **apCell,                    /* Array of cells */
  u16 *szCell                     /* Array of cell sizes */
){
  u8 * const aData = pPg->aData;
  const int hdr = pPg->hdrOffset;
  u8 *pBegin = &pPg->aCellIdx[nNew * 2];
  int nCell = pPg->nCell;       /* Cells stored on pPg */
  u8 *pData;
  u8 *pCellptr;

  int i;
  int iOldEnd = iOld + pPg->nCell + pPg->nOverflow;
  int iNewEnd = iNew + nNew;




#ifdef SQLITE_DEBUG
  u8 *pTmp = sqlite3PagerTempSpace(pPg->pBt->pPager);
  memcpy(pTmp, aData, pPg->pBt->usableSize);
#endif

  /* Remove cells from the start and end of the page */
  if( iOld<iNew ){
    int nShift = pageFreeArray(
        pPg, iNew-iOld, &apCell[iOld], &szCell[iOld]
    );
    memmove(pPg->aCellIdx, &pPg->aCellIdx[nShift*2], nCell*2);
    nCell -= nShift;
  }
  if( iNewEnd < iOldEnd ){
    nCell -= pageFreeArray(
        pPg, iOldEnd-iNewEnd, &apCell[iNewEnd], &szCell[iNewEnd]
    );
  }

  pData = &aData[get2byteNotZero(&aData[hdr+5])];
  if( pData<pBegin ) goto editpage_fail;

  /* Add cells to the start of the page */
  if( iNew<iOld ){
    int nAdd = MIN(nNew,iOld-iNew);
    assert( (iOld-iNew)<nNew || nCell==0 || CORRUPT_DB );
    pCellptr = pPg->aCellIdx;
    memmove(&pCellptr[nAdd*2], pCellptr, nCell*2);
    if( pageInsertArray(
          pPg, pBegin, &pData, pCellptr,
          nAdd, &apCell[iNew], &szCell[iNew]
    ) ) goto editpage_fail;
    nCell += nAdd;
  }

  /* Add any overflow cells */
  for(i=0; i<pPg->nOverflow; i++){
    int iCell = (iOld + pPg->aiOvfl[i]) - iNew;
    if( iCell>=0 && iCell<nNew ){
      pCellptr = &pPg->aCellIdx[iCell * 2];
      memmove(&pCellptr[2], pCellptr, (nCell - iCell) * 2);
      nCell++;
      if( pageInsertArray(
            pPg, pBegin, &pData, pCellptr,
            1, &apCell[iCell + iNew], &szCell[iCell + iNew]
      ) ) goto editpage_fail;
    }
  }

  /* Append cells to the end of the page */
  pCellptr = &pPg->aCellIdx[nCell*2];
  if( pageInsertArray(
        pPg, pBegin, &pData, pCellptr,
        nNew-nCell, &apCell[iNew+nCell], &szCell[iNew+nCell]
  ) ) goto editpage_fail;

  pPg->nCell = nNew;
  pPg->nOverflow = 0;

  put2byte(&aData[hdr+3], pPg->nCell);
  put2byte(&aData[hdr+5], pData - aData);

#ifdef SQLITE_DEBUG
  for(i=0; i<nNew && !CORRUPT_DB; i++){
    u8 *pCell = apCell[i+iNew];
    int iOff = get2byte(&pPg->aCellIdx[i*2]);
    if( pCell>=aData && pCell<&aData[pPg->pBt->usableSize] ){
      pCell = &pTmp[pCell - aData];
    }
    assert( 0==memcmp(pCell, &aData[iOff], szCell[i+iNew]) );
  }
#endif

  return;
 editpage_fail:
  /* Unable to edit this page. Rebuild it from scratch instead. */
  rebuildPage(pPg, nNew, &apCell[iNew], &szCell[iNew]);
}

/*
** The following parameters determine how many adjacent pages get involved
** in a balancing operation.  NN is the number of neighbors on either side
** of the page that participate in the balancing operation.  NB is the
** total number of pages that participate, including the target page and
................................................................................
  Pgno pgnoNew;                        /* Page number of pNew */

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
  assert( pPage->nOverflow==1 );

  /* This error condition is now caught prior to reaching this function */
  if( NEVER(pPage->nCell==0) ) return SQLITE_CORRUPT_BKPT;

  /* Allocate a new page. This page will become the right-sibling of 
  ** pPage. Make the parent page writable, so that the new divider cell
  ** may be inserted. If both these operations are successful, proceed.
  */
  rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);

................................................................................
    u8 *pCell = pPage->apOvfl[0];
    u16 szCell = cellSizePtr(pPage, pCell);
    u8 *pStop;

    assert( sqlite3PagerIswriteable(pNew->pDbPage) );
    assert( pPage->aData[0]==(PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF) );
    zeroPage(pNew, PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF);
    rebuildPage(pNew, 1, &pCell, &szCell);
    pNew->nFree = pBt->usableSize - pNew->cellOffset - 2 - szCell;

    /* If this is an auto-vacuum database, update the pointer map
    ** with entries for the new page, and any pointer from the 
    ** cell on the page to an overflow page. If either of these
    ** operations fails, the return code is set, but the contents
    ** of the parent page are still manipulated by thh code below.
    ** That is Ok, at this point the parent page is guaranteed to
................................................................................
  int usableSpace;             /* Bytes in pPage beyond the header */
  int pageFlags;               /* Value of pPage->aData[0] */
  int subtotal;                /* Subtotal of bytes in cells on one page */
  int iSpace1 = 0;             /* First unused byte of aSpace1[] */
  int iOvflSpace = 0;          /* First unused byte of aOvflSpace[] */
  int szScratch;               /* Size of scratch memory requested */
  MemPage *apOld[NB];          /* pPage and up to two siblings */

  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
  u8 *pRight;                  /* Location in parent of right-sibling pointer */
  u8 *apDiv[NB-1];             /* Divider cells in pParent */
  int cntNew[NB+2];            /* Index in aCell[] of cell after i-th page */
  int cntOld[NB+2];            /* Old index in aCell[] after i-th page */
  int szNew[NB+2];             /* Combined size of cells placed on i-th page */
  u8 **apCell = 0;             /* All cells begin balanced */
  u16 *szCell;                 /* Local size of all cells in apCell[] */
  u8 *aSpace1;                 /* Space for copies of dividers cells */
  Pgno pgno;                   /* Temp var to store a page number in */
  u8 abDone[NB+2];             /* True after i'th new page is populated */
  Pgno aPgno[NB+2];            /* Page numbers of new pages before shuffling */
  Pgno aPgOrder[NB+2];         /* Copy of aPgno[] used for sorting pages */
  u16 aPgFlags[NB+2];          /* flags field of new pages before shuffling */

  memset(abDone, 0, sizeof(abDone));
  pBt = pParent->pBt;
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( sqlite3PagerIswriteable(pParent->pDbPage) );

#if 0
  TRACE(("BALANCE: begin page %d child of %d\n", pPage->pgno, pParent->pgno));
#endif
................................................................................
  /* Make nMaxCells a multiple of 4 in order to preserve 8-byte
  ** alignment */
  nMaxCells = (nMaxCells + 3)&~3;

  /*
  ** Allocate space for memory structures
  */

  szScratch =
       nMaxCells*sizeof(u8*)                       /* apCell */
     + nMaxCells*sizeof(u16)                       /* szCell */

     + pBt->pageSize;                              /* aSpace1 */

  /* EVIDENCE-OF: R-28375-38319 SQLite will never request a scratch buffer
  ** that is more than 6 times the database page size. */
  assert( szScratch<=6*(int)pBt->pageSize );
  apCell = sqlite3ScratchMalloc( szScratch ); 
  if( apCell==0 ){
    rc = SQLITE_NOMEM;
    goto balance_cleanup;
  }
  szCell = (u16*)&apCell[nMaxCells];
  aSpace1 = (u8*)&szCell[nMaxCells];
  assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );

  /*
  ** Load pointers to all cells on sibling pages and the divider cells
  ** into the local apCell[] array.  Make copies of the divider cells
  ** into space obtained from aSpace1[]. The divider cells have already
  ** been removed from pParent.
  **
  ** If the siblings are on leaf pages, then the child pointers of the
  ** divider cells are stripped from the cells before they are copied
  ** into aSpace1[].  In this way, all cells in apCell[] are without
  ** child pointers.  If siblings are not leaves, then all cell in
  ** apCell[] include child pointers.  Either way, all cells in apCell[]
  ** are alike.
  **
  ** leafCorrection:  4 if pPage is a leaf.  0 if pPage is not a leaf.
  **       leafData:  1 if pPage holds key+data and pParent holds only keys.
  */
  leafCorrection = apOld[0]->leaf*4;
  leafData = apOld[0]->intKeyLeaf;
  for(i=0; i<nOld; i++){
    int limit;





    MemPage *pOld = apOld[i];




    limit = pOld->nCell+pOld->nOverflow;
    if( pOld->nOverflow>0 ){
      for(j=0; j<limit; j++){
        assert( nCell<nMaxCells );
        apCell[nCell] = findOverflowCell(pOld, j);
        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
................................................................................
      for(j=0; j<limit; j++){
        assert( nCell<nMaxCells );
        apCell[nCell] = findCellv2(aData, maskPage, cellOffset, j);
        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
        nCell++;
      }
    }       
    cntOld[i] = nCell;
    if( i<nOld-1 && !leafData){
      u16 sz = (u16)szNew[i];
      u8 *pTemp;
      assert( nCell<nMaxCells );
      szCell[nCell] = sz;
      pTemp = &aSpace1[iSpace1];
      iSpace1 += sz;
................................................................................
        assert( pOld->hdrOffset==0 );
        /* The right pointer of the child page pOld becomes the left
        ** pointer of the divider cell */
        memcpy(apCell[nCell], &pOld->aData[8], 4);
      }else{
        assert( leafCorrection==4 );
        if( szCell[nCell]<4 ){
          /* Do not allow any cells smaller than 4 bytes. If a smaller cell
          ** does exist, pad it with 0x00 bytes. */
          assert( szCell[nCell]==3 );
          assert( apCell[nCell]==&pTemp[iSpace1-3] );
          pTemp[iSpace1++] = 0x00;
          szCell[nCell] = 4;
        }
      }
      nCell++;
    }
  }

................................................................................
  ** 
  */
  usableSpace = pBt->usableSize - 12 + leafCorrection;
  for(subtotal=k=i=0; i<nCell; i++){
    assert( i<nMaxCells );
    subtotal += szCell[i] + 2;
    if( subtotal > usableSpace ){
      szNew[k] = subtotal - szCell[i] - 2;
      cntNew[k] = i;
      if( leafData ){ i--; }
      subtotal = 0;
      k++;
      if( k>NB+1 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
    }
  }
  szNew[k] = subtotal;
  cntNew[k] = nCell;
  k++;

  /*
  ** The packing computed by the previous block is biased toward the siblings
  ** on the left side (siblings with smaller keys). The left siblings are
  ** always nearly full, while the right-most sibling might be nearly empty.
  ** The next block of code attempts to adjust the packing of siblings to
  ** get a better balance.
  **
  ** This adjustment is more than an optimization.  The packing above might
  ** be so out of balance as to be illegal.  For example, the right-most
  ** sibling might be completely empty.  This adjustment is not optional.
  */
  for(i=k-1; i>0; i--){
    int szRight = szNew[i];  /* Size of sibling on the right */
................................................................................
      r = cntNew[i-1] - 1;
      d = r + 1 - leafData;
    }
    szNew[i] = szRight;
    szNew[i-1] = szLeft;
  }

  /* Sanity check:  For a non-corrupt database file one of the follwing
  ** must be true:
  **    (1) We found one or more cells (cntNew[0])>0), or
  **    (2) pPage is a virtual root page.  A virtual root page is when
  **        the real root page is page 1 and we are the only child of


  **        that page.

  */

  assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) || CORRUPT_DB);


  TRACE(("BALANCE: old: %d(nc=%d) %d(nc=%d) %d(nc=%d)\n",
    apOld[0]->pgno, apOld[0]->nCell,
    nOld>=2 ? apOld[1]->pgno : 0, nOld>=2 ? apOld[1]->nCell : 0,
    nOld>=3 ? apOld[2]->pgno : 0, nOld>=3 ? apOld[2]->nCell : 0
  ));

  /*
  ** Allocate k new pages.  Reuse old pages where possible.
  */
  if( apOld[0]->pgno<=1 ){
    rc = SQLITE_CORRUPT_BKPT;
................................................................................
      rc = sqlite3PagerWrite(pNew->pDbPage);
      nNew++;
      if( rc ) goto balance_cleanup;
    }else{
      assert( i>0 );
      rc = allocateBtreePage(pBt, &pNew, &pgno, (bBulk ? 1 : pgno), 0);
      if( rc ) goto balance_cleanup;
      zeroPage(pNew, pageFlags);
      apNew[i] = pNew;
      nNew++;
      cntOld[i] = nCell;

      /* Set the pointer-map entry for the new sibling page. */
      if( ISAUTOVACUUM ){
        ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno, &rc);
        if( rc!=SQLITE_OK ){
          goto balance_cleanup;
        }
      }
    }
  }











  /*

  ** Reassign page numbers so that the new pages are in ascending order. 
  ** This helps to keep entries in the disk file in order so that a scan
  ** of the table is closer to a linear scan through the file. That in turn 
  ** helps the operating system to deliver pages from the disk more rapidly.

  **
  ** An O(n^2) insertion sort algorithm is used, but since n is never more 
  ** than (NB+2) (a small constant), that should not be a problem.

  **
  ** When NB==3, this one optimization makes the database about 25% faster 
  ** for large insertions and deletions.
  */
  for(i=0; i<nNew; i++){
    aPgOrder[i] = aPgno[i] = apNew[i]->pgno;
    aPgFlags[i] = apNew[i]->pDbPage->flags;



    for(j=0; j<i; j++){
      if( aPgno[j]==aPgno[i] ){
        /* This branch is taken if the set of sibling pages somehow contains
        ** duplicate entries. This can happen if the database is corrupt. 
        ** It would be simpler to detect this as part of the loop below, but
        ** we do the detection here in order to avoid populating the pager
        ** cache with two separate objects associated with the same
        ** page number.  */
        assert( CORRUPT_DB );
        rc = SQLITE_CORRUPT_BKPT;
        goto balance_cleanup;
      }
    }
  }
  for(i=0; i<nNew; i++){
    int iBest = 0;                /* aPgno[] index of page number to use */
    for(j=1; j<nNew; j++){
      if( aPgOrder[j]<aPgOrder[iBest] ) iBest = j;
    }
    pgno = aPgOrder[iBest];
    aPgOrder[iBest] = 0xffffffff;
    if( iBest!=i ){
      if( iBest>i ){
        sqlite3PagerRekey(apNew[iBest]->pDbPage, pBt->nPage+iBest+1, 0);
      }


      sqlite3PagerRekey(apNew[i]->pDbPage, pgno, aPgFlags[iBest]);
      apNew[i]->pgno = pgno;


    }
  }


  TRACE(("BALANCE: new: %d(%d nc=%d) %d(%d nc=%d) %d(%d nc=%d) "
         "%d(%d nc=%d) %d(%d nc=%d)\n",
    apNew[0]->pgno, szNew[0], cntNew[0],
    nNew>=2 ? apNew[1]->pgno : 0, nNew>=2 ? szNew[1] : 0,
    nNew>=2 ? cntNew[1] - cntNew[0] - !leafData : 0,
    nNew>=3 ? apNew[2]->pgno : 0, nNew>=3 ? szNew[2] : 0,
    nNew>=3 ? cntNew[2] - cntNew[1] - !leafData : 0,
    nNew>=4 ? apNew[3]->pgno : 0, nNew>=4 ? szNew[3] : 0,
    nNew>=4 ? cntNew[3] - cntNew[2] - !leafData : 0,
    nNew>=5 ? apNew[4]->pgno : 0, nNew>=5 ? szNew[4] : 0,
    nNew>=5 ? cntNew[4] - cntNew[3] - !leafData : 0
  ));

  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
  put4byte(pRight, apNew[nNew-1]->pgno);

  /* If the sibling pages are not leaves, ensure that the right-child pointer
  ** of the right-most new sibling page is set to the value that was 
  ** originally in the same field of the right-most old sibling page. */
  if( (pageFlags & PTF_LEAF)==0 && nOld!=nNew ){
    MemPage *pOld = (nNew>nOld ? apNew : apOld)[nOld-1];
    memcpy(&apNew[nNew-1]->aData[8], &pOld->aData[8], 4);
  }

  /* Make any required updates to pointer map entries associated with 
  ** cells stored on sibling pages following the balance operation. Pointer
  ** map entries associated with divider cells are set by the insertCell()
  ** routine. The associated pointer map entries are:
  **


  **   a) if the cell contains a reference to an overflow chain, the
  **      entry associated with the first page in the overflow chain, and
  **
  **   b) if the sibling pages are not leaves, the child page associated
  **      with the cell.
  **
  ** If the sibling pages are not leaves, then the pointer map entry 
  ** associated with the right-child of each sibling may also need to be 
  ** updated. This happens below, after the sibling pages have been 
  ** populated, not here.
  */



  if( ISAUTOVACUUM ){
    MemPage *pNew = apNew[0];




    u8 *aOld = pNew->aData;
    int cntOldNext = pNew->nCell + pNew->nOverflow;
    int usableSize = pBt->usableSize;
    int iNew = 0;
    int iOld = 0;

    for(i=0; i<nCell; i++){
      u8 *pCell = apCell[i];
      if( i==cntOldNext ){
        MemPage *pOld = (++iOld)<nNew ? apNew[iOld] : apOld[iOld];
        cntOldNext += pOld->nCell + pOld->nOverflow + !leafData;
        aOld = pOld->aData;
      }
      if( i==cntNew[iNew] ){
        pNew = apNew[++iNew];
        if( !leafData ) continue;
      }






      /* Cell pCell is destined for new sibling page pNew. Originally, it
      ** was either part of sibling page iOld (possibly an overflow cell), 
      ** or else the divider cell to the left of sibling page iOld. So,
      ** if sibling page iOld had the same page number as pNew, and if
      ** pCell really was a part of sibling page iOld (not a divider or
      ** overflow cell), we can skip updating the pointer map entries.  */
      if( iOld>=nNew
       || pNew->pgno!=aPgno[iOld]
       || pCell<aOld
       || pCell>=&aOld[usableSize]
      ){
        if( !leafCorrection ){
          ptrmapPut(pBt, get4byte(pCell), PTRMAP_BTREE, pNew->pgno, &rc);
        }
        if( szCell[i]>pNew->minLocal ){
          ptrmapPutOvflPtr(pNew, pCell, &rc);
        }
      }
    }
  }

  /* Insert new divider cells into pParent. */
  for(i=0; i<nNew-1; i++){
    u8 *pCell;
    u8 *pTemp;
    int sz;
    MemPage *pNew = apNew[i];
    j = cntNew[i];

    assert( j<nMaxCells );
    pCell = apCell[j];
    sz = szCell[j] + leafCorrection;
    pTemp = &aOvflSpace[iOvflSpace];
    if( !pNew->leaf ){
      memcpy(&pNew->aData[8], pCell, 4);
    }else if( leafData ){
      /* If the tree is a leaf-data tree, and the siblings are leaves, 
      ** then there is no divider cell in apCell[]. Instead, the divider 
      ** cell consists of the integer key for the right-most cell of 
      ** the sibling-page assembled above only.
      */
      CellInfo info;
      j--;
      btreeParseCellPtr(pNew, apCell[j], &info);
      pCell = pTemp;
      sz = 4 + putVarint(&pCell[4], info.nKey);
      pTemp = 0;
    }else{
      pCell -= 4;
      /* Obscure case for non-leaf-data trees: If the cell at pCell was
      ** previously stored on a leaf node, and its reported size was 4
      ** bytes, then it may actually be smaller than this 
      ** (see btreeParseCellPtr(), 4 bytes is the minimum size of
      ** any cell). But it is important to pass the correct size to 
      ** insertCell(), so reparse the cell now.
      **
      ** Note that this can never happen in an SQLite data file, as all
      ** cells are at least 4 bytes. It only happens in b-trees used
      ** to evaluate "IN (SELECT ...)" and similar clauses.
      */
      if( szCell[j]==4 ){
        assert(leafCorrection==4);
        sz = cellSizePtr(pParent, pCell);
      }
    }
    iOvflSpace += sz;
    assert( sz<=pBt->maxLocal+23 );
    assert( iOvflSpace <= (int)pBt->pageSize );
    insertCell(pParent, nxDiv+i, pCell, sz, pTemp, pNew->pgno, &rc);
    if( rc!=SQLITE_OK ) goto balance_cleanup;
    assert( sqlite3PagerIswriteable(pParent->pDbPage) );
  }



  /* Now update the actual sibling pages. The order in which they are updated
  ** is important, as this code needs to avoid disrupting any page from which
  ** cells may still to be read. In practice, this means:
  **
  **  (1) If cells are moving left (from apNew[iPg] to apNew[iPg-1])
  **      then it is not safe to update page apNew[iPg] until after
  **      the left-hand sibling apNew[iPg-1] has been updated.
  **
  **  (2) If cells are moving right (from apNew[iPg] to apNew[iPg+1])
  **      then it is not safe to update page apNew[iPg] until after
  **      the right-hand sibling apNew[iPg+1] has been updated.
  **
  ** If neither of the above apply, the page is safe to update.
  **
  ** The iPg value in the following loop starts at nNew-1 goes down
  ** to 0, then back up to nNew-1 again, thus making two passes over
  ** the pages.  On the initial downward pass, only condition (1) above
  ** needs to be tested because (2) will always be true from the previous
  ** step.  On the upward pass, both conditions are always true, so the
  ** upwards pass simply processes pages that were missed on the downward
  ** pass.
  */
  for(i=1-nNew; i<nNew; i++){
    int iPg = i<0 ? -i : i;
    assert( iPg>=0 && iPg<nNew );
    if( abDone[iPg] ) continue;         /* Skip pages already processed */
    if( i>=0                            /* On the upwards pass, or... */
     || cntOld[iPg-1]>=cntNew[iPg-1]    /* Condition (1) is true */
    ){
      int iNew;
      int iOld;
      int nNewCell;


      /* Verify condition (1):  If cells are moving left, update iPg
      ** only after iPg-1 has already been updated. */
      assert( iPg==0 || cntOld[iPg-1]>=cntNew[iPg-1] || abDone[iPg-1] );

      /* Verify condition (2):  If cells are moving right, update iPg
      ** only after iPg+1 has already been updated. */
      assert( cntNew[iPg]>=cntOld[iPg] || abDone[iPg+1] );

      if( iPg==0 ){
        iNew = iOld = 0;
        nNewCell = cntNew[0];
      }else{
        iOld = iPg<nOld ? (cntOld[iPg-1] + !leafData) : nCell;
        iNew = cntNew[iPg-1] + !leafData;
        nNewCell = cntNew[iPg] - iNew;
      }

      editPage(apNew[iPg], iOld, iNew, nNewCell, apCell, szCell);
      abDone[iPg]++;
      apNew[iPg]->nFree = usableSpace-szNew[iPg];
      assert( apNew[iPg]->nOverflow==0 );
      assert( apNew[iPg]->nCell==nNewCell );
    }
  }

  /* All pages have been processed exactly once */
  assert( memcmp(abDone, "\01\01\01\01\01", nNew)==0 );

  assert( nOld>0 );
  assert( nNew>0 );





  if( isRoot && pParent->nCell==0 && pParent->hdrOffset<=apNew[0]->nFree ){
    /* The root page of the b-tree now contains no cells. The only sibling
    ** page is the right-child of the parent. Copy the contents of the
    ** child page into the parent, decreasing the overall height of the
    ** b-tree structure by one. This is described as the "balance-shallower"
    ** sub-algorithm in some documentation.
    **
    ** If this is an auto-vacuum database, the call to copyNodeContent() 
    ** sets all pointer-map entries corresponding to database image pages 
    ** for which the pointer is stored within the content being copied.
    **
    ** It is critical that the child page be defragmented before being
    ** copied into the parent, because if the parent is page 1 then it will
    ** by smaller than the child due to the database header, and so all the
    ** free space needs to be up front.
    */
    assert( nNew==1 );
    rc = defragmentPage(apNew[0]);
    testcase( rc!=SQLITE_OK );
    assert( apNew[0]->nFree == 
        (get2byte(&apNew[0]->aData[5])-apNew[0]->cellOffset-apNew[0]->nCell*2)
      || rc!=SQLITE_OK
    );
    copyNodeContent(apNew[0], pParent, &rc);
    freePage(apNew[0], &rc);
  }else if( ISAUTOVACUUM && !leafCorrection ){











    /* Fix the pointer map entries associated with the right-child of each


























    ** sibling page. All other pointer map entries have already been taken
    ** care of.  */
    for(i=0; i<nNew; i++){












      u32 key = get4byte(&apNew[i]->aData[8]);
      ptrmapPut(pBt, key, PTRMAP_BTREE, apNew[i]->pgno, &rc);
    }

  }


















  assert( pParent->isInit );

  TRACE(("BALANCE: finished: old=%d new=%d cells=%d\n",
          nOld, nNew, nCell));








  /* Free any old pages that were not reused as new pages.
  */
  for(i=nNew; i<nOld; i++){
    freePage(apOld[i], &rc);
  }













#if 0
  if( ISAUTOVACUUM && rc==SQLITE_OK && apNew[0]->isInit ){
    /* The ptrmapCheckPages() contains assert() statements that verify that
    ** all pointer map pages are set correctly. This is helpful while 
    ** debugging. This is usually disabled because a corrupt database may
    ** cause an assert() statement to fail.  */
    ptrmapCheckPages(apNew, nNew);
    ptrmapCheckPages(&pParent, 1);

  }




#endif

  /*
  ** Cleanup before returning.
  */
balance_cleanup:
  sqlite3ScratchFree(apCell);
  for(i=0; i<nOld; i++){
................................................................................
    }else{
      MemPage * const pParent = pCur->apPage[iPage-1];
      int const iIdx = pCur->aiIdx[iPage-1];

      rc = sqlite3PagerWrite(pParent->pDbPage);
      if( rc==SQLITE_OK ){
#ifndef SQLITE_OMIT_QUICKBALANCE
        if( pPage->intKeyLeaf
         && pPage->nOverflow==1
         && pPage->aiOvfl[0]==pPage->nCell
         && pParent->pgno!=1
         && pParent->nCell==iIdx
        ){
          /* Call balance_quick() to create a new sibling of pPage on which
          ** to store the overflow cell. balance_quick() inserts a new cell
          ** into pParent, which may cause pParent overflow. If this
          ** happens, the next iteration of the do-loop will balance pParent 
          ** use either balance_nonroot() or balance_deeper(). Until this
          ** happens, the overflow cell is stored in the aBalanceQuickSpace[]
          ** buffer. 
          **
          ** The purpose of the following assert() is to check that only a
          ** single call to balance_quick() is made for each call to this
          ** function. If this were not verified, a subtle bug involving reuse
................................................................................
** For an INTKEY table, only the nKey value of the key is used.  pKey is
** ignored.  For a ZERODATA table, the pData and nData are both ignored.
**
** If the seekResult parameter is non-zero, then a successful call to
** MovetoUnpacked() to seek cursor pCur to (pKey, nKey) has already
** been performed. seekResult is the search result returned (a negative
** number if pCur points at an entry that is smaller than (pKey, nKey), or
** a positive value if pCur points at an entry that is larger than 
** (pKey, nKey)). 
**
** If the seekResult parameter is non-zero, then the caller guarantees that
** cursor pCur is pointing at the existing copy of a row that is to be
** overwritten.  If the seekResult parameter is 0, then cursor pCur may
** point to any entry or to no entry at all and so this function has to seek
** the cursor before the new key can be inserted.
................................................................................

  if( pCur->eState==CURSOR_FAULT ){
    assert( pCur->skipNext!=SQLITE_OK );
    return pCur->skipNext;
  }

  assert( cursorHoldsMutex(pCur) );
  assert( (pCur->curFlags & BTCF_WriteFlag)!=0
              && pBt->inTransaction==TRANS_WRITE
              && (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );

  /* Assert that the caller has been consistent. If this cursor was opened
  ** expecting an index b-tree, then the caller should be inserting blob
  ** keys with no associated data. If the cursor was opened expecting an
  ** intkey table, the caller should be inserting integer keys with a
................................................................................
    /* If this is an insert into a table b-tree, invalidate any incrblob 
    ** cursors open on the row being replaced */
    invalidateIncrblobCursors(p, nKey, 0);

    /* If the cursor is currently on the last row and we are appending a
    ** new row onto the end, set the "loc" to avoid an unnecessary btreeMoveto()
    ** call */
    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && nKey>0
      && pCur->info.nKey==nKey-1 ){
      loc = -1;
    }
  }

  if( !loc ){
    rc = btreeMoveto(pCur, pKey, nKey, appendBias, &loc);
    if( rc ) return rc;
................................................................................
  assert( pPage->intKey || nKey>=0 );
  assert( pPage->leaf || !pPage->intKey );

  TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
          pCur->pgnoRoot, nKey, nData, pPage->pgno,
          loc==0 ? "overwrite" : "new entry"));
  assert( pPage->isInit );

  newCell = pBt->pTmpSpace;

  assert( newCell!=0 );
  rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
  if( rc ) goto end_insert;
  assert( szNew==cellSizePtr(pPage, newCell) );
  assert( szNew <= MX_CELL_SIZE(pBt) );
  idx = pCur->aiIdx[pCur->iPage];
  if( loc==0 ){
    u16 szOld;
................................................................................
    if( rc ){
      goto end_insert;
    }
    oldCell = findCell(pPage, idx);
    if( !pPage->leaf ){
      memcpy(newCell, oldCell, 4);
    }

    rc = clearCell(pPage, oldCell, &szOld);
    dropCell(pPage, idx, szOld, &rc);
    if( rc ) goto end_insert;
  }else if( loc<0 && pPage->nCell>0 ){
    assert( pPage->leaf );
    idx = ++pCur->aiIdx[pCur->iPage];
  }else{
    assert( pPage->leaf );
................................................................................

end_insert:
  return rc;
}

/*
** Delete the entry that the cursor is pointing to.  The cursor
** is left pointing at an arbitrary location.
*/
int sqlite3BtreeDelete(BtCursor *pCur){
  Btree *p = pCur->pBtree;
  BtShared *pBt = p->pBt;              
  int rc;                              /* Return code */
  MemPage *pPage;                      /* Page to delete cell from */
  unsigned char *pCell;                /* Pointer to cell to delete */
  int iCellIdx;                        /* Index of cell to delete */
  int iCellDepth;                      /* Depth of node containing pCell */ 
  u16 szCell;                          /* Size of the cell being deleted */

  assert( cursorHoldsMutex(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( pCur->curFlags & BTCF_WriteFlag );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
  assert( !hasReadConflicts(p, pCur->pgnoRoot) );
................................................................................
  ** invalidate any incrblob cursors open on the row being deleted.  */
  if( pCur->pKeyInfo==0 ){
    invalidateIncrblobCursors(p, pCur->info.nKey, 0);
  }

  rc = sqlite3PagerWrite(pPage->pDbPage);
  if( rc ) return rc;
  rc = clearCell(pPage, pCell, &szCell);
  dropCell(pPage, iCellIdx, szCell, &rc);
  if( rc ) return rc;

  /* If the cell deleted was not located on a leaf page, then the cursor
  ** is currently pointing to the largest entry in the sub-tree headed
  ** by the child-page of the cell that was just deleted from an internal
  ** node. The cell from the leaf node needs to be moved to the internal
  ** node to replace the deleted cell.  */
................................................................................
    int nCell;
    Pgno n = pCur->apPage[iCellDepth+1]->pgno;
    unsigned char *pTmp;

    pCell = findCell(pLeaf, pLeaf->nCell-1);
    nCell = cellSizePtr(pLeaf, pCell);
    assert( MX_CELL_SIZE(pBt) >= nCell );


    pTmp = pBt->pTmpSpace;

    assert( pTmp!=0 );
    rc = sqlite3PagerWrite(pLeaf->pDbPage);
    insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n, &rc);
    dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
    if( rc ) return rc;
  }

  /* Balance the tree. If the entry deleted was located on a leaf page,
................................................................................
  int *pnChange            /* Add number of Cells freed to this counter */
){
  MemPage *pPage;
  int rc;
  unsigned char *pCell;
  int i;
  int hdr;
  u16 szCell;

  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pgno>btreePagecount(pBt) ){
    return SQLITE_CORRUPT_BKPT;
  }

  rc = getAndInitPage(pBt, pgno, &pPage, 0);
................................................................................
  hdr = pPage->hdrOffset;
  for(i=0; i<pPage->nCell; i++){
    pCell = findCell(pPage, i);
    if( !pPage->leaf ){
      rc = clearDatabasePage(pBt, get4byte(pCell), 1, pnChange);
      if( rc ) goto cleardatabasepage_out;
    }
    rc = clearCell(pPage, pCell, &szCell);
    if( rc ) goto cleardatabasepage_out;
  }
  if( !pPage->leaf ){
    rc = clearDatabasePage(pBt, get4byte(&pPage->aData[hdr+8]), 1, pnChange);
    if( rc ) goto cleardatabasepage_out;
  }else if( pnChange ){
    assert( pPage->intKey );
................................................................................

#ifndef SQLITE_OMIT_INTEGRITY_CHECK
/*
** Append a message to the error message string.
*/
static void checkAppendMsg(
  IntegrityCk *pCheck,

  const char *zFormat,
  ...
){
  va_list ap;
  char zBuf[200];
  if( !pCheck->mxErr ) return;
  pCheck->mxErr--;
  pCheck->nErr++;
  va_start(ap, zFormat);
  if( pCheck->errMsg.nChar ){
    sqlite3StrAccumAppend(&pCheck->errMsg, "\n", 1);
  }
  if( pCheck->zPfx ){
    sqlite3_snprintf(sizeof(zBuf), zBuf, pCheck->zPfx, pCheck->v1, pCheck->v2);
    sqlite3StrAccumAppendAll(&pCheck->errMsg, zBuf);
  }
  sqlite3VXPrintf(&pCheck->errMsg, 1, zFormat, ap);
  va_end(ap);
  if( pCheck->errMsg.accError==STRACCUM_NOMEM ){
    pCheck->mallocFailed = 1;
  }
}
................................................................................
  pCheck->aPgRef[iPg/8] |= (1 << (iPg & 0x07));
}


/*
** Add 1 to the reference count for page iPage.  If this is the second
** reference to the page, add an error message to pCheck->zErrMsg.
** Return 1 if there are 2 or more references to the page and 0 if
** if this is the first reference to the page.
**
** Also check that the page number is in bounds.
*/
static int checkRef(IntegrityCk *pCheck, Pgno iPage){
  if( iPage==0 ) return 1;
  if( iPage>pCheck->nPage ){
    checkAppendMsg(pCheck, "invalid page number %d", iPage);
    return 1;
  }
  if( getPageReferenced(pCheck, iPage) ){
    checkAppendMsg(pCheck, "2nd reference to page %d", iPage);
    return 1;
  }
  setPageReferenced(pCheck, iPage);
  return 0;
}

#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
** page iParent, pointer type ptrType. If not, append an error message
** to pCheck.
*/
static void checkPtrmap(
  IntegrityCk *pCheck,   /* Integrity check context */
  Pgno iChild,           /* Child page number */
  u8 eType,              /* Expected pointer map type */
  Pgno iParent           /* Expected pointer map parent page number */

){
  int rc;
  u8 ePtrmapType;
  Pgno iPtrmapParent;

  rc = ptrmapGet(pCheck->pBt, iChild, &ePtrmapType, &iPtrmapParent);
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ) pCheck->mallocFailed = 1;
    checkAppendMsg(pCheck, "Failed to read ptrmap key=%d", iChild);
    return;
  }

  if( ePtrmapType!=eType || iPtrmapParent!=iParent ){
    checkAppendMsg(pCheck,
      "Bad ptr map entry key=%d expected=(%d,%d) got=(%d,%d)", 
      iChild, eType, iParent, ePtrmapType, iPtrmapParent);
  }
}
#endif

/*
................................................................................
** Check the integrity of the freelist or of an overflow page list.
** Verify that the number of pages on the list is N.
*/
static void checkList(
  IntegrityCk *pCheck,  /* Integrity checking context */
  int isFreeList,       /* True for a freelist.  False for overflow page list */
  int iPage,            /* Page number for first page in the list */
  int N                 /* Expected number of pages in the list */

){
  int i;
  int expected = N;
  int iFirst = iPage;
  while( N-- > 0 && pCheck->mxErr ){
    DbPage *pOvflPage;
    unsigned char *pOvflData;
    if( iPage<1 ){
      checkAppendMsg(pCheck,
         "%d of %d pages missing from overflow list starting at %d",
          N+1, expected, iFirst);
      break;
    }
    if( checkRef(pCheck, iPage) ) break;
    if( sqlite3PagerGet(pCheck->pPager, (Pgno)iPage, &pOvflPage) ){
      checkAppendMsg(pCheck, "failed to get page %d", iPage);
      break;
    }
    pOvflData = (unsigned char *)sqlite3PagerGetData(pOvflPage);
    if( isFreeList ){
      int n = get4byte(&pOvflData[4]);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pCheck->pBt->autoVacuum ){
        checkPtrmap(pCheck, iPage, PTRMAP_FREEPAGE, 0);
      }
#endif
      if( n>(int)pCheck->pBt->usableSize/4-2 ){
        checkAppendMsg(pCheck,
           "freelist leaf count too big on page %d", iPage);
        N--;
      }else{
        for(i=0; i<n; i++){
          Pgno iFreePage = get4byte(&pOvflData[8+i*4]);
#ifndef SQLITE_OMIT_AUTOVACUUM
          if( pCheck->pBt->autoVacuum ){
            checkPtrmap(pCheck, iFreePage, PTRMAP_FREEPAGE, 0);
          }
#endif
          checkRef(pCheck, iFreePage);
        }
        N -= n;
      }
    }
#ifndef SQLITE_OMIT_AUTOVACUUM
    else{
      /* If this database supports auto-vacuum and iPage is not the last
      ** page in this overflow list, check that the pointer-map entry for
      ** the following page matches iPage.
      */
      if( pCheck->pBt->autoVacuum && N>0 ){
        i = get4byte(pOvflData);
        checkPtrmap(pCheck, i, PTRMAP_OVERFLOW2, iPage);
      }
    }
#endif
    iPage = get4byte(pOvflData);
    sqlite3PagerUnref(pOvflPage);
  }
}
................................................................................
**      7.  Verify that the depth of all children is the same.
**      8.  Make sure this page is at least 33% full or else it is
**          the root of the tree.
*/
static int checkTreePage(
  IntegrityCk *pCheck,  /* Context for the sanity check */
  int iPage,            /* Page number of the page to check */

  i64 *pnParentMinKey, 
  i64 *pnParentMaxKey
){
  MemPage *pPage;
  int i, rc, depth, d2, pgno, cnt;
  int hdr, cellStart;
  int nCell;
  u8 *data;
  BtShared *pBt;
  int usableSize;

  char *hit = 0;
  i64 nMinKey = 0;
  i64 nMaxKey = 0;
  const char *saved_zPfx = pCheck->zPfx;
  int saved_v1 = pCheck->v1;
  int saved_v2 = pCheck->v2;

  /* Check that the page exists
  */
  pBt = pCheck->pBt;
  usableSize = pBt->usableSize;
  if( iPage==0 ) return 0;
  if( checkRef(pCheck, iPage) ) return 0;
  pCheck->zPfx = "Page %d: ";
  pCheck->v1 = iPage;
  if( (rc = btreeGetPage(pBt, (Pgno)iPage, &pPage, 0))!=0 ){
    checkAppendMsg(pCheck,
       "unable to get the page. error code=%d", rc);

    depth = -1;
    goto end_of_check;
  }

  /* Clear MemPage.isInit to make sure the corruption detection code in
  ** btreeInitPage() is executed.  */
  pPage->isInit = 0;
  if( (rc = btreeInitPage(pPage))!=0 ){
    assert( rc==SQLITE_CORRUPT );  /* The only possible error from InitPage */
    checkAppendMsg(pCheck,
                   "btreeInitPage() returns error code %d", rc);
    releasePage(pPage);
    depth = -1;
    goto end_of_check;
  }

  /* Check out all the cells.
  */
  depth = 0;
  for(i=0; i<pPage->nCell && pCheck->mxErr; i++){
    u8 *pCell;
    u32 sz;
    CellInfo info;

    /* Check payload overflow pages
    */

    pCheck->zPfx = "On tree page %d cell %d: ";
    pCheck->v1 = iPage;
    pCheck->v2 = i;
    pCell = findCell(pPage,i);
    btreeParseCellPtr(pPage, pCell, &info);
    sz = info.nPayload;

    /* For intKey pages, check that the keys are in order.
    */
    if( pPage->intKey ){
      if( i==0 ){
        nMinKey = nMaxKey = info.nKey;

      }else if( info.nKey <= nMaxKey ){
        checkAppendMsg(pCheck,
           "Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
      }
      nMaxKey = info.nKey;
    }

    if( (sz>info.nLocal) 
     && (&pCell[info.iOverflow]<=&pPage->aData[pBt->usableSize])
    ){
      int nPage = (sz - info.nLocal + usableSize - 5)/(usableSize - 4);
      Pgno pgnoOvfl = get4byte(&pCell[info.iOverflow]);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pBt->autoVacuum ){
        checkPtrmap(pCheck, pgnoOvfl, PTRMAP_OVERFLOW1, iPage);
      }
#endif
      checkList(pCheck, 0, pgnoOvfl, nPage);
    }

    /* Check sanity of left child page.
    */
    if( !pPage->leaf ){
      pgno = get4byte(pCell);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pBt->autoVacuum ){
        checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage);
      }
#endif
      d2 = checkTreePage(pCheck, pgno, &nMinKey, i==0?NULL:&nMaxKey);
      if( i>0 && d2!=depth ){
        checkAppendMsg(pCheck, "Child page depth differs");
      }
      depth = d2;
    }
  }

  if( !pPage->leaf ){
    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);

    pCheck->zPfx = "On page %d at right child: ";
    pCheck->v1 = iPage;
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pBt->autoVacuum ){
      checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage);
    }
#endif
    checkTreePage(pCheck, pgno, NULL, !pPage->nCell?NULL:&nMaxKey);
  }
 
  /* For intKey leaf pages, check that the min/max keys are in order
  ** with any left/parent/right pages.
  */
  pCheck->zPfx = "Page %d: ";
  pCheck->v1 = iPage;
  if( pPage->leaf && pPage->intKey ){
    /* if we are a left child page */
    if( pnParentMinKey ){
      /* if we are the left most child page */
      if( !pnParentMaxKey ){
        if( nMaxKey > *pnParentMinKey ){
          checkAppendMsg(pCheck,
              "Rowid %lld out of order (max larger than parent min of %lld)",
              nMaxKey, *pnParentMinKey);
        }
      }else{
        if( nMinKey <= *pnParentMinKey ){
          checkAppendMsg(pCheck,
              "Rowid %lld out of order (min less than parent min of %lld)",
              nMinKey, *pnParentMinKey);
        }
        if( nMaxKey > *pnParentMaxKey ){
          checkAppendMsg(pCheck,
              "Rowid %lld out of order (max larger than parent max of %lld)",
              nMaxKey, *pnParentMaxKey);
        }
        *pnParentMinKey = nMaxKey;
      }
    /* else if we're a right child page */
    } else if( pnParentMaxKey ){
      if( nMinKey <= *pnParentMaxKey ){
        checkAppendMsg(pCheck,
            "Rowid %lld out of order (min less than parent max of %lld)",
            nMinKey, *pnParentMaxKey);
      }
    }
  }

  /* Check for complete coverage of the page
  */
  data = pPage->aData;
  hdr = pPage->hdrOffset;
  hit = sqlite3PageMalloc( pBt->pageSize );
  pCheck->zPfx = 0;
  if( hit==0 ){
    pCheck->mallocFailed = 1;
  }else{
    int contentOffset = get2byteNotZero(&data[hdr+5]);
    assert( contentOffset<=usableSize );  /* Enforced by btreeInitPage() */
    memset(hit+contentOffset, 0, usableSize-contentOffset);
    memset(hit, 1, contentOffset);
    /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
    ** number of cells on the page. */
    nCell = get2byte(&data[hdr+3]);
    /* EVIDENCE-OF: R-23882-45353 The cell pointer array of a b-tree page
    ** immediately follows the b-tree page header. */
    cellStart = hdr + 12 - 4*pPage->leaf;
    /* EVIDENCE-OF: R-02776-14802 The cell pointer array consists of K 2-byte
    ** integer offsets to the cell contents. */
    for(i=0; i<nCell; i++){
      int pc = get2byte(&data[cellStart+i*2]);
      u32 size = 65536;
      int j;
      if( pc<=usableSize-4 ){
        size = cellSizePtr(pPage, &data[pc]);
      }
      if( (int)(pc+size-1)>=usableSize ){
        pCheck->zPfx = 0;
        checkAppendMsg(pCheck,
            "Corruption detected in cell %d on page %d",i,iPage);
      }else{
        for(j=pc+size-1; j>=pc; j--) hit[j]++;
      }
    }
    /* EVIDENCE-OF: R-20690-50594 The second field of the b-tree page header
    ** is the offset of the first freeblock, or zero if there are no
    ** freeblocks on the page. */
    i = get2byte(&data[hdr+1]);
    while( i>0 ){
      int size, j;
      assert( i<=usableSize-4 );     /* Enforced by btreeInitPage() */
      size = get2byte(&data[i+2]);
      assert( i+size<=usableSize );  /* Enforced by btreeInitPage() */
      for(j=i+size-1; j>=i; j--) hit[j]++;
      /* EVIDENCE-OF: R-58208-19414 The first 2 bytes of a freeblock are a
      ** big-endian integer which is the offset in the b-tree page of the next
      ** freeblock in the chain, or zero if the freeblock is the last on the
      ** chain. */
      j = get2byte(&data[i]);
      /* EVIDENCE-OF: R-06866-39125 Freeblocks are always connected in order of
      ** increasing offset. */
      assert( j==0 || j>i+size );  /* Enforced by btreeInitPage() */
      assert( j<=usableSize-4 );   /* Enforced by btreeInitPage() */
      i = j;
    }
    for(i=cnt=0; i<usableSize; i++){
      if( hit[i]==0 ){
        cnt++;
      }else if( hit[i]>1 ){
        checkAppendMsg(pCheck,
          "Multiple uses for byte %d of page %d", i, iPage);
        break;
      }
    }
    /* EVIDENCE-OF: R-43263-13491 The total number of bytes in all fragments
    ** is stored in the fifth field of the b-tree page header.
    ** EVIDENCE-OF: R-07161-27322 The one-byte integer at offset 7 gives the
    ** number of fragmented free bytes within the cell content area.
    */
    if( cnt!=data[hdr+7] ){
      checkAppendMsg(pCheck,
          "Fragmentation of %d bytes reported as %d on page %d",
          cnt, data[hdr+7], iPage);
    }
  }
  sqlite3PageFree(hit);
  releasePage(pPage);

end_of_check:
  pCheck->zPfx = saved_zPfx;
  pCheck->v1 = saved_v1;
  pCheck->v2 = saved_v2;
  return depth+1;
}
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */

#ifndef SQLITE_OMIT_INTEGRITY_CHECK
/*
** This routine does a complete check of the given BTree file.  aRoot[] is
................................................................................
  nRef = sqlite3PagerRefcount(pBt->pPager);
  sCheck.pBt = pBt;
  sCheck.pPager = pBt->pPager;
  sCheck.nPage = btreePagecount(sCheck.pBt);
  sCheck.mxErr = mxErr;
  sCheck.nErr = 0;
  sCheck.mallocFailed = 0;
  sCheck.zPfx = 0;
  sCheck.v1 = 0;
  sCheck.v2 = 0;
  *pnErr = 0;
  if( sCheck.nPage==0 ){
    sqlite3BtreeLeave(p);
    return 0;
  }

  sCheck.aPgRef = sqlite3MallocZero((sCheck.nPage / 8)+ 1);
................................................................................
  i = PENDING_BYTE_PAGE(pBt);
  if( i<=sCheck.nPage ) setPageReferenced(&sCheck, i);
  sqlite3StrAccumInit(&sCheck.errMsg, zErr, sizeof(zErr), SQLITE_MAX_LENGTH);
  sCheck.errMsg.useMalloc = 2;

  /* Check the integrity of the freelist
  */
  sCheck.zPfx = "Main freelist: ";
  checkList(&sCheck, 1, get4byte(&pBt->pPage1->aData[32]),
            get4byte(&pBt->pPage1->aData[36]));
  sCheck.zPfx = 0;

  /* Check all the tables.
  */
  for(i=0; (int)i<nRoot && sCheck.mxErr; i++){
    if( aRoot[i]==0 ) continue;
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pBt->autoVacuum && aRoot[i]>1 ){
      checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0);
    }
#endif
    sCheck.zPfx = "List of tree roots: ";
    checkTreePage(&sCheck, aRoot[i], NULL, NULL);
    sCheck.zPfx = 0;
  }

  /* Make sure every page in the file is referenced
  */
  for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
#ifdef SQLITE_OMIT_AUTOVACUUM
    if( getPageReferenced(&sCheck, i)==0 ){
      checkAppendMsg(&sCheck, "Page %d is never used", i);
    }
#else
    /* If the database supports auto-vacuum, make sure no tables contain
    ** references to pointer-map pages.
    */
    if( getPageReferenced(&sCheck, i)==0 && 
       (PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
      checkAppendMsg(&sCheck, "Page %d is never used", i);
    }
    if( getPageReferenced(&sCheck, i)!=0 && 
       (PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
      checkAppendMsg(&sCheck, "Pointer map page %d is referenced", i);
    }
#endif
  }

  /* Make sure this analysis did not leave any unref() pages.
  ** This is an internal consistency check; an integrity check
  ** of the integrity check.
  */
  if( NEVER(nRef != sqlite3PagerRefcount(pBt->pPager)) ){
    checkAppendMsg(&sCheck,
      "Outstanding page count goes from %d to %d during this analysis",
      nRef, sqlite3PagerRefcount(pBt->pPager)
    );
  }

  /* Clean  up and report errors.
  */
................................................................................
    return SQLITE_ABORT;
  }

  /* Save the positions of all other cursors open on this table. This is
  ** required in case any of them are holding references to an xFetch
  ** version of the b-tree page modified by the accessPayload call below.
  **
  ** Note that pCsr must be open on a INTKEY table and saveCursorPosition()
  ** and hence saveAllCursors() cannot fail on a BTREE_INTKEY table, hence
  ** saveAllCursors can only return SQLITE_OK.
  */
  VVA_ONLY(rc =) saveAllCursors(pCsr->pBt, pCsr->pgnoRoot, pCsr);
  assert( rc==SQLITE_OK );

  /* Check some assumptions: 
................................................................................

/*
** Return true if the given Btree is read-only.
*/
int sqlite3BtreeIsReadonly(Btree *p){
  return (p->pBt->btsFlags & BTS_READ_ONLY)!=0;
}

/*
** Return the size of the header added to each page by this module.
*/
int sqlite3HeaderSizeBtree(void){ return sizeof(MemPage); }

#endif
int sqlite3BtreeSetAutoVacuum(Btree *, int);
int sqlite3BtreeGetAutoVacuum(Btree *);
int sqlite3BtreeBeginTrans(Btree*,int);
int sqlite3BtreeCommitPhaseOne(Btree*, const char *zMaster);
int sqlite3BtreeCommitPhaseTwo(Btree*, int);
int sqlite3BtreeCommit(Btree*);
int sqlite3BtreeRollback(Btree*,int);
int sqlite3BtreeBeginStmt(Btree*,int);
int sqlite3BtreeCreateTable(Btree*, int*, int flags);
int sqlite3BtreeIsInTrans(Btree*);
int sqlite3BtreeIsInReadTrans(Btree*);
int sqlite3BtreeIsInBackup(Btree*);
void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));
int sqlite3BtreeSchemaLocked(Btree *pBtree);
................................................................................
*/
#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
#define BTREE_BLOBKEY    2    /* Table has keys only - no data */

int sqlite3BtreeDropTable(Btree*, int, int*);
int sqlite3BtreeClearTable(Btree*, int, int*);
int sqlite3BtreeClearTableOfCursor(BtCursor*);
void sqlite3BtreeTripAllCursors(Btree*, int);

void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);

int sqlite3BtreeNewDb(Btree *p);

/*
................................................................................

int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*);
void sqlite3BtreeIncrblobCursor(BtCursor *);
void sqlite3BtreeClearCursor(BtCursor *);
int sqlite3BtreeSetVersion(Btree *pBt, int iVersion);
void sqlite3BtreeCursorHints(BtCursor *, unsigned int mask);
int sqlite3BtreeIsReadonly(Btree *pBt);


#ifndef NDEBUG
int sqlite3BtreeCursorIsValid(BtCursor*);
#endif

#ifndef SQLITE_OMIT_BTREECOUNT
int sqlite3BtreeCount(BtCursor *, i64 *);

#endif
int sqlite3BtreeSetAutoVacuum(Btree *, int);
int sqlite3BtreeGetAutoVacuum(Btree *);
int sqlite3BtreeBeginTrans(Btree*,int);
int sqlite3BtreeCommitPhaseOne(Btree*, const char *zMaster);
int sqlite3BtreeCommitPhaseTwo(Btree*, int);
int sqlite3BtreeCommit(Btree*);
int sqlite3BtreeRollback(Btree*,int,int);
int sqlite3BtreeBeginStmt(Btree*,int);
int sqlite3BtreeCreateTable(Btree*, int*, int flags);
int sqlite3BtreeIsInTrans(Btree*);
int sqlite3BtreeIsInReadTrans(Btree*);
int sqlite3BtreeIsInBackup(Btree*);
void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));
int sqlite3BtreeSchemaLocked(Btree *pBtree);
................................................................................
*/
#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
#define BTREE_BLOBKEY    2    /* Table has keys only - no data */

int sqlite3BtreeDropTable(Btree*, int, int*);
int sqlite3BtreeClearTable(Btree*, int, int*);
int sqlite3BtreeClearTableOfCursor(BtCursor*);
int sqlite3BtreeTripAllCursors(Btree*, int, int);

void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);

int sqlite3BtreeNewDb(Btree *p);

/*
................................................................................

int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*);
void sqlite3BtreeIncrblobCursor(BtCursor *);
void sqlite3BtreeClearCursor(BtCursor *);
int sqlite3BtreeSetVersion(Btree *pBt, int iVersion);
void sqlite3BtreeCursorHints(BtCursor *, unsigned int mask);
int sqlite3BtreeIsReadonly(Btree *pBt);
int sqlite3HeaderSizeBtree(void);

#ifndef NDEBUG
int sqlite3BtreeCursorIsValid(BtCursor*);
#endif

#ifndef SQLITE_OMIT_BTREECOUNT
int sqlite3BtreeCount(BtCursor *, i64 *);

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
**
** The basic idea is that each page of the file contains N database
................................................................................
**      3       2      number of cells on this page
**      5       2      first byte of the cell content area
**      7       1      number of fragmented free bytes
**      8       4      Right child (the Ptr(N) value).  Omitted on leaves.
**
** The flags define the format of this btree page.  The leaf flag means that
** this page has no children.  The zerodata flag means that this page carries
** only keys and no data.  The intkey flag means that the key is a integer
** which is stored in the key size entry of the cell header rather than in
** the payload area.
**
** The cell pointer array begins on the first byte after the page header.
** The cell pointer array contains zero or more 2-byte numbers which are
** offsets from the beginning of the page to the cell content in the cell
** content area.  The cell pointers occur in sorted order.  The system strives
................................................................................
**
** Access to all fields of this structure is controlled by the mutex
** stored in MemPage.pBt->mutex.
*/
struct MemPage {
  u8 isInit;           /* True if previously initialized. MUST BE FIRST! */
  u8 nOverflow;        /* Number of overflow cell bodies in aCell[] */
  u8 intKey;           /* True if intkey flag is set */


  u8 leaf;             /* True if leaf flag is set */
  u8 hasData;          /* True if this page stores data */
  u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
  u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
  u8 max1bytePayload;  /* min(maxLocal,127) */
  u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
  u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
  u16 cellOffset;      /* Index in aData of first cell pointer */
  u16 nFree;           /* Number of free bytes on the page */
................................................................................
  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
  BtLock *pLock;        /* List of locks held on this shared-btree struct */
  Btree *pWriter;       /* Btree with currently open write transaction */
#endif
  u8 *pTmpSpace;        /* BtShared.pageSize bytes of space for tmp use */
};

/*
** Allowed values for BtShared.btsFlags
*/
#define BTS_READ_ONLY        0x0001   /* Underlying file is readonly */
#define BTS_PAGESIZE_FIXED   0x0002   /* Page size can no longer be changed */
................................................................................
/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
*/
typedef struct CellInfo CellInfo;
struct CellInfo {
  i64 nKey;      /* The key for INTKEY tables, or number of bytes in key */
  u8 *pCell;     /* Pointer to the start of cell content */
  u32 nData;     /* Number of bytes of data */
  u32 nPayload;  /* Total amount of payload */
  u16 nHeader;   /* Size of the cell content header in bytes */
  u16 nLocal;    /* Amount of payload held locally */
  u16 iOverflow; /* Offset to overflow page number.  Zero if no overflow */
  u16 nSize;     /* Size of the cell content on the main b-tree page */
};

/*
** Maximum depth of an SQLite B-Tree structure. Any B-Tree deeper than
** this will be declared corrupt. This value is calculated based on a
................................................................................
**
** A single database file can be shared by two more database connections,
** but cursors cannot be shared.  Each cursor is associated with a
** particular database connection identified BtCursor.pBtree.db.
**
** Fields in this structure are accessed under the BtShared.mutex
** found at self->pBt->mutex. 





*/
struct BtCursor {
  Btree *pBtree;            /* The Btree to which this cursor belongs */
  BtShared *pBt;            /* The BtShared this cursor points to */
  BtCursor *pNext, *pPrev;  /* Forms a linked list of all cursors */
  struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */
  Pgno *aOverflow;          /* Cache of overflow page locations */
  CellInfo info;            /* A parse of the cell we are pointing at */
  i64 nKey;                 /* Size of pKey, or last integer key */
  void *pKey;               /* Saved key that was cursor last known position */
  Pgno pgnoRoot;            /* The root page of this tree */
  int nOvflAlloc;           /* Allocated size of aOverflow[] array */
  int skipNext;    /* Prev() is noop if negative. Next() is noop if positive */

  u8 curFlags;              /* zero or more BTCF_* flags defined below */
  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
  u8 hints;                             /* As configured by CursorSetHints() */
  i16 iPage;                            /* Index of current page in apPage */
  u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
};
................................................................................
**   The table that this cursor was opened on still exists, but has been 
**   modified since the cursor was last used. The cursor position is saved
**   in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in 
**   this state, restoreCursorPosition() can be called to attempt to
**   seek the cursor to the saved position.
**
** CURSOR_FAULT:
**   A unrecoverable error (an I/O error or a malloc failure) has occurred
**   on a different connection that shares the BtShared cache with this
**   cursor.  The error has left the cache in an inconsistent state.
**   Do nothing else with this cursor.  Any attempt to use the cursor
**   should return the error code stored in BtCursor.skip
*/
#define CURSOR_INVALID           0
#define CURSOR_VALID             1
#define CURSOR_SKIPNEXT          2
#define CURSOR_REQUIRESEEK       3
#define CURSOR_FAULT             4

................................................................................
  BtShared *pBt;    /* The tree being checked out */
  Pager *pPager;    /* The associated pager.  Also accessible by pBt->pPager */
  u8 *aPgRef;       /* 1 bit per page in the db (see above) */
  Pgno nPage;       /* Number of pages in the database */
  int mxErr;        /* Stop accumulating errors when this reaches zero */
  int nErr;         /* Number of messages written to zErrMsg so far */
  int mallocFailed; /* A memory allocation error has occurred */


  StrAccum errMsg;  /* Accumulate the error message text here */
};

/*
** Routines to read or write a two- and four-byte big-endian integer values.
*/
#define get2byte(x)   ((x)[0]<<8 | (x)[1])
#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
#define get4byte sqlite3Get4byte
#define put4byte sqlite3Put4byte

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements an external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
**
** The basic idea is that each page of the file contains N database
................................................................................
**      3       2      number of cells on this page
**      5       2      first byte of the cell content area
**      7       1      number of fragmented free bytes
**      8       4      Right child (the Ptr(N) value).  Omitted on leaves.
**
** The flags define the format of this btree page.  The leaf flag means that
** this page has no children.  The zerodata flag means that this page carries
** only keys and no data.  The intkey flag means that the key is an integer
** which is stored in the key size entry of the cell header rather than in
** the payload area.
**
** The cell pointer array begins on the first byte after the page header.
** The cell pointer array contains zero or more 2-byte numbers which are
** offsets from the beginning of the page to the cell content in the cell
** content area.  The cell pointers occur in sorted order.  The system strives
................................................................................
**
** Access to all fields of this structure is controlled by the mutex
** stored in MemPage.pBt->mutex.
*/
struct MemPage {
  u8 isInit;           /* True if previously initialized. MUST BE FIRST! */
  u8 nOverflow;        /* Number of overflow cell bodies in aCell[] */
  u8 intKey;           /* True if table b-trees.  False for index b-trees */
  u8 intKeyLeaf;       /* True if the leaf of an intKey table */
  u8 noPayload;        /* True if internal intKey page (thus w/o data) */
  u8 leaf;             /* True if a leaf page */

  u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
  u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
  u8 max1bytePayload;  /* min(maxLocal,127) */
  u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
  u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
  u16 cellOffset;      /* Index in aData of first cell pointer */
  u16 nFree;           /* Number of free bytes on the page */
................................................................................
  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
  BtLock *pLock;        /* List of locks held on this shared-btree struct */
  Btree *pWriter;       /* Btree with currently open write transaction */
#endif
  u8 *pTmpSpace;        /* Temp space sufficient to hold a single cell */
};

/*
** Allowed values for BtShared.btsFlags
*/
#define BTS_READ_ONLY        0x0001   /* Underlying file is readonly */
#define BTS_PAGESIZE_FIXED   0x0002   /* Page size can no longer be changed */
................................................................................
/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
*/
typedef struct CellInfo CellInfo;
struct CellInfo {
  i64 nKey;      /* The key for INTKEY tables, or nPayload otherwise */
  u8 *pPayload;  /* Pointer to the start of payload */

  u32 nPayload;  /* Bytes of payload */

  u16 nLocal;    /* Amount of payload held locally, not on overflow */
  u16 iOverflow; /* Offset to overflow page number.  Zero if no overflow */
  u16 nSize;     /* Size of the cell content on the main b-tree page */
};

/*
** Maximum depth of an SQLite B-Tree structure. Any B-Tree deeper than
** this will be declared corrupt. This value is calculated based on a
................................................................................
**
** A single database file can be shared by two more database connections,
** but cursors cannot be shared.  Each cursor is associated with a
** particular database connection identified BtCursor.pBtree.db.
**
** Fields in this structure are accessed under the BtShared.mutex
** found at self->pBt->mutex. 
**
** skipNext meaning:
**    eState==SKIPNEXT && skipNext>0:  Next sqlite3BtreeNext() is no-op.
**    eState==SKIPNEXT && skipNext<0:  Next sqlite3BtreePrevious() is no-op.
**    eState==FAULT:                   Cursor fault with skipNext as error code.
*/
struct BtCursor {
  Btree *pBtree;            /* The Btree to which this cursor belongs */
  BtShared *pBt;            /* The BtShared this cursor points to */
  BtCursor *pNext, *pPrev;  /* Forms a linked list of all cursors */
  struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */
  Pgno *aOverflow;          /* Cache of overflow page locations */
  CellInfo info;            /* A parse of the cell we are pointing at */
  i64 nKey;                 /* Size of pKey, or last integer key */
  void *pKey;               /* Saved key that was cursor last known position */
  Pgno pgnoRoot;            /* The root page of this tree */
  int nOvflAlloc;           /* Allocated size of aOverflow[] array */
  int skipNext;    /* Prev() is noop if negative. Next() is noop if positive.
                   ** Error code if eState==CURSOR_FAULT */
  u8 curFlags;              /* zero or more BTCF_* flags defined below */
  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
  u8 hints;                             /* As configured by CursorSetHints() */
  i16 iPage;                            /* Index of current page in apPage */
  u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
};
................................................................................
**   The table that this cursor was opened on still exists, but has been 
**   modified since the cursor was last used. The cursor position is saved
**   in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in 
**   this state, restoreCursorPosition() can be called to attempt to
**   seek the cursor to the saved position.
**
** CURSOR_FAULT:
**   An unrecoverable error (an I/O error or a malloc failure) has occurred
**   on a different connection that shares the BtShared cache with this
**   cursor.  The error has left the cache in an inconsistent state.
**   Do nothing else with this cursor.  Any attempt to use the cursor
**   should return the error code stored in BtCursor.skipNext
*/
#define CURSOR_INVALID           0
#define CURSOR_VALID             1
#define CURSOR_SKIPNEXT          2
#define CURSOR_REQUIRESEEK       3
#define CURSOR_FAULT             4

................................................................................
  BtShared *pBt;    /* The tree being checked out */
  Pager *pPager;    /* The associated pager.  Also accessible by pBt->pPager */
  u8 *aPgRef;       /* 1 bit per page in the db (see above) */
  Pgno nPage;       /* Number of pages in the database */
  int mxErr;        /* Stop accumulating errors when this reaches zero */
  int nErr;         /* Number of messages written to zErrMsg so far */
  int mallocFailed; /* A memory allocation error has occurred */
  const char *zPfx; /* Error message prefix */
  int v1, v2;       /* Values for up to two %d fields in zPfx */
  StrAccum errMsg;  /* Accumulate the error message text here */
};

/*
** Routines to read or write a two- and four-byte big-endian integer values.
*/
#define get2byte(x)   ((x)[0]<<8 | (x)[1])
#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
#define get4byte sqlite3Get4byte
#define put4byte sqlite3Put4byte

  */
  v = sqlite3GetVdbe(pParse);
  assert( !pParse->isMultiWrite 
       || sqlite3VdbeAssertMayAbort(v, pParse->mayAbort));
  if( v ){
    while( sqlite3VdbeDeletePriorOpcode(v, OP_Close) ){}
    sqlite3VdbeAddOp0(v, OP_Halt);












    /* The cookie mask contains one bit for each database file open.
    ** (Bit 0 is for main, bit 1 is for temp, and so forth.)  Bits are
    ** set for each database that is used.  Generate code to start a
    ** transaction on each used database and to verify the schema cookie
    ** on each used database.
    */
................................................................................
  sqlite3RunParser(pParse, zSql, &zErrMsg);
  sqlite3DbFree(db, zErrMsg);
  sqlite3DbFree(db, zSql);
  memcpy(&pParse->nVar, saveBuf, SAVE_SZ);
  pParse->nested--;
}











/*
** Locate the in-memory structure that describes a particular database
** table given the name of that table and (optionally) the name of the
** database containing the table.  Return NULL if not found.
**
** If zDatabase is 0, all databases are searched for the table and the
** first matching table is returned.  (No checking for duplicate table
................................................................................
** auxiliary databases added using the ATTACH command.
**
** See also sqlite3LocateTable().
*/
Table *sqlite3FindTable(sqlite3 *db, const char *zName, const char *zDatabase){
  Table *p = 0;
  int i;
  assert( zName!=0 );





  /* All mutexes are required for schema access.  Make sure we hold them. */
  assert( zDatabase!=0 || sqlite3BtreeHoldsAllMutexes(db) );







  for(i=OMIT_TEMPDB; i<db->nDb; i++){
    int j = (i<2) ? i^1 : i;   /* Search TEMP before MAIN */
    if( zDatabase!=0 && sqlite3StrICmp(zDatabase, db->aDb[j].zName) ) continue;
    assert( sqlite3SchemaMutexHeld(db, j, 0) );
    p = sqlite3HashFind(&db->aDb[j].pSchema->tblHash, zName);
    if( p ) break;
  }
................................................................................
    if( zDbase ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
    }
    pParse->checkSchema = 1;
  }






  return p;
}

/*
** Locate the table identified by *p.
**
** This is a wrapper around sqlite3LocateTable(). The difference between
................................................................................
#ifndef SQLITE_OMIT_ANALYZE
  sqlite3DeleteIndexSamples(db, p);
#endif
  if( db==0 || db->pnBytesFreed==0 ) sqlite3KeyInfoUnref(p->pKeyInfo);
  sqlite3ExprDelete(db, p->pPartIdxWhere);
  sqlite3DbFree(db, p->zColAff);
  if( p->isResized ) sqlite3DbFree(db, p->azColl);



  sqlite3DbFree(db, p);
}

/*
** For the index called zIdxName which is found in the database iDb,
** unlike that index from its Table then remove the index from
** the index hash table and free all memory structures associated
................................................................................
    }
  }

  /* If pszEst is not NULL, store an estimate of the field size.  The
  ** estimate is scaled so that the size of an integer is 1.  */
  if( pszEst ){
    *pszEst = 1;   /* default size is approx 4 bytes */
    if( aff<=SQLITE_AFF_NONE ){
      if( zChar ){
        while( zChar[0] ){
          if( sqlite3Isdigit(zChar[0]) ){
            int v = 0;
            sqlite3GetInt32(zChar, &v);
            v = v/4 + 1;
            if( v>255 ) v = 255;
................................................................................
void sqlite3AddDefaultValue(Parse *pParse, ExprSpan *pSpan){
  Table *p;
  Column *pCol;
  sqlite3 *db = pParse->db;
  p = pParse->pNewTable;
  if( p!=0 ){
    pCol = &(p->aCol[p->nCol-1]);
    if( !sqlite3ExprIsConstantOrFunction(pSpan->pExpr) ){
      sqlite3ErrorMsg(pParse, "default value of column [%s] is not constant",
          pCol->zName);
    }else{
      /* A copy of pExpr is used instead of the original, as pExpr contains
      ** tokens that point to volatile memory. The 'span' of the expression
      ** is required by pragma table_info.
      */
................................................................................
  }
  sqlite3_snprintf(n, zStmt, "CREATE TABLE ");
  k = sqlite3Strlen30(zStmt);
  identPut(zStmt, &k, p->zName);
  zStmt[k++] = '(';
  for(pCol=p->aCol, i=0; i<p->nCol; i++, pCol++){
    static const char * const azType[] = {
        /* SQLITE_AFF_TEXT    */ " TEXT",
        /* SQLITE_AFF_NONE    */ "",

        /* SQLITE_AFF_NUMERIC */ " NUM",
        /* SQLITE_AFF_INTEGER */ " INT",
        /* SQLITE_AFF_REAL    */ " REAL"
    };
    int len;
    const char *zType;

    sqlite3_snprintf(n-k, &zStmt[k], zSep);
    k += sqlite3Strlen30(&zStmt[k]);
    zSep = zSep2;
    identPut(zStmt, &k, pCol->zName);
    assert( pCol->affinity-SQLITE_AFF_TEXT >= 0 );
    assert( pCol->affinity-SQLITE_AFF_TEXT < ArraySize(azType) );
    testcase( pCol->affinity==SQLITE_AFF_TEXT );
    testcase( pCol->affinity==SQLITE_AFF_NONE );
    testcase( pCol->affinity==SQLITE_AFF_NUMERIC );
    testcase( pCol->affinity==SQLITE_AFF_INTEGER );
    testcase( pCol->affinity==SQLITE_AFF_REAL );
    
    zType = azType[pCol->affinity - SQLITE_AFF_TEXT];
    len = sqlite3Strlen30(zType);
    assert( pCol->affinity==SQLITE_AFF_NONE 
            || pCol->affinity==sqlite3AffinityType(zType, 0) );
    memcpy(&zStmt[k], zType, len);
    k += len;
    assert( k<=n );
  }
................................................................................
** are appropriate for a WITHOUT ROWID table instead of a rowid table.
** Changes include:
**
**     (1)  Convert the OP_CreateTable into an OP_CreateIndex.  There is
**          no rowid btree for a WITHOUT ROWID.  Instead, the canonical
**          data storage is a covering index btree.
**     (2)  Bypass the creation of the sqlite_master table entry
**          for the PRIMARY KEY as the the primary key index is now
**          identified by the sqlite_master table entry of the table itself.
**     (3)  Set the Index.tnum of the PRIMARY KEY Index object in the
**          schema to the rootpage from the main table.
**     (4)  Set all columns of the PRIMARY KEY schema object to be NOT NULL.
**     (5)  Add all table columns to the PRIMARY KEY Index object
**          so that the PRIMARY KEY is a covering index.  The surplus
**          columns are part of KeyInfo.nXField and are not used for
................................................................................
  Index *pPk;
  int nPk;
  int i, j;
  sqlite3 *db = pParse->db;
  Vdbe *v = pParse->pVdbe;

  /* Convert the OP_CreateTable opcode that would normally create the
  ** root-page for the table into a OP_CreateIndex opcode.  The index
  ** created will become the PRIMARY KEY index.
  */
  if( pParse->addrCrTab ){
    assert( v );
    sqlite3VdbeGetOp(v, pParse->addrCrTab)->opcode = OP_CreateIndex;
  }

................................................................................
*/
int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
  Table *pSelTab;   /* A fake table from which we get the result set */
  Select *pSel;     /* Copy of the SELECT that implements the view */
  int nErr = 0;     /* Number of errors encountered */
  int n;            /* Temporarily holds the number of cursors assigned */
  sqlite3 *db = pParse->db;  /* Database connection for malloc errors */
  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);

  assert( pTable );

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( sqlite3VtabCallConnect(pParse, pTable) ){
    return SQLITE_ERROR;
  }
................................................................................
  int iSorter;                   /* Cursor opened by OpenSorter (if in use) */
  int addr1;                     /* Address of top of loop */
  int addr2;                     /* Address to jump to for next iteration */
  int tnum;                      /* Root page of index */
  int iPartIdxLabel;             /* Jump to this label to skip a row */
  Vdbe *v;                       /* Generate code into this virtual machine */
  KeyInfo *pKey;                 /* KeyInfo for index */
  int regRecord;                 /* Register holding assemblied index record */
  sqlite3 *db = pParse->db;      /* The database connection */
  int iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);

#ifndef SQLITE_OMIT_AUTHORIZATION
  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
      db->aDb[iDb].zName ) ){
    return;
................................................................................
  }else{
    tnum = pIndex->tnum;
  }
  pKey = sqlite3KeyInfoOfIndex(pParse, pIndex);

  /* Open the sorter cursor if we are to use one. */
  iSorter = pParse->nTab++;
  sqlite3VdbeAddOp4(v, OP_SorterOpen, iSorter, 0, 0, (char*)
                    sqlite3KeyInfoRef(pKey), P4_KEYINFO);

  /* Open the table. Loop through all rows of the table, inserting index
  ** records into the sorter. */
  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
  addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0); VdbeCoverage(v);
  regRecord = sqlite3GetTempReg(pParse);
................................................................................
    addr2 = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp4Int(v, OP_SorterCompare, iSorter, j2, regRecord,
                         pIndex->nKeyCol); VdbeCoverage(v);
    sqlite3UniqueConstraint(pParse, OE_Abort, pIndex);
  }else{
    addr2 = sqlite3VdbeCurrentAddr(v);
  }
  sqlite3VdbeAddOp2(v, OP_SorterData, iSorter, regRecord);
  sqlite3VdbeAddOp3(v, OP_IdxInsert, iIdx, regRecord, 1);
  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3VdbeAddOp2(v, OP_SorterNext, iSorter, addr2); VdbeCoverage(v);
  sqlite3VdbeJumpHere(v, addr1);

  sqlite3VdbeAddOp1(v, OP_Close, iTab);
................................................................................
    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  }
  pDb = &db->aDb[iDb];

  assert( pTab!=0 );
  assert( pParse->nErr==0 );
  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 




       && sqlite3StrNICmp(&pTab->zName[7],"altertab_",9)!=0 ){
    sqlite3ErrorMsg(pParse, "table %s may not be indexed", pTab->zName);
    goto exit_create_index;
  }
#ifndef SQLITE_OMIT_VIEW
  if( pTab->pSelect ){
    sqlite3ErrorMsg(pParse, "views may not be indexed");
................................................................................
    }
    if( j>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "table %s has no column named %s",
        pTab->zName, zColName);
      pParse->checkSchema = 1;
      goto exit_create_index;
    }
    assert( pTab->nCol<=0x7fff && j<=0x7fff );
    pIndex->aiColumn[i] = (i16)j;
    if( pListItem->pExpr ){
      int nColl;
      assert( pListItem->pExpr->op==TK_COLLATE );
      zColl = pListItem->pExpr->u.zToken;
      nColl = sqlite3Strlen30(zColl) + 1;
      assert( nExtra>=nColl );
................................................................................
  return pRet;
}

/*
** Fill the Index.aiRowEst[] array with default information - information
** to be used when we have not run the ANALYZE command.
**
** aiRowEst[0] is suppose to contain the number of elements in the index.
** Since we do not know, guess 1 million.  aiRowEst[1] is an estimate of the
** number of rows in the table that match any particular value of the
** first column of the index.  aiRowEst[2] is an estimate of the number
** of rows that match any particular combination of the first 2 columns
** of the index.  And so forth.  It must always be the case that
*
**           aiRowEst[N]<=aiRowEst[N-1]
................................................................................
/*
** This routine is called by the parser to add a new term to the
** end of a growing FROM clause.  The "p" parameter is the part of
** the FROM clause that has already been constructed.  "p" is NULL
** if this is the first term of the FROM clause.  pTable and pDatabase
** are the name of the table and database named in the FROM clause term.
** pDatabase is NULL if the database name qualifier is missing - the
** usual case.  If the term has a alias, then pAlias points to the
** alias token.  If the term is a subquery, then pSubquery is the
** SELECT statement that the subquery encodes.  The pTable and
** pDatabase parameters are NULL for subqueries.  The pOn and pUsing
** parameters are the content of the ON and USING clauses.
**
** Return a new SrcList which encodes is the FROM with the new
** term added.

  */
  v = sqlite3GetVdbe(pParse);
  assert( !pParse->isMultiWrite 
       || sqlite3VdbeAssertMayAbort(v, pParse->mayAbort));
  if( v ){
    while( sqlite3VdbeDeletePriorOpcode(v, OP_Close) ){}
    sqlite3VdbeAddOp0(v, OP_Halt);

#if SQLITE_USER_AUTHENTICATION
    if( pParse->nTableLock>0 && db->init.busy==0 ){
      sqlite3UserAuthInit(db);
      if( db->auth.authLevel<UAUTH_User ){
        pParse->rc = SQLITE_AUTH_USER;
        sqlite3ErrorMsg(pParse, "user not authenticated");
        return;
      }
    }
#endif

    /* The cookie mask contains one bit for each database file open.
    ** (Bit 0 is for main, bit 1 is for temp, and so forth.)  Bits are
    ** set for each database that is used.  Generate code to start a
    ** transaction on each used database and to verify the schema cookie
    ** on each used database.
    */
................................................................................
  sqlite3RunParser(pParse, zSql, &zErrMsg);
  sqlite3DbFree(db, zErrMsg);
  sqlite3DbFree(db, zSql);
  memcpy(&pParse->nVar, saveBuf, SAVE_SZ);
  pParse->nested--;
}

#if SQLITE_USER_AUTHENTICATION
/*
** Return TRUE if zTable is the name of the system table that stores the
** list of users and their access credentials.
*/
int sqlite3UserAuthTable(const char *zTable){
  return sqlite3_stricmp(zTable, "sqlite_user")==0;
}
#endif

/*
** Locate the in-memory structure that describes a particular database
** table given the name of that table and (optionally) the name of the
** database containing the table.  Return NULL if not found.
**
** If zDatabase is 0, all databases are searched for the table and the
** first matching table is returned.  (No checking for duplicate table
................................................................................
** auxiliary databases added using the ATTACH command.
**
** See also sqlite3LocateTable().
*/
Table *sqlite3FindTable(sqlite3 *db, const char *zName, const char *zDatabase){
  Table *p = 0;
  int i;


#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return 0;
#endif

  /* All mutexes are required for schema access.  Make sure we hold them. */
  assert( zDatabase!=0 || sqlite3BtreeHoldsAllMutexes(db) );
#if SQLITE_USER_AUTHENTICATION
  /* Only the admin user is allowed to know that the sqlite_user table
  ** exists */
  if( db->auth.authLevel<UAUTH_Admin && sqlite3UserAuthTable(zName)!=0 ){
    return 0;
  }
#endif
  for(i=OMIT_TEMPDB; i<db->nDb; i++){
    int j = (i<2) ? i^1 : i;   /* Search TEMP before MAIN */
    if( zDatabase!=0 && sqlite3StrICmp(zDatabase, db->aDb[j].zName) ) continue;
    assert( sqlite3SchemaMutexHeld(db, j, 0) );
    p = sqlite3HashFind(&db->aDb[j].pSchema->tblHash, zName);
    if( p ) break;
  }
................................................................................
    if( zDbase ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
    }
    pParse->checkSchema = 1;
  }
#if SQLITE_USER_AUTHENICATION
  else if( pParse->db->auth.authLevel<UAUTH_User ){
    sqlite3ErrorMsg(pParse, "user not authenticated");
    p = 0;
  }
#endif
  return p;
}

/*
** Locate the table identified by *p.
**
** This is a wrapper around sqlite3LocateTable(). The difference between
................................................................................
#ifndef SQLITE_OMIT_ANALYZE
  sqlite3DeleteIndexSamples(db, p);
#endif
  if( db==0 || db->pnBytesFreed==0 ) sqlite3KeyInfoUnref(p->pKeyInfo);
  sqlite3ExprDelete(db, p->pPartIdxWhere);
  sqlite3DbFree(db, p->zColAff);
  if( p->isResized ) sqlite3DbFree(db, p->azColl);
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
  sqlite3_free(p->aiRowEst);
#endif
  sqlite3DbFree(db, p);
}

/*
** For the index called zIdxName which is found in the database iDb,
** unlike that index from its Table then remove the index from
** the index hash table and free all memory structures associated
................................................................................
    }
  }

  /* If pszEst is not NULL, store an estimate of the field size.  The
  ** estimate is scaled so that the size of an integer is 1.  */
  if( pszEst ){
    *pszEst = 1;   /* default size is approx 4 bytes */
    if( aff<SQLITE_AFF_NUMERIC ){
      if( zChar ){
        while( zChar[0] ){
          if( sqlite3Isdigit(zChar[0]) ){
            int v = 0;
            sqlite3GetInt32(zChar, &v);
            v = v/4 + 1;
            if( v>255 ) v = 255;
................................................................................
void sqlite3AddDefaultValue(Parse *pParse, ExprSpan *pSpan){
  Table *p;
  Column *pCol;
  sqlite3 *db = pParse->db;
  p = pParse->pNewTable;
  if( p!=0 ){
    pCol = &(p->aCol[p->nCol-1]);
    if( !sqlite3ExprIsConstantOrFunction(pSpan->pExpr, db->init.busy) ){
      sqlite3ErrorMsg(pParse, "default value of column [%s] is not constant",
          pCol->zName);
    }else{
      /* A copy of pExpr is used instead of the original, as pExpr contains
      ** tokens that point to volatile memory. The 'span' of the expression
      ** is required by pragma table_info.
      */
................................................................................
  }
  sqlite3_snprintf(n, zStmt, "CREATE TABLE ");
  k = sqlite3Strlen30(zStmt);
  identPut(zStmt, &k, p->zName);
  zStmt[k++] = '(';
  for(pCol=p->aCol, i=0; i<p->nCol; i++, pCol++){
    static const char * const azType[] = {

        /* SQLITE_AFF_NONE    */ "",
        /* SQLITE_AFF_TEXT    */ " TEXT",
        /* SQLITE_AFF_NUMERIC */ " NUM",
        /* SQLITE_AFF_INTEGER */ " INT",
        /* SQLITE_AFF_REAL    */ " REAL"
    };
    int len;
    const char *zType;

    sqlite3_snprintf(n-k, &zStmt[k], zSep);
    k += sqlite3Strlen30(&zStmt[k]);
    zSep = zSep2;
    identPut(zStmt, &k, pCol->zName);
    assert( pCol->affinity-SQLITE_AFF_NONE >= 0 );
    assert( pCol->affinity-SQLITE_AFF_NONE < ArraySize(azType) );
    testcase( pCol->affinity==SQLITE_AFF_NONE );
    testcase( pCol->affinity==SQLITE_AFF_TEXT );
    testcase( pCol->affinity==SQLITE_AFF_NUMERIC );
    testcase( pCol->affinity==SQLITE_AFF_INTEGER );
    testcase( pCol->affinity==SQLITE_AFF_REAL );
    
    zType = azType[pCol->affinity - SQLITE_AFF_NONE];
    len = sqlite3Strlen30(zType);
    assert( pCol->affinity==SQLITE_AFF_NONE 
            || pCol->affinity==sqlite3AffinityType(zType, 0) );
    memcpy(&zStmt[k], zType, len);
    k += len;
    assert( k<=n );
  }
................................................................................
** are appropriate for a WITHOUT ROWID table instead of a rowid table.
** Changes include:
**
**     (1)  Convert the OP_CreateTable into an OP_CreateIndex.  There is
**          no rowid btree for a WITHOUT ROWID.  Instead, the canonical
**          data storage is a covering index btree.
**     (2)  Bypass the creation of the sqlite_master table entry
**          for the PRIMARY KEY as the primary key index is now
**          identified by the sqlite_master table entry of the table itself.
**     (3)  Set the Index.tnum of the PRIMARY KEY Index object in the
**          schema to the rootpage from the main table.
**     (4)  Set all columns of the PRIMARY KEY schema object to be NOT NULL.
**     (5)  Add all table columns to the PRIMARY KEY Index object
**          so that the PRIMARY KEY is a covering index.  The surplus
**          columns are part of KeyInfo.nXField and are not used for
................................................................................
  Index *pPk;
  int nPk;
  int i, j;
  sqlite3 *db = pParse->db;
  Vdbe *v = pParse->pVdbe;

  /* Convert the OP_CreateTable opcode that would normally create the
  ** root-page for the table into an OP_CreateIndex opcode.  The index
  ** created will become the PRIMARY KEY index.
  */
  if( pParse->addrCrTab ){
    assert( v );
    sqlite3VdbeGetOp(v, pParse->addrCrTab)->opcode = OP_CreateIndex;
  }

................................................................................
*/
int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
  Table *pSelTab;   /* A fake table from which we get the result set */
  Select *pSel;     /* Copy of the SELECT that implements the view */
  int nErr = 0;     /* Number of errors encountered */
  int n;            /* Temporarily holds the number of cursors assigned */
  sqlite3 *db = pParse->db;  /* Database connection for malloc errors */
  sqlite3_xauth xAuth;       /* Saved xAuth pointer */

  assert( pTable );

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( sqlite3VtabCallConnect(pParse, pTable) ){
    return SQLITE_ERROR;
  }
................................................................................
  int iSorter;                   /* Cursor opened by OpenSorter (if in use) */
  int addr1;                     /* Address of top of loop */
  int addr2;                     /* Address to jump to for next iteration */
  int tnum;                      /* Root page of index */
  int iPartIdxLabel;             /* Jump to this label to skip a row */
  Vdbe *v;                       /* Generate code into this virtual machine */
  KeyInfo *pKey;                 /* KeyInfo for index */
  int regRecord;                 /* Register holding assembled index record */
  sqlite3 *db = pParse->db;      /* The database connection */
  int iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);

#ifndef SQLITE_OMIT_AUTHORIZATION
  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
      db->aDb[iDb].zName ) ){
    return;
................................................................................
  }else{
    tnum = pIndex->tnum;
  }
  pKey = sqlite3KeyInfoOfIndex(pParse, pIndex);

  /* Open the sorter cursor if we are to use one. */
  iSorter = pParse->nTab++;
  sqlite3VdbeAddOp4(v, OP_SorterOpen, iSorter, 0, pIndex->nKeyCol, (char*)
                    sqlite3KeyInfoRef(pKey), P4_KEYINFO);

  /* Open the table. Loop through all rows of the table, inserting index
  ** records into the sorter. */
  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
  addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0); VdbeCoverage(v);
  regRecord = sqlite3GetTempReg(pParse);
................................................................................
    addr2 = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp4Int(v, OP_SorterCompare, iSorter, j2, regRecord,
                         pIndex->nKeyCol); VdbeCoverage(v);
    sqlite3UniqueConstraint(pParse, OE_Abort, pIndex);
  }else{
    addr2 = sqlite3VdbeCurrentAddr(v);
  }
  sqlite3VdbeAddOp3(v, OP_SorterData, iSorter, regRecord, iIdx);
  sqlite3VdbeAddOp3(v, OP_IdxInsert, iIdx, regRecord, 1);
  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3VdbeAddOp2(v, OP_SorterNext, iSorter, addr2); VdbeCoverage(v);
  sqlite3VdbeJumpHere(v, addr1);

  sqlite3VdbeAddOp1(v, OP_Close, iTab);
................................................................................
    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  }
  pDb = &db->aDb[iDb];

  assert( pTab!=0 );
  assert( pParse->nErr==0 );
  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 
       && db->init.busy==0
#if SQLITE_USER_AUTHENTICATION
       && sqlite3UserAuthTable(pTab->zName)==0
#endif
       && sqlite3StrNICmp(&pTab->zName[7],"altertab_",9)!=0 ){
    sqlite3ErrorMsg(pParse, "table %s may not be indexed", pTab->zName);
    goto exit_create_index;
  }
#ifndef SQLITE_OMIT_VIEW
  if( pTab->pSelect ){
    sqlite3ErrorMsg(pParse, "views may not be indexed");
................................................................................
    }
    if( j>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "table %s has no column named %s",
        pTab->zName, zColName);
      pParse->checkSchema = 1;
      goto exit_create_index;
    }
    assert( j<=0x7fff );
    pIndex->aiColumn[i] = (i16)j;
    if( pListItem->pExpr ){
      int nColl;
      assert( pListItem->pExpr->op==TK_COLLATE );
      zColl = pListItem->pExpr->u.zToken;
      nColl = sqlite3Strlen30(zColl) + 1;
      assert( nExtra>=nColl );
................................................................................
  return pRet;
}

/*
** Fill the Index.aiRowEst[] array with default information - information
** to be used when we have not run the ANALYZE command.
**
** aiRowEst[0] is supposed to contain the number of elements in the index.
** Since we do not know, guess 1 million.  aiRowEst[1] is an estimate of the
** number of rows in the table that match any particular value of the
** first column of the index.  aiRowEst[2] is an estimate of the number
** of rows that match any particular combination of the first 2 columns
** of the index.  And so forth.  It must always be the case that
*
**           aiRowEst[N]<=aiRowEst[N-1]
................................................................................
/*
** This routine is called by the parser to add a new term to the
** end of a growing FROM clause.  The "p" parameter is the part of
** the FROM clause that has already been constructed.  "p" is NULL
** if this is the first term of the FROM clause.  pTable and pDatabase
** are the name of the table and database named in the FROM clause term.
** pDatabase is NULL if the database name qualifier is missing - the
** usual case.  If the term has an alias, then pAlias points to the
** alias token.  If the term is a subquery, then pSubquery is the
** SELECT statement that the subquery encodes.  The pTable and
** pDatabase parameters are NULL for subqueries.  The pOn and pUsing
** parameters are the content of the ON and USING clauses.
**
** Return a new SrcList which encodes is the FROM with the new
** term added.

/*
** Locate and return an entry from the db.aCollSeq hash table. If the entry
** specified by zName and nName is not found and parameter 'create' is
** true, then create a new entry. Otherwise return NULL.
**
** Each pointer stored in the sqlite3.aCollSeq hash table contains an
** array of three CollSeq structures. The first is the collation sequence
** prefferred for UTF-8, the second UTF-16le, and the third UTF-16be.
**
** Stored immediately after the three collation sequences is a copy of
** the collation sequence name. A pointer to this string is stored in
** each collation sequence structure.
*/
static CollSeq *findCollSeqEntry(
  sqlite3 *db,          /* Database connection */

/*
** Locate and return an entry from the db.aCollSeq hash table. If the entry
** specified by zName and nName is not found and parameter 'create' is
** true, then create a new entry. Otherwise return NULL.
**
** Each pointer stored in the sqlite3.aCollSeq hash table contains an
** array of three CollSeq structures. The first is the collation sequence
** preferred for UTF-8, the second UTF-16le, and the third UTF-16be.
**
** Stored immediately after the three collation sequences is a copy of
** the collation sequence name. A pointer to this string is stored in
** each collation sequence structure.
*/
static CollSeq *findCollSeqEntry(
  sqlite3 *db,          /* Database connection */

**   (2) NORMAL    We are in the middle of statement which ends with a single
**                 semicolon.
**
**   (3) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of 
**                 a statement.
**
**   (4) CREATE    The keyword CREATE has been seen at the beginning of a
**                 statement, possibly preceeded by EXPLAIN and/or followed by
**                 TEMP or TEMPORARY
**
**   (5) TRIGGER   We are in the middle of a trigger definition that must be
**                 ended by a semicolon, the keyword END, and another semicolon.
**
**   (6) SEMI      We've seen the first semicolon in the ";END;" that occurs at
**                 the end of a trigger definition.
**
**   (7) END       We've seen the ";END" of the ";END;" that occurs at the end
**                 of a trigger difinition.
**
** Transitions between states above are determined by tokens extracted
** from the input.  The following tokens are significant:
**
**   (0) tkSEMI      A semicolon.
**   (1) tkWS        Whitespace.
**   (2) tkOTHER     Any other SQL token.
................................................................................
** If we compile with SQLITE_OMIT_TRIGGER, all of the computation needed
** to recognize the end of a trigger can be omitted.  All we have to do
** is look for a semicolon that is not part of an string or comment.
*/
int sqlite3_complete(const char *zSql){
  u8 state = 0;   /* Current state, using numbers defined in header comment */
  u8 token;       /* Value of the next token */








#ifndef SQLITE_OMIT_TRIGGER
  /* A complex statement machine used to detect the end of a CREATE TRIGGER
  ** statement.  This is the normal case.
  */
  static const u8 trans[8][8] = {
                     /* Token:                                                */
................................................................................
     /* 4  CREATE: */ {    1,  4,     2,       2,      2,    4,       5,   2, },
     /* 5 TRIGGER: */ {    6,  5,     5,       5,      5,    5,       5,   5, },
     /* 6    SEMI: */ {    6,  6,     5,       5,      5,    5,       5,   7, },
     /* 7     END: */ {    1,  7,     5,       5,      5,    5,       5,   5, },
  };
#else
  /* If triggers are not supported by this compile then the statement machine
  ** used to detect the end of a statement is much simplier
  */
  static const u8 trans[3][3] = {
                     /* Token:           */
     /* State:       **  SEMI  WS  OTHER */
     /* 0 INVALID: */ {    1,  0,     2, },
     /* 1   START: */ {    1,  1,     2, },
     /* 2  NORMAL: */ {    1,  2,     2, },

**   (2) NORMAL    We are in the middle of statement which ends with a single
**                 semicolon.
**
**   (3) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of 
**                 a statement.
**
**   (4) CREATE    The keyword CREATE has been seen at the beginning of a
**                 statement, possibly preceded by EXPLAIN and/or followed by
**                 TEMP or TEMPORARY
**
**   (5) TRIGGER   We are in the middle of a trigger definition that must be
**                 ended by a semicolon, the keyword END, and another semicolon.
**
**   (6) SEMI      We've seen the first semicolon in the ";END;" that occurs at
**                 the end of a trigger definition.
**
**   (7) END       We've seen the ";END" of the ";END;" that occurs at the end
**                 of a trigger definition.
**
** Transitions between states above are determined by tokens extracted
** from the input.  The following tokens are significant:
**
**   (0) tkSEMI      A semicolon.
**   (1) tkWS        Whitespace.
**   (2) tkOTHER     Any other SQL token.
................................................................................
** If we compile with SQLITE_OMIT_TRIGGER, all of the computation needed
** to recognize the end of a trigger can be omitted.  All we have to do
** is look for a semicolon that is not part of an string or comment.
*/
int sqlite3_complete(const char *zSql){
  u8 state = 0;   /* Current state, using numbers defined in header comment */
  u8 token;       /* Value of the next token */

#ifdef SQLITE_ENABLE_API_ARMOR
  if( zSql==0 ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif

#ifndef SQLITE_OMIT_TRIGGER
  /* A complex statement machine used to detect the end of a CREATE TRIGGER
  ** statement.  This is the normal case.
  */
  static const u8 trans[8][8] = {
                     /* Token:                                                */
................................................................................
     /* 4  CREATE: */ {    1,  4,     2,       2,      2,    4,       5,   2, },
     /* 5 TRIGGER: */ {    6,  5,     5,       5,      5,    5,       5,   5, },
     /* 6    SEMI: */ {    6,  6,     5,       5,      5,    5,       5,   7, },
     /* 7     END: */ {    1,  7,     5,       5,      5,    5,       5,   5, },
  };
#else
  /* If triggers are not supported by this compile then the statement machine
  ** used to detect the end of a statement is much simpler
  */
  static const u8 trans[3][3] = {
                     /* Token:           */
     /* State:       **  SEMI  WS  OTHER */
     /* 0 INVALID: */ {    1,  0,     2, },
     /* 1   START: */ {    1,  1,     2, },
     /* 2  NORMAL: */ {    1,  2,     2, },

  "DEFAULT_MMAP_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_MMAP_SIZE),
#endif
#ifdef SQLITE_DISABLE_DIRSYNC
  "DISABLE_DIRSYNC",
#endif
#ifdef SQLITE_DISABLE_LFS
  "DISABLE_LFS",



#endif
#ifdef SQLITE_ENABLE_ATOMIC_WRITE
  "ENABLE_ATOMIC_WRITE",
#endif
#ifdef SQLITE_ENABLE_CEROD
  "ENABLE_CEROD",
#endif
................................................................................
  "TEST",
#endif
#if defined(SQLITE_THREADSAFE)
  "THREADSAFE=" CTIMEOPT_VAL(SQLITE_THREADSAFE),
#endif
#ifdef SQLITE_USE_ALLOCA
  "USE_ALLOCA",



#endif
#ifdef SQLITE_WIN32_MALLOC
  "WIN32_MALLOC",
#endif
#ifdef SQLITE_ZERO_MALLOC
  "ZERO_MALLOC"
#endif
................................................................................
** was used and false if not.
**
** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
** is not required for a match.
*/
int sqlite3_compileoption_used(const char *zOptName){
  int i, n;







  if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
  n = sqlite3Strlen30(zOptName);

  /* Since ArraySize(azCompileOpt) is normally in single digits, a
  ** linear search is adequate.  No need for a binary search. */
  for(i=0; i<ArraySize(azCompileOpt); i++){
    if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
     && sqlite3CtypeMap[(unsigned char)azCompileOpt[i][n]]==0
    ){
      return 1;
    }
  }
  return 0;
}

  "DEFAULT_MMAP_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_MMAP_SIZE),
#endif
#ifdef SQLITE_DISABLE_DIRSYNC
  "DISABLE_DIRSYNC",
#endif
#ifdef SQLITE_DISABLE_LFS
  "DISABLE_LFS",
#endif
#ifdef SQLITE_ENABLE_API_ARMOR
  "ENABLE_API_ARMOR",
#endif
#ifdef SQLITE_ENABLE_ATOMIC_WRITE
  "ENABLE_ATOMIC_WRITE",
#endif
#ifdef SQLITE_ENABLE_CEROD
  "ENABLE_CEROD",
#endif
................................................................................
  "TEST",
#endif
#if defined(SQLITE_THREADSAFE)
  "THREADSAFE=" CTIMEOPT_VAL(SQLITE_THREADSAFE),
#endif
#ifdef SQLITE_USE_ALLOCA
  "USE_ALLOCA",
#endif
#ifdef SQLITE_USER_AUTHENTICATION
  "USER_AUTHENTICATION",
#endif
#ifdef SQLITE_WIN32_MALLOC
  "WIN32_MALLOC",
#endif
#ifdef SQLITE_ZERO_MALLOC
  "ZERO_MALLOC"
#endif
................................................................................
** was used and false if not.
**
** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
** is not required for a match.
*/
int sqlite3_compileoption_used(const char *zOptName){
  int i, n;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( zOptName==0 ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
  n = sqlite3Strlen30(zOptName);

  /* Since ArraySize(azCompileOpt) is normally in single digits, a
  ** linear search is adequate.  No need for a binary search. */
  for(i=0; i<ArraySize(azCompileOpt); i++){
    if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
     && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
    ){
      return 1;
    }
  }
  return 0;
}

** This file contains the C functions that implement date and time
** functions for SQLite.  
**
** There is only one exported symbol in this file - the function
** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
** All other code has file scope.
**
** SQLite processes all times and dates as Julian Day numbers.  The
** dates and times are stored as the number of days since noon
** in Greenwich on November 24, 4714 B.C. according to the Gregorian
** calendar system. 
**
** 1970-01-01 00:00:00 is JD 2440587.5
** 2000-01-01 00:00:00 is JD 2451544.5
**
** This implemention requires years to be expressed as a 4-digit number
** which means that only dates between 0000-01-01 and 9999-12-31 can
** be represented, even though julian day numbers allow a much wider
** range of dates.
**
** The Gregorian calendar system is used for all dates and times,
** even those that predate the Gregorian calendar.  Historians usually
** use the Julian calendar for dates prior to 1582-10-15 and for some
** dates afterwards, depending on locale.  Beware of this difference.
**
** The conversion algorithms are implemented based on descriptions
** in the following text:
**
**      Jean Meeus
**      Astronomical Algorithms, 2nd Edition, 1998
................................................................................
    return 0;
  }else{
    return 1;
  }
}

/*
** Attempt to parse the given string into a Julian Day Number.  Return
** the number of errors.
**
** The following are acceptable forms for the input string:
**
**      YYYY-MM-DD HH:MM:SS.FFF  +/-HH:MM
**      DDDD.DD 
**      now
................................................................................
**
** Return a string described by FORMAT.  Conversions as follows:
**
**   %d  day of month
**   %f  ** fractional seconds  SS.SSS
**   %H  hour 00-24
**   %j  day of year 000-366
**   %J  ** Julian day number
**   %m  month 01-12
**   %M  minute 00-59
**   %s  seconds since 1970-01-01
**   %S  seconds 00-59
**   %w  day of week 0-6  sunday==0
**   %W  week of year 00-53
**   %Y  year 0000-9999

** This file contains the C functions that implement date and time
** functions for SQLite.  
**
** There is only one exported symbol in this file - the function
** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
** All other code has file scope.
**
** SQLite processes all times and dates as julian day numbers.  The
** dates and times are stored as the number of days since noon
** in Greenwich on November 24, 4714 B.C. according to the Gregorian
** calendar system. 
**
** 1970-01-01 00:00:00 is JD 2440587.5
** 2000-01-01 00:00:00 is JD 2451544.5
**
** This implementation requires years to be expressed as a 4-digit number
** which means that only dates between 0000-01-01 and 9999-12-31 can
** be represented, even though julian day numbers allow a much wider
** range of dates.
**
** The Gregorian calendar system is used for all dates and times,
** even those that predate the Gregorian calendar.  Historians usually
** use the julian calendar for dates prior to 1582-10-15 and for some
** dates afterwards, depending on locale.  Beware of this difference.
**
** The conversion algorithms are implemented based on descriptions
** in the following text:
**
**      Jean Meeus
**      Astronomical Algorithms, 2nd Edition, 1998
................................................................................
    return 0;
  }else{
    return 1;
  }
}

/*
** Attempt to parse the given string into a julian day number.  Return
** the number of errors.
**
** The following are acceptable forms for the input string:
**
**      YYYY-MM-DD HH:MM:SS.FFF  +/-HH:MM
**      DDDD.DD 
**      now
................................................................................
**
** Return a string described by FORMAT.  Conversions as follows:
**
**   %d  day of month
**   %f  ** fractional seconds  SS.SSS
**   %H  hour 00-24
**   %j  day of year 000-366
**   %J  ** julian day number
**   %m  month 01-12
**   %M  minute 00-59
**   %s  seconds since 1970-01-01
**   %S  seconds 00-59
**   %w  day of week 0-6  sunday==0
**   %W  week of year 00-53
**   %Y  year 0000-9999

** pWhere argument is an optional WHERE clause that restricts the
** set of rows in the view that are to be added to the ephemeral table.
*/
void sqlite3MaterializeView(
  Parse *pParse,       /* Parsing context */
  Table *pView,        /* View definition */
  Expr *pWhere,        /* Optional WHERE clause to be added */
  int iCur             /* Cursor number for ephemerial table */
){
  SelectDest dest;
  Select *pSel;
  SrcList *pFrom;
  sqlite3 *db = pParse->db;
  int iDb = sqlite3SchemaToIndex(db, pView->pSchema);
  pWhere = sqlite3ExprDup(db, pWhere, 0);
................................................................................
  int iKey;              /* Memory cell holding key of row to be deleted */
  i16 nKey;              /* Number of memory cells in the row key */
  int iEphCur = 0;       /* Ephemeral table holding all primary key values */
  int iRowSet = 0;       /* Register for rowset of rows to delete */
  int addrBypass = 0;    /* Address of jump over the delete logic */
  int addrLoop = 0;      /* Top of the delete loop */
  int addrDelete = 0;    /* Jump directly to the delete logic */
  int addrEphOpen = 0;   /* Instruction to open the Ephermeral table */
 
#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  Trigger *pTrigger;           /* List of table triggers, if required */
#endif

  memset(&sContext, 0, sizeof(sContext));
................................................................................
  if( v==0 ){
    goto delete_from_cleanup;
  }
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);

  /* If we are trying to delete from a view, realize that view into
  ** a ephemeral table.
  */
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
  if( isView ){
    sqlite3MaterializeView(pParse, pTab, pWhere, iTabCur);
    iDataCur = iIdxCur = iTabCur;
  }
#endif
................................................................................
    if( HasRowid(pTab) ){
      /* For a rowid table, initialize the RowSet to an empty set */
      pPk = 0;
      nPk = 1;
      iRowSet = ++pParse->nMem;
      sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
    }else{
      /* For a WITHOUT ROWID table, create an ephermeral table used to
      ** hold all primary keys for rows to be deleted. */
      pPk = sqlite3PrimaryKeyIndex(pTab);
      assert( pPk!=0 );
      nPk = pPk->nKeyCol;
      iPk = pParse->nMem+1;
      pParse->nMem += nPk;
      iEphCur = pParse->nTab++;
................................................................................
    ** where-clause loop above.
    */
    if( okOnePass ){
      /* Just one row.  Hence the top-of-loop is a no-op */
      assert( nKey==nPk );  /* OP_Found will use an unpacked key */
      assert( !IsVirtual(pTab) );
      if( aToOpen[iDataCur-iTabCur] ){
        assert( pPk!=0 );
        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey);
        VdbeCoverage(v);
      }
    }else if( pPk ){
      addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v);
      sqlite3VdbeAddOp2(v, OP_RowKey, iEphCur, iKey);
      assert( nKey==0 );  /* OP_Found will use a composite key */
................................................................................
  sqlite3AuthContextPop(&sContext);
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprDelete(db, pWhere);
  sqlite3DbFree(db, aToOpen);
  return;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
** thely may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation).  */
#ifdef isView
 #undef isView
#endif
#ifdef pTrigger
 #undef pTrigger
#endif

** pWhere argument is an optional WHERE clause that restricts the
** set of rows in the view that are to be added to the ephemeral table.
*/
void sqlite3MaterializeView(
  Parse *pParse,       /* Parsing context */
  Table *pView,        /* View definition */
  Expr *pWhere,        /* Optional WHERE clause to be added */
  int iCur             /* Cursor number for ephemeral table */
){
  SelectDest dest;
  Select *pSel;
  SrcList *pFrom;
  sqlite3 *db = pParse->db;
  int iDb = sqlite3SchemaToIndex(db, pView->pSchema);
  pWhere = sqlite3ExprDup(db, pWhere, 0);
................................................................................
  int iKey;              /* Memory cell holding key of row to be deleted */
  i16 nKey;              /* Number of memory cells in the row key */
  int iEphCur = 0;       /* Ephemeral table holding all primary key values */
  int iRowSet = 0;       /* Register for rowset of rows to delete */
  int addrBypass = 0;    /* Address of jump over the delete logic */
  int addrLoop = 0;      /* Top of the delete loop */
  int addrDelete = 0;    /* Jump directly to the delete logic */
  int addrEphOpen = 0;   /* Instruction to open the Ephemeral table */
 
#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  Trigger *pTrigger;           /* List of table triggers, if required */
#endif

  memset(&sContext, 0, sizeof(sContext));
................................................................................
  if( v==0 ){
    goto delete_from_cleanup;
  }
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);

  /* If we are trying to delete from a view, realize that view into
  ** an ephemeral table.
  */
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
  if( isView ){
    sqlite3MaterializeView(pParse, pTab, pWhere, iTabCur);
    iDataCur = iIdxCur = iTabCur;
  }
#endif
................................................................................
    if( HasRowid(pTab) ){
      /* For a rowid table, initialize the RowSet to an empty set */
      pPk = 0;
      nPk = 1;
      iRowSet = ++pParse->nMem;
      sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
    }else{
      /* For a WITHOUT ROWID table, create an ephemeral table used to
      ** hold all primary keys for rows to be deleted. */
      pPk = sqlite3PrimaryKeyIndex(pTab);
      assert( pPk!=0 );
      nPk = pPk->nKeyCol;
      iPk = pParse->nMem+1;
      pParse->nMem += nPk;
      iEphCur = pParse->nTab++;
................................................................................
    ** where-clause loop above.
    */
    if( okOnePass ){
      /* Just one row.  Hence the top-of-loop is a no-op */
      assert( nKey==nPk );  /* OP_Found will use an unpacked key */
      assert( !IsVirtual(pTab) );
      if( aToOpen[iDataCur-iTabCur] ){
        assert( pPk!=0 || pTab->pSelect!=0 );
        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey);
        VdbeCoverage(v);
      }
    }else if( pPk ){
      addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v);
      sqlite3VdbeAddOp2(v, OP_RowKey, iEphCur, iKey);
      assert( nKey==0 );  /* OP_Found will use a composite key */
................................................................................
  sqlite3AuthContextPop(&sContext);
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprDelete(db, pWhere);
  sqlite3DbFree(db, aToOpen);
  return;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
** they may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation).  */
#ifdef isView
 #undef isView
#endif
#ifdef pTrigger
 #undef pTrigger
#endif

** Return the 'affinity' of the expression pExpr if any.
**
** If pExpr is a column, a reference to a column via an 'AS' alias,
** or a sub-select with a column as the return value, then the 
** affinity of that column is returned. Otherwise, 0x00 is returned,
** indicating no affinity for the expression.
**
** i.e. the WHERE clause expresssions in the following statements all
** have an affinity:
**
** CREATE TABLE t1(a);
** SELECT * FROM t1 WHERE a;
** SELECT a AS b FROM t1 WHERE b;
** SELECT * FROM t1 WHERE (select a from t1);
*/
................................................................................
      pRoot->flags |= EP_Collate & pLeft->flags;
    }
    exprSetHeight(pRoot);
  }
}

/*
** Allocate a Expr node which joins as many as two subtrees.
**
** One or both of the subtrees can be NULL.  Return a pointer to the new
** Expr node.  Or, if an OOM error occurs, set pParse->db->mallocFailed,
** free the subtrees and return NULL.
*/
Expr *sqlite3PExpr(
  Parse *pParse,          /* Parsing context */
................................................................................
**
** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
** sure "nnn" is not too be to avoid a denial of service attack when
** the SQL statement comes from an external source.
**
** Wildcards of the form ":aaa", "@aaa", or "$aaa" are assigned the same number
** as the previous instance of the same wildcard.  Or if this is the first
** instance of the wildcard, the next sequenial variable number is
** assigned.
*/
void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
  sqlite3 *db = pParse->db;
  const char *z;

  if( pExpr==0 ) return;
................................................................................
** return value with EP_Reduced|EP_TokenOnly.
**
** Note that with flags==EXPRDUP_REDUCE, this routines works on full-size
** (unreduced) Expr objects as they or originally constructed by the parser.
** During expression analysis, extra information is computed and moved into
** later parts of teh Expr object and that extra information might get chopped
** off if the expression is reduced.  Note also that it does not work to
** make a EXPRDUP_REDUCE copy of a reduced expression.  It is only legal
** to reduce a pristine expression tree from the parser.  The implementation
** of dupedExprStructSize() contain multiple assert() statements that attempt
** to enforce this constraint.
*/
static int dupedExprStructSize(Expr *p, int flags){
  int nSize;
  assert( flags==EXPRDUP_REDUCE || flags==0 ); /* Only one flag value allowed */
................................................................................
}

/*
** This function is similar to sqlite3ExprDup(), except that if pzBuffer 
** is not NULL then *pzBuffer is assumed to point to a buffer large enough 
** to store the copy of expression p, the copies of p->u.zToken
** (if applicable), and the copies of the p->pLeft and p->pRight expressions,
** if any. Before returning, *pzBuffer is set to the first byte passed the
** portion of the buffer copied into by this function.
*/
static Expr *exprDup(sqlite3 *db, Expr *p, int flags, u8 **pzBuffer){
  Expr *pNew = 0;                      /* Value to return */
  if( p ){
    const int isReduced = (flags&EXPRDUP_REDUCE);
    u8 *zAlloc;
................................................................................
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->nSelectRow = p->nSelectRow;
  pNew->pWith = withDup(db, p->pWith);

  return pNew;
}
#else
Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
  assert( p==0 );
  return 0;
}
................................................................................
    sqlite3DbFree(db, pItem->zSpan);
  }
  sqlite3DbFree(db, pList->a);
  sqlite3DbFree(db, pList);
}

/*
** These routines are Walker callbacks.  Walker.u.pi is a pointer
** to an integer.  These routines are checking an expression to see
** if it is a constant.  Set *Walker.u.pi to 0 if the expression is
** not constant.
**
** These callback routines are used to implement the following:
**
**     sqlite3ExprIsConstant()
**     sqlite3ExprIsConstantNotJoin()

**     sqlite3ExprIsConstantOrFunction()
**











*/
static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){

  /* If pWalker->u.i is 3 then any term of the expression that comes from
  ** the ON or USING clauses of a join disqualifies the expression
  ** from being considered constant. */
  if( pWalker->u.i==3 && ExprHasProperty(pExpr, EP_FromJoin) ){
    pWalker->u.i = 0;
    return WRC_Abort;
  }

  switch( pExpr->op ){
    /* Consider functions to be constant if all their arguments are constant
    ** and either pWalker->u.i==2 or the function as the SQLITE_FUNC_CONST
    ** flag. */
    case TK_FUNCTION:
      if( pWalker->u.i==2 || ExprHasProperty(pExpr,EP_Constant) ){
        return WRC_Continue;



      }
      /* Fall through */
    case TK_ID:
    case TK_COLUMN:
    case TK_AGG_FUNCTION:
    case TK_AGG_COLUMN:
      testcase( pExpr->op==TK_ID );
      testcase( pExpr->op==TK_COLUMN );
      testcase( pExpr->op==TK_AGG_FUNCTION );
      testcase( pExpr->op==TK_AGG_COLUMN );



      pWalker->u.i = 0;
      return WRC_Abort;














    default:
      testcase( pExpr->op==TK_SELECT ); /* selectNodeIsConstant will disallow */
      testcase( pExpr->op==TK_EXISTS ); /* selectNodeIsConstant will disallow */
      return WRC_Continue;
  }
}
static int selectNodeIsConstant(Walker *pWalker, Select *NotUsed){
  UNUSED_PARAMETER(NotUsed);
  pWalker->u.i = 0;
  return WRC_Abort;
}
static int exprIsConst(Expr *p, int initFlag){
  Walker w;
  memset(&w, 0, sizeof(w));
  w.u.i = initFlag;
  w.xExprCallback = exprNodeIsConstant;
  w.xSelectCallback = selectNodeIsConstant;

  sqlite3WalkExpr(&w, p);
  return w.u.i;
}

/*
** Walk an expression tree.  Return 1 if the expression is constant
** and 0 if it involves variables or function calls.
**
** For the purposes of this function, a double-quoted string (ex: "abc")
** is considered a variable but a single-quoted string (ex: 'abc') is
** a constant.
*/
int sqlite3ExprIsConstant(Expr *p){
  return exprIsConst(p, 1);
}

/*
** Walk an expression tree.  Return 1 if the expression is constant
** that does no originate from the ON or USING clauses of a join.
** Return 0 if it involves variables or function calls or terms from
** an ON or USING clause.
*/
int sqlite3ExprIsConstantNotJoin(Expr *p){
  return exprIsConst(p, 3);
}

/*
** Walk an expression tree.  Return 1 if the expression is constant










** or a function call with constant arguments.  Return and 0 if there
** are any variables.
**
** For the purposes of this function, a double-quoted string (ex: "abc")
** is considered a variable but a single-quoted string (ex: 'abc') is
** a constant.
*/
int sqlite3ExprIsConstantOrFunction(Expr *p){

  return exprIsConst(p, 2);
}

/*
** If the expression p codes a constant integer that is small enough
** to fit in a 32-bit integer, return 1 and put the value of the integer
** in *pValue.  If the expression is not an integer or if it is too big
** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
................................................................................
    case TK_INTEGER:
    case TK_STRING:
    case TK_FLOAT:
    case TK_BLOB:
      return 0;
    case TK_COLUMN:
      assert( p->pTab!=0 );

      return p->iColumn>=0 && p->pTab->aCol[p->iColumn].notNull==0;
    default:
      return 1;
  }
}

/*
** Return TRUE if the given expression is a constant which would be
................................................................................
** An existing b-tree might be used if the RHS expression pX is a simple
** subquery such as:
**
**     SELECT <column> FROM <table>
**
** If the RHS of the IN operator is a list or a more complex subquery, then
** an ephemeral table might need to be generated from the RHS and then
** pX->iTable made to point to the ephermeral table instead of an
** existing table.
**
** The inFlags parameter must contain exactly one of the bits
** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP.  If inFlags contains
** IN_INDEX_MEMBERSHIP, then the generated table will be used for a
** fast membership test.  When the IN_INDEX_LOOP bit is set, the
** IN index will be used to loop over all values of the RHS of the
................................................................................
    }
  }

  /* If no preexisting index is available for the IN clause
  ** and IN_INDEX_NOOP is an allowed reply
  ** and the RHS of the IN operator is a list, not a subquery
  ** and the RHS is not contant or has two or fewer terms,
  ** then it is not worth creating an ephermeral table to evaluate
  ** the IN operator so return IN_INDEX_NOOP.
  */
  if( eType==0
   && (inFlags & IN_INDEX_NOOP_OK)
   && !ExprHasProperty(pX, EP_xIsSelect)
   && (!sqlite3InRhsIsConstant(pX) || pX->x.pList->nExpr<=2)
  ){
................................................................................

        assert( !isRowid );
        sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
        dest.affSdst = (u8)affinity;
        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
        pSelect->iLimit = 0;
        testcase( pSelect->selFlags & SF_Distinct );
        pSelect->selFlags &= ~SF_Distinct;
        testcase( pKeyInfo==0 ); /* Caused by OOM in sqlite3KeyInfoAlloc() */
        if( sqlite3Select(pParse, pSelect, &dest) ){
          sqlite3KeyInfoUnref(pKeyInfo);
          return 0;
        }
        pEList = pSelect->pEList;
        assert( pKeyInfo!=0 ); /* OOM will cause exit after sqlite3Select() */
................................................................................
}

/*
** Generate code to move content from registers iFrom...iFrom+nReg-1
** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
*/
void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
  int i;
  struct yColCache *p;
  assert( iFrom>=iTo+nReg || iFrom+nReg<=iTo );
  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
    int x = p->iReg;
    if( x>=iFrom && x<iFrom+nReg ){
      p->iReg += iTo-iFrom;
    }
  }

}

#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
/*
** Return true if any register in the range iFrom..iTo (inclusive)
** is used as part of the column cache.
**
................................................................................
      pDef = sqlite3FindFunction(db, zId, nId, nFarg, enc, 0);
      if( pDef==0 || pDef->xFunc==0 ){
        sqlite3ErrorMsg(pParse, "unknown function: %.*s()", nId, zId);
        break;
      }

      /* Attempt a direct implementation of the built-in COALESCE() and
      ** IFNULL() functions.  This avoids unnecessary evalation of
      ** arguments past the first non-NULL argument.
      */
      if( pDef->funcFlags & SQLITE_FUNC_COALESCE ){
        int endCoalesce = sqlite3VdbeMakeLabel(v);
        assert( nFarg>=2 );
        sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
        for(i=1; i<nFarg; i++){
................................................................................
        (pExpr->iTable ? "new" : "old"),
        (pExpr->iColumn<0 ? "rowid" : pExpr->pTab->aCol[pExpr->iColumn].zName),
        target
      ));

#ifndef SQLITE_OMIT_FLOATING_POINT
      /* If the column has REAL affinity, it may currently be stored as an
      ** integer. Use OP_RealAffinity to make sure it is really real.  */



      if( pExpr->iColumn>=0 
       && pTab->aCol[pExpr->iColumn].affinity==SQLITE_AFF_REAL
      ){
        sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
      }
#endif
      break;
................................................................................
    sqlite3ExprCodeAtInit(pParse, pExpr, target, 0);
  }else{
    sqlite3ExprCode(pParse, pExpr, target);
  }
}

/*
** Generate code that evalutes the given expression and puts the result
** in register target.
**
** Also make a copy of the expression results into another "cache" register
** and modify the expression so that the next time it is evaluated,
** the result is a copy of the cache register.
**
** This routine is used for expressions that are used multiple 
................................................................................
  assert( pExpr->op!=TK_REGISTER );
  sqlite3ExprCode(pParse, pExpr, target);
  iMem = ++pParse->nMem;
  sqlite3VdbeAddOp2(v, OP_Copy, target, iMem);
  exprToRegister(pExpr, iMem);
}

#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
/*
** Generate a human-readable explanation of an expression tree.
*/
void sqlite3ExplainExpr(Vdbe *pOut, Expr *pExpr){
  int op;                   /* The opcode being coded */
  const char *zBinOp = 0;   /* Binary operator */
  const char *zUniOp = 0;   /* Unary operator */

  if( pExpr==0 ){
    op = TK_NULL;
  }else{
    op = pExpr->op;
  }
  switch( op ){
    case TK_AGG_COLUMN: {
      sqlite3ExplainPrintf(pOut, "AGG{%d:%d}",
            pExpr->iTable, pExpr->iColumn);
      break;
    }
    case TK_COLUMN: {
      if( pExpr->iTable<0 ){
        /* This only happens when coding check constraints */
        sqlite3ExplainPrintf(pOut, "COLUMN(%d)", pExpr->iColumn);
      }else{
        sqlite3ExplainPrintf(pOut, "{%d:%d}",
                             pExpr->iTable, pExpr->iColumn);
      }
      break;
    }
    case TK_INTEGER: {
      if( pExpr->flags & EP_IntValue ){
        sqlite3ExplainPrintf(pOut, "%d", pExpr->u.iValue);
      }else{
        sqlite3ExplainPrintf(pOut, "%s", pExpr->u.zToken);
      }
      break;
    }
#ifndef SQLITE_OMIT_FLOATING_POINT
    case TK_FLOAT: {
      sqlite3ExplainPrintf(pOut,"%s", pExpr->u.zToken);
      break;
    }
#endif
    case TK_STRING: {
      sqlite3ExplainPrintf(pOut,"%Q", pExpr->u.zToken);
      break;
    }
    case TK_NULL: {
      sqlite3ExplainPrintf(pOut,"NULL");
      break;
    }
#ifndef SQLITE_OMIT_BLOB_LITERAL
    case TK_BLOB: {
      sqlite3ExplainPrintf(pOut,"%s", pExpr->u.zToken);
      break;
    }
#endif
    case TK_VARIABLE: {
      sqlite3ExplainPrintf(pOut,"VARIABLE(%s,%d)",
                           pExpr->u.zToken, pExpr->iColumn);
      break;
    }
    case TK_REGISTER: {
      sqlite3ExplainPrintf(pOut,"REGISTER(%d)", pExpr->iTable);
      break;
    }
    case TK_AS: {
      sqlite3ExplainExpr(pOut, pExpr->pLeft);





      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */
      const char *zAff = "unk";
      switch( sqlite3AffinityType(pExpr->u.zToken, 0) ){
        case SQLITE_AFF_TEXT:    zAff = "TEXT";     break;
        case SQLITE_AFF_NONE:    zAff = "NONE";     break;
        case SQLITE_AFF_NUMERIC: zAff = "NUMERIC";  break;
        case SQLITE_AFF_INTEGER: zAff = "INTEGER";  break;
        case SQLITE_AFF_REAL:    zAff = "REAL";     break;
      }
      sqlite3ExplainPrintf(pOut, "CAST-%s(", zAff);
      sqlite3ExplainExpr(pOut, pExpr->pLeft);
      sqlite3ExplainPrintf(pOut, ")");
      break;
    }
#endif /* SQLITE_OMIT_CAST */
    case TK_LT:      zBinOp = "LT";     break;
    case TK_LE:      zBinOp = "LE";     break;
    case TK_GT:      zBinOp = "GT";     break;
    case TK_GE:      zBinOp = "GE";     break;
................................................................................
    case TK_REM:     zBinOp = "REM";    break;
    case TK_BITAND:  zBinOp = "BITAND"; break;
    case TK_BITOR:   zBinOp = "BITOR";  break;
    case TK_SLASH:   zBinOp = "DIV";    break;
    case TK_LSHIFT:  zBinOp = "LSHIFT"; break;
    case TK_RSHIFT:  zBinOp = "RSHIFT"; break;
    case TK_CONCAT:  zBinOp = "CONCAT"; break;


    case TK_UMINUS:  zUniOp = "UMINUS"; break;
    case TK_UPLUS:   zUniOp = "UPLUS";  break;
    case TK_BITNOT:  zUniOp = "BITNOT"; break;
    case TK_NOT:     zUniOp = "NOT";    break;
    case TK_ISNULL:  zUniOp = "ISNULL"; break;
    case TK_NOTNULL: zUniOp = "NOTNULL"; break;

    case TK_COLLATE: {
      sqlite3ExplainExpr(pOut, pExpr->pLeft);
      sqlite3ExplainPrintf(pOut,".COLLATE(%s)",pExpr->u.zToken);
      break;
    }

    case TK_AGG_FUNCTION:
    case TK_FUNCTION: {
      ExprList *pFarg;       /* List of function arguments */
      if( ExprHasProperty(pExpr, EP_TokenOnly) ){
        pFarg = 0;
      }else{
        pFarg = pExpr->x.pList;
      }
      if( op==TK_AGG_FUNCTION ){
        sqlite3ExplainPrintf(pOut, "AGG_FUNCTION%d:%s(",
                             pExpr->op2, pExpr->u.zToken);
      }else{
        sqlite3ExplainPrintf(pOut, "FUNCTION:%s(", pExpr->u.zToken);
      }
      if( pFarg ){
        sqlite3ExplainExprList(pOut, pFarg);
      }
      sqlite3ExplainPrintf(pOut, ")");
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS: {
      sqlite3ExplainPrintf(pOut, "EXISTS(");
      sqlite3ExplainSelect(pOut, pExpr->x.pSelect);
      sqlite3ExplainPrintf(pOut,")");
      break;
    }
    case TK_SELECT: {
      sqlite3ExplainPrintf(pOut, "(");
      sqlite3ExplainSelect(pOut, pExpr->x.pSelect);
      sqlite3ExplainPrintf(pOut, ")");
      break;
    }
    case TK_IN: {
      sqlite3ExplainPrintf(pOut, "IN(");
      sqlite3ExplainExpr(pOut, pExpr->pLeft);
      sqlite3ExplainPrintf(pOut, ",");
      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        sqlite3ExplainSelect(pOut, pExpr->x.pSelect);
      }else{
        sqlite3ExplainExprList(pOut, pExpr->x.pList);

      }
      sqlite3ExplainPrintf(pOut, ")");
      break;
    }
#endif /* SQLITE_OMIT_SUBQUERY */

    /*
    **    x BETWEEN y AND z
    **
................................................................................
    ** Y is stored in pExpr->pList->a[0].pExpr.
    ** Z is stored in pExpr->pList->a[1].pExpr.
    */
    case TK_BETWEEN: {
      Expr *pX = pExpr->pLeft;
      Expr *pY = pExpr->x.pList->a[0].pExpr;
      Expr *pZ = pExpr->x.pList->a[1].pExpr;
      sqlite3ExplainPrintf(pOut, "BETWEEN(");
      sqlite3ExplainExpr(pOut, pX);
      sqlite3ExplainPrintf(pOut, ",");
      sqlite3ExplainExpr(pOut, pY);
      sqlite3ExplainPrintf(pOut, ",");
      sqlite3ExplainExpr(pOut, pZ);
      sqlite3ExplainPrintf(pOut, ")");
      break;
    }
    case TK_TRIGGER: {
      /* If the opcode is TK_TRIGGER, then the expression is a reference
      ** to a column in the new.* or old.* pseudo-tables available to
      ** trigger programs. In this case Expr.iTable is set to 1 for the
      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
      ** is set to the column of the pseudo-table to read, or to -1 to
      ** read the rowid field.
      */
      sqlite3ExplainPrintf(pOut, "%s(%d)", 
          pExpr->iTable ? "NEW" : "OLD", pExpr->iColumn);
      break;
    }
    case TK_CASE: {
      sqlite3ExplainPrintf(pOut, "CASE(");
      sqlite3ExplainExpr(pOut, pExpr->pLeft);
      sqlite3ExplainPrintf(pOut, ",");
      sqlite3ExplainExprList(pOut, pExpr->x.pList);
      break;
    }
#ifndef SQLITE_OMIT_TRIGGER
    case TK_RAISE: {
      const char *zType = "unk";
      switch( pExpr->affinity ){
        case OE_Rollback:   zType = "rollback";  break;
        case OE_Abort:      zType = "abort";     break;
        case OE_Fail:       zType = "fail";      break;
        case OE_Ignore:     zType = "ignore";    break;
      }
      sqlite3ExplainPrintf(pOut, "RAISE-%s(%s)", zType, pExpr->u.zToken);
      break;
    }
#endif



  }

  if( zBinOp ){
    sqlite3ExplainPrintf(pOut,"%s(", zBinOp);
    sqlite3ExplainExpr(pOut, pExpr->pLeft);
    sqlite3ExplainPrintf(pOut,",");
    sqlite3ExplainExpr(pOut, pExpr->pRight);
    sqlite3ExplainPrintf(pOut,")");


  }else if( zUniOp ){
    sqlite3ExplainPrintf(pOut,"%s(", zUniOp);
    sqlite3ExplainExpr(pOut, pExpr->pLeft);
    sqlite3ExplainPrintf(pOut,")");

  }

}
#endif /* defined(SQLITE_ENABLE_TREE_EXPLAIN) */


#if defined(SQLITE_ENABLE_TREE_EXPLAIN)

/*
** Generate a human-readable explanation of an expression list.
*/
void sqlite3ExplainExprList(Vdbe *pOut, ExprList *pList){
  int i;
  if( pList==0 || pList->nExpr==0 ){
    sqlite3ExplainPrintf(pOut, "(empty-list)");
    return;
  }else if( pList->nExpr==1 ){
    sqlite3ExplainExpr(pOut, pList->a[0].pExpr);
  }else{
    sqlite3ExplainPush(pOut);
    for(i=0; i<pList->nExpr; i++){
      sqlite3ExplainPrintf(pOut, "item[%d] = ", i);
      sqlite3ExplainPush(pOut);
      sqlite3ExplainExpr(pOut, pList->a[i].pExpr);
      sqlite3ExplainPop(pOut);
      if( pList->a[i].zName ){


        sqlite3ExplainPrintf(pOut, " AS %s", pList->a[i].zName);
      }
      if( pList->a[i].bSpanIsTab ){
        sqlite3ExplainPrintf(pOut, " (%s)", pList->a[i].zSpan);
      }
      if( i<pList->nExpr-1 ){
        sqlite3ExplainNL(pOut);
      }
    }
    sqlite3ExplainPop(pOut);
  }

}
#endif /* SQLITE_DEBUG */

/*
** Generate code that pushes the value of every element of the given
** expression list into a sequence of registers beginning at target.
**
................................................................................
**    x BETWEEN y AND z
**
** The above is equivalent to 
**
**    x>=y AND x<=z
**
** Code it as such, taking care to do the common subexpression
** elementation of x.
*/
static void exprCodeBetween(
  Parse *pParse,    /* Parsing and code generating context */
  Expr *pExpr,      /* The BETWEEN expression */
  int dest,         /* Jump here if the jump is taken */
  int jumpIfTrue,   /* Take the jump if the BETWEEN is true */
  int jumpIfNull    /* Take the jump if the BETWEEN is NULL */
................................................................................
}

/*
** Deallocate a register, making available for reuse for some other
** purpose.
**
** If a register is currently being used by the column cache, then
** the dallocation is deferred until the column cache line that uses
** the register becomes stale.
*/
void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
  if( iReg && pParse->nTempReg<ArraySize(pParse->aTempReg) ){
    int i;
    struct yColCache *p;
    for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){

** Return the 'affinity' of the expression pExpr if any.
**
** If pExpr is a column, a reference to a column via an 'AS' alias,
** or a sub-select with a column as the return value, then the 
** affinity of that column is returned. Otherwise, 0x00 is returned,
** indicating no affinity for the expression.
**
** i.e. the WHERE clause expressions in the following statements all
** have an affinity:
**
** CREATE TABLE t1(a);
** SELECT * FROM t1 WHERE a;
** SELECT a AS b FROM t1 WHERE b;
** SELECT * FROM t1 WHERE (select a from t1);
*/
................................................................................
      pRoot->flags |= EP_Collate & pLeft->flags;
    }
    exprSetHeight(pRoot);
  }
}

/*
** Allocate an Expr node which joins as many as two subtrees.
**
** One or both of the subtrees can be NULL.  Return a pointer to the new
** Expr node.  Or, if an OOM error occurs, set pParse->db->mallocFailed,
** free the subtrees and return NULL.
*/
Expr *sqlite3PExpr(
  Parse *pParse,          /* Parsing context */
................................................................................
**
** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
** sure "nnn" is not too be to avoid a denial of service attack when
** the SQL statement comes from an external source.
**
** Wildcards of the form ":aaa", "@aaa", or "$aaa" are assigned the same number
** as the previous instance of the same wildcard.  Or if this is the first
** instance of the wildcard, the next sequential variable number is
** assigned.
*/
void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
  sqlite3 *db = pParse->db;
  const char *z;

  if( pExpr==0 ) return;
................................................................................
** return value with EP_Reduced|EP_TokenOnly.
**
** Note that with flags==EXPRDUP_REDUCE, this routines works on full-size
** (unreduced) Expr objects as they or originally constructed by the parser.
** During expression analysis, extra information is computed and moved into
** later parts of teh Expr object and that extra information might get chopped
** off if the expression is reduced.  Note also that it does not work to
** make an EXPRDUP_REDUCE copy of a reduced expression.  It is only legal
** to reduce a pristine expression tree from the parser.  The implementation
** of dupedExprStructSize() contain multiple assert() statements that attempt
** to enforce this constraint.
*/
static int dupedExprStructSize(Expr *p, int flags){
  int nSize;
  assert( flags==EXPRDUP_REDUCE || flags==0 ); /* Only one flag value allowed */
................................................................................
}

/*
** This function is similar to sqlite3ExprDup(), except that if pzBuffer 
** is not NULL then *pzBuffer is assumed to point to a buffer large enough 
** to store the copy of expression p, the copies of p->u.zToken
** (if applicable), and the copies of the p->pLeft and p->pRight expressions,
** if any. Before returning, *pzBuffer is set to the first byte past the
** portion of the buffer copied into by this function.
*/
static Expr *exprDup(sqlite3 *db, Expr *p, int flags, u8 **pzBuffer){
  Expr *pNew = 0;                      /* Value to return */
  if( p ){
    const int isReduced = (flags&EXPRDUP_REDUCE);
    u8 *zAlloc;
................................................................................
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->nSelectRow = p->nSelectRow;
  pNew->pWith = withDup(db, p->pWith);
  sqlite3SelectSetName(pNew, p->zSelName);
  return pNew;
}
#else
Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
  assert( p==0 );
  return 0;
}
................................................................................
    sqlite3DbFree(db, pItem->zSpan);
  }
  sqlite3DbFree(db, pList->a);
  sqlite3DbFree(db, pList);
}

/*
** These routines are Walker callbacks used to check expressions to
** see if they are "constant" for some definition of constant.  The
** Walker.eCode value determines the type of "constant" we are looking
** for.
**
** These callback routines are used to implement the following:
**
**     sqlite3ExprIsConstant()                  pWalker->eCode==1
**     sqlite3ExprIsConstantNotJoin()           pWalker->eCode==2
**     sqlite3ExprRefOneTableOnly()             pWalker->eCode==3
**     sqlite3ExprIsConstantOrFunction()        pWalker->eCode==4 or 5
**
** In all cases, the callbacks set Walker.eCode=0 and abort if the expression
** is found to not be a constant.
**
** The sqlite3ExprIsConstantOrFunction() is used for evaluating expressions
** in a CREATE TABLE statement.  The Walker.eCode value is 5 when parsing
** an existing schema and 4 when processing a new statement.  A bound
** parameter raises an error for new statements, but is silently converted
** to NULL for existing schemas.  This allows sqlite_master tables that 
** contain a bound parameter because they were generated by older versions
** of SQLite to be parsed by newer versions of SQLite without raising a
** malformed schema error.
*/
static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){

  /* If pWalker->eCode is 2 then any term of the expression that comes from
  ** the ON or USING clauses of a left join disqualifies the expression
  ** from being considered constant. */
  if( pWalker->eCode==2 && ExprHasProperty(pExpr, EP_FromJoin) ){
    pWalker->eCode = 0;
    return WRC_Abort;
  }

  switch( pExpr->op ){
    /* Consider functions to be constant if all their arguments are constant
    ** and either pWalker->eCode==4 or 5 or the function has the
    ** SQLITE_FUNC_CONST flag. */
    case TK_FUNCTION:
      if( pWalker->eCode>=4 || ExprHasProperty(pExpr,EP_Constant) ){
        return WRC_Continue;
      }else{
        pWalker->eCode = 0;
        return WRC_Abort;
      }

    case TK_ID:
    case TK_COLUMN:
    case TK_AGG_FUNCTION:
    case TK_AGG_COLUMN:
      testcase( pExpr->op==TK_ID );
      testcase( pExpr->op==TK_COLUMN );
      testcase( pExpr->op==TK_AGG_FUNCTION );
      testcase( pExpr->op==TK_AGG_COLUMN );
      if( pWalker->eCode==3 && pExpr->iTable==pWalker->u.iCur ){
        return WRC_Continue;
      }else{
        pWalker->eCode = 0;
        return WRC_Abort;
      }
    case TK_VARIABLE:
      if( pWalker->eCode==5 ){
        /* Silently convert bound parameters that appear inside of CREATE
        ** statements into a NULL when parsing the CREATE statement text out
        ** of the sqlite_master table */
        pExpr->op = TK_NULL;
      }else if( pWalker->eCode==4 ){
        /* A bound parameter in a CREATE statement that originates from
        ** sqlite3_prepare() causes an error */
        pWalker->eCode = 0;
        return WRC_Abort;
      }
      /* Fall through */
    default:
      testcase( pExpr->op==TK_SELECT ); /* selectNodeIsConstant will disallow */
      testcase( pExpr->op==TK_EXISTS ); /* selectNodeIsConstant will disallow */
      return WRC_Continue;
  }
}
static int selectNodeIsConstant(Walker *pWalker, Select *NotUsed){
  UNUSED_PARAMETER(NotUsed);
  pWalker->eCode = 0;
  return WRC_Abort;
}
static int exprIsConst(Expr *p, int initFlag, int iCur){
  Walker w;
  memset(&w, 0, sizeof(w));
  w.eCode = initFlag;
  w.xExprCallback = exprNodeIsConstant;
  w.xSelectCallback = selectNodeIsConstant;
  w.u.iCur = iCur;
  sqlite3WalkExpr(&w, p);
  return w.eCode;
}

/*
** Walk an expression tree.  Return non-zero if the expression is constant
** and 0 if it involves variables or function calls.
**
** For the purposes of this function, a double-quoted string (ex: "abc")
** is considered a variable but a single-quoted string (ex: 'abc') is
** a constant.
*/
int sqlite3ExprIsConstant(Expr *p){
  return exprIsConst(p, 1, 0);
}

/*
** Walk an expression tree.  Return non-zero if the expression is constant
** that does no originate from the ON or USING clauses of a join.
** Return 0 if it involves variables or function calls or terms from
** an ON or USING clause.
*/
int sqlite3ExprIsConstantNotJoin(Expr *p){
  return exprIsConst(p, 2, 0);
}

/*
** Walk an expression tree.  Return non-zero if the expression constant
** for any single row of the table with cursor iCur.  In other words, the
** expression must not refer to any non-deterministic function nor any
** table other than iCur.
*/
int sqlite3ExprIsTableConstant(Expr *p, int iCur){
  return exprIsConst(p, 3, iCur);
}

/*
** Walk an expression tree.  Return non-zero if the expression is constant
** or a function call with constant arguments.  Return and 0 if there
** are any variables.
**
** For the purposes of this function, a double-quoted string (ex: "abc")
** is considered a variable but a single-quoted string (ex: 'abc') is
** a constant.
*/
int sqlite3ExprIsConstantOrFunction(Expr *p, u8 isInit){
  assert( isInit==0 || isInit==1 );
  return exprIsConst(p, 4+isInit, 0);
}

/*
** If the expression p codes a constant integer that is small enough
** to fit in a 32-bit integer, return 1 and put the value of the integer
** in *pValue.  If the expression is not an integer or if it is too big
** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
................................................................................
    case TK_INTEGER:
    case TK_STRING:
    case TK_FLOAT:
    case TK_BLOB:
      return 0;
    case TK_COLUMN:
      assert( p->pTab!=0 );
      return ExprHasProperty(p, EP_CanBeNull) ||
             (p->iColumn>=0 && p->pTab->aCol[p->iColumn].notNull==0);
    default:
      return 1;
  }
}

/*
** Return TRUE if the given expression is a constant which would be
................................................................................
** An existing b-tree might be used if the RHS expression pX is a simple
** subquery such as:
**
**     SELECT <column> FROM <table>
**
** If the RHS of the IN operator is a list or a more complex subquery, then
** an ephemeral table might need to be generated from the RHS and then
** pX->iTable made to point to the ephemeral table instead of an
** existing table.
**
** The inFlags parameter must contain exactly one of the bits
** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP.  If inFlags contains
** IN_INDEX_MEMBERSHIP, then the generated table will be used for a
** fast membership test.  When the IN_INDEX_LOOP bit is set, the
** IN index will be used to loop over all values of the RHS of the
................................................................................
    }
  }

  /* If no preexisting index is available for the IN clause
  ** and IN_INDEX_NOOP is an allowed reply
  ** and the RHS of the IN operator is a list, not a subquery
  ** and the RHS is not contant or has two or fewer terms,
  ** then it is not worth creating an ephemeral table to evaluate
  ** the IN operator so return IN_INDEX_NOOP.
  */
  if( eType==0
   && (inFlags & IN_INDEX_NOOP_OK)
   && !ExprHasProperty(pX, EP_xIsSelect)
   && (!sqlite3InRhsIsConstant(pX) || pX->x.pList->nExpr<=2)
  ){
................................................................................

        assert( !isRowid );
        sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
        dest.affSdst = (u8)affinity;
        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
        pSelect->iLimit = 0;
        testcase( pSelect->selFlags & SF_Distinct );

        testcase( pKeyInfo==0 ); /* Caused by OOM in sqlite3KeyInfoAlloc() */
        if( sqlite3Select(pParse, pSelect, &dest) ){
          sqlite3KeyInfoUnref(pKeyInfo);
          return 0;
        }
        pEList = pSelect->pEList;
        assert( pKeyInfo!=0 ); /* OOM will cause exit after sqlite3Select() */
................................................................................
}

/*
** Generate code to move content from registers iFrom...iFrom+nReg-1
** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
*/
void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){


  assert( iFrom>=iTo+nReg || iFrom+nReg<=iTo );
  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);






  sqlite3ExprCacheRemove(pParse, iFrom, nReg);
}

#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
/*
** Return true if any register in the range iFrom..iTo (inclusive)
** is used as part of the column cache.
**
................................................................................
      pDef = sqlite3FindFunction(db, zId, nId, nFarg, enc, 0);
      if( pDef==0 || pDef->xFunc==0 ){
        sqlite3ErrorMsg(pParse, "unknown function: %.*s()", nId, zId);
        break;
      }

      /* Attempt a direct implementation of the built-in COALESCE() and
      ** IFNULL() functions.  This avoids unnecessary evaluation of
      ** arguments past the first non-NULL argument.
      */
      if( pDef->funcFlags & SQLITE_FUNC_COALESCE ){
        int endCoalesce = sqlite3VdbeMakeLabel(v);
        assert( nFarg>=2 );
        sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
        for(i=1; i<nFarg; i++){
................................................................................
        (pExpr->iTable ? "new" : "old"),
        (pExpr->iColumn<0 ? "rowid" : pExpr->pTab->aCol[pExpr->iColumn].zName),
        target
      ));

#ifndef SQLITE_OMIT_FLOATING_POINT
      /* If the column has REAL affinity, it may currently be stored as an
      ** integer. Use OP_RealAffinity to make sure it is really real.
      **
      ** EVIDENCE-OF: R-60985-57662 SQLite will convert the value back to
      ** floating point when extracting it from the record.  */
      if( pExpr->iColumn>=0 
       && pTab->aCol[pExpr->iColumn].affinity==SQLITE_AFF_REAL
      ){
        sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
      }
#endif
      break;
................................................................................
    sqlite3ExprCodeAtInit(pParse, pExpr, target, 0);
  }else{
    sqlite3ExprCode(pParse, pExpr, target);
  }
}

/*
** Generate code that evaluates the given expression and puts the result
** in register target.
**
** Also make a copy of the expression results into another "cache" register
** and modify the expression so that the next time it is evaluated,
** the result is a copy of the cache register.
**
** This routine is used for expressions that are used multiple 
................................................................................
  assert( pExpr->op!=TK_REGISTER );
  sqlite3ExprCode(pParse, pExpr, target);
  iMem = ++pParse->nMem;
  sqlite3VdbeAddOp2(v, OP_Copy, target, iMem);
  exprToRegister(pExpr, iMem);
}

#ifdef SQLITE_DEBUG
/*
** Generate a human-readable explanation of an expression tree.
*/
void sqlite3TreeViewExpr(TreeView *pView, const Expr *pExpr, u8 moreToFollow){

  const char *zBinOp = 0;   /* Binary operator */
  const char *zUniOp = 0;   /* Unary operator */
  pView = sqlite3TreeViewPush(pView, moreToFollow);
  if( pExpr==0 ){
    sqlite3TreeViewLine(pView, "nil");
    sqlite3TreeViewPop(pView);
    return;
  }
  switch( pExpr->op ){
    case TK_AGG_COLUMN: {
      sqlite3TreeViewLine(pView, "AGG{%d:%d}",
            pExpr->iTable, pExpr->iColumn);
      break;
    }
    case TK_COLUMN: {
      if( pExpr->iTable<0 ){
        /* This only happens when coding check constraints */
        sqlite3TreeViewLine(pView, "COLUMN(%d)", pExpr->iColumn);
      }else{
        sqlite3TreeViewLine(pView, "{%d:%d}",
                             pExpr->iTable, pExpr->iColumn);
      }
      break;
    }
    case TK_INTEGER: {
      if( pExpr->flags & EP_IntValue ){
        sqlite3TreeViewLine(pView, "%d", pExpr->u.iValue);
      }else{
        sqlite3TreeViewLine(pView, "%s", pExpr->u.zToken);
      }
      break;
    }
#ifndef SQLITE_OMIT_FLOATING_POINT
    case TK_FLOAT: {
      sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
      break;
    }
#endif
    case TK_STRING: {
      sqlite3TreeViewLine(pView,"%Q", pExpr->u.zToken);
      break;
    }
    case TK_NULL: {
      sqlite3TreeViewLine(pView,"NULL");
      break;
    }
#ifndef SQLITE_OMIT_BLOB_LITERAL
    case TK_BLOB: {
      sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
      break;
    }
#endif
    case TK_VARIABLE: {
      sqlite3TreeViewLine(pView,"VARIABLE(%s,%d)",
                          pExpr->u.zToken, pExpr->iColumn);
      break;
    }
    case TK_REGISTER: {
      sqlite3TreeViewLine(pView,"REGISTER(%d)", pExpr->iTable);
      break;
    }
    case TK_AS: {
      sqlite3TreeViewLine(pView,"AS %Q", pExpr->u.zToken);
      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
      break;
    }
    case TK_ID: {
      sqlite3TreeViewLine(pView,"ID %Q", pExpr->u.zToken);
      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */
      sqlite3TreeViewLine(pView,"CAST %Q", pExpr->u.zToken);
      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);









      break;
    }
#endif /* SQLITE_OMIT_CAST */
    case TK_LT:      zBinOp = "LT";     break;
    case TK_LE:      zBinOp = "LE";     break;
    case TK_GT:      zBinOp = "GT";     break;
    case TK_GE:      zBinOp = "GE";     break;
................................................................................
    case TK_REM:     zBinOp = "REM";    break;
    case TK_BITAND:  zBinOp = "BITAND"; break;
    case TK_BITOR:   zBinOp = "BITOR";  break;
    case TK_SLASH:   zBinOp = "DIV";    break;
    case TK_LSHIFT:  zBinOp = "LSHIFT"; break;
    case TK_RSHIFT:  zBinOp = "RSHIFT"; break;
    case TK_CONCAT:  zBinOp = "CONCAT"; break;
    case TK_DOT:     zBinOp = "DOT";    break;

    case TK_UMINUS:  zUniOp = "UMINUS"; break;
    case TK_UPLUS:   zUniOp = "UPLUS";  break;
    case TK_BITNOT:  zUniOp = "BITNOT"; break;
    case TK_NOT:     zUniOp = "NOT";    break;
    case TK_ISNULL:  zUniOp = "ISNULL"; break;
    case TK_NOTNULL: zUniOp = "NOTNULL"; break;

    case TK_COLLATE: {
      sqlite3TreeViewLine(pView, "COLLATE %Q", pExpr->u.zToken);
      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
      break;
    }

    case TK_AGG_FUNCTION:
    case TK_FUNCTION: {
      ExprList *pFarg;       /* List of function arguments */
      if( ExprHasProperty(pExpr, EP_TokenOnly) ){
        pFarg = 0;
      }else{
        pFarg = pExpr->x.pList;
      }
      if( pExpr->op==TK_AGG_FUNCTION ){
        sqlite3TreeViewLine(pView, "AGG_FUNCTION%d %Q",
                             pExpr->op2, pExpr->u.zToken);
      }else{
        sqlite3TreeViewLine(pView, "FUNCTION %Q", pExpr->u.zToken);
      }
      if( pFarg ){
        sqlite3TreeViewExprList(pView, pFarg, 0, 0);
      }

      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS: {
      sqlite3TreeViewLine(pView, "EXISTS-expr");
      sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);

      break;
    }
    case TK_SELECT: {
      sqlite3TreeViewLine(pView, "SELECT-expr");
      sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);

      break;
    }
    case TK_IN: {
      sqlite3TreeViewLine(pView, "IN");
      sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);

      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
      }else{

        sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, 0);
      }

      break;
    }
#endif /* SQLITE_OMIT_SUBQUERY */

    /*
    **    x BETWEEN y AND z
    **
................................................................................
    ** Y is stored in pExpr->pList->a[0].pExpr.
    ** Z is stored in pExpr->pList->a[1].pExpr.
    */
    case TK_BETWEEN: {
      Expr *pX = pExpr->pLeft;
      Expr *pY = pExpr->x.pList->a[0].pExpr;
      Expr *pZ = pExpr->x.pList->a[1].pExpr;
      sqlite3TreeViewLine(pView, "BETWEEN");
      sqlite3TreeViewExpr(pView, pX, 1);
      sqlite3TreeViewExpr(pView, pY, 1);
      sqlite3TreeViewExpr(pView, pZ, 0);



      break;
    }
    case TK_TRIGGER: {
      /* If the opcode is TK_TRIGGER, then the expression is a reference
      ** to a column in the new.* or old.* pseudo-tables available to
      ** trigger programs. In this case Expr.iTable is set to 1 for the
      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
      ** is set to the column of the pseudo-table to read, or to -1 to
      ** read the rowid field.
      */
      sqlite3TreeViewLine(pView, "%s(%d)", 
          pExpr->iTable ? "NEW" : "OLD", pExpr->iColumn);
      break;
    }
    case TK_CASE: {
      sqlite3TreeViewLine(pView, "CASE");
      sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
      sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, 0);

      break;
    }
#ifndef SQLITE_OMIT_TRIGGER
    case TK_RAISE: {
      const char *zType = "unk";
      switch( pExpr->affinity ){
        case OE_Rollback:   zType = "rollback";  break;
        case OE_Abort:      zType = "abort";     break;
        case OE_Fail:       zType = "fail";      break;
        case OE_Ignore:     zType = "ignore";    break;
      }
      sqlite3TreeViewLine(pView, "RAISE %s(%Q)", zType, pExpr->u.zToken);
      break;
    }
#endif
    default: {
      sqlite3TreeViewLine(pView, "op=%d", pExpr->op);
      break;
    }
  }
  if( zBinOp ){




    sqlite3TreeViewLine(pView, "%s", zBinOp);
    sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
    sqlite3TreeViewExpr(pView, pExpr->pRight, 0);
  }else if( zUniOp ){


    sqlite3TreeViewLine(pView, "%s", zUniOp);
    sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
  }
  sqlite3TreeViewPop(pView);
}

#endif /* SQLITE_DEBUG */


#ifdef SQLITE_DEBUG
/*
** Generate a human-readable explanation of an expression list.
*/
void sqlite3TreeViewExprList(
  TreeView *pView,
  const ExprList *pList,
  u8 moreToFollow,
  const char *zLabel
){
  int i;
  pView = sqlite3TreeViewPush(pView, moreToFollow);
  if( zLabel==0 || zLabel[0]==0 ) zLabel = "LIST";
  if( pList==0 ){
    sqlite3TreeViewLine(pView, "%s (empty)", zLabel);
  }else{
    sqlite3TreeViewLine(pView, "%s", zLabel);
    for(i=0; i<pList->nExpr; i++){
      sqlite3TreeViewExpr(pView, pList->a[i].pExpr, i<pList->nExpr-1);
#if 0
     if( pList->a[i].zName ){
        sqlite3ExplainPrintf(pOut, " AS %s", pList->a[i].zName);
      }
      if( pList->a[i].bSpanIsTab ){
        sqlite3ExplainPrintf(pOut, " (%s)", pList->a[i].zSpan);
      }
#endif

    }
  }


  sqlite3TreeViewPop(pView);
}
#endif /* SQLITE_DEBUG */

/*
** Generate code that pushes the value of every element of the given
** expression list into a sequence of registers beginning at target.
**
................................................................................
**    x BETWEEN y AND z
**
** The above is equivalent to 
**
**    x>=y AND x<=z
**
** Code it as such, taking care to do the common subexpression
** elimination of x.
*/
static void exprCodeBetween(
  Parse *pParse,    /* Parsing and code generating context */
  Expr *pExpr,      /* The BETWEEN expression */
  int dest,         /* Jump here if the jump is taken */
  int jumpIfTrue,   /* Take the jump if the BETWEEN is true */
  int jumpIfNull    /* Take the jump if the BETWEEN is NULL */
................................................................................
}

/*
** Deallocate a register, making available for reuse for some other
** purpose.
**
** If a register is currently being used by the column cache, then
** the deallocation is deferred until the column cache line that uses
** the register becomes stale.
*/
void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
  if( iReg && pParse->nTempReg<ArraySize(pParse->aTempReg) ){
    int i;
    struct yColCache *p;
    for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){

**
**   3) No parent key columns were provided explicitly as part of the
**      foreign key definition, and the parent table does not have a
**      PRIMARY KEY, or
**
**   4) No parent key columns were provided explicitly as part of the
**      foreign key definition, and the PRIMARY KEY of the parent table 
**      consists of a a different number of columns to the child key in 
**      the child table.
**
** then non-zero is returned, and a "foreign key mismatch" error loaded
** into pParse. If an OOM error occurs, non-zero is returned and the
** pParse->db->mallocFailed flag is set.
*/
int sqlite3FkLocateIndex(

**
**   3) No parent key columns were provided explicitly as part of the
**      foreign key definition, and the parent table does not have a
**      PRIMARY KEY, or
**
**   4) No parent key columns were provided explicitly as part of the
**      foreign key definition, and the PRIMARY KEY of the parent table 
**      consists of a different number of columns to the child key in 
**      the child table.
**
** then non-zero is returned, and a "foreign key mismatch" error loaded
** into pParse. If an OOM error occurs, non-zero is returned and the
** pParse->db->mallocFailed flag is set.
*/
int sqlite3FkLocateIndex(

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C-language implementions for many of the SQL
** functions of SQLite.  (Some function, and in particular the date and
** time functions, are implemented separately.)
*/
#include "sqliteInt.h"
#include <stdlib.h>
#include <assert.h>
#include "vdbeInt.h"

/*
** Return the collating function associated with a function.
*/
static CollSeq *sqlite3GetFuncCollSeq(sqlite3_context *context){
  return context->pColl;



}

/*
** Indicate that the accumulator load should be skipped on this
** iteration of the aggregate loop.
*/
static void sqlite3SkipAccumulatorLoad(sqlite3_context *context){
................................................................................
      /* IMP: R-37434-19929 Abs(X) returns NULL if X is NULL. */
      sqlite3_result_null(context);
      break;
    }
    default: {
      /* Because sqlite3_value_double() returns 0.0 if the argument is not
      ** something that can be converted into a number, we have:
      ** IMP: R-57326-31541 Abs(X) return 0.0 if X is a string or blob that
      ** cannot be converted to a numeric value. 
      */
      double rVal = sqlite3_value_double(argv[0]);
      if( rVal<0 ) rVal = -rVal;
      sqlite3_result_double(context, rVal);
      break;
    }
  }
................................................................................
    while( *z && p1 ){
      SQLITE_SKIP_UTF8(z);
      p1--;
    }
    for(z2=z; *z2 && p2; p2--){
      SQLITE_SKIP_UTF8(z2);
    }
    sqlite3_result_text(context, (char*)z, (int)(z2-z), SQLITE_TRANSIENT);

  }else{
    if( p1+p2>len ){
      p2 = len-p1;
      if( p2<0 ) p2 = 0;
    }
    sqlite3_result_blob(context, (char*)&z[p1], (int)p2, SQLITE_TRANSIENT);
  }
}

/*
** Implementation of the round() function
*/
#ifndef SQLITE_OMIT_FLOATING_POINT
................................................................................
  assert( nByte>0 );
  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH] );
  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH]+1 );
  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
    sqlite3_result_error_toobig(context);
    z = 0;
  }else{
    z = sqlite3Malloc((int)nByte);
    if( !z ){
      sqlite3_result_error_nomem(context);
    }
  }
  return z;
}

................................................................................
/*
** For LIKE and GLOB matching on EBCDIC machines, assume that every
** character is exactly one byte in size.  Also, all characters are
** able to participate in upper-case-to-lower-case mappings in EBCDIC
** whereas only characters less than 0x80 do in ASCII.
*/
#if defined(SQLITE_EBCDIC)
# define sqlite3Utf8Read(A)    (*((*A)++))
# define GlobUpperToLower(A)   A = sqlite3UpperToLower[A]

#else
# define GlobUpperToLower(A)   if( !((A)&~0x7f) ){ A = sqlite3UpperToLower[A]; }

#endif

static const struct compareInfo globInfo = { '*', '?', '[', 0 };
/* The correct SQL-92 behavior is for the LIKE operator to ignore
** case.  Thus  'a' LIKE 'A' would be true. */
static const struct compareInfo likeInfoNorm = { '%', '_',   0, 1 };
/* If SQLITE_CASE_SENSITIVE_LIKE is defined, then the LIKE operator
** is case sensitive causing 'a' LIKE 'A' to be false */
static const struct compareInfo likeInfoAlt = { '%', '_',   0, 0 };

/*
** Compare two UTF-8 strings for equality where the first string can
** potentially be a "glob" expression.  Return true (1) if they
** are the same and false (0) if they are different.
**
** Globbing rules:
**
**      '*'       Matches any sequence of zero or more characters.
**
**      '?'       Matches exactly one character.
................................................................................
**
** With the [...] and [^...] matching, a ']' character can be included
** in the list by making it the first character after '[' or '^'.  A
** range of characters can be specified using '-'.  Example:
** "[a-z]" matches any single lower-case letter.  To match a '-', make
** it the last character in the list.
**
** This routine is usually quick, but can be N**2 in the worst case.
**
** Hints: to match '*' or '?', put them in "[]".  Like this:
**
**         abc[*]xyz        Matches "abc*xyz" only







*/
static int patternCompare(
  const u8 *zPattern,              /* The glob pattern */
  const u8 *zString,               /* The string to compare against the glob */
  const struct compareInfo *pInfo, /* Information about how to do the compare */
  u32 esc                          /* The escape character */
){
  u32 c, c2;
  int invert;
  int seen;
  u8 matchOne = pInfo->matchOne;
  u8 matchAll = pInfo->matchAll;
  u8 matchSet = pInfo->matchSet;

  u8 noCase = pInfo->noCase; 


  int prevEscape = 0;     /* True if the previous character was 'escape' */






  while( (c = sqlite3Utf8Read(&zPattern))!=0 ){
    if( c==matchAll && !prevEscape ){



      while( (c=sqlite3Utf8Read(&zPattern)) == matchAll
               || c == matchOne ){
        if( c==matchOne && sqlite3Utf8Read(&zString)==0 ){
          return 0;
        }
      }
      if( c==0 ){
        return 1;
      }else if( c==esc ){

        c = sqlite3Utf8Read(&zPattern);
        if( c==0 ){
          return 0;
        }
      }else if( c==matchSet ){
        assert( esc==0 );         /* This is GLOB, not LIKE */
        assert( matchSet<0x80 );  /* '[' is a single-byte character */

        while( *zString && patternCompare(&zPattern[-1],zString,pInfo,esc)==0 ){
          SQLITE_SKIP_UTF8(zString);
        }
        return *zString!=0;
      }
      while( (c2 = sqlite3Utf8Read(&zString))!=0 ){













        if( noCase ){
          GlobUpperToLower(c2);
          GlobUpperToLower(c);
          while( c2 != 0 && c2 != c ){

            c2 = sqlite3Utf8Read(&zString);
            GlobUpperToLower(c2);


          }




        }else{
          while( c2 != 0 && c2 != c ){
            c2 = sqlite3Utf8Read(&zString);


          }
        }
        if( c2==0 ) return 0;
        if( patternCompare(zPattern,zString,pInfo,esc) ) return 1;
      }
      return 0;
    }else if( c==matchOne && !prevEscape ){

      if( sqlite3Utf8Read(&zString)==0 ){
        return 0;
      }
    }else if( c==matchSet ){


      u32 prior_c = 0;
      assert( esc==0 );    /* This only occurs for GLOB, not LIKE */
      seen = 0;
      invert = 0;
      c = sqlite3Utf8Read(&zString);
      if( c==0 ) return 0;
      c2 = sqlite3Utf8Read(&zPattern);
      if( c2=='^' ){
        invert = 1;
        c2 = sqlite3Utf8Read(&zPattern);
      }
      if( c2==']' ){
        if( c==']' ) seen = 1;
        c2 = sqlite3Utf8Read(&zPattern);
      }
      while( c2 && c2!=']' ){
        if( c2=='-' && zPattern[0]!=']' && zPattern[0]!=0 && prior_c>0 ){
          c2 = sqlite3Utf8Read(&zPattern);
          if( c>=prior_c && c<=c2 ) seen = 1;
          prior_c = 0;
        }else{
          if( c==c2 ){
            seen = 1;
          }
          prior_c = c2;
        }
        c2 = sqlite3Utf8Read(&zPattern);
      }
      if( c2==0 || (seen ^ invert)==0 ){
        return 0;
      }
    }else if( esc==c && !prevEscape ){
      prevEscape = 1;
    }else{
      c2 = sqlite3Utf8Read(&zString);
      if( noCase ){
        GlobUpperToLower(c);
        GlobUpperToLower(c2);

      }
      if( c!=c2 ){
        return 0;
      }
      prevEscape = 0;




    }


  }
  return *zString==0;
}

/*
** The sqlite3_strglob() interface.
*/
................................................................................
    }else{
      *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);
      *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);
      *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);
      *zOut++ = 0x80 + (u8)(c & 0x3F);
    }                                                    \
  }
  sqlite3_result_text(context, (char*)z, (int)(zOut-z), sqlite3_free);
}

/*
** The hex() function.  Interpret the argument as a blob.  Return
** a hexadecimal rendering as text.
*/
static void hexFunc(
................................................................................
    cmp = sqlite3MemCompare(pBest, pArg, pColl);
    if( (max && cmp<0) || (!max && cmp>0) ){
      sqlite3VdbeMemCopy(pBest, pArg);
    }else{
      sqlite3SkipAccumulatorLoad(context);
    }
  }else{

    sqlite3VdbeMemCopy(pBest, pArg);
  }
}
static void minMaxFinalize(sqlite3_context *context){
  sqlite3_value *pRes;
  pRes = (sqlite3_value *)sqlite3_aggregate_context(context, 0);
  if( pRes ){
................................................................................
  assert( &((char*)&likeInfoAlt)[1] == (char*)&likeInfoAlt.matchOne );
  assert( &((char*)&likeInfoAlt)[2] == (char*)&likeInfoAlt.matchSet );
  *pIsNocase = (pDef->funcFlags & SQLITE_FUNC_CASE)==0;
  return 1;
}

/*
** All all of the FuncDef structures in the aBuiltinFunc[] array above
** to the global function hash table.  This occurs at start-time (as
** a consequence of calling sqlite3_initialize()).
**
** After this routine runs
*/
void sqlite3RegisterGlobalFunctions(void){
  /*
................................................................................
    FUNCTION(ltrim,              2, 1, 0, trimFunc         ),
    FUNCTION(rtrim,              1, 2, 0, trimFunc         ),
    FUNCTION(rtrim,              2, 2, 0, trimFunc         ),
    FUNCTION(trim,               1, 3, 0, trimFunc         ),
    FUNCTION(trim,               2, 3, 0, trimFunc         ),
    FUNCTION(min,               -1, 0, 1, minmaxFunc       ),
    FUNCTION(min,                0, 0, 1, 0                ),
    AGGREGATE(min,               1, 0, 1, minmaxStep,      minMaxFinalize ),

    FUNCTION(max,               -1, 1, 1, minmaxFunc       ),
    FUNCTION(max,                0, 1, 1, 0                ),
    AGGREGATE(max,               1, 1, 1, minmaxStep,      minMaxFinalize ),

    FUNCTION2(typeof,            1, 0, 0, typeofFunc,  SQLITE_FUNC_TYPEOF),
    FUNCTION2(length,            1, 0, 0, lengthFunc,  SQLITE_FUNC_LENGTH),
    FUNCTION(instr,              2, 0, 0, instrFunc        ),
    FUNCTION(substr,             2, 0, 0, substrFunc       ),
    FUNCTION(substr,             3, 0, 0, substrFunc       ),
    FUNCTION(printf,            -1, 0, 0, printfFunc       ),
    FUNCTION(unicode,            1, 0, 0, unicodeFunc      ),
................................................................................
    FUNCTION2(likely,            1, 0, 0, noopFunc,  SQLITE_FUNC_UNLIKELY),
    VFUNCTION(random,            0, 0, 0, randomFunc       ),
    VFUNCTION(randomblob,        1, 0, 0, randomBlob       ),
    FUNCTION(nullif,             2, 0, 1, nullifFunc       ),
    FUNCTION(sqlite_version,     0, 0, 0, versionFunc      ),
    FUNCTION(sqlite_source_id,   0, 0, 0, sourceidFunc     ),
    FUNCTION(sqlite_log,         2, 0, 0, errlogFunc       ),



#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
    FUNCTION(sqlite_compileoption_used,1, 0, 0, compileoptionusedFunc  ),
    FUNCTION(sqlite_compileoption_get, 1, 0, 0, compileoptiongetFunc  ),
#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
    FUNCTION(quote,              1, 0, 0, quoteFunc        ),
    VFUNCTION(last_insert_rowid, 0, 0, 0, last_insert_rowid),
    VFUNCTION(changes,           0, 0, 0, changes          ),
................................................................................
  #ifndef SQLITE_OMIT_LOAD_EXTENSION
    FUNCTION(load_extension,     1, 0, 0, loadExt          ),
    FUNCTION(load_extension,     2, 0, 0, loadExt          ),
  #endif
    AGGREGATE(sum,               1, 0, 0, sumStep,         sumFinalize    ),
    AGGREGATE(total,             1, 0, 0, sumStep,         totalFinalize    ),
    AGGREGATE(avg,               1, 0, 0, sumStep,         avgFinalize    ),
 /* AGGREGATE(count,             0, 0, 0, countStep,       countFinalize  ), */
    {0,SQLITE_UTF8|SQLITE_FUNC_COUNT,0,0,0,countStep,countFinalize,"count",0,0},
    AGGREGATE(count,             1, 0, 0, countStep,       countFinalize  ),
    AGGREGATE(group_concat,      1, 0, 0, groupConcatStep, groupConcatFinalize),
    AGGREGATE(group_concat,      2, 0, 0, groupConcatStep, groupConcatFinalize),
  
    LIKEFUNC(glob, 2, &globInfo, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
  #ifdef SQLITE_CASE_SENSITIVE_LIKE
    LIKEFUNC(like, 2, &likeInfoAlt, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C-language implementations for many of the SQL
** functions of SQLite.  (Some function, and in particular the date and
** time functions, are implemented separately.)
*/
#include "sqliteInt.h"
#include <stdlib.h>
#include <assert.h>
#include "vdbeInt.h"

/*
** Return the collating function associated with a function.
*/
static CollSeq *sqlite3GetFuncCollSeq(sqlite3_context *context){
  VdbeOp *pOp = &context->pVdbe->aOp[context->iOp-1];
  assert( pOp->opcode==OP_CollSeq );
  assert( pOp->p4type==P4_COLLSEQ );
  return pOp->p4.pColl;
}

/*
** Indicate that the accumulator load should be skipped on this
** iteration of the aggregate loop.
*/
static void sqlite3SkipAccumulatorLoad(sqlite3_context *context){
................................................................................
      /* IMP: R-37434-19929 Abs(X) returns NULL if X is NULL. */
      sqlite3_result_null(context);
      break;
    }
    default: {
      /* Because sqlite3_value_double() returns 0.0 if the argument is not
      ** something that can be converted into a number, we have:
      ** IMP: R-01992-00519 Abs(X) returns 0.0 if X is a string or blob
      ** that cannot be converted to a numeric value.
      */
      double rVal = sqlite3_value_double(argv[0]);
      if( rVal<0 ) rVal = -rVal;
      sqlite3_result_double(context, rVal);
      break;
    }
  }
................................................................................
    while( *z && p1 ){
      SQLITE_SKIP_UTF8(z);
      p1--;
    }
    for(z2=z; *z2 && p2; p2--){
      SQLITE_SKIP_UTF8(z2);
    }
    sqlite3_result_text64(context, (char*)z, z2-z, SQLITE_TRANSIENT,
                          SQLITE_UTF8);
  }else{
    if( p1+p2>len ){
      p2 = len-p1;
      if( p2<0 ) p2 = 0;
    }
    sqlite3_result_blob64(context, (char*)&z[p1], (u64)p2, SQLITE_TRANSIENT);
  }
}

/*
** Implementation of the round() function
*/
#ifndef SQLITE_OMIT_FLOATING_POINT
................................................................................
  assert( nByte>0 );
  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH] );
  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH]+1 );
  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
    sqlite3_result_error_toobig(context);
    z = 0;
  }else{
    z = sqlite3Malloc(nByte);
    if( !z ){
      sqlite3_result_error_nomem(context);
    }
  }
  return z;
}

................................................................................
/*
** For LIKE and GLOB matching on EBCDIC machines, assume that every
** character is exactly one byte in size.  Also, all characters are
** able to participate in upper-case-to-lower-case mappings in EBCDIC
** whereas only characters less than 0x80 do in ASCII.
*/
#if defined(SQLITE_EBCDIC)
# define sqlite3Utf8Read(A)        (*((*A)++))
# define GlobUpperToLower(A)       A = sqlite3UpperToLower[A]
# define GlobUpperToLowerAscii(A)  A = sqlite3UpperToLower[A]
#else
# define GlobUpperToLower(A)       if( A<=0x7f ){ A = sqlite3UpperToLower[A]; }
# define GlobUpperToLowerAscii(A)  A = sqlite3UpperToLower[A]
#endif

static const struct compareInfo globInfo = { '*', '?', '[', 0 };
/* The correct SQL-92 behavior is for the LIKE operator to ignore
** case.  Thus  'a' LIKE 'A' would be true. */
static const struct compareInfo likeInfoNorm = { '%', '_',   0, 1 };
/* If SQLITE_CASE_SENSITIVE_LIKE is defined, then the LIKE operator
** is case sensitive causing 'a' LIKE 'A' to be false */
static const struct compareInfo likeInfoAlt = { '%', '_',   0, 0 };

/*
** Compare two UTF-8 strings for equality where the first string can
** potentially be a "glob" or "like" expression.  Return true (1) if they
** are the same and false (0) if they are different.
**
** Globbing rules:
**
**      '*'       Matches any sequence of zero or more characters.
**
**      '?'       Matches exactly one character.
................................................................................
**
** With the [...] and [^...] matching, a ']' character can be included
** in the list by making it the first character after '[' or '^'.  A
** range of characters can be specified using '-'.  Example:
** "[a-z]" matches any single lower-case letter.  To match a '-', make
** it the last character in the list.
**
** Like matching rules:
** 
**      '%'       Matches any sequence of zero or more characters
**
***     '_'       Matches any one character
**
**      Ec        Where E is the "esc" character and c is any other
**                character, including '%', '_', and esc, match exactly c.
**
** The comments through this routine usually assume glob matching.
**
** This routine is usually quick, but can be N**2 in the worst case.
*/
static int patternCompare(
  const u8 *zPattern,              /* The glob pattern */
  const u8 *zString,               /* The string to compare against the glob */
  const struct compareInfo *pInfo, /* Information about how to do the compare */
  u32 esc                          /* The escape character */
){
  u32 c, c2;                       /* Next pattern and input string chars */


  u32 matchOne = pInfo->matchOne;  /* "?" or "_" */
  u32 matchAll = pInfo->matchAll;  /* "*" or "%" */

  u32 matchOther;                  /* "[" or the escape character */
  u8 noCase = pInfo->noCase;       /* True if uppercase==lowercase */
  const u8 *zEscaped = 0;          /* One past the last escaped input char */
  
  /* The GLOB operator does not have an ESCAPE clause.  And LIKE does not
  ** have the matchSet operator.  So we either have to look for one or
  ** the other, never both.  Hence the single variable matchOther is used
  ** to store the one we have to look for.
  */
  matchOther = esc ? esc : pInfo->matchSet;

  while( (c = sqlite3Utf8Read(&zPattern))!=0 ){
    if( c==matchAll ){  /* Match "*" */
      /* Skip over multiple "*" characters in the pattern.  If there
      ** are also "?" characters, skip those as well, but consume a
      ** single character of the input string for each "?" skipped */
      while( (c=sqlite3Utf8Read(&zPattern)) == matchAll
               || c == matchOne ){
        if( c==matchOne && sqlite3Utf8Read(&zString)==0 ){
          return 0;
        }
      }
      if( c==0 ){
        return 1;   /* "*" at the end of the pattern matches */
      }else if( c==matchOther ){
        if( esc ){
          c = sqlite3Utf8Read(&zPattern);
          if( c==0 ) return 0;

        }else{
          /* "[...]" immediately follows the "*".  We have to do a slow
          ** recursive search in this case, but it is an unusual case. */
          assert( matchOther<0x80 );  /* '[' is a single-byte character */
          while( *zString
                 && patternCompare(&zPattern[-1],zString,pInfo,esc)==0 ){
            SQLITE_SKIP_UTF8(zString);
          }
          return *zString!=0;
        }

      }

      /* At this point variable c contains the first character of the
      ** pattern string past the "*".  Search in the input string for the
      ** first matching character and recursively contine the match from
      ** that point.
      **
      ** For a case-insensitive search, set variable cx to be the same as
      ** c but in the other case and search the input string for either
      ** c or cx.
      */
      if( c<=0x80 ){
        u32 cx;
        if( noCase ){



          cx = sqlite3Toupper(c);
          c = sqlite3Tolower(c);

        }else{
          cx = c;
        }
        while( (c2 = *(zString++))!=0 ){
          if( c2!=c && c2!=cx ) continue;
          if( patternCompare(zPattern,zString,pInfo,esc) ) return 1;
        }
      }else{

        while( (c2 = sqlite3Utf8Read(&zString))!=0 ){
          if( c2!=c ) continue;
          if( patternCompare(zPattern,zString,pInfo,esc) ) return 1;
        }
      }
      return 0;

    }

    if( c==matchOther ){
      if( esc ){
        c = sqlite3Utf8Read(&zPattern);
        if( c==0 ) return 0;


        zEscaped = zPattern;
      }else{
        u32 prior_c = 0;

        int seen = 0;
        int invert = 0;
        c = sqlite3Utf8Read(&zString);
        if( c==0 ) return 0;
        c2 = sqlite3Utf8Read(&zPattern);
        if( c2=='^' ){
          invert = 1;
          c2 = sqlite3Utf8Read(&zPattern);
        }
        if( c2==']' ){
          if( c==']' ) seen = 1;
          c2 = sqlite3Utf8Read(&zPattern);
        }
        while( c2 && c2!=']' ){
          if( c2=='-' && zPattern[0]!=']' && zPattern[0]!=0 && prior_c>0 ){
            c2 = sqlite3Utf8Read(&zPattern);
            if( c>=prior_c && c<=c2 ) seen = 1;
            prior_c = 0;
          }else{
            if( c==c2 ){
              seen = 1;
            }
            prior_c = c2;
          }
          c2 = sqlite3Utf8Read(&zPattern);
        }
        if( c2==0 || (seen ^ invert)==0 ){
          return 0;
        }







        continue;
      }


    }

    c2 = sqlite3Utf8Read(&zString);
    if( c==c2 ) continue;
    if( noCase && c<0x80 && c2<0x80 && sqlite3Tolower(c)==sqlite3Tolower(c2) ){
      continue;
    }
    if( c==matchOne && zPattern!=zEscaped && c2!=0 ) continue;
    return 0;
  }
  return *zString==0;
}

/*
** The sqlite3_strglob() interface.
*/
................................................................................
    }else{
      *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);
      *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);
      *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);
      *zOut++ = 0x80 + (u8)(c & 0x3F);
    }                                                    \
  }
  sqlite3_result_text64(context, (char*)z, zOut-z, sqlite3_free, SQLITE_UTF8);
}

/*
** The hex() function.  Interpret the argument as a blob.  Return
** a hexadecimal rendering as text.
*/
static void hexFunc(
................................................................................
    cmp = sqlite3MemCompare(pBest, pArg, pColl);
    if( (max && cmp<0) || (!max && cmp>0) ){
      sqlite3VdbeMemCopy(pBest, pArg);
    }else{
      sqlite3SkipAccumulatorLoad(context);
    }
  }else{
    pBest->db = sqlite3_context_db_handle(context);
    sqlite3VdbeMemCopy(pBest, pArg);
  }
}
static void minMaxFinalize(sqlite3_context *context){
  sqlite3_value *pRes;
  pRes = (sqlite3_value *)sqlite3_aggregate_context(context, 0);
  if( pRes ){
................................................................................
  assert( &((char*)&likeInfoAlt)[1] == (char*)&likeInfoAlt.matchOne );
  assert( &((char*)&likeInfoAlt)[2] == (char*)&likeInfoAlt.matchSet );
  *pIsNocase = (pDef->funcFlags & SQLITE_FUNC_CASE)==0;
  return 1;
}

/*
** All of the FuncDef structures in the aBuiltinFunc[] array above
** to the global function hash table.  This occurs at start-time (as
** a consequence of calling sqlite3_initialize()).
**
** After this routine runs
*/
void sqlite3RegisterGlobalFunctions(void){
  /*
................................................................................
    FUNCTION(ltrim,              2, 1, 0, trimFunc         ),
    FUNCTION(rtrim,              1, 2, 0, trimFunc         ),
    FUNCTION(rtrim,              2, 2, 0, trimFunc         ),
    FUNCTION(trim,               1, 3, 0, trimFunc         ),
    FUNCTION(trim,               2, 3, 0, trimFunc         ),
    FUNCTION(min,               -1, 0, 1, minmaxFunc       ),
    FUNCTION(min,                0, 0, 1, 0                ),
    AGGREGATE2(min,              1, 0, 1, minmaxStep,      minMaxFinalize,
                                          SQLITE_FUNC_MINMAX ),
    FUNCTION(max,               -1, 1, 1, minmaxFunc       ),
    FUNCTION(max,                0, 1, 1, 0                ),
    AGGREGATE2(max,              1, 1, 1, minmaxStep,      minMaxFinalize,
                                          SQLITE_FUNC_MINMAX ),
    FUNCTION2(typeof,            1, 0, 0, typeofFunc,  SQLITE_FUNC_TYPEOF),
    FUNCTION2(length,            1, 0, 0, lengthFunc,  SQLITE_FUNC_LENGTH),
    FUNCTION(instr,              2, 0, 0, instrFunc        ),
    FUNCTION(substr,             2, 0, 0, substrFunc       ),
    FUNCTION(substr,             3, 0, 0, substrFunc       ),
    FUNCTION(printf,            -1, 0, 0, printfFunc       ),
    FUNCTION(unicode,            1, 0, 0, unicodeFunc      ),
................................................................................
    FUNCTION2(likely,            1, 0, 0, noopFunc,  SQLITE_FUNC_UNLIKELY),
    VFUNCTION(random,            0, 0, 0, randomFunc       ),
    VFUNCTION(randomblob,        1, 0, 0, randomBlob       ),
    FUNCTION(nullif,             2, 0, 1, nullifFunc       ),
    FUNCTION(sqlite_version,     0, 0, 0, versionFunc      ),
    FUNCTION(sqlite_source_id,   0, 0, 0, sourceidFunc     ),
    FUNCTION(sqlite_log,         2, 0, 0, errlogFunc       ),
#if SQLITE_USER_AUTHENTICATION
    FUNCTION(sqlite_crypt,       2, 0, 0, sqlite3CryptFunc ),
#endif
#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
    FUNCTION(sqlite_compileoption_used,1, 0, 0, compileoptionusedFunc  ),
    FUNCTION(sqlite_compileoption_get, 1, 0, 0, compileoptiongetFunc  ),
#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
    FUNCTION(quote,              1, 0, 0, quoteFunc        ),
    VFUNCTION(last_insert_rowid, 0, 0, 0, last_insert_rowid),
    VFUNCTION(changes,           0, 0, 0, changes          ),
................................................................................
  #ifndef SQLITE_OMIT_LOAD_EXTENSION
    FUNCTION(load_extension,     1, 0, 0, loadExt          ),
    FUNCTION(load_extension,     2, 0, 0, loadExt          ),
  #endif
    AGGREGATE(sum,               1, 0, 0, sumStep,         sumFinalize    ),
    AGGREGATE(total,             1, 0, 0, sumStep,         totalFinalize    ),
    AGGREGATE(avg,               1, 0, 0, sumStep,         avgFinalize    ),
    AGGREGATE2(count,            0, 0, 0, countStep,       countFinalize,
               SQLITE_FUNC_COUNT  ),
    AGGREGATE(count,             1, 0, 0, countStep,       countFinalize  ),
    AGGREGATE(group_concat,      1, 0, 0, groupConcatStep, groupConcatFinalize),
    AGGREGATE(group_concat,      2, 0, 0, groupConcatStep, groupConcatFinalize),
  
    LIKEFUNC(glob, 2, &globInfo, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
  #ifdef SQLITE_CASE_SENSITIVE_LIKE
    LIKEFUNC(like, 2, &likeInfoAlt, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),

**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains definitions of global variables and contants.
*/
#include "sqliteInt.h"

/* An array to map all upper-case characters into their corresponding
** lower-case character. 
**
** SQLite only considers US-ASCII (or EBCDIC) characters.  We do not
................................................................................
  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e0..e7    ........ */
  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e8..ef    ........ */
  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* f0..f7    ........ */
  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40   /* f8..ff    ........ */
};
#endif












#ifndef SQLITE_USE_URI
# define  SQLITE_USE_URI 0
#endif





#ifndef SQLITE_ALLOW_COVERING_INDEX_SCAN
# define SQLITE_ALLOW_COVERING_INDEX_SCAN 1
#endif

/*
** The following singleton contains the global configuration for
** the SQLite library.
................................................................................
** a different position in the file.  This allows code that has to
** deal with the pending byte to run on files that are much smaller
** than 1 GiB.  The sqlite3_test_control() interface can be used to
** move the pending byte.
**
** IMPORTANT:  Changing the pending byte to any value other than
** 0x40000000 results in an incompatible database file format!
** Changing the pending byte during operating results in undefined
** and dileterious behavior.
*/
#ifndef SQLITE_OMIT_WSD
int sqlite3PendingByte = 0x40000000;
#endif

#include "opcodes.h"
/*
** Properties of opcodes.  The OPFLG_INITIALIZER macro is
** created by mkopcodeh.awk during compilation.  Data is obtained
** from the comments following the "case OP_xxxx:" statements in
** the vdbe.c file.  
*/
const unsigned char sqlite3OpcodeProperty[] = OPFLG_INITIALIZER;

**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains definitions of global variables and constants.
*/
#include "sqliteInt.h"

/* An array to map all upper-case characters into their corresponding
** lower-case character. 
**
** SQLite only considers US-ASCII (or EBCDIC) characters.  We do not
................................................................................
  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e0..e7    ........ */
  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e8..ef    ........ */
  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* f0..f7    ........ */
  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40   /* f8..ff    ........ */
};
#endif

/* EVIDENCE-OF: R-02982-34736 In order to maintain full backwards
** compatibility for legacy applications, the URI filename capability is
** disabled by default.
**
** EVIDENCE-OF: R-38799-08373 URI filenames can be enabled or disabled
** using the SQLITE_USE_URI=1 or SQLITE_USE_URI=0 compile-time options.
**
** EVIDENCE-OF: R-43642-56306 By default, URI handling is globally
** disabled. The default value may be changed by compiling with the
** SQLITE_USE_URI symbol defined.
*/
#ifndef SQLITE_USE_URI
# define  SQLITE_USE_URI 0
#endif

/* EVIDENCE-OF: R-38720-18127 The default setting is determined by the
** SQLITE_ALLOW_COVERING_INDEX_SCAN compile-time option, or is "on" if
** that compile-time option is omitted.
*/
#ifndef SQLITE_ALLOW_COVERING_INDEX_SCAN
# define SQLITE_ALLOW_COVERING_INDEX_SCAN 1
#endif

/*
** The following singleton contains the global configuration for
** the SQLite library.
................................................................................
** a different position in the file.  This allows code that has to
** deal with the pending byte to run on files that are much smaller
** than 1 GiB.  The sqlite3_test_control() interface can be used to
** move the pending byte.
**
** IMPORTANT:  Changing the pending byte to any value other than
** 0x40000000 results in an incompatible database file format!
** Changing the pending byte during operation will result in undefined
** and incorrect behavior.
*/
#ifndef SQLITE_OMIT_WSD
int sqlite3PendingByte = 0x40000000;
#endif

#include "opcodes.h"
/*
** Properties of opcodes.  The OPFLG_INITIALIZER macro is
** created by mkopcodeh.awk during compilation.  Data is obtained
** from the comments following the "case OP_xxxx:" statements in
** the vdbe.c file.  
*/
const unsigned char sqlite3OpcodeProperty[] = OPFLG_INITIALIZER;

/*
** Return a pointer to the column affinity string associated with index
** pIdx. A column affinity string has one character for each column in 
** the table, according to the affinity of the column:
**
**  Character      Column affinity
**  ------------------------------
**  'a'            TEXT
**  'b'            NONE
**  'c'            NUMERIC
**  'd'            INTEGER
**  'e'            REAL
**
** An extra 'd' is appended to the end of the string to cover the
** rowid that appears as the last column in every index.
**
** Memory for the buffer containing the column index affinity string
** is managed along with the rest of the Index structure. It will be
** released when sqlite3DeleteIndex() is called.
*/
const char *sqlite3IndexAffinityStr(Vdbe *v, Index *pIdx){
................................................................................
** then just set the P4 operand of the previous opcode (which should  be
** an OP_MakeRecord) to the affinity string.
**
** A column affinity string has one character per column:
**
**  Character      Column affinity
**  ------------------------------
**  'a'            TEXT
**  'b'            NONE
**  'c'            NUMERIC
**  'd'            INTEGER
**  'e'            REAL
*/
void sqlite3TableAffinity(Vdbe *v, Table *pTab, int iReg){
  int i;
  char *zColAff = pTab->zColAff;
  if( zColAff==0 ){
    sqlite3 *db = sqlite3VdbeDb(v);
    zColAff = (char *)sqlite3DbMallocRaw(0, pTab->nCol+1);
................................................................................
**         insert the select result into <table> from R..R+n
**         goto C
**      D: cleanup
**
** The 4th template is used if the insert statement takes its
** values from a SELECT but the data is being inserted into a table
** that is also read as part of the SELECT.  In the third form,
** we have to use a intermediate table to store the results of
** the select.  The template is like this:
**
**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the tables in the SELECT
**           load value into register R..R+n
................................................................................

  /* If this is an AUTOINCREMENT table, look up the sequence number in the
  ** sqlite_sequence table and store it in memory cell regAutoinc.
  */
  regAutoinc = autoIncBegin(pParse, iDb, pTab);

  /* Allocate registers for holding the rowid of the new row,
  ** the content of the new row, and the assemblied row record.
  */
  regRowid = regIns = pParse->nMem+1;
  pParse->nMem += pTab->nCol + 1;
  if( IsVirtual(pTab) ){
    regRowid++;
    pParse->nMem++;
  }
................................................................................
  sqlite3ExprListDelete(db, pList);
  sqlite3SelectDelete(db, pSelect);
  sqlite3IdListDelete(db, pColumn);
  sqlite3DbFree(db, aRegIdx);
}

/* Make sure "isView" and other macros defined above are undefined. Otherwise
** thely may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation).  */
#ifdef isView
 #undef isView
#endif
#ifdef pTrigger
 #undef pTrigger
#endif
................................................................................
  Index *pIdx;         /* Pointer to one of the indices */
  Index *pPk = 0;      /* The PRIMARY KEY index */
  sqlite3 *db;         /* Database connection */
  int i;               /* loop counter */
  int ix;              /* Index loop counter */
  int nCol;            /* Number of columns */
  int onError;         /* Conflict resolution strategy */
  int j1;              /* Addresss of jump instruction */
  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
  int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
  int ipkTop = 0;      /* Top of the rowid change constraint check */
  int ipkBottom = 0;   /* Bottom of the rowid change constraint check */
  u8 isUpdate;         /* True if this is an UPDATE operation */
  u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
  int regRowid = -1;   /* Register holding ROWID value */
................................................................................
  int appendBias,     /* True if this is likely to be an append */
  int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
){
  Vdbe *v;            /* Prepared statements under construction */
  Index *pIdx;        /* An index being inserted or updated */
  u8 pik_flags;       /* flag values passed to the btree insert */
  int regData;        /* Content registers (after the rowid) */
  int regRec;         /* Register holding assemblied record for the table */
  int i;              /* Loop counter */
  u8 bAffinityDone = 0; /* True if OP_Affinity has been run already */

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
................................................................................


#ifdef SQLITE_TEST
/*
** The following global variable is incremented whenever the
** transfer optimization is used.  This is used for testing
** purposes only - to make sure the transfer optimization really
** is happening when it is suppose to.
*/
int sqlite3_xferopt_count;
#endif /* SQLITE_TEST */


#ifndef SQLITE_OMIT_XFER_OPT
/*
................................................................................

/*
** Attempt the transfer optimization on INSERTs of the form
**
**     INSERT INTO tab1 SELECT * FROM tab2;
**
** The xfer optimization transfers raw records from tab2 over to tab1.  
** Columns are not decoded and reassemblied, which greatly improves
** performance.  Raw index records are transferred in the same way.
**
** The xfer optimization is only attempted if tab1 and tab2 are compatible.
** There are lots of rules for determining compatibility - see comments
** embedded in the code for details.
**
** This routine returns TRUE if the optimization is guaranteed to be used.

/*
** Return a pointer to the column affinity string associated with index
** pIdx. A column affinity string has one character for each column in 
** the table, according to the affinity of the column:
**
**  Character      Column affinity
**  ------------------------------
**  'A'            NONE
**  'B'            TEXT
**  'C'            NUMERIC
**  'D'            INTEGER
**  'F'            REAL
**
** An extra 'D' is appended to the end of the string to cover the
** rowid that appears as the last column in every index.
**
** Memory for the buffer containing the column index affinity string
** is managed along with the rest of the Index structure. It will be
** released when sqlite3DeleteIndex() is called.
*/
const char *sqlite3IndexAffinityStr(Vdbe *v, Index *pIdx){
................................................................................
** then just set the P4 operand of the previous opcode (which should  be
** an OP_MakeRecord) to the affinity string.
**
** A column affinity string has one character per column:
**
**  Character      Column affinity
**  ------------------------------
**  'A'            NONE
**  'B'            TEXT
**  'C'            NUMERIC
**  'D'            INTEGER
**  'E'            REAL
*/
void sqlite3TableAffinity(Vdbe *v, Table *pTab, int iReg){
  int i;
  char *zColAff = pTab->zColAff;
  if( zColAff==0 ){
    sqlite3 *db = sqlite3VdbeDb(v);
    zColAff = (char *)sqlite3DbMallocRaw(0, pTab->nCol+1);
................................................................................
**         insert the select result into <table> from R..R+n
**         goto C
**      D: cleanup
**
** The 4th template is used if the insert statement takes its
** values from a SELECT but the data is being inserted into a table
** that is also read as part of the SELECT.  In the third form,
** we have to use an intermediate table to store the results of
** the select.  The template is like this:
**
**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the tables in the SELECT
**           load value into register R..R+n
................................................................................

  /* If this is an AUTOINCREMENT table, look up the sequence number in the
  ** sqlite_sequence table and store it in memory cell regAutoinc.
  */
  regAutoinc = autoIncBegin(pParse, iDb, pTab);

  /* Allocate registers for holding the rowid of the new row,
  ** the content of the new row, and the assembled row record.
  */
  regRowid = regIns = pParse->nMem+1;
  pParse->nMem += pTab->nCol + 1;
  if( IsVirtual(pTab) ){
    regRowid++;
    pParse->nMem++;
  }
................................................................................
  sqlite3ExprListDelete(db, pList);
  sqlite3SelectDelete(db, pSelect);
  sqlite3IdListDelete(db, pColumn);
  sqlite3DbFree(db, aRegIdx);
}

/* Make sure "isView" and other macros defined above are undefined. Otherwise
** they may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation).  */
#ifdef isView
 #undef isView
#endif
#ifdef pTrigger
 #undef pTrigger
#endif
................................................................................
  Index *pIdx;         /* Pointer to one of the indices */
  Index *pPk = 0;      /* The PRIMARY KEY index */
  sqlite3 *db;         /* Database connection */
  int i;               /* loop counter */
  int ix;              /* Index loop counter */
  int nCol;            /* Number of columns */
  int onError;         /* Conflict resolution strategy */
  int j1;              /* Address of jump instruction */
  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
  int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
  int ipkTop = 0;      /* Top of the rowid change constraint check */
  int ipkBottom = 0;   /* Bottom of the rowid change constraint check */
  u8 isUpdate;         /* True if this is an UPDATE operation */
  u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
  int regRowid = -1;   /* Register holding ROWID value */
................................................................................
  int appendBias,     /* True if this is likely to be an append */
  int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
){
  Vdbe *v;            /* Prepared statements under construction */
  Index *pIdx;        /* An index being inserted or updated */
  u8 pik_flags;       /* flag values passed to the btree insert */
  int regData;        /* Content registers (after the rowid) */
  int regRec;         /* Register holding assembled record for the table */
  int i;              /* Loop counter */
  u8 bAffinityDone = 0; /* True if OP_Affinity has been run already */

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
................................................................................


#ifdef SQLITE_TEST
/*
** The following global variable is incremented whenever the
** transfer optimization is used.  This is used for testing
** purposes only - to make sure the transfer optimization really
** is happening when it is supposed to.
*/
int sqlite3_xferopt_count;
#endif /* SQLITE_TEST */


#ifndef SQLITE_OMIT_XFER_OPT
/*
................................................................................

/*
** Attempt the transfer optimization on INSERTs of the form
**
**     INSERT INTO tab1 SELECT * FROM tab2;
**
** The xfer optimization transfers raw records from tab2 over to tab1.  
** Columns are not decoded and reassembled, which greatly improves
** performance.  Raw index records are transferred in the same way.
**
** The xfer optimization is only attempted if tab1 and tab2 are compatible.
** There are lots of rules for determining compatibility - see comments
** embedded in the code for details.
**
** This routine returns TRUE if the optimization is guaranteed to be used.

  }

exec_out:
  if( pStmt ) sqlite3VdbeFinalize((Vdbe *)pStmt);
  sqlite3DbFree(db, azCols);

  rc = sqlite3ApiExit(db, rc);
  if( rc!=SQLITE_OK && ALWAYS(rc==sqlite3_errcode(db)) && pzErrMsg ){
    int nErrMsg = 1 + sqlite3Strlen30(sqlite3_errmsg(db));
    *pzErrMsg = sqlite3Malloc(nErrMsg);
    if( *pzErrMsg ){
      memcpy(*pzErrMsg, sqlite3_errmsg(db), nErrMsg);
    }else{
      rc = SQLITE_NOMEM;
      sqlite3Error(db, SQLITE_NOMEM);

  }

exec_out:
  if( pStmt ) sqlite3VdbeFinalize((Vdbe *)pStmt);
  sqlite3DbFree(db, azCols);

  rc = sqlite3ApiExit(db, rc);
  if( rc!=SQLITE_OK && pzErrMsg ){
    int nErrMsg = 1 + sqlite3Strlen30(sqlite3_errmsg(db));
    *pzErrMsg = sqlite3Malloc(nErrMsg);
    if( *pzErrMsg ){
      memcpy(*pzErrMsg, sqlite3_errmsg(db), nErrMsg);
    }else{
      rc = SQLITE_NOMEM;
      sqlite3Error(db, SQLITE_NOMEM);

** Inputs:
** A pointer to the function used to allocate memory.
**
** Outputs:
** A pointer to a parser.  This pointer is used in subsequent calls
** to Parse and ParseFree.
*/
void *ParseAlloc(void *(*mallocProc)(size_t)){
  yyParser *pParser;
  pParser = (yyParser*)(*mallocProc)( (size_t)sizeof(yyParser) );
  if( pParser ){
    pParser->yyidx = -1;
#ifdef YYTRACKMAXSTACKDEPTH
    pParser->yyidxMax = 0;
#endif
#if YYSTACKDEPTH<=0
    pParser->yystack = NULL;

** Inputs:
** A pointer to the function used to allocate memory.
**
** Outputs:
** A pointer to a parser.  This pointer is used in subsequent calls
** to Parse and ParseFree.
*/
void *ParseAlloc(void *(*mallocProc)(u64)){
  yyParser *pParser;
  pParser = (yyParser*)(*mallocProc)( (u64)sizeof(yyParser) );
  if( pParser ){
    pParser->yyidx = -1;
#ifdef YYTRACKMAXSTACKDEPTH
    pParser->yyidxMax = 0;
#endif
#if YYSTACKDEPTH<=0
    pParser->yystack = NULL;

#ifndef SQLITE_ENABLE_COLUMN_METADATA
# define sqlite3_column_database_name   0
# define sqlite3_column_database_name16 0
# define sqlite3_column_table_name      0
# define sqlite3_column_table_name16    0
# define sqlite3_column_origin_name     0
# define sqlite3_column_origin_name16   0
# define sqlite3_table_column_metadata  0
#endif

#ifdef SQLITE_OMIT_AUTHORIZATION
# define sqlite3_set_authorizer         0
#endif

#ifdef SQLITE_OMIT_UTF16
................................................................................
  sqlite3_stmt_busy,
  sqlite3_stmt_readonly,
  sqlite3_stricmp,
  sqlite3_uri_boolean,
  sqlite3_uri_int64,
  sqlite3_uri_parameter,
  sqlite3_vsnprintf,
  sqlite3_wal_checkpoint_v2













};

/*
** Attempt to load an SQLite extension library contained in the file
** zFile.  The entry point is zProc.  zProc may be 0 in which case a
** default entry point name (sqlite3_extension_init) is used.  Use
** of the default name is recommended.

#ifndef SQLITE_ENABLE_COLUMN_METADATA
# define sqlite3_column_database_name   0
# define sqlite3_column_database_name16 0
# define sqlite3_column_table_name      0
# define sqlite3_column_table_name16    0
# define sqlite3_column_origin_name     0
# define sqlite3_column_origin_name16   0

#endif

#ifdef SQLITE_OMIT_AUTHORIZATION
# define sqlite3_set_authorizer         0
#endif

#ifdef SQLITE_OMIT_UTF16
................................................................................
  sqlite3_stmt_busy,
  sqlite3_stmt_readonly,
  sqlite3_stricmp,
  sqlite3_uri_boolean,
  sqlite3_uri_int64,
  sqlite3_uri_parameter,
  sqlite3_vsnprintf,
  sqlite3_wal_checkpoint_v2,
  /* Version 3.8.7 and later */
  sqlite3_auto_extension,
  sqlite3_bind_blob64,
  sqlite3_bind_text64,
  sqlite3_cancel_auto_extension,
  sqlite3_load_extension,
  sqlite3_malloc64,
  sqlite3_msize,
  sqlite3_realloc64,
  sqlite3_reset_auto_extension,
  sqlite3_result_blob64,
  sqlite3_result_text64,
  sqlite3_strglob
};

/*
** Attempt to load an SQLite extension library contained in the file
** zFile.  The entry point is zProc.  zProc may be 0 in which case a
** default entry point name (sqlite3_extension_init) is used.  Use
** of the default name is recommended.

  ** the SQLite library is in use. */
  if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;

  va_start(ap, op);
  switch( op ){

    /* Mutex configuration options are only available in a threadsafe
    ** compile. 
    */
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0
    case SQLITE_CONFIG_SINGLETHREAD: {
      /* Disable all mutexing */
      sqlite3GlobalConfig.bCoreMutex = 0;
      sqlite3GlobalConfig.bFullMutex = 0;
      break;
    }


    case SQLITE_CONFIG_MULTITHREAD: {
      /* Disable mutexing of database connections */
      /* Enable mutexing of core data structures */
      sqlite3GlobalConfig.bCoreMutex = 1;
      sqlite3GlobalConfig.bFullMutex = 0;
      break;
    }


    case SQLITE_CONFIG_SERIALIZED: {
      /* Enable all mutexing */
      sqlite3GlobalConfig.bCoreMutex = 1;
      sqlite3GlobalConfig.bFullMutex = 1;
      break;
    }


    case SQLITE_CONFIG_MUTEX: {
      /* Specify an alternative mutex implementation */
      sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
      break;
    }


    case SQLITE_CONFIG_GETMUTEX: {
      /* Retrieve the current mutex implementation */
      *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
      break;
    }
#endif


    case SQLITE_CONFIG_MALLOC: {

      /* Specify an alternative malloc implementation */



      sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
      break;
    }
    case SQLITE_CONFIG_GETMALLOC: {
      /* Retrieve the current malloc() implementation */



      if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
      *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
      break;
    }
    case SQLITE_CONFIG_MEMSTATUS: {
      /* Enable or disable the malloc status collection */


      sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
      break;
    }
    case SQLITE_CONFIG_SCRATCH: {
      /* Designate a buffer for scratch memory space */



      sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
      sqlite3GlobalConfig.szScratch = va_arg(ap, int);
      sqlite3GlobalConfig.nScratch = va_arg(ap, int);
      break;
    }
    case SQLITE_CONFIG_PAGECACHE: {
      /* Designate a buffer for page cache memory space */


      sqlite3GlobalConfig.pPage = va_arg(ap, void*);
      sqlite3GlobalConfig.szPage = va_arg(ap, int);
      sqlite3GlobalConfig.nPage = va_arg(ap, int);
      break;











    }

    case SQLITE_CONFIG_PCACHE: {
      /* no-op */
      break;
    }
    case SQLITE_CONFIG_GETPCACHE: {
      /* now an error */
      rc = SQLITE_ERROR;
      break;
    }

    case SQLITE_CONFIG_PCACHE2: {



      /* Specify an alternative page cache implementation */
      sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
      break;
    }
    case SQLITE_CONFIG_GETPCACHE2: {




      if( sqlite3GlobalConfig.pcache2.xInit==0 ){
        sqlite3PCacheSetDefault();
      }
      *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
      break;
    }




#if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
    case SQLITE_CONFIG_HEAP: {
      /* Designate a buffer for heap memory space */



      sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
      sqlite3GlobalConfig.nHeap = va_arg(ap, int);
      sqlite3GlobalConfig.mnReq = va_arg(ap, int);

      if( sqlite3GlobalConfig.mnReq<1 ){
        sqlite3GlobalConfig.mnReq = 1;
      }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
        /* cap min request size at 2^12 */
        sqlite3GlobalConfig.mnReq = (1<<12);
      }

      if( sqlite3GlobalConfig.pHeap==0 ){
        /* If the heap pointer is NULL, then restore the malloc implementation
        ** back to NULL pointers too.  This will cause the malloc to go




        ** back to its default implementation when sqlite3_initialize() is
        ** run.
        */
        memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
      }else{
        /* The heap pointer is not NULL, then install one of the
        ** mem5.c/mem3.c methods.  The enclosing #if guarantees at
        ** least one of these methods is currently enabled.
        */
#ifdef SQLITE_ENABLE_MEMSYS3
        sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
#endif
#ifdef SQLITE_ENABLE_MEMSYS5
        sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
#endif
      }
................................................................................
      */
      typedef void(*LOGFUNC_t)(void*,int,const char*);
      sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
      sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
      break;
    }






    case SQLITE_CONFIG_URI: {




      sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
      break;
    }

    case SQLITE_CONFIG_COVERING_INDEX_SCAN: {




      sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
      break;
    }

#ifdef SQLITE_ENABLE_SQLLOG
    case SQLITE_CONFIG_SQLLOG: {
      typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
................................................................................
      sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
      sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
      break;
    }
#endif

    case SQLITE_CONFIG_MMAP_SIZE: {




      sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
      sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);





      if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){


        mxMmap = SQLITE_MAX_MMAP_SIZE;
      }
      sqlite3GlobalConfig.mxMmap = mxMmap;
      if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
      if( szMmap>mxMmap) szMmap = mxMmap;

      sqlite3GlobalConfig.szMmap = szMmap;
      break;
    }

#if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC)
    case SQLITE_CONFIG_WIN32_HEAPSIZE: {



      sqlite3GlobalConfig.nHeap = va_arg(ap, int);
      break;
    }
#endif

    default: {
      rc = SQLITE_ERROR;
................................................................................
  return SQLITE_OK;
}

/*
** Return the mutex associated with a database connection.
*/
sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){






  return db->mutex;
}

/*
** Free up as much memory as we can from the given database
** connection.
*/
int sqlite3_db_release_memory(sqlite3 *db){
  int i;




  sqlite3_mutex_enter(db->mutex);
  sqlite3BtreeEnterAll(db);
  for(i=0; i<db->nDb; i++){
    Btree *pBt = db->aDb[i].pBt;
    if( pBt ){
      Pager *pPager = sqlite3BtreePager(pBt);
      sqlite3PagerShrink(pPager);
................................................................................
static int binCollFunc(
  void *padFlag,
  int nKey1, const void *pKey1,
  int nKey2, const void *pKey2
){
  int rc, n;
  n = nKey1<nKey2 ? nKey1 : nKey2;



  rc = memcmp(pKey1, pKey2, n);
  if( rc==0 ){
    if( padFlag
     && allSpaces(((char*)pKey1)+n, nKey1-n)
     && allSpaces(((char*)pKey2)+n, nKey2-n)
    ){
      /* Leave rc unchanged at 0 */




    }else{
      rc = nKey1 - nKey2;
    }
  }
  return rc;
}

................................................................................
  return r;
}

/*
** Return the ROWID of the most recent insert
*/
sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){






  return db->lastRowid;
}

/*
** Return the number of changes in the most recent call to sqlite3_exec().
*/
int sqlite3_changes(sqlite3 *db){






  return db->nChange;
}

/*
** Return the number of changes since the database handle was opened.
*/
int sqlite3_total_changes(sqlite3 *db){






  return db->nTotalChange;
}

/*
** Close all open savepoints. This function only manipulates fields of the
** database handle object, it does not close any savepoints that may be open
** at the b-tree/pager level.
................................................................................
  /* Free any outstanding Savepoint structures. */
  sqlite3CloseSavepoints(db);

  /* Close all database connections */
  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];
    if( pDb->pBt ){










      sqlite3BtreeClose(pDb->pBt);
      pDb->pBt = 0;
      if( j!=1 ){
        pDb->pSchema = 0;
      }
    }
  }
................................................................................
  }
  sqlite3HashClear(&db->aModule);
#endif

  sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
  sqlite3ValueFree(db->pErr);
  sqlite3CloseExtensions(db);





  db->magic = SQLITE_MAGIC_ERROR;

  /* The temp-database schema is allocated differently from the other schema
  ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
  ** So it needs to be freed here. Todo: Why not roll the temp schema into
  ** the same sqliteMalloc() as the one that allocates the database 
................................................................................
    sqlite3_free(db->lookaside.pStart);
  }
  sqlite3_free(db);
}

/*
** Rollback all database files.  If tripCode is not SQLITE_OK, then
** any open cursors are invalidated ("tripped" - as in "tripping a circuit
** breaker") and made to return tripCode if there are any further
** attempts to use that cursor.

*/
void sqlite3RollbackAll(sqlite3 *db, int tripCode){
  int i;
  int inTrans = 0;

  assert( sqlite3_mutex_held(db->mutex) );
  sqlite3BeginBenignMalloc();

  /* Obtain all b-tree mutexes before making any calls to BtreeRollback(). 
  ** This is important in case the transaction being rolled back has
  ** modified the database schema. If the b-tree mutexes are not taken
  ** here, then another shared-cache connection might sneak in between
  ** the database rollback and schema reset, which can cause false
  ** corruption reports in some cases.  */
  sqlite3BtreeEnterAll(db);


  for(i=0; i<db->nDb; i++){
    Btree *p = db->aDb[i].pBt;
    if( p ){
      if( sqlite3BtreeIsInTrans(p) ){
        inTrans = 1;
      }
      sqlite3BtreeRollback(p, tripCode);
    }
  }
  sqlite3VtabRollback(db);
  sqlite3EndBenignMalloc();

  if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
    sqlite3ExpirePreparedStatements(db);
................................................................................
** given callback function with the given argument.
*/
int sqlite3_busy_handler(
  sqlite3 *db,
  int (*xBusy)(void*,int),
  void *pArg
){



  sqlite3_mutex_enter(db->mutex);
  db->busyHandler.xFunc = xBusy;
  db->busyHandler.pArg = pArg;
  db->busyHandler.nBusy = 0;
  db->busyTimeout = 0;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
................................................................................
*/
void sqlite3_progress_handler(
  sqlite3 *db, 
  int nOps,
  int (*xProgress)(void*), 
  void *pArg
){






  sqlite3_mutex_enter(db->mutex);
  if( nOps>0 ){
    db->xProgress = xProgress;
    db->nProgressOps = (unsigned)nOps;
    db->pProgressArg = pArg;
  }else{
    db->xProgress = 0;
................................................................................


/*
** This routine installs a default busy handler that waits for the
** specified number of milliseconds before returning 0.
*/
int sqlite3_busy_timeout(sqlite3 *db, int ms){



  if( ms>0 ){
    sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
    db->busyTimeout = ms;
  }else{
    sqlite3_busy_handler(db, 0, 0);
  }
  return SQLITE_OK;
}

/*
** Cause any pending operation to stop at its earliest opportunity.
*/
void sqlite3_interrupt(sqlite3 *db){






  db->u1.isInterrupted = 1;
}


/*
** This function is exactly the same as sqlite3_create_function(), except
** that it is designed to be called by internal code. The difference is
................................................................................
  void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
  void (*xFinal)(sqlite3_context*),
  void (*xDestroy)(void *)
){
  int rc = SQLITE_ERROR;
  FuncDestructor *pArg = 0;






  sqlite3_mutex_enter(db->mutex);
  if( xDestroy ){
    pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
    if( !pArg ){
      xDestroy(p);
      goto out;
    }
................................................................................
  void *p,
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
  void (*xFinal)(sqlite3_context*)
){
  int rc;
  char *zFunc8;




  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
  rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal,0);
  sqlite3DbFree(db, zFunc8);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
................................................................................
int sqlite3_overload_function(
  sqlite3 *db,
  const char *zName,
  int nArg
){
  int nName = sqlite3Strlen30(zName);
  int rc = SQLITE_OK;






  sqlite3_mutex_enter(db->mutex);
  if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
    rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
                           0, sqlite3InvalidFunction, 0, 0, 0);
  }
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
................................................................................
**
** A NULL trace function means that no tracing is executes.  A non-NULL
** trace is a pointer to a function that is invoked at the start of each
** SQL statement.
*/
void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
  void *pOld;







  sqlite3_mutex_enter(db->mutex);
  pOld = db->pTraceArg;
  db->xTrace = xTrace;
  db->pTraceArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}
................................................................................
*/
void *sqlite3_profile(
  sqlite3 *db,
  void (*xProfile)(void*,const char*,sqlite_uint64),
  void *pArg
){
  void *pOld;







  sqlite3_mutex_enter(db->mutex);
  pOld = db->pProfileArg;
  db->xProfile = xProfile;
  db->pProfileArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}
................................................................................
*/
void *sqlite3_commit_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  int (*xCallback)(void*),  /* Function to invoke on each commit */
  void *pArg                /* Argument to the function */
){
  void *pOld;







  sqlite3_mutex_enter(db->mutex);
  pOld = db->pCommitArg;
  db->xCommitCallback = xCallback;
  db->pCommitArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}
................................................................................
*/
void *sqlite3_update_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
  void *pArg                /* Argument to the function */
){
  void *pRet;







  sqlite3_mutex_enter(db->mutex);
  pRet = db->pUpdateArg;
  db->xUpdateCallback = xCallback;
  db->pUpdateArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}
................................................................................
*/
void *sqlite3_rollback_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  void (*xCallback)(void*), /* Callback function */
  void *pArg                /* Argument to the function */
){
  void *pRet;







  sqlite3_mutex_enter(db->mutex);
  pRet = db->pRollbackArg;
  db->xRollbackCallback = xCallback;
  db->pRollbackArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}
................................................................................
** configured by this function.
*/
int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
#ifdef SQLITE_OMIT_WAL
  UNUSED_PARAMETER(db);
  UNUSED_PARAMETER(nFrame);
#else



  if( nFrame>0 ){
    sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
  }else{
    sqlite3_wal_hook(db, 0, 0);
  }
#endif
  return SQLITE_OK;
................................................................................
void *sqlite3_wal_hook(
  sqlite3 *db,                    /* Attach the hook to this db handle */
  int(*xCallback)(void *, sqlite3*, const char*, int),
  void *pArg                      /* First argument passed to xCallback() */
){
#ifndef SQLITE_OMIT_WAL
  void *pRet;






  sqlite3_mutex_enter(db->mutex);
  pRet = db->pWalArg;
  db->xWalCallback = xCallback;
  db->pWalArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
#else
................................................................................
  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
){
#ifdef SQLITE_OMIT_WAL
  return SQLITE_OK;
#else
  int rc;                         /* Return code */
  int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */





  /* Initialize the output variables to -1 in case an error occurs. */
  if( pnLog ) *pnLog = -1;
  if( pnCkpt ) *pnCkpt = -1;

  assert( SQLITE_CHECKPOINT_FULL>SQLITE_CHECKPOINT_PASSIVE );
  assert( SQLITE_CHECKPOINT_FULL<SQLITE_CHECKPOINT_RESTART );
  assert( SQLITE_CHECKPOINT_PASSIVE+2==SQLITE_CHECKPOINT_RESTART );

  if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_RESTART ){


    return SQLITE_MISUSE;
  }

  sqlite3_mutex_enter(db->mutex);
  if( zDb && zDb[0] ){
    iDb = sqlite3FindDbName(db, zDb);
  }
................................................................................

/*
** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
** to contains a zero-length string, all attached databases are 
** checkpointed.
*/
int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){


  return sqlite3_wal_checkpoint_v2(db, zDb, SQLITE_CHECKPOINT_PASSIVE, 0, 0);
}

#ifndef SQLITE_OMIT_WAL
/*
** Run a checkpoint on database iDb. This is a no-op if database iDb is
** not currently open in WAL mode.
**
................................................................................
  SQLITE_MAX_COMPOUND_SELECT,
  SQLITE_MAX_VDBE_OP,
  SQLITE_MAX_FUNCTION_ARG,
  SQLITE_MAX_ATTACHED,
  SQLITE_MAX_LIKE_PATTERN_LENGTH,
  SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
  SQLITE_MAX_TRIGGER_DEPTH,

};

/*
** Make sure the hard limits are set to reasonable values
*/
#if SQLITE_MAX_LENGTH<100
# error SQLITE_MAX_LENGTH must be at least 100
................................................................................
#endif
#if SQLITE_MAX_COLUMN>32767
# error SQLITE_MAX_COLUMN must not exceed 32767
#endif
#if SQLITE_MAX_TRIGGER_DEPTH<1
# error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
#endif





/*
** Change the value of a limit.  Report the old value.
** If an invalid limit index is supplied, report -1.
** Make no changes but still report the old value if the
** new limit is negative.
................................................................................
** A new lower limit does not shrink existing constructs.
** It merely prevents new constructs that exceed the limit
** from forming.
*/
int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
  int oldLimit;








  /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
  ** there is a hard upper bound set at compile-time by a C preprocessor
  ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
  ** "_MAX_".)
  */
  assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
................................................................................
  assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
  assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
  assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
  assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
                                               SQLITE_MAX_LIKE_PATTERN_LENGTH );
  assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
  assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );

  assert( SQLITE_LIMIT_TRIGGER_DEPTH==(SQLITE_N_LIMIT-1) );


  if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
    return -1;
  }
  oldLimit = db->aLimit[limitId];
  if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
................................................................................
  const char *zVfs = zDefaultVfs;
  char *zFile;
  char c;
  int nUri = sqlite3Strlen30(zUri);

  assert( *pzErrMsg==0 );


  if( ((flags & SQLITE_OPEN_URI) || sqlite3GlobalConfig.bOpenUri) 
   && nUri>=5 && memcmp(zUri, "file:", 5)==0 
  ){
    char *zOpt;
    int eState;                   /* Parser state when parsing URI */
    int iIn;                      /* Input character index */
    int iOut = 0;                 /* Output character index */
    int nByte = nUri+2;           /* Bytes of space to allocate */

................................................................................
){
  sqlite3 *db;                    /* Store allocated handle here */
  int rc;                         /* Return code */
  int isThreadsafe;               /* True for threadsafe connections */
  char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
  char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */




  *ppDb = 0;
#ifndef SQLITE_OMIT_AUTOINIT
  rc = sqlite3_initialize();
  if( rc ) return rc;
#endif

  /* Only allow sensible combinations of bits in the flags argument.  
................................................................................
  */
  assert( SQLITE_OPEN_READONLY  == 0x01 );
  assert( SQLITE_OPEN_READWRITE == 0x02 );
  assert( SQLITE_OPEN_CREATE    == 0x04 );
  testcase( (1<<(flags&7))==0x02 ); /* READONLY */
  testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
  testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
  if( ((1<<(flags&7)) & 0x46)==0 ) return SQLITE_MISUSE_BKPT;



  if( sqlite3GlobalConfig.bCoreMutex==0 ){
    isThreadsafe = 0;
  }else if( flags & SQLITE_OPEN_NOMUTEX ){
    isThreadsafe = 0;
  }else if( flags & SQLITE_OPEN_FULLMUTEX ){
    isThreadsafe = 1;
................................................................................
  db->errMask = 0xff;
  db->nDb = 2;
  db->magic = SQLITE_MAGIC_BUSY;
  db->aDb = db->aDbStatic;

  assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
  memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));

  db->autoCommit = 1;
  db->nextAutovac = -1;
  db->szMmap = sqlite3GlobalConfig.szMmap;
  db->nextPagesize = 0;

  db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
#if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
                 | SQLITE_AutoIndex
#endif
#if SQLITE_DEFAULT_FILE_FORMAT<4
                 | SQLITE_LegacyFileFmt
#endif
................................................................................
#endif
#if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
                 | SQLITE_RecTriggers
#endif
#if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
                 | SQLITE_ForeignKeys
#endif



      ;
  sqlite3HashInit(&db->aCollSeq);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3HashInit(&db->aModule);
#endif

  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
  ** and UTF-16, so add a version for each to avoid any unnecessary
  ** conversions. The only error that can occur here is a malloc() failure.



  */
  createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
  createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
  createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);

  createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
  if( db->mallocFailed ){
    goto opendb_out;
  }



  db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
  assert( db->pDfltColl!=0 );

  /* Also add a UTF-8 case-insensitive collation sequence. */
  createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);

  /* Parse the filename/URI argument. */
  db->openFlags = flags;
  rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
    sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
    sqlite3_free(zErrMsg);
................................................................................
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_IOERR_NOMEM ){
      rc = SQLITE_NOMEM;
    }
    sqlite3Error(db, rc);
    goto opendb_out;
  }

  db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);

  db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);


  /* The default safety_level for the main database is 'full'; for the temp
  ** database it is 'NONE'. This matches the pager layer defaults.  
  */
  db->aDb[0].zName = "main";
  db->aDb[0].safety_level = 3;
  db->aDb[1].zName = "temp";
................................................................................
  const void *zFilename, 
  sqlite3 **ppDb
){
  char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
  sqlite3_value *pVal;
  int rc;

  assert( zFilename );
  assert( ppDb );

  *ppDb = 0;
#ifndef SQLITE_OMIT_AUTOINIT
  rc = sqlite3_initialize();
  if( rc ) return rc;
#endif

  pVal = sqlite3ValueNew(0);
  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zFilename8 ){
    rc = openDatabase(zFilename8, ppDb,
                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
    assert( *ppDb || rc==SQLITE_NOMEM );
................................................................................
int sqlite3_create_collation(
  sqlite3* db, 
  const char *zName, 
  int enc, 
  void* pCtx,
  int(*xCompare)(void*,int,const void*,int,const void*)
){
  int rc;
  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, 0);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

/*
** Register a new collation sequence with the database handle db.
*/
int sqlite3_create_collation_v2(
  sqlite3* db, 
................................................................................
  const char *zName, 
  int enc, 
  void* pCtx,
  int(*xCompare)(void*,int,const void*,int,const void*),
  void(*xDel)(void*)
){
  int rc;




  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}
................................................................................
  const void *zName,
  int enc, 
  void* pCtx,
  int(*xCompare)(void*,int,const void*,int,const void*)
){
  int rc = SQLITE_OK;
  char *zName8;




  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
  if( zName8 ){
    rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
    sqlite3DbFree(db, zName8);
  }
................................................................................
** db. Replace any previously installed collation sequence factory.
*/
int sqlite3_collation_needed(
  sqlite3 *db, 
  void *pCollNeededArg, 
  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
){



  sqlite3_mutex_enter(db->mutex);
  db->xCollNeeded = xCollNeeded;
  db->xCollNeeded16 = 0;
  db->pCollNeededArg = pCollNeededArg;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}
................................................................................
** db. Replace any previously installed collation sequence factory.
*/
int sqlite3_collation_needed16(
  sqlite3 *db, 
  void *pCollNeededArg, 
  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
){



  sqlite3_mutex_enter(db->mutex);
  db->xCollNeeded = 0;
  db->xCollNeeded16 = xCollNeeded16;
  db->pCollNeededArg = pCollNeededArg;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}
................................................................................
/*
** Test to see whether or not the database connection is in autocommit
** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
** by default.  Autocommit is disabled by a BEGIN statement and reenabled
** by the next COMMIT or ROLLBACK.
*/
int sqlite3_get_autocommit(sqlite3 *db){






  return db->autoCommit;
}

/*
** The following routines are subtitutes for constants SQLITE_CORRUPT,
** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
** constants.  They server two purposes:
**
**   1.  Serve as a convenient place to set a breakpoint in a debugger
**       to detect when version error conditions occurs.
**
**   2.  Invoke sqlite3_log() to provide the source code location where
**       a low-level error is first detected.
*/
................................................................................
}
#endif

/*
** Return meta information about a specific column of a database table.
** See comment in sqlite3.h (sqlite.h.in) for details.
*/
#ifdef SQLITE_ENABLE_COLUMN_METADATA
int sqlite3_table_column_metadata(
  sqlite3 *db,                /* Connection handle */
  const char *zDbName,        /* Database name or NULL */
  const char *zTableName,     /* Table name */
  const char *zColumnName,    /* Column name */
  char const **pzDataType,    /* OUTPUT: Declared data type */
  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
................................................................................
  pTab = sqlite3FindTable(db, zTableName, zDbName);
  if( !pTab || pTab->pSelect ){
    pTab = 0;
    goto error_out;
  }

  /* Find the column for which info is requested */
  if( sqlite3IsRowid(zColumnName) ){
    iCol = pTab->iPKey;
    if( iCol>=0 ){
      pCol = &pTab->aCol[iCol];
    }
  }else{
    for(iCol=0; iCol<pTab->nCol; iCol++){
      pCol = &pTab->aCol[iCol];
      if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
        break;
      }
    }
    if( iCol==pTab->nCol ){




      pTab = 0;
      goto error_out;

    }
  }

  /* The following block stores the meta information that will be returned
  ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
  ** and autoinc. At this point there are two possibilities:
  ** 
................................................................................
  }
  sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
  sqlite3DbFree(db, zErrMsg);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}
#endif

/*
** Sleep for a little while.  Return the amount of time slept.
*/
int sqlite3_sleep(int ms){
  sqlite3_vfs *pVfs;
  int rc;
................................................................................
  return rc;
}

/*
** Enable or disable the extended result codes.
*/
int sqlite3_extended_result_codes(sqlite3 *db, int onoff){



  sqlite3_mutex_enter(db->mutex);
  db->errMask = onoff ? 0xffffffff : 0xff;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}

/*
** Invoke the xFileControl method on a particular database.
*/
int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
  int rc = SQLITE_ERROR;
  Btree *pBtree;




  sqlite3_mutex_enter(db->mutex);
  pBtree = sqlite3DbNameToBtree(db, zDbName);
  if( pBtree ){
    Pager *pPager;
    sqlite3_file *fd;
    sqlite3BtreeEnter(pBtree);
    pPager = sqlite3BtreePager(pBtree);
................................................................................
    ** Set the PENDING byte to the value in the argument, if X>0.
    ** Make no changes if X==0.  Return the value of the pending byte
    ** as it existing before this routine was called.
    **
    ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
    ** an incompatible database file format.  Changing the PENDING byte
    ** while any database connection is open results in undefined and
    ** dileterious behavior.
    */
    case SQLITE_TESTCTRL_PENDING_BYTE: {
      rc = PENDING_BYTE;
#ifndef SQLITE_OMIT_WSD
      {
        unsigned int newVal = va_arg(ap, unsigned int);
        if( newVal ) sqlite3PendingByte = newVal;
................................................................................
    ** undo this setting.
    */
    case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
      sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
      break;
    }

#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
    /*   sqlite3_test_control(SQLITE_TESTCTRL_EXPLAIN_STMT,
    **                        sqlite3_stmt*,const char**);
    **
    ** If compiled with SQLITE_ENABLE_TREE_EXPLAIN, each sqlite3_stmt holds
    ** a string that describes the optimized parse tree.  This test-control
    ** returns a pointer to that string.
    */
    case SQLITE_TESTCTRL_EXPLAIN_STMT: {
      sqlite3_stmt *pStmt = va_arg(ap, sqlite3_stmt*);
      const char **pzRet = va_arg(ap, const char**);
      *pzRet = sqlite3VdbeExplanation((Vdbe*)pStmt);
      break;
    }
#endif

    /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
    **
    ** Set or clear a flag that indicates that the database file is always well-
    ** formed and never corrupt.  This flag is clear by default, indicating that
    ** database files might have arbitrary corruption.  Setting the flag during
    ** testing causes certain assert() statements in the code to be activated
    ** that demonstrat invariants on well-formed database files.
................................................................................
#ifdef SQLITE_VDBE_COVERAGE
      typedef void (*branch_callback)(void*,int,u8,u8);
      sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
      sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
#endif
      break;
    }








    /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
    **
    ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
    ** not.
    */
    case SQLITE_TESTCTRL_ISINIT: {
      if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
      break;
    }

  }
  va_end(ap);
#endif /* SQLITE_OMIT_BUILTIN_TEST */
  return rc;
}

/*
................................................................................
** The zFilename argument is the filename pointer passed into the xOpen()
** method of a VFS implementation.  The zParam argument is the name of the
** query parameter we seek.  This routine returns the value of the zParam
** parameter if it exists.  If the parameter does not exist, this routine
** returns a NULL pointer.
*/
const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
  if( zFilename==0 ) return 0;
  zFilename += sqlite3Strlen30(zFilename) + 1;
  while( zFilename[0] ){
    int x = strcmp(zFilename, zParam);
    zFilename += sqlite3Strlen30(zFilename) + 1;
    if( x==0 ) return zFilename;
    zFilename += sqlite3Strlen30(zFilename) + 1;
  }
................................................................................
}

/*
** Return the filename of the database associated with a database
** connection.
*/
const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){






  Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
  return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
}

/*
** Return 1 if database is read-only or 0 if read/write.  Return -1 if
** no such database exists.
*/
int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){






  Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
  return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
}

  ** the SQLite library is in use. */
  if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;

  va_start(ap, op);
  switch( op ){

    /* Mutex configuration options are only available in a threadsafe
    ** compile.
    */
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
    case SQLITE_CONFIG_SINGLETHREAD: {
      /* Disable all mutexing */
      sqlite3GlobalConfig.bCoreMutex = 0;
      sqlite3GlobalConfig.bFullMutex = 0;
      break;
    }
#endif
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
    case SQLITE_CONFIG_MULTITHREAD: {
      /* Disable mutexing of database connections */
      /* Enable mutexing of core data structures */
      sqlite3GlobalConfig.bCoreMutex = 1;
      sqlite3GlobalConfig.bFullMutex = 0;
      break;
    }
#endif
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
    case SQLITE_CONFIG_SERIALIZED: {
      /* Enable all mutexing */
      sqlite3GlobalConfig.bCoreMutex = 1;
      sqlite3GlobalConfig.bFullMutex = 1;
      break;
    }
#endif
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
    case SQLITE_CONFIG_MUTEX: {
      /* Specify an alternative mutex implementation */
      sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
      break;
    }
#endif
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
    case SQLITE_CONFIG_GETMUTEX: {
      /* Retrieve the current mutex implementation */
      *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
      break;
    }
#endif


    case SQLITE_CONFIG_MALLOC: {
      /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
      ** single argument which is a pointer to an instance of the
      ** sqlite3_mem_methods structure. The argument specifies alternative
      ** low-level memory allocation routines to be used in place of the memory
      ** allocation routines built into SQLite. */
      sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
      break;
    }
    case SQLITE_CONFIG_GETMALLOC: {
      /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
      ** single argument which is a pointer to an instance of the
      ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
      ** filled with the currently defined memory allocation routines. */
      if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
      *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
      break;
    }
    case SQLITE_CONFIG_MEMSTATUS: {
      /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
      ** single argument of type int, interpreted as a boolean, which enables
      ** or disables the collection of memory allocation statistics. */
      sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
      break;
    }
    case SQLITE_CONFIG_SCRATCH: {
      /* EVIDENCE-OF: R-08404-60887 There are three arguments to
      ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
      ** which the scratch allocations will be drawn, the size of each scratch
      ** allocation (sz), and the maximum number of scratch allocations (N). */
      sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
      sqlite3GlobalConfig.szScratch = va_arg(ap, int);
      sqlite3GlobalConfig.nScratch = va_arg(ap, int);
      break;
    }
    case SQLITE_CONFIG_PAGECACHE: {
      /* EVIDENCE-OF: R-31408-40510 There are three arguments to
      ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory, the size
      ** of each page buffer (sz), and the number of pages (N). */
      sqlite3GlobalConfig.pPage = va_arg(ap, void*);
      sqlite3GlobalConfig.szPage = va_arg(ap, int);
      sqlite3GlobalConfig.nPage = va_arg(ap, int);
      break;
    }
    case SQLITE_CONFIG_PCACHE_HDRSZ: {
      /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
      ** a single parameter which is a pointer to an integer and writes into
      ** that integer the number of extra bytes per page required for each page
      ** in SQLITE_CONFIG_PAGECACHE. */
      *va_arg(ap, int*) = 
          sqlite3HeaderSizeBtree() +
          sqlite3HeaderSizePcache() +
          sqlite3HeaderSizePcache1();
      break;
    }

    case SQLITE_CONFIG_PCACHE: {
      /* no-op */
      break;
    }
    case SQLITE_CONFIG_GETPCACHE: {
      /* now an error */
      rc = SQLITE_ERROR;
      break;
    }

    case SQLITE_CONFIG_PCACHE2: {
      /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
      ** single argument which is a pointer to an sqlite3_pcache_methods2
      ** object. This object specifies the interface to a custom page cache
      ** implementation. */
      sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
      break;
    }
    case SQLITE_CONFIG_GETPCACHE2: {
      /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
      ** single argument which is a pointer to an sqlite3_pcache_methods2
      ** object. SQLite copies of the current page cache implementation into
      ** that object. */
      if( sqlite3GlobalConfig.pcache2.xInit==0 ){
        sqlite3PCacheSetDefault();
      }
      *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
      break;
    }

/* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
#if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
    case SQLITE_CONFIG_HEAP: {

      /* EVIDENCE-OF: R-19854-42126 There are three arguments to
      ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
      ** number of bytes in the memory buffer, and the minimum allocation size. */
      sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
      sqlite3GlobalConfig.nHeap = va_arg(ap, int);
      sqlite3GlobalConfig.mnReq = va_arg(ap, int);

      if( sqlite3GlobalConfig.mnReq<1 ){
        sqlite3GlobalConfig.mnReq = 1;
      }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
        /* cap min request size at 2^12 */
        sqlite3GlobalConfig.mnReq = (1<<12);
      }

      if( sqlite3GlobalConfig.pHeap==0 ){
        /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
        ** is NULL, then SQLite reverts to using its default memory allocator
        ** (the system malloc() implementation), undoing any prior invocation of
        ** SQLITE_CONFIG_MALLOC.
        **
        ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
        ** revert to its default implementation when sqlite3_initialize() is run

        */
        memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
      }else{
        /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
        ** alternative memory allocator is engaged to handle all of SQLites
        ** memory allocation needs. */

#ifdef SQLITE_ENABLE_MEMSYS3
        sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
#endif
#ifdef SQLITE_ENABLE_MEMSYS5
        sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
#endif
      }
................................................................................
      */
      typedef void(*LOGFUNC_t)(void*,int,const char*);
      sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
      sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
      break;
    }

    /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
    ** can be changed at start-time using the
    ** sqlite3_config(SQLITE_CONFIG_URI,1) or
    ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
    */
    case SQLITE_CONFIG_URI: {
      /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
      ** argument of type int. If non-zero, then URI handling is globally
      ** enabled. If the parameter is zero, then URI handling is globally
      ** disabled. */
      sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
      break;
    }

    case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
      /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
      ** option takes a single integer argument which is interpreted as a
      ** boolean in order to enable or disable the use of covering indices for
      ** full table scans in the query optimizer. */
      sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
      break;
    }

#ifdef SQLITE_ENABLE_SQLLOG
    case SQLITE_CONFIG_SQLLOG: {
      typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
................................................................................
      sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
      sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
      break;
    }
#endif

    case SQLITE_CONFIG_MMAP_SIZE: {
      /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
      ** integer (sqlite3_int64) values that are the default mmap size limit
      ** (the default setting for PRAGMA mmap_size) and the maximum allowed
      ** mmap size limit. */
      sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
      sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
      /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
      ** negative, then that argument is changed to its compile-time default.
      **
      ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
      ** silently truncated if necessary so that it does not exceed the
      ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
      ** compile-time option.
      */
      if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ) mxMmap = SQLITE_MAX_MMAP_SIZE;


      if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
      if( szMmap>mxMmap) szMmap = mxMmap;
      sqlite3GlobalConfig.mxMmap = mxMmap;
      sqlite3GlobalConfig.szMmap = szMmap;
      break;
    }

#if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
    case SQLITE_CONFIG_WIN32_HEAPSIZE: {
      /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
      ** unsigned integer value that specifies the maximum size of the created
      ** heap. */
      sqlite3GlobalConfig.nHeap = va_arg(ap, int);
      break;
    }
#endif

    default: {
      rc = SQLITE_ERROR;
................................................................................
  return SQLITE_OK;
}

/*
** Return the mutex associated with a database connection.
*/
sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  return db->mutex;
}

/*
** Free up as much memory as we can from the given database
** connection.
*/
int sqlite3_db_release_memory(sqlite3 *db){
  int i;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  sqlite3BtreeEnterAll(db);
  for(i=0; i<db->nDb; i++){
    Btree *pBt = db->aDb[i].pBt;
    if( pBt ){
      Pager *pPager = sqlite3BtreePager(pBt);
      sqlite3PagerShrink(pPager);
................................................................................
static int binCollFunc(
  void *padFlag,
  int nKey1, const void *pKey1,
  int nKey2, const void *pKey2
){
  int rc, n;
  n = nKey1<nKey2 ? nKey1 : nKey2;
  /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
  ** strings byte by byte using the memcmp() function from the standard C
  ** library. */
  rc = memcmp(pKey1, pKey2, n);
  if( rc==0 ){
    if( padFlag
     && allSpaces(((char*)pKey1)+n, nKey1-n)
     && allSpaces(((char*)pKey2)+n, nKey2-n)
    ){
      /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
      ** spaces at the end of either string do not change the result. In other
      ** words, strings will compare equal to one another as long as they
      ** differ only in the number of spaces at the end.
      */
    }else{
      rc = nKey1 - nKey2;
    }
  }
  return rc;
}

................................................................................
  return r;
}

/*
** Return the ROWID of the most recent insert
*/
sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  return db->lastRowid;
}

/*
** Return the number of changes in the most recent call to sqlite3_exec().
*/
int sqlite3_changes(sqlite3 *db){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  return db->nChange;
}

/*
** Return the number of changes since the database handle was opened.
*/
int sqlite3_total_changes(sqlite3 *db){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  return db->nTotalChange;
}

/*
** Close all open savepoints. This function only manipulates fields of the
** database handle object, it does not close any savepoints that may be open
** at the b-tree/pager level.
................................................................................
  /* Free any outstanding Savepoint structures. */
  sqlite3CloseSavepoints(db);

  /* Close all database connections */
  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];
    if( pDb->pBt ){
      if( pDb->pSchema ){
        /* Must clear the KeyInfo cache.  See ticket [e4a18565a36884b00edf] */
        sqlite3BtreeEnter(pDb->pBt);
        for(i=sqliteHashFirst(&pDb->pSchema->idxHash); i; i=sqliteHashNext(i)){
          Index *pIdx = sqliteHashData(i);
          sqlite3KeyInfoUnref(pIdx->pKeyInfo);
          pIdx->pKeyInfo = 0;
        }
        sqlite3BtreeLeave(pDb->pBt);
      }
      sqlite3BtreeClose(pDb->pBt);
      pDb->pBt = 0;
      if( j!=1 ){
        pDb->pSchema = 0;
      }
    }
  }
................................................................................
  }
  sqlite3HashClear(&db->aModule);
#endif

  sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
  sqlite3ValueFree(db->pErr);
  sqlite3CloseExtensions(db);
#if SQLITE_USER_AUTHENTICATION
  sqlite3_free(db->auth.zAuthUser);
  sqlite3_free(db->auth.zAuthPW);
#endif

  db->magic = SQLITE_MAGIC_ERROR;

  /* The temp-database schema is allocated differently from the other schema
  ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
  ** So it needs to be freed here. Todo: Why not roll the temp schema into
  ** the same sqliteMalloc() as the one that allocates the database 
................................................................................
    sqlite3_free(db->lookaside.pStart);
  }
  sqlite3_free(db);
}

/*
** Rollback all database files.  If tripCode is not SQLITE_OK, then
** any write cursors are invalidated ("tripped" - as in "tripping a circuit
** breaker") and made to return tripCode if there are any further
** attempts to use that cursor.  Read cursors remain open and valid
** but are "saved" in case the table pages are moved around.
*/
void sqlite3RollbackAll(sqlite3 *db, int tripCode){
  int i;
  int inTrans = 0;
  int schemaChange;
  assert( sqlite3_mutex_held(db->mutex) );
  sqlite3BeginBenignMalloc();

  /* Obtain all b-tree mutexes before making any calls to BtreeRollback(). 
  ** This is important in case the transaction being rolled back has
  ** modified the database schema. If the b-tree mutexes are not taken
  ** here, then another shared-cache connection might sneak in between
  ** the database rollback and schema reset, which can cause false
  ** corruption reports in some cases.  */
  sqlite3BtreeEnterAll(db);
  schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;

  for(i=0; i<db->nDb; i++){
    Btree *p = db->aDb[i].pBt;
    if( p ){
      if( sqlite3BtreeIsInTrans(p) ){
        inTrans = 1;
      }
      sqlite3BtreeRollback(p, tripCode, !schemaChange);
    }
  }
  sqlite3VtabRollback(db);
  sqlite3EndBenignMalloc();

  if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
    sqlite3ExpirePreparedStatements(db);
................................................................................
** given callback function with the given argument.
*/
int sqlite3_busy_handler(
  sqlite3 *db,
  int (*xBusy)(void*,int),
  void *pArg
){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE;
#endif
  sqlite3_mutex_enter(db->mutex);
  db->busyHandler.xFunc = xBusy;
  db->busyHandler.pArg = pArg;
  db->busyHandler.nBusy = 0;
  db->busyTimeout = 0;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
................................................................................
*/
void sqlite3_progress_handler(
  sqlite3 *db, 
  int nOps,
  int (*xProgress)(void*), 
  void *pArg
){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  if( nOps>0 ){
    db->xProgress = xProgress;
    db->nProgressOps = (unsigned)nOps;
    db->pProgressArg = pArg;
  }else{
    db->xProgress = 0;
................................................................................


/*
** This routine installs a default busy handler that waits for the
** specified number of milliseconds before returning 0.
*/
int sqlite3_busy_timeout(sqlite3 *db, int ms){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  if( ms>0 ){
    sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
    db->busyTimeout = ms;
  }else{
    sqlite3_busy_handler(db, 0, 0);
  }
  return SQLITE_OK;
}

/*
** Cause any pending operation to stop at its earliest opportunity.
*/
void sqlite3_interrupt(sqlite3 *db){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return;
  }
#endif
  db->u1.isInterrupted = 1;
}


/*
** This function is exactly the same as sqlite3_create_function(), except
** that it is designed to be called by internal code. The difference is
................................................................................
  void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
  void (*xFinal)(sqlite3_context*),
  void (*xDestroy)(void *)
){
  int rc = SQLITE_ERROR;
  FuncDestructor *pArg = 0;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  if( xDestroy ){
    pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
    if( !pArg ){
      xDestroy(p);
      goto out;
    }
................................................................................
  void *p,
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
  void (*xFinal)(sqlite3_context*)
){
  int rc;
  char *zFunc8;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
  rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal,0);
  sqlite3DbFree(db, zFunc8);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
................................................................................
int sqlite3_overload_function(
  sqlite3 *db,
  const char *zName,
  int nArg
){
  int nName = sqlite3Strlen30(zName);
  int rc = SQLITE_OK;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
    rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
                           0, sqlite3InvalidFunction, 0, 0, 0);
  }
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
................................................................................
**
** A NULL trace function means that no tracing is executes.  A non-NULL
** trace is a pointer to a function that is invoked at the start of each
** SQL statement.
*/
void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
  void *pOld;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  pOld = db->pTraceArg;
  db->xTrace = xTrace;
  db->pTraceArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}
................................................................................
*/
void *sqlite3_profile(
  sqlite3 *db,
  void (*xProfile)(void*,const char*,sqlite_uint64),
  void *pArg
){
  void *pOld;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  pOld = db->pProfileArg;
  db->xProfile = xProfile;
  db->pProfileArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}
................................................................................
*/
void *sqlite3_commit_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  int (*xCallback)(void*),  /* Function to invoke on each commit */
  void *pArg                /* Argument to the function */
){
  void *pOld;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  pOld = db->pCommitArg;
  db->xCommitCallback = xCallback;
  db->pCommitArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pOld;
}
................................................................................
*/
void *sqlite3_update_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
  void *pArg                /* Argument to the function */
){
  void *pRet;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  pRet = db->pUpdateArg;
  db->xUpdateCallback = xCallback;
  db->pUpdateArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}
................................................................................
*/
void *sqlite3_rollback_hook(
  sqlite3 *db,              /* Attach the hook to this database */
  void (*xCallback)(void*), /* Callback function */
  void *pArg                /* Argument to the function */
){
  void *pRet;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  pRet = db->pRollbackArg;
  db->xRollbackCallback = xCallback;
  db->pRollbackArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}
................................................................................
** configured by this function.
*/
int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
#ifdef SQLITE_OMIT_WAL
  UNUSED_PARAMETER(db);
  UNUSED_PARAMETER(nFrame);
#else
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  if( nFrame>0 ){
    sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
  }else{
    sqlite3_wal_hook(db, 0, 0);
  }
#endif
  return SQLITE_OK;
................................................................................
void *sqlite3_wal_hook(
  sqlite3 *db,                    /* Attach the hook to this db handle */
  int(*xCallback)(void *, sqlite3*, const char*, int),
  void *pArg                      /* First argument passed to xCallback() */
){
#ifndef SQLITE_OMIT_WAL
  void *pRet;
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  pRet = db->pWalArg;
  db->xWalCallback = xCallback;
  db->pWalArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
#else
................................................................................
  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
){
#ifdef SQLITE_OMIT_WAL
  return SQLITE_OK;
#else
  int rc;                         /* Return code */
  int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif

  /* Initialize the output variables to -1 in case an error occurs. */
  if( pnLog ) *pnLog = -1;
  if( pnCkpt ) *pnCkpt = -1;

  assert( SQLITE_CHECKPOINT_PASSIVE==0 );
  assert( SQLITE_CHECKPOINT_FULL==1 );
  assert( SQLITE_CHECKPOINT_RESTART==2 );
  assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
  if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
    /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
    ** mode: */
    return SQLITE_MISUSE;
  }

  sqlite3_mutex_enter(db->mutex);
  if( zDb && zDb[0] ){
    iDb = sqlite3FindDbName(db, zDb);
  }
................................................................................

/*
** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
** to contains a zero-length string, all attached databases are 
** checkpointed.
*/
int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
  /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
  ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
  return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
}

#ifndef SQLITE_OMIT_WAL
/*
** Run a checkpoint on database iDb. This is a no-op if database iDb is
** not currently open in WAL mode.
**
................................................................................
  SQLITE_MAX_COMPOUND_SELECT,
  SQLITE_MAX_VDBE_OP,
  SQLITE_MAX_FUNCTION_ARG,
  SQLITE_MAX_ATTACHED,
  SQLITE_MAX_LIKE_PATTERN_LENGTH,
  SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
  SQLITE_MAX_TRIGGER_DEPTH,
  SQLITE_MAX_WORKER_THREADS,
};

/*
** Make sure the hard limits are set to reasonable values
*/
#if SQLITE_MAX_LENGTH<100
# error SQLITE_MAX_LENGTH must be at least 100
................................................................................
#endif
#if SQLITE_MAX_COLUMN>32767
# error SQLITE_MAX_COLUMN must not exceed 32767
#endif
#if SQLITE_MAX_TRIGGER_DEPTH<1
# error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
#endif
#if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
# error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
#endif


/*
** Change the value of a limit.  Report the old value.
** If an invalid limit index is supplied, report -1.
** Make no changes but still report the old value if the
** new limit is negative.
................................................................................
** A new lower limit does not shrink existing constructs.
** It merely prevents new constructs that exceed the limit
** from forming.
*/
int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
  int oldLimit;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return -1;
  }
#endif

  /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
  ** there is a hard upper bound set at compile-time by a C preprocessor
  ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
  ** "_MAX_".)
  */
  assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
................................................................................
  assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
  assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
  assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
  assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
                                               SQLITE_MAX_LIKE_PATTERN_LENGTH );
  assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
  assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
  assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
  assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );


  if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
    return -1;
  }
  oldLimit = db->aLimit[limitId];
  if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
................................................................................
  const char *zVfs = zDefaultVfs;
  char *zFile;
  char c;
  int nUri = sqlite3Strlen30(zUri);

  assert( *pzErrMsg==0 );

  if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
            || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
   && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
  ){
    char *zOpt;
    int eState;                   /* Parser state when parsing URI */
    int iIn;                      /* Input character index */
    int iOut = 0;                 /* Output character index */
    int nByte = nUri+2;           /* Bytes of space to allocate */

................................................................................
){
  sqlite3 *db;                    /* Store allocated handle here */
  int rc;                         /* Return code */
  int isThreadsafe;               /* True for threadsafe connections */
  char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
  char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */

#ifdef SQLITE_ENABLE_API_ARMOR
  if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
#endif
  *ppDb = 0;
#ifndef SQLITE_OMIT_AUTOINIT
  rc = sqlite3_initialize();
  if( rc ) return rc;
#endif

  /* Only allow sensible combinations of bits in the flags argument.  
................................................................................
  */
  assert( SQLITE_OPEN_READONLY  == 0x01 );
  assert( SQLITE_OPEN_READWRITE == 0x02 );
  assert( SQLITE_OPEN_CREATE    == 0x04 );
  testcase( (1<<(flags&7))==0x02 ); /* READONLY */
  testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
  testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
  if( ((1<<(flags&7)) & 0x46)==0 ){
    return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
  }

  if( sqlite3GlobalConfig.bCoreMutex==0 ){
    isThreadsafe = 0;
  }else if( flags & SQLITE_OPEN_NOMUTEX ){
    isThreadsafe = 0;
  }else if( flags & SQLITE_OPEN_FULLMUTEX ){
    isThreadsafe = 1;
................................................................................
  db->errMask = 0xff;
  db->nDb = 2;
  db->magic = SQLITE_MAGIC_BUSY;
  db->aDb = db->aDbStatic;

  assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
  memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
  db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
  db->autoCommit = 1;
  db->nextAutovac = -1;
  db->szMmap = sqlite3GlobalConfig.szMmap;
  db->nextPagesize = 0;
  db->nMaxSorterMmap = 0x7FFFFFFF;
  db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
#if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
                 | SQLITE_AutoIndex
#endif
#if SQLITE_DEFAULT_FILE_FORMAT<4
                 | SQLITE_LegacyFileFmt
#endif
................................................................................
#endif
#if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
                 | SQLITE_RecTriggers
#endif
#if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
                 | SQLITE_ForeignKeys
#endif
#if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
                 | SQLITE_ReverseOrder
#endif
      ;
  sqlite3HashInit(&db->aCollSeq);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3HashInit(&db->aModule);
#endif

  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
  ** and UTF-16, so add a version for each to avoid any unnecessary
  ** conversions. The only error that can occur here is a malloc() failure.
  **
  ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
  ** functions:
  */
  createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
  createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
  createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
  createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
  createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
  if( db->mallocFailed ){
    goto opendb_out;
  }
  /* EVIDENCE-OF: R-08308-17224 The default collating function for all
  ** strings is BINARY. 
  */
  db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
  assert( db->pDfltColl!=0 );




  /* Parse the filename/URI argument. */
  db->openFlags = flags;
  rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
    sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
    sqlite3_free(zErrMsg);
................................................................................
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_IOERR_NOMEM ){
      rc = SQLITE_NOMEM;
    }
    sqlite3Error(db, rc);
    goto opendb_out;
  }
  sqlite3BtreeEnter(db->aDb[0].pBt);
  db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
  sqlite3BtreeLeave(db->aDb[0].pBt);
  db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);


  /* The default safety_level for the main database is 'full'; for the temp
  ** database it is 'NONE'. This matches the pager layer defaults.  
  */
  db->aDb[0].zName = "main";
  db->aDb[0].safety_level = 3;
  db->aDb[1].zName = "temp";
................................................................................
  const void *zFilename, 
  sqlite3 **ppDb
){
  char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
  sqlite3_value *pVal;
  int rc;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
#endif
  *ppDb = 0;
#ifndef SQLITE_OMIT_AUTOINIT
  rc = sqlite3_initialize();
  if( rc ) return rc;
#endif
  if( zFilename==0 ) zFilename = "\000\000";
  pVal = sqlite3ValueNew(0);
  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zFilename8 ){
    rc = openDatabase(zFilename8, ppDb,
                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
    assert( *ppDb || rc==SQLITE_NOMEM );
................................................................................
int sqlite3_create_collation(
  sqlite3* db, 
  const char *zName, 
  int enc, 
  void* pCtx,
  int(*xCompare)(void*,int,const void*,int,const void*)
){
  return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);






}

/*
** Register a new collation sequence with the database handle db.
*/
int sqlite3_create_collation_v2(
  sqlite3* db, 
................................................................................
  const char *zName, 
  int enc, 
  void* pCtx,
  int(*xCompare)(void*,int,const void*,int,const void*),
  void(*xDel)(void*)
){
  int rc;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}
................................................................................
  const void *zName,
  int enc, 
  void* pCtx,
  int(*xCompare)(void*,int,const void*,int,const void*)
){
  int rc = SQLITE_OK;
  char *zName8;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  assert( !db->mallocFailed );
  zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
  if( zName8 ){
    rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
    sqlite3DbFree(db, zName8);
  }
................................................................................
** db. Replace any previously installed collation sequence factory.
*/
int sqlite3_collation_needed(
  sqlite3 *db, 
  void *pCollNeededArg, 
  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  db->xCollNeeded = xCollNeeded;
  db->xCollNeeded16 = 0;
  db->pCollNeededArg = pCollNeededArg;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}
................................................................................
** db. Replace any previously installed collation sequence factory.
*/
int sqlite3_collation_needed16(
  sqlite3 *db, 
  void *pCollNeededArg, 
  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  db->xCollNeeded = 0;
  db->xCollNeeded16 = xCollNeeded16;
  db->pCollNeededArg = pCollNeededArg;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}
................................................................................
/*
** Test to see whether or not the database connection is in autocommit
** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
** by default.  Autocommit is disabled by a BEGIN statement and reenabled
** by the next COMMIT or ROLLBACK.
*/
int sqlite3_get_autocommit(sqlite3 *db){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  return db->autoCommit;
}

/*
** The following routines are substitutes for constants SQLITE_CORRUPT,
** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
** constants.  They serve two purposes:
**
**   1.  Serve as a convenient place to set a breakpoint in a debugger
**       to detect when version error conditions occurs.
**
**   2.  Invoke sqlite3_log() to provide the source code location where
**       a low-level error is first detected.
*/
................................................................................
}
#endif

/*
** Return meta information about a specific column of a database table.
** See comment in sqlite3.h (sqlite.h.in) for details.
*/

int sqlite3_table_column_metadata(
  sqlite3 *db,                /* Connection handle */
  const char *zDbName,        /* Database name or NULL */
  const char *zTableName,     /* Table name */
  const char *zColumnName,    /* Column name */
  char const **pzDataType,    /* OUTPUT: Declared data type */
  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
................................................................................
  pTab = sqlite3FindTable(db, zTableName, zDbName);
  if( !pTab || pTab->pSelect ){
    pTab = 0;
    goto error_out;
  }

  /* Find the column for which info is requested */
  if( zColumnName==0 ){
    /* Query for existance of table only */



  }else{
    for(iCol=0; iCol<pTab->nCol; iCol++){
      pCol = &pTab->aCol[iCol];
      if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
        break;
      }
    }
    if( iCol==pTab->nCol ){
      if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
        iCol = pTab->iPKey;
        pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
      }else{
        pTab = 0;
        goto error_out;
      }
    }
  }

  /* The following block stores the meta information that will be returned
  ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
  ** and autoinc. At this point there are two possibilities:
  ** 
................................................................................
  }
  sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
  sqlite3DbFree(db, zErrMsg);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}


/*
** Sleep for a little while.  Return the amount of time slept.
*/
int sqlite3_sleep(int ms){
  sqlite3_vfs *pVfs;
  int rc;
................................................................................
  return rc;
}

/*
** Enable or disable the extended result codes.
*/
int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  db->errMask = onoff ? 0xffffffff : 0xff;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}

/*
** Invoke the xFileControl method on a particular database.
*/
int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
  int rc = SQLITE_ERROR;
  Btree *pBtree;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
  sqlite3_mutex_enter(db->mutex);
  pBtree = sqlite3DbNameToBtree(db, zDbName);
  if( pBtree ){
    Pager *pPager;
    sqlite3_file *fd;
    sqlite3BtreeEnter(pBtree);
    pPager = sqlite3BtreePager(pBtree);
................................................................................
    ** Set the PENDING byte to the value in the argument, if X>0.
    ** Make no changes if X==0.  Return the value of the pending byte
    ** as it existing before this routine was called.
    **
    ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
    ** an incompatible database file format.  Changing the PENDING byte
    ** while any database connection is open results in undefined and
    ** deleterious behavior.
    */
    case SQLITE_TESTCTRL_PENDING_BYTE: {
      rc = PENDING_BYTE;
#ifndef SQLITE_OMIT_WSD
      {
        unsigned int newVal = va_arg(ap, unsigned int);
        if( newVal ) sqlite3PendingByte = newVal;
................................................................................
    ** undo this setting.
    */
    case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
      sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
      break;
    }

















    /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
    **
    ** Set or clear a flag that indicates that the database file is always well-
    ** formed and never corrupt.  This flag is clear by default, indicating that
    ** database files might have arbitrary corruption.  Setting the flag during
    ** testing causes certain assert() statements in the code to be activated
    ** that demonstrat invariants on well-formed database files.
................................................................................
#ifdef SQLITE_VDBE_COVERAGE
      typedef void (*branch_callback)(void*,int,u8,u8);
      sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
      sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
#endif
      break;
    }

    /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
    case SQLITE_TESTCTRL_SORTER_MMAP: {
      sqlite3 *db = va_arg(ap, sqlite3*);
      db->nMaxSorterMmap = va_arg(ap, int);
      break;
    }

    /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
    **
    ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
    ** not.
    */
    case SQLITE_TESTCTRL_ISINIT: {
      if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
      break;
    }

  }
  va_end(ap);
#endif /* SQLITE_OMIT_BUILTIN_TEST */
  return rc;
}

/*
................................................................................
** The zFilename argument is the filename pointer passed into the xOpen()
** method of a VFS implementation.  The zParam argument is the name of the
** query parameter we seek.  This routine returns the value of the zParam
** parameter if it exists.  If the parameter does not exist, this routine
** returns a NULL pointer.
*/
const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
  if( zFilename==0 || zParam==0 ) return 0;
  zFilename += sqlite3Strlen30(zFilename) + 1;
  while( zFilename[0] ){
    int x = strcmp(zFilename, zParam);
    zFilename += sqlite3Strlen30(zFilename) + 1;
    if( x==0 ) return zFilename;
    zFilename += sqlite3Strlen30(zFilename) + 1;
  }
................................................................................
}

/*
** Return the filename of the database associated with a database
** connection.
*/
const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return 0;
  }
#endif
  Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
  return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
}

/*
** Return 1 if database is read-only or 0 if read/write.  Return -1 if
** no such database exists.
*/
int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    (void)SQLITE_MISUSE_BKPT;
    return -1;
  }
#endif
  Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
  return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
}

  return nFull;
}

/*
** Allocate memory.  This routine is like sqlite3_malloc() except that it
** assumes the memory subsystem has already been initialized.
*/
void *sqlite3Malloc(int n){
  void *p;
  if( n<=0               /* IMP: R-65312-04917 */ 
   || n>=0x7fffff00
  ){
    /* A memory allocation of a number of bytes which is near the maximum
    ** signed integer value might cause an integer overflow inside of the
    ** xMalloc().  Hence we limit the maximum size to 0x7fffff00, giving
    ** 255 bytes of overhead.  SQLite itself will never use anything near
    ** this amount.  The only way to reach the limit is with sqlite3_malloc() */
    p = 0;
  }else if( sqlite3GlobalConfig.bMemstat ){
    sqlite3_mutex_enter(mem0.mutex);
    mallocWithAlarm(n, &p);
    sqlite3_mutex_leave(mem0.mutex);
  }else{
    p = sqlite3GlobalConfig.m.xMalloc(n);
  }
  assert( EIGHT_BYTE_ALIGNMENT(p) );  /* IMP: R-04675-44850 */
  return p;
}

/*
** This version of the memory allocation is for use by the application.
** First make sure the memory subsystem is initialized, then do the
** allocation.
*/
void *sqlite3_malloc(int n){
#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return 0;
#endif






  return sqlite3Malloc(n);
}

/*
** Each thread may only have a single outstanding allocation from
** xScratchMalloc().  We verify this constraint in the single-threaded
** case by setting scratchAllocOut to 1 when an allocation
................................................................................
    }
    sqlite3MemdebugSetType(p, MEMTYPE_SCRATCH);
  }
  assert( sqlite3_mutex_notheld(mem0.mutex) );


#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
  /* Verify that no more than two scratch allocations per thread
  ** are outstanding at one time.  (This is only checked in the
  ** single-threaded case since checking in the multi-threaded case
  ** would be much more complicated.) */

  assert( scratchAllocOut<=1 );
  if( p ) scratchAllocOut++;
#endif

  return p;
}
void sqlite3ScratchFree(void *p){
  if( p ){
................................................................................

/*
** Return the size of a memory allocation previously obtained from
** sqlite3Malloc() or sqlite3_malloc().
*/
int sqlite3MallocSize(void *p){
  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
  assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );
  return sqlite3GlobalConfig.m.xSize(p);
}
int sqlite3DbMallocSize(sqlite3 *db, void *p){
  assert( db!=0 );




  assert( sqlite3_mutex_held(db->mutex) );
  if( isLookaside(db, p) ){
    return db->lookaside.sz;
  }else{
    assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
    assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );
    assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
    return sqlite3GlobalConfig.m.xSize(p);
  }
}







/*
** Free memory previously obtained from sqlite3Malloc().
*/
void sqlite3_free(void *p){
  if( p==0 ) return;  /* IMP: R-49053-54554 */
  assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );
  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );

  if( sqlite3GlobalConfig.bMemstat ){
    sqlite3_mutex_enter(mem0.mutex);
    sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -sqlite3MallocSize(p));
    sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);
    sqlite3GlobalConfig.m.xFree(p);
    sqlite3_mutex_leave(mem0.mutex);
  }else{
................................................................................
#endif
      pBuf->pNext = db->lookaside.pFree;
      db->lookaside.pFree = pBuf;
      db->lookaside.nOut--;
      return;
    }
  }
  assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
  assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );
  assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
  sqlite3_free(p);
}

/*
** Change the size of an existing memory allocation
*/
void *sqlite3Realloc(void *pOld, int nBytes){
  int nOld, nNew, nDiff;
  void *pNew;


  if( pOld==0 ){
    return sqlite3Malloc(nBytes); /* IMP: R-28354-25769 */
  }
  if( nBytes<=0 ){
    sqlite3_free(pOld); /* IMP: R-31593-10574 */
    return 0;
  }
  if( nBytes>=0x7fffff00 ){
    /* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */
    return 0;
  }
  nOld = sqlite3MallocSize(pOld);
  /* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second
  ** argument to xRealloc is always a value returned by a prior call to
  ** xRoundup. */
  nNew = sqlite3GlobalConfig.m.xRoundup(nBytes);
  if( nOld==nNew ){
    pNew = pOld;
  }else if( sqlite3GlobalConfig.bMemstat ){
    sqlite3_mutex_enter(mem0.mutex);
    sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, nBytes);
    nDiff = nNew - nOld;
    if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED) >= 
          mem0.alarmThreshold-nDiff ){
      sqlite3MallocAlarm(nDiff);
    }
    assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
    assert( sqlite3MemdebugNoType(pOld, ~MEMTYPE_HEAP) );
    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
    if( pNew==0 && mem0.alarmCallback ){
      sqlite3MallocAlarm(nBytes);
      pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
    }
    if( pNew ){
      nNew = sqlite3MallocSize(pNew);
      sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
    }
    sqlite3_mutex_leave(mem0.mutex);
  }else{
    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
  }
  assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-04675-44850 */
  return pNew;
}

/*
** The public interface to sqlite3Realloc.  Make sure that the memory
** subsystem is initialized prior to invoking sqliteRealloc.
*/
void *sqlite3_realloc(void *pOld, int n){
#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return 0;
#endif







  return sqlite3Realloc(pOld, n);
}


/*
** Allocate and zero memory.
*/ 
void *sqlite3MallocZero(int n){
  void *p = sqlite3Malloc(n);
  if( p ){
    memset(p, 0, n);
  }
  return p;
}

/*
** Allocate and zero memory.  If the allocation fails, make
** the mallocFailed flag in the connection pointer.
*/
void *sqlite3DbMallocZero(sqlite3 *db, int n){
  void *p = sqlite3DbMallocRaw(db, n);
  if( p ){
    memset(p, 0, n);
  }
  return p;
}

/*
** Allocate and zero memory.  If the allocation fails, make
** the mallocFailed flag in the connection pointer.
................................................................................
**         int *a = (int*)sqlite3DbMallocRaw(db, 100);
**         int *b = (int*)sqlite3DbMallocRaw(db, 200);
**         if( b ) a[10] = 9;
**
** In other words, if a subsequent malloc (ex: "b") worked, it is assumed
** that all prior mallocs (ex: "a") worked too.
*/
void *sqlite3DbMallocRaw(sqlite3 *db, int n){
  void *p;
  assert( db==0 || sqlite3_mutex_held(db->mutex) );
  assert( db==0 || db->pnBytesFreed==0 );
#ifndef SQLITE_OMIT_LOOKASIDE
  if( db ){
    LookasideSlot *pBuf;
    if( db->mallocFailed ){
................................................................................
    return 0;
  }
#endif
  p = sqlite3Malloc(n);
  if( !p && db ){
    db->mallocFailed = 1;
  }
  sqlite3MemdebugSetType(p, MEMTYPE_DB |
         ((db && db->lookaside.bEnabled) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
  return p;
}

/*
** Resize the block of memory pointed to by p to n bytes. If the
** resize fails, set the mallocFailed flag in the connection object.
*/
void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
  void *pNew = 0;
  assert( db!=0 );
  assert( sqlite3_mutex_held(db->mutex) );
  if( db->mallocFailed==0 ){
    if( p==0 ){
      return sqlite3DbMallocRaw(db, n);
    }
................................................................................
      }
      pNew = sqlite3DbMallocRaw(db, n);
      if( pNew ){
        memcpy(pNew, p, db->lookaside.sz);
        sqlite3DbFree(db, p);
      }
    }else{
      assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
      assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );
      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
      pNew = sqlite3_realloc(p, n);
      if( !pNew ){
        sqlite3MemdebugSetType(p, MEMTYPE_DB|MEMTYPE_HEAP);
        db->mallocFailed = 1;
      }
      sqlite3MemdebugSetType(pNew, MEMTYPE_DB | 
            (db->lookaside.bEnabled ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
    }
  }
  return pNew;
}

/*
** Attempt to reallocate p.  If the reallocation fails, then free p
** and set the mallocFailed flag in the database connection.
*/
void *sqlite3DbReallocOrFree(sqlite3 *db, void *p, int n){
  void *pNew;
  pNew = sqlite3DbRealloc(db, p, n);
  if( !pNew ){
    sqlite3DbFree(db, p);
  }
  return pNew;
}
................................................................................
  assert( (n&0x7fffffff)==n );
  zNew = sqlite3DbMallocRaw(db, (int)n);
  if( zNew ){
    memcpy(zNew, z, n);
  }
  return zNew;
}
char *sqlite3DbStrNDup(sqlite3 *db, const char *z, int n){
  char *zNew;
  if( z==0 ){
    return 0;
  }
  assert( (n&0x7fffffff)==n );
  zNew = sqlite3DbMallocRaw(db, n+1);
  if( zNew ){
    memcpy(zNew, z, n);
    zNew[n] = 0;
  }
  return zNew;
}

/*
** Create a string from the zFromat argument and the va_list that follows.

  return nFull;
}

/*
** Allocate memory.  This routine is like sqlite3_malloc() except that it
** assumes the memory subsystem has already been initialized.
*/
void *sqlite3Malloc(u64 n){
  void *p;

  if( n==0 || n>=0x7fffff00 ){

    /* A memory allocation of a number of bytes which is near the maximum
    ** signed integer value might cause an integer overflow inside of the
    ** xMalloc().  Hence we limit the maximum size to 0x7fffff00, giving
    ** 255 bytes of overhead.  SQLite itself will never use anything near
    ** this amount.  The only way to reach the limit is with sqlite3_malloc() */
    p = 0;
  }else if( sqlite3GlobalConfig.bMemstat ){
    sqlite3_mutex_enter(mem0.mutex);
    mallocWithAlarm((int)n, &p);
    sqlite3_mutex_leave(mem0.mutex);
  }else{
    p = sqlite3GlobalConfig.m.xMalloc((int)n);
  }
  assert( EIGHT_BYTE_ALIGNMENT(p) );  /* IMP: R-11148-40995 */
  return p;
}

/*
** This version of the memory allocation is for use by the application.
** First make sure the memory subsystem is initialized, then do the
** allocation.
*/
void *sqlite3_malloc(int n){
#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return 0;
#endif
  return n<=0 ? 0 : sqlite3Malloc(n);
}
void *sqlite3_malloc64(sqlite3_uint64 n){
#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return 0;
#endif
  return sqlite3Malloc(n);
}

/*
** Each thread may only have a single outstanding allocation from
** xScratchMalloc().  We verify this constraint in the single-threaded
** case by setting scratchAllocOut to 1 when an allocation
................................................................................
    }
    sqlite3MemdebugSetType(p, MEMTYPE_SCRATCH);
  }
  assert( sqlite3_mutex_notheld(mem0.mutex) );


#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
  /* EVIDENCE-OF: R-12970-05880 SQLite will not use more than one scratch
  ** buffers per thread.
  **
  ** This can only be checked in single-threaded mode.
  */
  assert( scratchAllocOut==0 );
  if( p ) scratchAllocOut++;
#endif

  return p;
}
void sqlite3ScratchFree(void *p){
  if( p ){
................................................................................

/*
** Return the size of a memory allocation previously obtained from
** sqlite3Malloc() or sqlite3_malloc().
*/
int sqlite3MallocSize(void *p){
  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );

  return sqlite3GlobalConfig.m.xSize(p);
}
int sqlite3DbMallocSize(sqlite3 *db, void *p){
  if( db==0 ){
    assert( sqlite3MemdebugNoType(p, ~MEMTYPE_HEAP) );
    assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
    return sqlite3MallocSize(p);
  }else{
    assert( sqlite3_mutex_held(db->mutex) );
    if( isLookaside(db, p) ){
      return db->lookaside.sz;
    }else{
      assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
      assert( sqlite3MemdebugNoType(p, ~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );

      return sqlite3GlobalConfig.m.xSize(p);
    }
  }
}
sqlite3_uint64 sqlite3_msize(void *p){
  assert( sqlite3MemdebugNoType(p, ~MEMTYPE_HEAP) );
  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
  return (sqlite3_uint64)sqlite3GlobalConfig.m.xSize(p);
}

/*
** Free memory previously obtained from sqlite3Malloc().
*/
void sqlite3_free(void *p){
  if( p==0 ) return;  /* IMP: R-49053-54554 */

  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
  assert( sqlite3MemdebugNoType(p, ~MEMTYPE_HEAP) );
  if( sqlite3GlobalConfig.bMemstat ){
    sqlite3_mutex_enter(mem0.mutex);
    sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -sqlite3MallocSize(p));
    sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);
    sqlite3GlobalConfig.m.xFree(p);
    sqlite3_mutex_leave(mem0.mutex);
  }else{
................................................................................
#endif
      pBuf->pNext = db->lookaside.pFree;
      db->lookaside.pFree = pBuf;
      db->lookaside.nOut--;
      return;
    }
  }
  assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
  assert( sqlite3MemdebugNoType(p, ~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
  assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
  sqlite3_free(p);
}

/*
** Change the size of an existing memory allocation
*/
void *sqlite3Realloc(void *pOld, u64 nBytes){
  int nOld, nNew, nDiff;
  void *pNew;
  assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
  assert( sqlite3MemdebugNoType(pOld, ~MEMTYPE_HEAP) );
  if( pOld==0 ){
    return sqlite3Malloc(nBytes); /* IMP: R-04300-56712 */
  }
  if( nBytes==0 ){
    sqlite3_free(pOld); /* IMP: R-26507-47431 */
    return 0;
  }
  if( nBytes>=0x7fffff00 ){
    /* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */
    return 0;
  }
  nOld = sqlite3MallocSize(pOld);
  /* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second
  ** argument to xRealloc is always a value returned by a prior call to
  ** xRoundup. */
  nNew = sqlite3GlobalConfig.m.xRoundup((int)nBytes);
  if( nOld==nNew ){
    pNew = pOld;
  }else if( sqlite3GlobalConfig.bMemstat ){
    sqlite3_mutex_enter(mem0.mutex);
    sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, (int)nBytes);
    nDiff = nNew - nOld;
    if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED) >= 
          mem0.alarmThreshold-nDiff ){
      sqlite3MallocAlarm(nDiff);
    }


    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
    if( pNew==0 && mem0.alarmCallback ){
      sqlite3MallocAlarm((int)nBytes);
      pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
    }
    if( pNew ){
      nNew = sqlite3MallocSize(pNew);
      sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
    }
    sqlite3_mutex_leave(mem0.mutex);
  }else{
    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
  }
  assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-11148-40995 */
  return pNew;
}

/*
** The public interface to sqlite3Realloc.  Make sure that the memory
** subsystem is initialized prior to invoking sqliteRealloc.
*/
void *sqlite3_realloc(void *pOld, int n){
#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return 0;
#endif
  if( n<0 ) n = 0;  /* IMP: R-26507-47431 */
  return sqlite3Realloc(pOld, n);
}
void *sqlite3_realloc64(void *pOld, sqlite3_uint64 n){
#ifndef SQLITE_OMIT_AUTOINIT
  if( sqlite3_initialize() ) return 0;
#endif
  return sqlite3Realloc(pOld, n);
}


/*
** Allocate and zero memory.
*/ 
void *sqlite3MallocZero(u64 n){
  void *p = sqlite3Malloc(n);
  if( p ){
    memset(p, 0, (size_t)n);
  }
  return p;
}

/*
** Allocate and zero memory.  If the allocation fails, make
** the mallocFailed flag in the connection pointer.
*/
void *sqlite3DbMallocZero(sqlite3 *db, u64 n){
  void *p = sqlite3DbMallocRaw(db, n);
  if( p ){
    memset(p, 0, (size_t)n);
  }
  return p;
}

/*
** Allocate and zero memory.  If the allocation fails, make
** the mallocFailed flag in the connection pointer.
................................................................................
**         int *a = (int*)sqlite3DbMallocRaw(db, 100);
**         int *b = (int*)sqlite3DbMallocRaw(db, 200);
**         if( b ) a[10] = 9;
**
** In other words, if a subsequent malloc (ex: "b") worked, it is assumed
** that all prior mallocs (ex: "a") worked too.
*/
void *sqlite3DbMallocRaw(sqlite3 *db, u64 n){
  void *p;
  assert( db==0 || sqlite3_mutex_held(db->mutex) );
  assert( db==0 || db->pnBytesFreed==0 );
#ifndef SQLITE_OMIT_LOOKASIDE
  if( db ){
    LookasideSlot *pBuf;
    if( db->mallocFailed ){
................................................................................
    return 0;
  }
#endif
  p = sqlite3Malloc(n);
  if( !p && db ){
    db->mallocFailed = 1;
  }
  sqlite3MemdebugSetType(p, 
         (db && db->lookaside.bEnabled) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP);
  return p;
}

/*
** Resize the block of memory pointed to by p to n bytes. If the
** resize fails, set the mallocFailed flag in the connection object.
*/
void *sqlite3DbRealloc(sqlite3 *db, void *p, u64 n){
  void *pNew = 0;
  assert( db!=0 );
  assert( sqlite3_mutex_held(db->mutex) );
  if( db->mallocFailed==0 ){
    if( p==0 ){
      return sqlite3DbMallocRaw(db, n);
    }
................................................................................
      }
      pNew = sqlite3DbMallocRaw(db, n);
      if( pNew ){
        memcpy(pNew, p, db->lookaside.sz);
        sqlite3DbFree(db, p);
      }
    }else{
      assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
      assert( sqlite3MemdebugNoType(p, ~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
      pNew = sqlite3_realloc64(p, n);
      if( !pNew ){

        db->mallocFailed = 1;
      }
      sqlite3MemdebugSetType(pNew,
            (db->lookaside.bEnabled ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
    }
  }
  return pNew;
}

/*
** Attempt to reallocate p.  If the reallocation fails, then free p
** and set the mallocFailed flag in the database connection.
*/
void *sqlite3DbReallocOrFree(sqlite3 *db, void *p, u64 n){
  void *pNew;
  pNew = sqlite3DbRealloc(db, p, n);
  if( !pNew ){
    sqlite3DbFree(db, p);
  }
  return pNew;
}
................................................................................
  assert( (n&0x7fffffff)==n );
  zNew = sqlite3DbMallocRaw(db, (int)n);
  if( zNew ){
    memcpy(zNew, z, n);
  }
  return zNew;
}
char *sqlite3DbStrNDup(sqlite3 *db, const char *z, u64 n){
  char *zNew;
  if( z==0 ){
    return 0;
  }
  assert( (n&0x7fffffff)==n );
  zNew = sqlite3DbMallocRaw(db, n+1);
  if( zNew ){
    memcpy(zNew, z, (size_t)n);
    zNew[n] = 0;
  }
  return zNew;
}

/*
** Create a string from the zFromat argument and the va_list that follows.

/*
** Like realloc().  Resize an allocation previously obtained from
** sqlite3MemMalloc().
**
** For this low-level interface, we know that pPrior!=0.  Cases where
** pPrior==0 while have been intercepted by higher-level routine and
** redirected to xMalloc.  Similarly, we know that nByte>0 becauses
** cases where nByte<=0 will have been intercepted by higher-level
** routines and redirected to xFree.
*/
static void *sqlite3MemRealloc(void *pPrior, int nByte){
#ifdef SQLITE_MALLOCSIZE
  void *p = SQLITE_REALLOC(pPrior, nByte);
  if( p==0 ){

/*
** Like realloc().  Resize an allocation previously obtained from
** sqlite3MemMalloc().
**
** For this low-level interface, we know that pPrior!=0.  Cases where
** pPrior==0 while have been intercepted by higher-level routine and
** redirected to xMalloc.  Similarly, we know that nByte>0 because
** cases where nByte<=0 will have been intercepted by higher-level
** routines and redirected to xFree.
*/
static void *sqlite3MemRealloc(void *pPrior, int nByte){
#ifdef SQLITE_MALLOCSIZE
  void *p = SQLITE_REALLOC(pPrior, nByte);
  if( p==0 ){

/*
** Return TRUE if the mask of type in eType matches the type of the
** allocation p.  Also return true if p==NULL.
**
** This routine is designed for use within an assert() statement, to
** verify the type of an allocation.  For example:
**
**     assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );
*/
int sqlite3MemdebugHasType(void *p, u8 eType){
  int rc = 1;
  if( p && sqlite3GlobalConfig.m.xMalloc==sqlite3MemMalloc ){
    struct MemBlockHdr *pHdr;
    pHdr = sqlite3MemsysGetHeader(p);
    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
................................................................................
/*
** Return TRUE if the mask of type in eType matches no bits of the type of the
** allocation p.  Also return true if p==NULL.
**
** This routine is designed for use within an assert() statement, to
** verify the type of an allocation.  For example:
**
**     assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );
*/
int sqlite3MemdebugNoType(void *p, u8 eType){
  int rc = 1;
  if( p && sqlite3GlobalConfig.m.xMalloc==sqlite3MemMalloc ){
    struct MemBlockHdr *pHdr;
    pHdr = sqlite3MemsysGetHeader(p);
    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */

/*
** Return TRUE if the mask of type in eType matches the type of the
** allocation p.  Also return true if p==NULL.
**
** This routine is designed for use within an assert() statement, to
** verify the type of an allocation.  For example:
**
**     assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
*/
int sqlite3MemdebugHasType(void *p, u8 eType){
  int rc = 1;
  if( p && sqlite3GlobalConfig.m.xMalloc==sqlite3MemMalloc ){
    struct MemBlockHdr *pHdr;
    pHdr = sqlite3MemsysGetHeader(p);
    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
................................................................................
/*
** Return TRUE if the mask of type in eType matches no bits of the type of the
** allocation p.  Also return true if p==NULL.
**
** This routine is designed for use within an assert() statement, to
** verify the type of an allocation.  For example:
**
**     assert( sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
*/
int sqlite3MemdebugNoType(void *p, u8 eType){
  int rc = 1;
  if( p && sqlite3GlobalConfig.m.xMalloc==sqlite3MemMalloc ){
    struct MemBlockHdr *pHdr;
    pHdr = sqlite3MemsysGetHeader(p);
    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */

** in the build only if SQLITE_ENABLE_MEMSYS5 is defined.
**
** This memory allocator uses the following algorithm:
**
**   1.  All memory allocations sizes are rounded up to a power of 2.
**
**   2.  If two adjacent free blocks are the halves of a larger block,
**       then the two blocks are coalesed into the single larger block.
**
**   3.  New memory is allocated from the first available free block.
**
** This algorithm is described in: J. M. Robson. "Bounds for Some Functions
** Concerning Dynamic Storage Allocation". Journal of the Association for
** Computing Machinery, Volume 21, Number 8, July 1974, pages 491-499.
** 

** in the build only if SQLITE_ENABLE_MEMSYS5 is defined.
**
** This memory allocator uses the following algorithm:
**
**   1.  All memory allocations sizes are rounded up to a power of 2.
**
**   2.  If two adjacent free blocks are the halves of a larger block,
**       then the two blocks are coalesced into the single larger block.
**
**   3.  New memory is allocated from the first available free block.
**
** This algorithm is described in: J. M. Robson. "Bounds for Some Functions
** Concerning Dynamic Storage Allocation". Journal of the Association for
** Computing Machinery, Volume 21, Number 8, July 1974, pages 491-499.
** 

typedef struct FileChunk FileChunk;

/* Space to hold the rollback journal is allocated in increments of
** this many bytes.
**
** The size chosen is a little less than a power of two.  That way,
** the FileChunk object will have a size that almost exactly fills
** a power-of-two allocation.  This mimimizes wasted space in power-of-two
** memory allocators.
*/
#define JOURNAL_CHUNKSIZE ((int)(1024-sizeof(FileChunk*)))

/*
** The rollback journal is composed of a linked list of these structures.
*/

typedef struct FileChunk FileChunk;

/* Space to hold the rollback journal is allocated in increments of
** this many bytes.
**
** The size chosen is a little less than a power of two.  That way,
** the FileChunk object will have a size that almost exactly fills
** a power-of-two allocation.  This minimizes wasted space in power-of-two
** memory allocators.
*/
#define JOURNAL_CHUNKSIZE ((int)(1024-sizeof(FileChunk*)))

/*
** The rollback journal is composed of a linked list of these structures.
*/

/*
** Retrieve a pointer to a static mutex or allocate a new dynamic one.
*/
sqlite3_mutex *sqlite3_mutex_alloc(int id){
#ifndef SQLITE_OMIT_AUTOINIT
  if( id<=SQLITE_MUTEX_RECURSIVE && sqlite3_initialize() ) return 0;

#endif
  return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
}

sqlite3_mutex *sqlite3MutexAlloc(int id){
  if( !sqlite3GlobalConfig.bCoreMutex ){
    return 0;

/*
** Retrieve a pointer to a static mutex or allocate a new dynamic one.
*/
sqlite3_mutex *sqlite3_mutex_alloc(int id){
#ifndef SQLITE_OMIT_AUTOINIT
  if( id<=SQLITE_MUTEX_RECURSIVE && sqlite3_initialize() ) return 0;
  if( id>SQLITE_MUTEX_RECURSIVE && sqlite3MutexInit() ) return 0;
#endif
  return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
}

sqlite3_mutex *sqlite3MutexAlloc(int id){
  if( !sqlite3GlobalConfig.bCoreMutex ){
    return 0;

*/


/*
** Figure out what version of the code to use.  The choices are
**
**   SQLITE_MUTEX_OMIT         No mutex logic.  Not even stubs.  The
**                             mutexes implemention cannot be overridden
**                             at start-time.
**
**   SQLITE_MUTEX_NOOP         For single-threaded applications.  No
**                             mutual exclusion is provided.  But this
**                             implementation can be overridden at
**                             start-time.
**

*/


/*
** Figure out what version of the code to use.  The choices are
**
**   SQLITE_MUTEX_OMIT         No mutex logic.  Not even stubs.  The
**                             mutexes implementation cannot be overridden
**                             at start-time.
**
**   SQLITE_MUTEX_NOOP         For single-threaded applications.  No
**                             mutual exclusion is provided.  But this
**                             implementation can be overridden at
**                             start-time.
**

        p->id = iType;
#endif
        pthread_mutex_init(&p->mutex, 0);
      }
      break;
    }
    default: {
      assert( iType-2 >= 0 );
      assert( iType-2 < ArraySize(staticMutexes) );




      p = &staticMutexes[iType-2];
#if SQLITE_MUTEX_NREF
      p->id = iType;
#endif
      break;
    }
  }

        p->id = iType;
#endif
        pthread_mutex_init(&p->mutex, 0);
      }
      break;
    }
    default: {
#ifdef SQLITE_ENABLE_API_ARMOR
      if( iType-2<0 || iType-2>=ArraySize(staticMutexes) ){
        (void)SQLITE_MISUSE_BKPT;
        return 0;
      }
#endif
      p = &staticMutexes[iType-2];
#if SQLITE_MUTEX_NREF
      p->id = iType;
#endif
      break;
    }
  }

*/
int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
  MUTEX_LOGIC(sqlite3_mutex *mutex;)
#ifndef SQLITE_OMIT_AUTOINIT
  int rc = sqlite3_initialize();
  if( rc ) return rc;
#endif




  MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
  sqlite3_mutex_enter(mutex);
  vfsUnlink(pVfs);
  if( makeDflt || vfsList==0 ){
    pVfs->pNext = vfsList;
    vfsList = pVfs;
  }else{

*/
int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
  MUTEX_LOGIC(sqlite3_mutex *mutex;)
#ifndef SQLITE_OMIT_AUTOINIT
  int rc = sqlite3_initialize();
  if( rc ) return rc;
#endif
#ifdef SQLITE_ENABLE_API_ARMOR
  if( pVfs==0 ) return SQLITE_MISUSE_BKPT;
#endif

  MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
  sqlite3_mutex_enter(mutex);
  vfsUnlink(pVfs);
  if( makeDflt || vfsList==0 ){
    pVfs->pNext = vfsList;
    vfsList = pVfs;
  }else{

**
** The following #defines specify the range of bytes used for locking.
** SHARED_SIZE is the number of bytes available in the pool from which
** a random byte is selected for a shared lock.  The pool of bytes for
** shared locks begins at SHARED_FIRST. 
**
** The same locking strategy and
** byte ranges are used for Unix.  This leaves open the possiblity of having
** clients on win95, winNT, and unix all talking to the same shared file
** and all locking correctly.  To do so would require that samba (or whatever
** tool is being used for file sharing) implements locks correctly between
** windows and unix.  I'm guessing that isn't likely to happen, but by
** using the same locking range we are at least open to the possibility.
**
** Locking in windows is manditory.  For this reason, we cannot store

**
** The following #defines specify the range of bytes used for locking.
** SHARED_SIZE is the number of bytes available in the pool from which
** a random byte is selected for a shared lock.  The pool of bytes for
** shared locks begins at SHARED_FIRST. 
**
** The same locking strategy and
** byte ranges are used for Unix.  This leaves open the possibility of having
** clients on win95, winNT, and unix all talking to the same shared file
** and all locking correctly.  To do so would require that samba (or whatever
** tool is being used for file sharing) implements locks correctly between
** windows and unix.  I'm guessing that isn't likely to happen, but by
** using the same locking range we are at least open to the possibility.
**
** Locking in windows is manditory.  For this reason, we cannot store

# if defined(__linux__) && defined(_GNU_SOURCE)
#  define HAVE_MREMAP 1
# else
#  define HAVE_MREMAP 0
# endif
#endif









/*
** Different Unix systems declare open() in different ways.  Same use
** open(const char*,int,mode_t).  Others use open(const char*,int,...).
** The difference is important when using a pointer to the function.
**
** The safest way to deal with the problem is to always use this wrapper
** which always has the same well-defined interface.
................................................................................
}
#endif


#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
/*
** Helper function for printing out trace information from debugging
** binaries. This returns the string represetation of the supplied
** integer lock-type.
*/
static const char *azFileLock(int eFileLock){
  switch( eFileLock ){
    case NO_LOCK: return "NONE";
    case SHARED_LOCK: return "SHARED";
    case RESERVED_LOCK: return "RESERVED";
................................................................................
}
#undef osFcntl
#define osFcntl lockTrace
#endif /* SQLITE_LOCK_TRACE */

/*
** Retry ftruncate() calls that fail due to EINTR




*/
static int robust_ftruncate(int h, sqlite3_int64 sz){
  int rc;









  do{ rc = osFtruncate(h,sz); }while( rc<0 && errno==EINTR );
  return rc;
}

/*
** This routine translates a standard POSIX errno code into something
** useful to the clients of the sqlite3 functions.  Specifically, it is
................................................................................
/*
** Seek to the offset passed as the second argument, then read cnt 
** bytes into pBuf. Return the number of bytes actually read.
**
** NB:  If you define USE_PREAD or USE_PREAD64, then it might also
** be necessary to define _XOPEN_SOURCE to be 500.  This varies from
** one system to another.  Since SQLite does not define USE_PREAD
** any any form by default, we will not attempt to define _XOPEN_SOURCE.
** See tickets #2741 and #2681.
**
** To avoid stomping the errno value on a failed read the lastErrno value
** is set before returning.
*/
static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
  int got;
................................................................................
  ** actual file size after the operation may be larger than the requested
  ** size).
  */
  if( pFile->szChunk>0 ){
    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
  }

  rc = robust_ftruncate(pFile->h, (off_t)nByte);
  if( rc ){
    pFile->lastErrno = errno;
    return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
  }else{
#ifdef SQLITE_DEBUG
    /* If we are doing a normal write to a database file (as opposed to
    ** doing a hot-journal rollback or a write to some file other than a
................................................................................
  }
#endif

  return SQLITE_OK;
}

/*
** If *pArg is inititially negative then this is a query.  Set *pArg to
** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
**
** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
*/
static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){
  if( *pArg<0 ){
    *pArg = (pFile->ctrlFlags & mask)!=0;
................................................................................
}
#endif /* __QNXNTO__ */

/*
** Return the device characteristics for the file.
**
** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default.
** However, that choice is contraversial since technically the underlying
** file system does not always provide powersafe overwrites.  (In other
** words, after a power-loss event, parts of the file that were never
** written might end up being altered.)  However, non-PSOW behavior is very,
** very rare.  And asserting PSOW makes a large reduction in the amount
** of required I/O for journaling, since a lot of padding is eliminated.
**  Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control
** available to turn it off and URI query parameter available to turn it off.
................................................................................
** the correct finder-function for that VFS.
**
** Most finder functions return a pointer to a fixed sqlite3_io_methods
** object.  The only interesting finder-function is autolockIoFinder, which
** looks at the filesystem type and tries to guess the best locking
** strategy from that.
**
** For finder-funtion F, two objects are created:
**
**    (1) The real finder-function named "FImpt()".
**
**    (2) A constant pointer to this function named just "F".
**
**
** A pointer to the F pointer is used as the pAppData value for VFS
................................................................................
**
**   *  A constant sqlite3_io_methods object call METHOD that has locking
**      methods CLOSE, LOCK, UNLOCK, CKRESLOCK.
**
**   *  An I/O method finder function called FINDER that returns a pointer
**      to the METHOD object in the previous bullet.
*/
#define IOMETHODS(FINDER, METHOD, VERSION, CLOSE, LOCK, UNLOCK, CKLOCK)      \
static const sqlite3_io_methods METHOD = {                                   \
   VERSION,                    /* iVersion */                                \
   CLOSE,                      /* xClose */                                  \
   unixRead,                   /* xRead */                                   \
   unixWrite,                  /* xWrite */                                  \
   unixTruncate,               /* xTruncate */                               \
   unixSync,                   /* xSync */                                   \
................................................................................
   unixFileSize,               /* xFileSize */                               \
   LOCK,                       /* xLock */                                   \
   UNLOCK,                     /* xUnlock */                                 \
   CKLOCK,                     /* xCheckReservedLock */                      \
   unixFileControl,            /* xFileControl */                            \
   unixSectorSize,             /* xSectorSize */                             \
   unixDeviceCharacteristics,  /* xDeviceCapabilities */                     \
   unixShmMap,                 /* xShmMap */                                 \
   unixShmLock,                /* xShmLock */                                \
   unixShmBarrier,             /* xShmBarrier */                             \
   unixShmUnmap,               /* xShmUnmap */                               \
   unixFetch,                  /* xFetch */                                  \
   unixUnfetch,                /* xUnfetch */                                \
};                                                                           \
static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){   \
................................................................................
IOMETHODS(
  posixIoFinder,            /* Finder function name */
  posixIoMethods,           /* sqlite3_io_methods object name */
  3,                        /* shared memory and mmap are enabled */
  unixClose,                /* xClose method */
  unixLock,                 /* xLock method */
  unixUnlock,               /* xUnlock method */
  unixCheckReservedLock     /* xCheckReservedLock method */

)
IOMETHODS(
  nolockIoFinder,           /* Finder function name */
  nolockIoMethods,          /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  nolockClose,              /* xClose method */
  nolockLock,               /* xLock method */
  nolockUnlock,             /* xUnlock method */
  nolockCheckReservedLock   /* xCheckReservedLock method */

)
IOMETHODS(
  dotlockIoFinder,          /* Finder function name */
  dotlockIoMethods,         /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  dotlockClose,             /* xClose method */
  dotlockLock,              /* xLock method */
  dotlockUnlock,            /* xUnlock method */
  dotlockCheckReservedLock  /* xCheckReservedLock method */

)

#if SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORKS
IOMETHODS(
  flockIoFinder,            /* Finder function name */
  flockIoMethods,           /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  flockClose,               /* xClose method */
  flockLock,                /* xLock method */
  flockUnlock,              /* xUnlock method */
  flockCheckReservedLock    /* xCheckReservedLock method */

)
#endif

#if OS_VXWORKS
IOMETHODS(
  semIoFinder,              /* Finder function name */
  semIoMethods,             /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  semClose,                 /* xClose method */
  semLock,                  /* xLock method */
  semUnlock,                /* xUnlock method */
  semCheckReservedLock      /* xCheckReservedLock method */

)
#endif

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  afpIoFinder,              /* Finder function name */
  afpIoMethods,             /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  afpClose,                 /* xClose method */
  afpLock,                  /* xLock method */
  afpUnlock,                /* xUnlock method */
  afpCheckReservedLock      /* xCheckReservedLock method */

)
#endif

/*
** The proxy locking method is a "super-method" in the sense that it
** opens secondary file descriptors for the conch and lock files and
** it uses proxy, dot-file, AFP, and flock() locking methods on those
................................................................................
IOMETHODS(
  proxyIoFinder,            /* Finder function name */
  proxyIoMethods,           /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  proxyClose,               /* xClose method */
  proxyLock,                /* xLock method */
  proxyUnlock,              /* xUnlock method */
  proxyCheckReservedLock    /* xCheckReservedLock method */

)
#endif

/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  nfsIoFinder,               /* Finder function name */
  nfsIoMethods,              /* sqlite3_io_methods object name */
  1,                         /* shared memory is disabled */
  unixClose,                 /* xClose method */
  unixLock,                  /* xLock method */
  nfsUnlock,                 /* xUnlock method */
  unixCheckReservedLock      /* xCheckReservedLock method */

)
#endif

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
/* 
** This "finder" function attempts to determine the best locking strategy 
** for the database file "filePath".  It then returns the sqlite3_io_methods
................................................................................
}
static const sqlite3_io_methods 
  *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;

#endif /* OS_VXWORKS && SQLITE_ENABLE_LOCKING_STYLE */

/*
** An abstract type for a pointer to a IO method finder function:
*/
typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*);


/****************************************************************************
**************************** sqlite3_vfs methods ****************************
**
................................................................................
  /* A stat() call may fail for various reasons. If this happens, it is
  ** almost certain that an open() call on the same path will also fail.
  ** For this reason, if an error occurs in the stat() call here, it is
  ** ignored and -1 is returned. The caller will try to open a new file
  ** descriptor on the same path, fail, and return an error to SQLite.
  **
  ** Even if a subsequent open() call does succeed, the consequences of
  ** not searching for a resusable file descriptor are not dire.  */
  if( 0==osStat(zPath, &sStat) ){
    unixInodeInfo *pInode;

    unixEnterMutex();
    pInode = inodeList;
    while( pInode && (pInode->fileId.dev!=sStat.st_dev
                     || pInode->fileId.ino!=sStat.st_ino) ){
................................................................................
/*
** This function is called by unixOpen() to determine the unix permissions
** to create new files with. If no error occurs, then SQLITE_OK is returned
** and a value suitable for passing as the third argument to open(2) is
** written to *pMode. If an IO error occurs, an SQLite error code is 
** returned and the value of *pMode is not modified.
**
** In most cases cases, this routine sets *pMode to 0, which will become
** an indication to robust_open() to create the file using
** SQLITE_DEFAULT_FILE_PERMISSIONS adjusted by the umask.
** But if the file being opened is a WAL or regular journal file, then 
** this function queries the file-system for the permissions on the 
** corresponding database file and sets *pMode to this value. Whenever 
** possible, WAL and journal files are created using the same permissions 
** as the associated database file.
................................................................................
){
  int rc = SQLITE_OK;
  UNUSED_PARAMETER(NotUsed);
  SimulateIOError(return SQLITE_IOERR_DELETE);
  if( osUnlink(zPath)==(-1) ){
    if( errno==ENOENT
#if OS_VXWORKS
        || errno==0x380003
#endif
    ){
      rc = SQLITE_IOERR_DELETE_NOENT;
    }else{
      rc = unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
    }
    return rc;
................................................................................
**
** The conch file - to use a proxy file, sqlite must first "hold the conch"
** by taking an sqlite-style shared lock on the conch file, reading the
** contents and comparing the host's unique host ID (see below) and lock
** proxy path against the values stored in the conch.  The conch file is
** stored in the same directory as the database file and the file name
** is patterned after the database file name as ".<databasename>-conch".
** If the conch file does not exist, or it's contents do not match the
** host ID and/or proxy path, then the lock is escalated to an exclusive
** lock and the conch file contents is updated with the host ID and proxy
** path and the lock is downgraded to a shared lock again.  If the conch
** is held by another process (with a shared lock), the exclusive lock
** will fail and SQLITE_BUSY is returned.
**
** The proxy file - a single-byte file used for all advisory file locks
................................................................................
**       lock proxy files, only used when LOCKPROXYDIR is not set.
**    
**    
** As mentioned above, when compiled with SQLITE_PREFER_PROXY_LOCKING,
** setting the environment variable SQLITE_FORCE_PROXY_LOCKING to 1 will
** force proxy locking to be used for every database file opened, and 0
** will force automatic proxy locking to be disabled for all database
** files (explicity calling the SQLITE_SET_LOCKPROXYFILE pragma or
** sqlite_file_control API is not affected by SQLITE_FORCE_PROXY_LOCKING).
*/

/*
** Proxy locking is only available on MacOSX 
*/
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE

# if defined(__linux__) && defined(_GNU_SOURCE)
#  define HAVE_MREMAP 1
# else
#  define HAVE_MREMAP 0
# endif
#endif

/*
** Explicitly call the 64-bit version of lseek() on Android. Otherwise, lseek()
** is the 32-bit version, even if _FILE_OFFSET_BITS=64 is defined.
*/
#ifdef __ANDROID__
# define lseek lseek64
#endif

/*
** Different Unix systems declare open() in different ways.  Same use
** open(const char*,int,mode_t).  Others use open(const char*,int,...).
** The difference is important when using a pointer to the function.
**
** The safest way to deal with the problem is to always use this wrapper
** which always has the same well-defined interface.
................................................................................
}
#endif


#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
/*
** Helper function for printing out trace information from debugging
** binaries. This returns the string representation of the supplied
** integer lock-type.
*/
static const char *azFileLock(int eFileLock){
  switch( eFileLock ){
    case NO_LOCK: return "NONE";
    case SHARED_LOCK: return "SHARED";
    case RESERVED_LOCK: return "RESERVED";
................................................................................
}
#undef osFcntl
#define osFcntl lockTrace
#endif /* SQLITE_LOCK_TRACE */

/*
** Retry ftruncate() calls that fail due to EINTR
**
** All calls to ftruncate() within this file should be made through this wrapper.
** On the Android platform, bypassing the logic below could lead to a corrupt
** database.
*/
static int robust_ftruncate(int h, sqlite3_int64 sz){
  int rc;
#ifdef __ANDROID__
  /* On Android, ftruncate() always uses 32-bit offsets, even if 
  ** _FILE_OFFSET_BITS=64 is defined. This means it is unsafe to attempt to
  ** truncate a file to any size larger than 2GiB. Silently ignore any
  ** such attempts.  */
  if( sz>(sqlite3_int64)0x7FFFFFFF ){
    rc = SQLITE_OK;
  }else
#endif
  do{ rc = osFtruncate(h,sz); }while( rc<0 && errno==EINTR );
  return rc;
}

/*
** This routine translates a standard POSIX errno code into something
** useful to the clients of the sqlite3 functions.  Specifically, it is
................................................................................
/*
** Seek to the offset passed as the second argument, then read cnt 
** bytes into pBuf. Return the number of bytes actually read.
**
** NB:  If you define USE_PREAD or USE_PREAD64, then it might also
** be necessary to define _XOPEN_SOURCE to be 500.  This varies from
** one system to another.  Since SQLite does not define USE_PREAD
** in any form by default, we will not attempt to define _XOPEN_SOURCE.
** See tickets #2741 and #2681.
**
** To avoid stomping the errno value on a failed read the lastErrno value
** is set before returning.
*/
static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
  int got;
................................................................................
  ** actual file size after the operation may be larger than the requested
  ** size).
  */
  if( pFile->szChunk>0 ){
    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
  }

  rc = robust_ftruncate(pFile->h, nByte);
  if( rc ){
    pFile->lastErrno = errno;
    return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
  }else{
#ifdef SQLITE_DEBUG
    /* If we are doing a normal write to a database file (as opposed to
    ** doing a hot-journal rollback or a write to some file other than a
................................................................................
  }
#endif

  return SQLITE_OK;
}

/*
** If *pArg is initially negative then this is a query.  Set *pArg to
** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
**
** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
*/
static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){
  if( *pArg<0 ){
    *pArg = (pFile->ctrlFlags & mask)!=0;
................................................................................
}
#endif /* __QNXNTO__ */

/*
** Return the device characteristics for the file.
**
** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default.
** However, that choice is controversial since technically the underlying
** file system does not always provide powersafe overwrites.  (In other
** words, after a power-loss event, parts of the file that were never
** written might end up being altered.)  However, non-PSOW behavior is very,
** very rare.  And asserting PSOW makes a large reduction in the amount
** of required I/O for journaling, since a lot of padding is eliminated.
**  Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control
** available to turn it off and URI query parameter available to turn it off.
................................................................................
** the correct finder-function for that VFS.
**
** Most finder functions return a pointer to a fixed sqlite3_io_methods
** object.  The only interesting finder-function is autolockIoFinder, which
** looks at the filesystem type and tries to guess the best locking
** strategy from that.
**
** For finder-function F, two objects are created:
**
**    (1) The real finder-function named "FImpt()".
**
**    (2) A constant pointer to this function named just "F".
**
**
** A pointer to the F pointer is used as the pAppData value for VFS
................................................................................
**
**   *  A constant sqlite3_io_methods object call METHOD that has locking
**      methods CLOSE, LOCK, UNLOCK, CKRESLOCK.
**
**   *  An I/O method finder function called FINDER that returns a pointer
**      to the METHOD object in the previous bullet.
*/
#define IOMETHODS(FINDER, METHOD, VERSION, CLOSE, LOCK, UNLOCK, CKLOCK, SHMMAP) \
static const sqlite3_io_methods METHOD = {                                   \
   VERSION,                    /* iVersion */                                \
   CLOSE,                      /* xClose */                                  \
   unixRead,                   /* xRead */                                   \
   unixWrite,                  /* xWrite */                                  \
   unixTruncate,               /* xTruncate */                               \
   unixSync,                   /* xSync */                                   \
................................................................................
   unixFileSize,               /* xFileSize */                               \
   LOCK,                       /* xLock */                                   \
   UNLOCK,                     /* xUnlock */                                 \
   CKLOCK,                     /* xCheckReservedLock */                      \
   unixFileControl,            /* xFileControl */                            \
   unixSectorSize,             /* xSectorSize */                             \
   unixDeviceCharacteristics,  /* xDeviceCapabilities */                     \
   SHMMAP,                     /* xShmMap */                                 \
   unixShmLock,                /* xShmLock */                                \
   unixShmBarrier,             /* xShmBarrier */                             \
   unixShmUnmap,               /* xShmUnmap */                               \
   unixFetch,                  /* xFetch */                                  \
   unixUnfetch,                /* xUnfetch */                                \
};                                                                           \
static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){   \
................................................................................
IOMETHODS(
  posixIoFinder,            /* Finder function name */
  posixIoMethods,           /* sqlite3_io_methods object name */
  3,                        /* shared memory and mmap are enabled */
  unixClose,                /* xClose method */
  unixLock,                 /* xLock method */
  unixUnlock,               /* xUnlock method */
  unixCheckReservedLock,    /* xCheckReservedLock method */
  unixShmMap                /* xShmMap method */
)
IOMETHODS(
  nolockIoFinder,           /* Finder function name */
  nolockIoMethods,          /* sqlite3_io_methods object name */
  3,                        /* shared memory is disabled */
  nolockClose,              /* xClose method */
  nolockLock,               /* xLock method */
  nolockUnlock,             /* xUnlock method */
  nolockCheckReservedLock,  /* xCheckReservedLock method */
  0                         /* xShmMap method */
)
IOMETHODS(
  dotlockIoFinder,          /* Finder function name */
  dotlockIoMethods,         /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  dotlockClose,             /* xClose method */
  dotlockLock,              /* xLock method */
  dotlockUnlock,            /* xUnlock method */
  dotlockCheckReservedLock, /* xCheckReservedLock method */
  0                         /* xShmMap method */
)

#if SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORKS
IOMETHODS(
  flockIoFinder,            /* Finder function name */
  flockIoMethods,           /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  flockClose,               /* xClose method */
  flockLock,                /* xLock method */
  flockUnlock,              /* xUnlock method */
  flockCheckReservedLock,   /* xCheckReservedLock method */
  0                         /* xShmMap method */
)
#endif

#if OS_VXWORKS
IOMETHODS(
  semIoFinder,              /* Finder function name */
  semIoMethods,             /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  semClose,                 /* xClose method */
  semLock,                  /* xLock method */
  semUnlock,                /* xUnlock method */
  semCheckReservedLock,     /* xCheckReservedLock method */
  0                         /* xShmMap method */
)
#endif

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  afpIoFinder,              /* Finder function name */
  afpIoMethods,             /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  afpClose,                 /* xClose method */
  afpLock,                  /* xLock method */
  afpUnlock,                /* xUnlock method */
  afpCheckReservedLock,     /* xCheckReservedLock method */
  0                         /* xShmMap method */
)
#endif

/*
** The proxy locking method is a "super-method" in the sense that it
** opens secondary file descriptors for the conch and lock files and
** it uses proxy, dot-file, AFP, and flock() locking methods on those
................................................................................
IOMETHODS(
  proxyIoFinder,            /* Finder function name */
  proxyIoMethods,           /* sqlite3_io_methods object name */
  1,                        /* shared memory is disabled */
  proxyClose,               /* xClose method */
  proxyLock,                /* xLock method */
  proxyUnlock,              /* xUnlock method */
  proxyCheckReservedLock,   /* xCheckReservedLock method */
  0                         /* xShmMap method */
)
#endif

/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  nfsIoFinder,               /* Finder function name */
  nfsIoMethods,              /* sqlite3_io_methods object name */
  1,                         /* shared memory is disabled */
  unixClose,                 /* xClose method */
  unixLock,                  /* xLock method */
  nfsUnlock,                 /* xUnlock method */
  unixCheckReservedLock,     /* xCheckReservedLock method */
  0                          /* xShmMap method */
)
#endif

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
/* 
** This "finder" function attempts to determine the best locking strategy 
** for the database file "filePath".  It then returns the sqlite3_io_methods
................................................................................
}
static const sqlite3_io_methods 
  *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;

#endif /* OS_VXWORKS && SQLITE_ENABLE_LOCKING_STYLE */

/*
** An abstract type for a pointer to an IO method finder function:
*/
typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*);


/****************************************************************************
**************************** sqlite3_vfs methods ****************************
**
................................................................................
  /* A stat() call may fail for various reasons. If this happens, it is
  ** almost certain that an open() call on the same path will also fail.
  ** For this reason, if an error occurs in the stat() call here, it is
  ** ignored and -1 is returned. The caller will try to open a new file
  ** descriptor on the same path, fail, and return an error to SQLite.
  **
  ** Even if a subsequent open() call does succeed, the consequences of
  ** not searching for a reusable file descriptor are not dire.  */
  if( 0==osStat(zPath, &sStat) ){
    unixInodeInfo *pInode;

    unixEnterMutex();
    pInode = inodeList;
    while( pInode && (pInode->fileId.dev!=sStat.st_dev
                     || pInode->fileId.ino!=sStat.st_ino) ){
................................................................................
/*
** This function is called by unixOpen() to determine the unix permissions
** to create new files with. If no error occurs, then SQLITE_OK is returned
** and a value suitable for passing as the third argument to open(2) is
** written to *pMode. If an IO error occurs, an SQLite error code is 
** returned and the value of *pMode is not modified.
**
** In most cases, this routine sets *pMode to 0, which will become
** an indication to robust_open() to create the file using
** SQLITE_DEFAULT_FILE_PERMISSIONS adjusted by the umask.
** But if the file being opened is a WAL or regular journal file, then 
** this function queries the file-system for the permissions on the 
** corresponding database file and sets *pMode to this value. Whenever 
** possible, WAL and journal files are created using the same permissions 
** as the associated database file.
................................................................................
){
  int rc = SQLITE_OK;
  UNUSED_PARAMETER(NotUsed);
  SimulateIOError(return SQLITE_IOERR_DELETE);
  if( osUnlink(zPath)==(-1) ){
    if( errno==ENOENT
#if OS_VXWORKS
        || osAccess(zPath,0)!=0
#endif
    ){
      rc = SQLITE_IOERR_DELETE_NOENT;
    }else{
      rc = unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
    }
    return rc;
................................................................................
**
** The conch file - to use a proxy file, sqlite must first "hold the conch"
** by taking an sqlite-style shared lock on the conch file, reading the
** contents and comparing the host's unique host ID (see below) and lock
** proxy path against the values stored in the conch.  The conch file is
** stored in the same directory as the database file and the file name
** is patterned after the database file name as ".<databasename>-conch".
** If the conch file does not exist, or its contents do not match the
** host ID and/or proxy path, then the lock is escalated to an exclusive
** lock and the conch file contents is updated with the host ID and proxy
** path and the lock is downgraded to a shared lock again.  If the conch
** is held by another process (with a shared lock), the exclusive lock
** will fail and SQLITE_BUSY is returned.
**
** The proxy file - a single-byte file used for all advisory file locks
................................................................................
**       lock proxy files, only used when LOCKPROXYDIR is not set.
**    
**    
** As mentioned above, when compiled with SQLITE_PREFER_PROXY_LOCKING,
** setting the environment variable SQLITE_FORCE_PROXY_LOCKING to 1 will
** force proxy locking to be used for every database file opened, and 0
** will force automatic proxy locking to be disabled for all database
** files (explicitly calling the SQLITE_SET_LOCKPROXYFILE pragma or
** sqlite_file_control API is not affected by SQLITE_FORCE_PROXY_LOCKING).
*/

/*
** Proxy locking is only available on MacOSX 
*/
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE

** available in Windows platforms based on the NT kernel.
*/
#if !SQLITE_OS_WINNT && !defined(SQLITE_OMIT_WAL)
#  error "WAL mode requires support from the Windows NT kernel, compile\
 with SQLITE_OMIT_WAL."
#endif






/*
** Are most of the Win32 ANSI APIs available (i.e. with certain exceptions
** based on the sub-platform)?
*/
#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(SQLITE_WIN32_NO_ANSI)
#  define SQLITE_WIN32_HAS_ANSI
#endif
................................................................................
*/
#ifndef winGetDirSep
#  define winGetDirSep()                '\\'
#endif

/*
** Do we need to manually define the Win32 file mapping APIs for use with WAL
** mode (e.g. these APIs are available in the Windows CE SDK; however, they
** are not present in the header file)?
*/
#if SQLITE_WIN32_FILEMAPPING_API && !defined(SQLITE_OMIT_WAL)

/*
** Two of the file mapping APIs are different under WinRT.  Figure out which
** set we need.
*/
#if SQLITE_OS_WINRT
WINBASEAPI HANDLE WINAPI CreateFileMappingFromApp(HANDLE, \
        LPSECURITY_ATTRIBUTES, ULONG, ULONG64, LPCWSTR);
................................................................................
WINBASEAPI LPVOID WINAPI MapViewOfFile(HANDLE, DWORD, DWORD, DWORD, SIZE_T);
#endif /* SQLITE_OS_WINRT */

/*
** This file mapping API is common to both Win32 and WinRT.
*/
WINBASEAPI BOOL WINAPI UnmapViewOfFile(LPCVOID);
#endif /* SQLITE_WIN32_FILEMAPPING_API && !defined(SQLITE_OMIT_WAL) */

/*
** Some Microsoft compilers lack this definition.
*/
#ifndef INVALID_FILE_ATTRIBUTES
# define INVALID_FILE_ATTRIBUTES ((DWORD)-1)
#endif
................................................................................
  { "CreateFileW",             (SYSCALL)0,                       0 },
#endif

#define osCreateFileW ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD, \
        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[5].pCurrent)

#if (!SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_ANSI) && \
        !defined(SQLITE_OMIT_WAL))
  { "CreateFileMappingA",      (SYSCALL)CreateFileMappingA,      0 },
#else
  { "CreateFileMappingA",      (SYSCALL)0,                       0 },
#endif

#define osCreateFileMappingA ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCSTR))aSyscall[6].pCurrent)

#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
        !defined(SQLITE_OMIT_WAL))
  { "CreateFileMappingW",      (SYSCALL)CreateFileMappingW,      0 },
#else
  { "CreateFileMappingW",      (SYSCALL)0,                       0 },
#endif

#define osCreateFileMappingW ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCWSTR))aSyscall[7].pCurrent)
................................................................................
#endif

#ifndef osLockFileEx
#define osLockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[48].pCurrent)
#endif

#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && !defined(SQLITE_OMIT_WAL))

  { "MapViewOfFile",           (SYSCALL)MapViewOfFile,           0 },
#else
  { "MapViewOfFile",           (SYSCALL)0,                       0 },
#endif

#define osMapViewOfFile ((LPVOID(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        SIZE_T))aSyscall[49].pCurrent)
................................................................................
#else
  { "UnlockFileEx",            (SYSCALL)0,                       0 },
#endif

#define osUnlockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[58].pCurrent)

#if SQLITE_OS_WINCE || !defined(SQLITE_OMIT_WAL)
  { "UnmapViewOfFile",         (SYSCALL)UnmapViewOfFile,         0 },
#else
  { "UnmapViewOfFile",         (SYSCALL)0,                       0 },
#endif

#define osUnmapViewOfFile ((BOOL(WINAPI*)(LPCVOID))aSyscall[59].pCurrent)

................................................................................
#else
  { "WaitForSingleObject",     (SYSCALL)0,                       0 },
#endif

#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
        DWORD))aSyscall[63].pCurrent)

#if SQLITE_OS_WINRT
  { "WaitForSingleObjectEx",   (SYSCALL)WaitForSingleObjectEx,   0 },
#else
  { "WaitForSingleObjectEx",   (SYSCALL)0,                       0 },
#endif

#define osWaitForSingleObjectEx ((DWORD(WINAPI*)(HANDLE,DWORD, \
        BOOL))aSyscall[64].pCurrent)
................................................................................
#else
  { "GetFileInformationByHandleEx", (SYSCALL)0,                  0 },
#endif

#define osGetFileInformationByHandleEx ((BOOL(WINAPI*)(HANDLE, \
        FILE_INFO_BY_HANDLE_CLASS,LPVOID,DWORD))aSyscall[66].pCurrent)

#if SQLITE_OS_WINRT && !defined(SQLITE_OMIT_WAL)
  { "MapViewOfFileFromApp",    (SYSCALL)MapViewOfFileFromApp,    0 },
#else
  { "MapViewOfFileFromApp",    (SYSCALL)0,                       0 },
#endif

#define osMapViewOfFileFromApp ((LPVOID(WINAPI*)(HANDLE,ULONG,ULONG64, \
        SIZE_T))aSyscall[67].pCurrent)
................................................................................

#define osOutputDebugStringW ((VOID(WINAPI*)(LPCWSTR))aSyscall[73].pCurrent)

  { "GetProcessHeap",          (SYSCALL)GetProcessHeap,          0 },

#define osGetProcessHeap ((HANDLE(WINAPI*)(VOID))aSyscall[74].pCurrent)

#if SQLITE_OS_WINRT && !defined(SQLITE_OMIT_WAL)
  { "CreateFileMappingFromApp", (SYSCALL)CreateFileMappingFromApp, 0 },
#else
  { "CreateFileMappingFromApp", (SYSCALL)0,                      0 },
#endif

#define osCreateFileMappingFromApp ((HANDLE(WINAPI*)(HANDLE, \
        LPSECURITY_ATTRIBUTES,ULONG,ULONG64,LPCWSTR))aSyscall[75].pCurrent)
................................................................................
** the sqlite3_memory_used() function does not return zero, SQLITE_BUSY will
** be returned and no changes will be made to the Win32 native heap.
*/
int sqlite3_win32_reset_heap(){
  int rc;
  MUTEX_LOGIC( sqlite3_mutex *pMaster; ) /* The main static mutex */
  MUTEX_LOGIC( sqlite3_mutex *pMem; )    /* The memsys static mutex */
  MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
  MUTEX_LOGIC( pMem = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM); )
  sqlite3_mutex_enter(pMaster);
  sqlite3_mutex_enter(pMem);
  winMemAssertMagic();
  if( winMemGetHeap()!=NULL && winMemGetOwned() && sqlite3_memory_used()==0 ){
    /*
    ** At this point, there should be no outstanding memory allocations on
    ** the heap.  Also, since both the master and memsys locks are currently
................................................................................
  assert( sleepObj!=NULL );
  osWaitForSingleObjectEx(sleepObj, milliseconds, FALSE);
#else
  osSleep(milliseconds);
#endif
}











/*
** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
**
** Here is an interesting observation:  Win95, Win98, and WinME lack
** the LockFileEx() API.  But we can still statically link against that
** API as long as we don't call it when running Win95/98/ME.  A call to
................................................................................
#endif

/*
** This function determines if the machine is running a version of Windows
** based on the NT kernel.
*/
int sqlite3_win32_is_nt(void){






#if defined(SQLITE_WIN32_GETVERSIONEX) && SQLITE_WIN32_GETVERSIONEX
  if( osInterlockedCompareExchange(&sqlite3_os_type, 0, 0)==0 ){
#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
        defined(NTDDI_VERSION) && NTDDI_VERSION >= NTDDI_WIN8
    OSVERSIONINFOW sInfo;
    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
    osGetVersionExW(&sInfo);
    osInterlockedCompareExchange(&sqlite3_os_type,
        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
#elif defined(SQLITE_WIN32_HAS_ANSI)
    OSVERSIONINFOA sInfo;
    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
    osGetVersionExA(&sInfo);






    osInterlockedCompareExchange(&sqlite3_os_type,
        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
#endif
  }
  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
#elif SQLITE_TEST
  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
#else




  return 1;
#endif
}

#ifdef SQLITE_WIN32_MALLOC
/*
** Allocate nBytes of memory.
................................................................................
  pFile->locktype = (u8)locktype;
  OSTRACE(("UNLOCK file=%p, lock=%d, rc=%s\n",
           pFile->h, pFile->locktype, sqlite3ErrName(rc)));
  return rc;
}

/*
** If *pArg is inititially negative then this is a query.  Set *pArg to
** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
**
** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
*/
static void winModeBit(winFile *pFile, unsigned char mask, int *pArg){
  if( *pArg<0 ){
    *pArg = (pFile->ctrlFlags & mask)!=0;
................................................................................
           osGetCurrentProcessId(), pFd, iOff, p));

  if( p ){
    pFd->nFetchOut--;
  }else{
    /* FIXME:  If Windows truly always prevents truncating or deleting a
    ** file while a mapping is held, then the following winUnmapfile() call
    ** is unnecessary can can be omitted - potentially improving
    ** performance.  */
    winUnmapfile(pFd);
  }

  assert( pFd->nFetchOut>=0 );
#endif

** available in Windows platforms based on the NT kernel.
*/
#if !SQLITE_OS_WINNT && !defined(SQLITE_OMIT_WAL)
#  error "WAL mode requires support from the Windows NT kernel, compile\
 with SQLITE_OMIT_WAL."
#endif

#if !SQLITE_OS_WINNT && SQLITE_MAX_MMAP_SIZE>0
#  error "Memory mapped files require support from the Windows NT kernel,\
 compile with SQLITE_MAX_MMAP_SIZE=0."
#endif

/*
** Are most of the Win32 ANSI APIs available (i.e. with certain exceptions
** based on the sub-platform)?
*/
#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(SQLITE_WIN32_NO_ANSI)
#  define SQLITE_WIN32_HAS_ANSI
#endif
................................................................................
*/
#ifndef winGetDirSep
#  define winGetDirSep()                '\\'
#endif

/*
** Do we need to manually define the Win32 file mapping APIs for use with WAL
** mode or memory mapped files (e.g. these APIs are available in the Windows
** CE SDK; however, they are not present in the header file)?
*/
#if SQLITE_WIN32_FILEMAPPING_API && \
        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
/*
** Two of the file mapping APIs are different under WinRT.  Figure out which
** set we need.
*/
#if SQLITE_OS_WINRT
WINBASEAPI HANDLE WINAPI CreateFileMappingFromApp(HANDLE, \
        LPSECURITY_ATTRIBUTES, ULONG, ULONG64, LPCWSTR);
................................................................................
WINBASEAPI LPVOID WINAPI MapViewOfFile(HANDLE, DWORD, DWORD, DWORD, SIZE_T);
#endif /* SQLITE_OS_WINRT */

/*
** This file mapping API is common to both Win32 and WinRT.
*/
WINBASEAPI BOOL WINAPI UnmapViewOfFile(LPCVOID);
#endif /* SQLITE_WIN32_FILEMAPPING_API */

/*
** Some Microsoft compilers lack this definition.
*/
#ifndef INVALID_FILE_ATTRIBUTES
# define INVALID_FILE_ATTRIBUTES ((DWORD)-1)
#endif
................................................................................
  { "CreateFileW",             (SYSCALL)0,                       0 },
#endif

#define osCreateFileW ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD, \
        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[5].pCurrent)

#if (!SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_ANSI) && \
        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0))
  { "CreateFileMappingA",      (SYSCALL)CreateFileMappingA,      0 },
#else
  { "CreateFileMappingA",      (SYSCALL)0,                       0 },
#endif

#define osCreateFileMappingA ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCSTR))aSyscall[6].pCurrent)

#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0))
  { "CreateFileMappingW",      (SYSCALL)CreateFileMappingW,      0 },
#else
  { "CreateFileMappingW",      (SYSCALL)0,                       0 },
#endif

#define osCreateFileMappingW ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCWSTR))aSyscall[7].pCurrent)
................................................................................
#endif

#ifndef osLockFileEx
#define osLockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[48].pCurrent)
#endif

#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && \
        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0))
  { "MapViewOfFile",           (SYSCALL)MapViewOfFile,           0 },
#else
  { "MapViewOfFile",           (SYSCALL)0,                       0 },
#endif

#define osMapViewOfFile ((LPVOID(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        SIZE_T))aSyscall[49].pCurrent)
................................................................................
#else
  { "UnlockFileEx",            (SYSCALL)0,                       0 },
#endif

#define osUnlockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[58].pCurrent)

#if SQLITE_OS_WINCE || !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
  { "UnmapViewOfFile",         (SYSCALL)UnmapViewOfFile,         0 },
#else
  { "UnmapViewOfFile",         (SYSCALL)0,                       0 },
#endif

#define osUnmapViewOfFile ((BOOL(WINAPI*)(LPCVOID))aSyscall[59].pCurrent)

................................................................................
#else
  { "WaitForSingleObject",     (SYSCALL)0,                       0 },
#endif

#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
        DWORD))aSyscall[63].pCurrent)

#if !SQLITE_OS_WINCE
  { "WaitForSingleObjectEx",   (SYSCALL)WaitForSingleObjectEx,   0 },
#else
  { "WaitForSingleObjectEx",   (SYSCALL)0,                       0 },
#endif

#define osWaitForSingleObjectEx ((DWORD(WINAPI*)(HANDLE,DWORD, \
        BOOL))aSyscall[64].pCurrent)
................................................................................
#else
  { "GetFileInformationByHandleEx", (SYSCALL)0,                  0 },
#endif

#define osGetFileInformationByHandleEx ((BOOL(WINAPI*)(HANDLE, \
        FILE_INFO_BY_HANDLE_CLASS,LPVOID,DWORD))aSyscall[66].pCurrent)

#if SQLITE_OS_WINRT && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
  { "MapViewOfFileFromApp",    (SYSCALL)MapViewOfFileFromApp,    0 },
#else
  { "MapViewOfFileFromApp",    (SYSCALL)0,                       0 },
#endif

#define osMapViewOfFileFromApp ((LPVOID(WINAPI*)(HANDLE,ULONG,ULONG64, \
        SIZE_T))aSyscall[67].pCurrent)
................................................................................

#define osOutputDebugStringW ((VOID(WINAPI*)(LPCWSTR))aSyscall[73].pCurrent)

  { "GetProcessHeap",          (SYSCALL)GetProcessHeap,          0 },

#define osGetProcessHeap ((HANDLE(WINAPI*)(VOID))aSyscall[74].pCurrent)

#if SQLITE_OS_WINRT && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
  { "CreateFileMappingFromApp", (SYSCALL)CreateFileMappingFromApp, 0 },
#else
  { "CreateFileMappingFromApp", (SYSCALL)0,                      0 },
#endif

#define osCreateFileMappingFromApp ((HANDLE(WINAPI*)(HANDLE, \
        LPSECURITY_ATTRIBUTES,ULONG,ULONG64,LPCWSTR))aSyscall[75].pCurrent)
................................................................................
** the sqlite3_memory_used() function does not return zero, SQLITE_BUSY will
** be returned and no changes will be made to the Win32 native heap.
*/
int sqlite3_win32_reset_heap(){
  int rc;
  MUTEX_LOGIC( sqlite3_mutex *pMaster; ) /* The main static mutex */
  MUTEX_LOGIC( sqlite3_mutex *pMem; )    /* The memsys static mutex */
  MUTEX_LOGIC( pMaster = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER); )
  MUTEX_LOGIC( pMem = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM); )
  sqlite3_mutex_enter(pMaster);
  sqlite3_mutex_enter(pMem);
  winMemAssertMagic();
  if( winMemGetHeap()!=NULL && winMemGetOwned() && sqlite3_memory_used()==0 ){
    /*
    ** At this point, there should be no outstanding memory allocations on
    ** the heap.  Also, since both the master and memsys locks are currently
................................................................................
  assert( sleepObj!=NULL );
  osWaitForSingleObjectEx(sleepObj, milliseconds, FALSE);
#else
  osSleep(milliseconds);
#endif
}

#if SQLITE_MAX_WORKER_THREADS>0 && !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && \
        SQLITE_THREADSAFE>0
DWORD sqlite3Win32Wait(HANDLE hObject){
  DWORD rc;
  while( (rc = osWaitForSingleObjectEx(hObject, INFINITE,
                                       TRUE))==WAIT_IO_COMPLETION ){}
  return rc;
}
#endif

/*
** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
**
** Here is an interesting observation:  Win95, Win98, and WinME lack
** the LockFileEx() API.  But we can still statically link against that
** API as long as we don't call it when running Win95/98/ME.  A call to
................................................................................
#endif

/*
** This function determines if the machine is running a version of Windows
** based on the NT kernel.
*/
int sqlite3_win32_is_nt(void){
#if SQLITE_OS_WINRT
  /*
  ** NOTE: The WinRT sub-platform is always assumed to be based on the NT
  **       kernel.
  */
  return 1;
#elif defined(SQLITE_WIN32_GETVERSIONEX) && SQLITE_WIN32_GETVERSIONEX
  if( osInterlockedCompareExchange(&sqlite3_os_type, 0, 0)==0 ){







#if defined(SQLITE_WIN32_HAS_ANSI)
    OSVERSIONINFOA sInfo;
    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
    osGetVersionExA(&sInfo);
    osInterlockedCompareExchange(&sqlite3_os_type,
        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
#elif defined(SQLITE_WIN32_HAS_WIDE)
    OSVERSIONINFOW sInfo;
    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
    osGetVersionExW(&sInfo);
    osInterlockedCompareExchange(&sqlite3_os_type,
        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
#endif
  }
  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
#elif SQLITE_TEST
  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
#else
  /*
  ** NOTE: All sub-platforms where the GetVersionEx[AW] functions are
  **       deprecated are always assumed to be based on the NT kernel.
  */
  return 1;
#endif
}

#ifdef SQLITE_WIN32_MALLOC
/*
** Allocate nBytes of memory.
................................................................................
  pFile->locktype = (u8)locktype;
  OSTRACE(("UNLOCK file=%p, lock=%d, rc=%s\n",
           pFile->h, pFile->locktype, sqlite3ErrName(rc)));
  return rc;
}

/*
** If *pArg is initially negative then this is a query.  Set *pArg to
** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
**
** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
*/
static void winModeBit(winFile *pFile, unsigned char mask, int *pArg){
  if( *pArg<0 ){
    *pArg = (pFile->ctrlFlags & mask)!=0;
................................................................................
           osGetCurrentProcessId(), pFd, iOff, p));

  if( p ){
    pFd->nFetchOut--;
  }else{
    /* FIXME:  If Windows truly always prevents truncating or deleting a
    ** file while a mapping is held, then the following winUnmapfile() call
    ** is unnecessary can be omitted - potentially improving
    ** performance.  */
    winUnmapfile(pFd);
  }

  assert( pFd->nFetchOut>=0 );
#endif

** 
** (6) If a master journal file is used, then all writes to the database file
**     are synced prior to the master journal being deleted.
** 
** Definition: Two databases (or the same database at two points it time)
** are said to be "logically equivalent" if they give the same answer to
** all queries.  Note in particular the content of freelist leaf
** pages can be changed arbitarily without effecting the logical equivalence
** of the database.
** 
** (7) At any time, if any subset, including the empty set and the total set,
**     of the unsynced changes to a rollback journal are removed and the 
**     journal is rolled back, the resulting database file will be logical
**     equivalent to the database file at the beginning of the transaction.
** 
** (8) When a transaction is rolled back, the xTruncate method of the VFS
**     is called to restore the database file to the same size it was at
**     the beginning of the transaction.  (In some VFSes, the xTruncate
**     method is a no-op, but that does not change the fact the SQLite will
**     invoke it.)
................................................................................
**
** This is usually safe. If an xUnlock fails or appears to fail, there may 
** be a few redundant xLock() calls or a lock may be held for longer than
** required, but nothing really goes wrong.
**
** The exception is when the database file is unlocked as the pager moves
** from ERROR to OPEN state. At this point there may be a hot-journal file 
** in the file-system that needs to be rolled back (as part of a OPEN->SHARED
** transition, by the same pager or any other). If the call to xUnlock()
** fails at this point and the pager is left holding an EXCLUSIVE lock, this
** can confuse the call to xCheckReservedLock() call made later as part
** of hot-journal detection.
**
** xCheckReservedLock() is defined as returning true "if there is a RESERVED 
** lock held by this process or any others". So xCheckReservedLock may 
................................................................................
** Bits of the Pager.doNotSpill flag.  See further description below.
*/
#define SPILLFLAG_OFF         0x01      /* Never spill cache.  Set via pragma */
#define SPILLFLAG_ROLLBACK    0x02      /* Current rolling back, so do not spill */
#define SPILLFLAG_NOSYNC      0x04      /* Spill is ok, but do not sync */

/*
** A open page cache is an instance of struct Pager. A description of
** some of the more important member variables follows:
**
** eState
**
**   The current 'state' of the pager object. See the comment and state
**   diagram above for a description of the pager state.
**
................................................................................
  u8 tempFile;                /* zFilename is a temporary or immutable file */
  u8 noLock;                  /* Do not lock (except in WAL mode) */
  u8 readOnly;                /* True for a read-only database */
  u8 memDb;                   /* True to inhibit all file I/O */

  /**************************************************************************
  ** The following block contains those class members that change during
  ** routine opertion.  Class members not in this block are either fixed
  ** when the pager is first created or else only change when there is a
  ** significant mode change (such as changing the page_size, locking_mode,
  ** or the journal_mode).  From another view, these class members describe
  ** the "state" of the pager, while other class members describe the
  ** "configuration" of the pager.
  */
  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
................................................................................
      assert( pPager->journalMode==PAGER_JOURNALMODE_MEMORY );
      sqlite3OsClose(pPager->jfd);
    }else if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE ){
      if( pPager->journalOff==0 ){
        rc = SQLITE_OK;
      }else{
        rc = sqlite3OsTruncate(pPager->jfd, 0);








      }
      pPager->journalOff = 0;
    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
      || (pPager->exclusiveMode && pPager->journalMode!=PAGER_JOURNALMODE_WAL)
    ){
      rc = zeroJournalHdr(pPager, hasMaster);
      pPager->journalOff = 0;
................................................................................
  ** sqlite3_malloc() and pointed to by zMasterJournal.   Also obtain
  ** sufficient space (in zMasterPtr) to hold the names of master
  ** journal files extracted from regular rollback-journals.
  */
  rc = sqlite3OsFileSize(pMaster, &nMasterJournal);
  if( rc!=SQLITE_OK ) goto delmaster_out;
  nMasterPtr = pVfs->mxPathname+1;
  zMasterJournal = sqlite3Malloc((int)nMasterJournal + nMasterPtr + 1);
  if( !zMasterJournal ){
    rc = SQLITE_NOMEM;
    goto delmaster_out;
  }
  zMasterPtr = &zMasterJournal[nMasterJournal+1];
  rc = sqlite3OsRead(pMaster, zMasterJournal, (int)nMasterJournal, 0);
  if( rc!=SQLITE_OK ) goto delmaster_out;
................................................................................
**
** If the main database file is not open, or the pager is not in either
** DBMOD or OPEN state, this function is a no-op. Otherwise, the size 
** of the file is changed to nPage pages (nPage*pPager->pageSize bytes). 
** If the file on disk is currently larger than nPage pages, then use the VFS
** xTruncate() method to truncate it.
**
** Or, it might might be the case that the file on disk is smaller than 
** nPage pages. Some operating system implementations can get confused if 
** you try to truncate a file to some size that is larger than it 
** currently is, so detect this case and write a single zero byte to 
** the end of the new file instead.
**
** If successful, return SQLITE_OK. If an IO error occurs while modifying
** the database file, return the error code to the caller.
................................................................................
  }
  return iRet;
}

/*
** Set the value of the Pager.sectorSize variable for the given
** pager based on the value returned by the xSectorSize method
** of the open database file. The sector size will be used used 
** to determine the size and alignment of journal header and 
** master journal pointers within created journal files.
**
** For temporary files the effective sector size is always 512 bytes.
**
** Otherwise, for non-temporary files, the effective sector size is
** the value returned by the xSectorSize() method rounded up to 32 if
................................................................................
      ** of bytes 24..39 of the database.  Bytes 28..31 should always be
      ** zero or the size of the database in page. Bytes 32..35 and 35..39
      ** should be page numbers which are never 0xffffffff.  So filling
      ** pPager->dbFileVers[] with all 0xff bytes should suffice.
      **
      ** For an encrypted database, the situation is more complex:  bytes
      ** 24..39 of the database are white noise.  But the probability of
      ** white noising equaling 16 bytes of 0xff is vanishingly small so
      ** we should still be ok.
      */
      memset(pPager->dbFileVers, 0xff, sizeof(pPager->dbFileVers));
    }else{
      u8 *dbFileVers = &((u8*)pPg->pData)[24];
      memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
    }
................................................................................
    if( rc==SQLITE_OK ){
      pNew = (char *)sqlite3PageMalloc(pageSize);
      if( !pNew ) rc = SQLITE_NOMEM;
    }

    if( rc==SQLITE_OK ){
      pager_reset(pPager);





      pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize);
      pPager->pageSize = pageSize;

      sqlite3PageFree(pPager->pTmpSpace);
      pPager->pTmpSpace = pNew;
      rc = sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
    }
  }

  *pPageSize = pPager->pageSize;
  if( rc==SQLITE_OK ){
    if( nReserve<0 ) nReserve = pPager->nReserve;
    assert( nReserve>=0 && nReserve<1000 );
................................................................................
** the lock. If the lock is obtained successfully, set the Pager.state 
** variable to locktype before returning.
*/
static int pager_wait_on_lock(Pager *pPager, int locktype){
  int rc;                              /* Return code */

  /* Check that this is either a no-op (because the requested lock is 
  ** already held, or one of the transistions that the busy-handler
  ** may be invoked during, according to the comment above
  ** sqlite3PagerSetBusyhandler().
  */
  assert( (pPager->eLock>=locktype)
       || (pPager->eLock==NO_LOCK && locktype==SHARED_LOCK)
       || (pPager->eLock==RESERVED_LOCK && locktype==EXCLUSIVE_LOCK)
  );
................................................................................
  ** pages belonging to the same sector.
  **
  ** The doNotSpill ROLLBACK and OFF bits inhibits all cache spilling
  ** regardless of whether or not a sync is required.  This is set during
  ** a rollback or by user request, respectively.
  **
  ** Spilling is also prohibited when in an error state since that could
  ** lead to database corruption.   In the current implementaton it 
  ** is impossible for sqlite3PcacheFetch() to be called with createFlag==3
  ** while in the error state, hence it is impossible for this routine to
  ** be called in the error state.  Nevertheless, we include a NEVER()
  ** test for the error state as a safeguard against future changes.
  */
  if( NEVER(pPager->errCode) ) return SQLITE_OK;
  testcase( pPager->doNotSpill & SPILLFLAG_ROLLBACK );
................................................................................
            }
            if( !jrnlOpen ){
              sqlite3OsClose(pPager->jfd);
            }
            *pExists = (first!=0);
          }else if( rc==SQLITE_CANTOPEN ){
            /* If we cannot open the rollback journal file in order to see if
            ** its has a zero header, that might be due to an I/O error, or
            ** it might be due to the race condition described above and in
            ** ticket #3883.  Either way, assume that the journal is hot.
            ** This might be a false positive.  But if it is, then the
            ** automatic journal playback and recovery mechanism will deal
            ** with it under an EXCLUSIVE lock where we do not need to
            ** worry so much with race conditions.
            */
................................................................................
    sqlite3PcacheMakeDirty(pPgHdr);
    sqlite3PagerUnrefNotNull(pPgHdr);
  }

  return SQLITE_OK;
}
#endif













/*
** Return a pointer to the data for the specified page.
*/
void *sqlite3PagerGetData(DbPage *pPg){
  assert( pPg->nRef>0 || pPg->pPager->memDb );
  return pPg->pData;
................................................................................
**
** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
*/
int sqlite3PagerCheckpoint(Pager *pPager, int eMode, int *pnLog, int *pnCkpt){
  int rc = SQLITE_OK;
  if( pPager->pWal ){
    rc = sqlite3WalCheckpoint(pPager->pWal, eMode,

        pPager->xBusyHandler, pPager->pBusyHandlerArg,
        pPager->ckptSyncFlags, pPager->pageSize, (u8 *)pPager->pTmpSpace,
        pnLog, pnCkpt
    );
  }
  return rc;
}

................................................................................
** A read-lock must be held on the pager when this function is called. If
** the pager is in WAL mode and the WAL file currently contains one or more
** frames, return the size in bytes of the page images stored within the
** WAL frames. Otherwise, if this is not a WAL database or the WAL file
** is empty, return 0.
*/
int sqlite3PagerWalFramesize(Pager *pPager){
  assert( pPager->eState==PAGER_READER );
  return sqlite3WalFramesize(pPager->pWal);
}
#endif


#endif /* SQLITE_OMIT_DISKIO */

** 
** (6) If a master journal file is used, then all writes to the database file
**     are synced prior to the master journal being deleted.
** 
** Definition: Two databases (or the same database at two points it time)
** are said to be "logically equivalent" if they give the same answer to
** all queries.  Note in particular the content of freelist leaf
** pages can be changed arbitrarily without affecting the logical equivalence
** of the database.
** 
** (7) At any time, if any subset, including the empty set and the total set,
**     of the unsynced changes to a rollback journal are removed and the 
**     journal is rolled back, the resulting database file will be logically
**     equivalent to the database file at the beginning of the transaction.
** 
** (8) When a transaction is rolled back, the xTruncate method of the VFS
**     is called to restore the database file to the same size it was at
**     the beginning of the transaction.  (In some VFSes, the xTruncate
**     method is a no-op, but that does not change the fact the SQLite will
**     invoke it.)
................................................................................
**
** This is usually safe. If an xUnlock fails or appears to fail, there may 
** be a few redundant xLock() calls or a lock may be held for longer than
** required, but nothing really goes wrong.
**
** The exception is when the database file is unlocked as the pager moves
** from ERROR to OPEN state. At this point there may be a hot-journal file 
** in the file-system that needs to be rolled back (as part of an OPEN->SHARED
** transition, by the same pager or any other). If the call to xUnlock()
** fails at this point and the pager is left holding an EXCLUSIVE lock, this
** can confuse the call to xCheckReservedLock() call made later as part
** of hot-journal detection.
**
** xCheckReservedLock() is defined as returning true "if there is a RESERVED 
** lock held by this process or any others". So xCheckReservedLock may 
................................................................................
** Bits of the Pager.doNotSpill flag.  See further description below.
*/
#define SPILLFLAG_OFF         0x01      /* Never spill cache.  Set via pragma */
#define SPILLFLAG_ROLLBACK    0x02      /* Current rolling back, so do not spill */
#define SPILLFLAG_NOSYNC      0x04      /* Spill is ok, but do not sync */

/*
** An open page cache is an instance of struct Pager. A description of
** some of the more important member variables follows:
**
** eState
**
**   The current 'state' of the pager object. See the comment and state
**   diagram above for a description of the pager state.
**
................................................................................
  u8 tempFile;                /* zFilename is a temporary or immutable file */
  u8 noLock;                  /* Do not lock (except in WAL mode) */
  u8 readOnly;                /* True for a read-only database */
  u8 memDb;                   /* True to inhibit all file I/O */

  /**************************************************************************
  ** The following block contains those class members that change during
  ** routine operation.  Class members not in this block are either fixed
  ** when the pager is first created or else only change when there is a
  ** significant mode change (such as changing the page_size, locking_mode,
  ** or the journal_mode).  From another view, these class members describe
  ** the "state" of the pager, while other class members describe the
  ** "configuration" of the pager.
  */
  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
................................................................................
      assert( pPager->journalMode==PAGER_JOURNALMODE_MEMORY );
      sqlite3OsClose(pPager->jfd);
    }else if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE ){
      if( pPager->journalOff==0 ){
        rc = SQLITE_OK;
      }else{
        rc = sqlite3OsTruncate(pPager->jfd, 0);
        if( rc==SQLITE_OK && pPager->fullSync ){
          /* Make sure the new file size is written into the inode right away.
          ** Otherwise the journal might resurrect following a power loss and
          ** cause the last transaction to roll back.  See
          ** https://bugzilla.mozilla.org/show_bug.cgi?id=1072773
          */
          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
        }
      }
      pPager->journalOff = 0;
    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
      || (pPager->exclusiveMode && pPager->journalMode!=PAGER_JOURNALMODE_WAL)
    ){
      rc = zeroJournalHdr(pPager, hasMaster);
      pPager->journalOff = 0;
................................................................................
  ** sqlite3_malloc() and pointed to by zMasterJournal.   Also obtain
  ** sufficient space (in zMasterPtr) to hold the names of master
  ** journal files extracted from regular rollback-journals.
  */
  rc = sqlite3OsFileSize(pMaster, &nMasterJournal);
  if( rc!=SQLITE_OK ) goto delmaster_out;
  nMasterPtr = pVfs->mxPathname+1;
  zMasterJournal = sqlite3Malloc(nMasterJournal + nMasterPtr + 1);
  if( !zMasterJournal ){
    rc = SQLITE_NOMEM;
    goto delmaster_out;
  }
  zMasterPtr = &zMasterJournal[nMasterJournal+1];
  rc = sqlite3OsRead(pMaster, zMasterJournal, (int)nMasterJournal, 0);
  if( rc!=SQLITE_OK ) goto delmaster_out;
................................................................................
**
** If the main database file is not open, or the pager is not in either
** DBMOD or OPEN state, this function is a no-op. Otherwise, the size 
** of the file is changed to nPage pages (nPage*pPager->pageSize bytes). 
** If the file on disk is currently larger than nPage pages, then use the VFS
** xTruncate() method to truncate it.
**
** Or, it might be the case that the file on disk is smaller than 
** nPage pages. Some operating system implementations can get confused if 
** you try to truncate a file to some size that is larger than it 
** currently is, so detect this case and write a single zero byte to 
** the end of the new file instead.
**
** If successful, return SQLITE_OK. If an IO error occurs while modifying
** the database file, return the error code to the caller.
................................................................................
  }
  return iRet;
}

/*
** Set the value of the Pager.sectorSize variable for the given
** pager based on the value returned by the xSectorSize method
** of the open database file. The sector size will be used 
** to determine the size and alignment of journal header and 
** master journal pointers within created journal files.
**
** For temporary files the effective sector size is always 512 bytes.
**
** Otherwise, for non-temporary files, the effective sector size is
** the value returned by the xSectorSize() method rounded up to 32 if
................................................................................
      ** of bytes 24..39 of the database.  Bytes 28..31 should always be
      ** zero or the size of the database in page. Bytes 32..35 and 35..39
      ** should be page numbers which are never 0xffffffff.  So filling
      ** pPager->dbFileVers[] with all 0xff bytes should suffice.
      **
      ** For an encrypted database, the situation is more complex:  bytes
      ** 24..39 of the database are white noise.  But the probability of
      ** white noise equaling 16 bytes of 0xff is vanishingly small so
      ** we should still be ok.
      */
      memset(pPager->dbFileVers, 0xff, sizeof(pPager->dbFileVers));
    }else{
      u8 *dbFileVers = &((u8*)pPg->pData)[24];
      memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
    }
................................................................................
    if( rc==SQLITE_OK ){
      pNew = (char *)sqlite3PageMalloc(pageSize);
      if( !pNew ) rc = SQLITE_NOMEM;
    }

    if( rc==SQLITE_OK ){
      pager_reset(pPager);
      rc = sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
    }
    if( rc==SQLITE_OK ){
      sqlite3PageFree(pPager->pTmpSpace);
      pPager->pTmpSpace = pNew;
      pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize);
      pPager->pageSize = pageSize;
    }else{
      sqlite3PageFree(pNew);


    }
  }

  *pPageSize = pPager->pageSize;
  if( rc==SQLITE_OK ){
    if( nReserve<0 ) nReserve = pPager->nReserve;
    assert( nReserve>=0 && nReserve<1000 );
................................................................................
** the lock. If the lock is obtained successfully, set the Pager.state 
** variable to locktype before returning.
*/
static int pager_wait_on_lock(Pager *pPager, int locktype){
  int rc;                              /* Return code */

  /* Check that this is either a no-op (because the requested lock is 
  ** already held), or one of the transitions that the busy-handler
  ** may be invoked during, according to the comment above
  ** sqlite3PagerSetBusyhandler().
  */
  assert( (pPager->eLock>=locktype)
       || (pPager->eLock==NO_LOCK && locktype==SHARED_LOCK)
       || (pPager->eLock==RESERVED_LOCK && locktype==EXCLUSIVE_LOCK)
  );
................................................................................
  ** pages belonging to the same sector.
  **
  ** The doNotSpill ROLLBACK and OFF bits inhibits all cache spilling
  ** regardless of whether or not a sync is required.  This is set during
  ** a rollback or by user request, respectively.
  **
  ** Spilling is also prohibited when in an error state since that could
  ** lead to database corruption.   In the current implementation it 
  ** is impossible for sqlite3PcacheFetch() to be called with createFlag==3
  ** while in the error state, hence it is impossible for this routine to
  ** be called in the error state.  Nevertheless, we include a NEVER()
  ** test for the error state as a safeguard against future changes.
  */
  if( NEVER(pPager->errCode) ) return SQLITE_OK;
  testcase( pPager->doNotSpill & SPILLFLAG_ROLLBACK );
................................................................................
            }
            if( !jrnlOpen ){
              sqlite3OsClose(pPager->jfd);
            }
            *pExists = (first!=0);
          }else if( rc==SQLITE_CANTOPEN ){
            /* If we cannot open the rollback journal file in order to see if
            ** it has a zero header, that might be due to an I/O error, or
            ** it might be due to the race condition described above and in
            ** ticket #3883.  Either way, assume that the journal is hot.
            ** This might be a false positive.  But if it is, then the
            ** automatic journal playback and recovery mechanism will deal
            ** with it under an EXCLUSIVE lock where we do not need to
            ** worry so much with race conditions.
            */
................................................................................
    sqlite3PcacheMakeDirty(pPgHdr);
    sqlite3PagerUnrefNotNull(pPgHdr);
  }

  return SQLITE_OK;
}
#endif

/*
** The page handle passed as the first argument refers to a dirty page 
** with a page number other than iNew. This function changes the page's 
** page number to iNew and sets the value of the PgHdr.flags field to 
** the value passed as the third parameter.
*/
void sqlite3PagerRekey(DbPage *pPg, Pgno iNew, u16 flags){
  assert( pPg->pgno!=iNew );
  pPg->flags = flags;
  sqlite3PcacheMove(pPg, iNew);
}

/*
** Return a pointer to the data for the specified page.
*/
void *sqlite3PagerGetData(DbPage *pPg){
  assert( pPg->nRef>0 || pPg->pPager->memDb );
  return pPg->pData;
................................................................................
**
** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
*/
int sqlite3PagerCheckpoint(Pager *pPager, int eMode, int *pnLog, int *pnCkpt){
  int rc = SQLITE_OK;
  if( pPager->pWal ){
    rc = sqlite3WalCheckpoint(pPager->pWal, eMode,
        (eMode==SQLITE_CHECKPOINT_PASSIVE ? 0 : pPager->xBusyHandler),
        pPager->pBusyHandlerArg,
        pPager->ckptSyncFlags, pPager->pageSize, (u8 *)pPager->pTmpSpace,
        pnLog, pnCkpt
    );
  }
  return rc;
}

................................................................................
** A read-lock must be held on the pager when this function is called. If
** the pager is in WAL mode and the WAL file currently contains one or more
** frames, return the size in bytes of the page images stored within the
** WAL frames. Otherwise, if this is not a WAL database or the WAL file
** is empty, return 0.
*/
int sqlite3PagerWalFramesize(Pager *pPager){
  assert( pPager->eState>=PAGER_READER );
  return sqlite3WalFramesize(pPager->pWal);
}
#endif


#endif /* SQLITE_OMIT_DISKIO */

int sqlite3PagerIsMemdb(Pager*);
void sqlite3PagerCacheStat(Pager *, int, int, int *);
void sqlite3PagerClearCache(Pager *);
int sqlite3SectorSize(sqlite3_file *);

/* Functions used to truncate the database file. */
void sqlite3PagerTruncateImage(Pager*,Pgno);



#if defined(SQLITE_HAS_CODEC) && !defined(SQLITE_OMIT_WAL)
void *sqlite3PagerCodec(DbPage *);
#endif

/* Functions to support testing and debugging. */
#if !defined(NDEBUG) || defined(SQLITE_TEST)

int sqlite3PagerIsMemdb(Pager*);
void sqlite3PagerCacheStat(Pager *, int, int, int *);
void sqlite3PagerClearCache(Pager *);
int sqlite3SectorSize(sqlite3_file *);

/* Functions used to truncate the database file. */
void sqlite3PagerTruncateImage(Pager*,Pgno);

void sqlite3PagerRekey(DbPage*, Pgno, u16);

#if defined(SQLITE_HAS_CODEC) && !defined(SQLITE_OMIT_WAL)
void *sqlite3PagerCodec(DbPage *);
#endif

/* Functions to support testing and debugging. */
#if !defined(NDEBUG) || defined(SQLITE_TEST)

%endif  SQLITE_OMIT_VIEW

//////////////////////// The SELECT statement /////////////////////////////////
//
cmd ::= select(X).  {
  SelectDest dest = {SRT_Output, 0, 0, 0, 0, 0};
  sqlite3Select(pParse, X, &dest);
  sqlite3ExplainBegin(pParse->pVdbe);
  sqlite3ExplainSelect(pParse->pVdbe, X);
  sqlite3ExplainFinish(pParse->pVdbe);
  sqlite3SelectDelete(pParse->db, X);
}

%type select {Select*}
%destructor select {sqlite3SelectDelete(pParse->db, $$);}
%type selectnowith {Select*}
%destructor selectnowith {sqlite3SelectDelete(pParse->db, $$);}
................................................................................
  A = pRhs;
}
%type multiselect_op {int}
multiselect_op(A) ::= UNION(OP).             {A = @OP;}
multiselect_op(A) ::= UNION ALL.             {A = TK_ALL;}
multiselect_op(A) ::= EXCEPT|INTERSECT(OP).  {A = @OP;}
%endif SQLITE_OMIT_COMPOUND_SELECT
oneselect(A) ::= SELECT distinct(D) selcollist(W) from(X) where_opt(Y)
                 groupby_opt(P) having_opt(Q) orderby_opt(Z) limit_opt(L). {
  A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset);
























}
oneselect(A) ::= values(X).    {A = X;}

%type values {Select*}
%destructor values {sqlite3SelectDelete(pParse->db, $$);}
values(A) ::= VALUES LP nexprlist(X) RP. {
  A = sqlite3SelectNew(pParse,X,0,0,0,0,0,SF_Values,0,0);
................................................................................
expr(A) ::= expr(X) NOT NULL(E). {spanUnaryPostfix(&A,pParse,TK_NOTNULL,&X,&E);}

%include {
  /* A routine to convert a binary TK_IS or TK_ISNOT expression into a
  ** unary TK_ISNULL or TK_NOTNULL expression. */
  static void binaryToUnaryIfNull(Parse *pParse, Expr *pY, Expr *pA, int op){
    sqlite3 *db = pParse->db;
    if( db->mallocFailed==0 && pY->op==TK_NULL ){
      pA->op = (u8)op;
      sqlite3ExprDelete(db, pA->pRight);
      pA->pRight = 0;
    }
  }
}

%endif  SQLITE_OMIT_VIEW

//////////////////////// The SELECT statement /////////////////////////////////
//
cmd ::= select(X).  {
  SelectDest dest = {SRT_Output, 0, 0, 0, 0, 0};
  sqlite3Select(pParse, X, &dest);



  sqlite3SelectDelete(pParse->db, X);
}

%type select {Select*}
%destructor select {sqlite3SelectDelete(pParse->db, $$);}
%type selectnowith {Select*}
%destructor selectnowith {sqlite3SelectDelete(pParse->db, $$);}
................................................................................
  A = pRhs;
}
%type multiselect_op {int}
multiselect_op(A) ::= UNION(OP).             {A = @OP;}
multiselect_op(A) ::= UNION ALL.             {A = TK_ALL;}
multiselect_op(A) ::= EXCEPT|INTERSECT(OP).  {A = @OP;}
%endif SQLITE_OMIT_COMPOUND_SELECT
oneselect(A) ::= SELECT(S) distinct(D) selcollist(W) from(X) where_opt(Y)
                 groupby_opt(P) having_opt(Q) orderby_opt(Z) limit_opt(L). {
  A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset);
#if SELECTTRACE_ENABLED
  /* Populate the Select.zSelName[] string that is used to help with
  ** query planner debugging, to differentiate between multiple Select
  ** objects in a complex query.
  **
  ** If the SELECT keyword is immediately followed by a C-style comment
  ** then extract the first few alphanumeric characters from within that
  ** comment to be the zSelName value.  Otherwise, the label is #N where
  ** is an integer that is incremented with each SELECT statement seen.
  */
  if( A!=0 ){
    const char *z = S.z+6;
    int i;
    sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "#%d",
                     ++pParse->nSelect);
    while( z[0]==' ' ) z++;
    if( z[0]=='/' && z[1]=='*' ){
      z += 2;
      while( z[0]==' ' ) z++;
      for(i=0; sqlite3Isalnum(z[i]); i++){}
      sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "%.*s", i, z);
    }
  }
#endif /* SELECTRACE_ENABLED */
}
oneselect(A) ::= values(X).    {A = X;}

%type values {Select*}
%destructor values {sqlite3SelectDelete(pParse->db, $$);}
values(A) ::= VALUES LP nexprlist(X) RP. {
  A = sqlite3SelectNew(pParse,X,0,0,0,0,0,SF_Values,0,0);
................................................................................
expr(A) ::= expr(X) NOT NULL(E). {spanUnaryPostfix(&A,pParse,TK_NOTNULL,&X,&E);}

%include {
  /* A routine to convert a binary TK_IS or TK_ISNOT expression into a
  ** unary TK_ISNULL or TK_NOTNULL expression. */
  static void binaryToUnaryIfNull(Parse *pParse, Expr *pY, Expr *pA, int op){
    sqlite3 *db = pParse->db;
    if( pY && pA && pY->op==TK_NULL ){
      pA->op = (u8)op;
      sqlite3ExprDelete(db, pA->pRight);
      pA->pRight = 0;
    }
  }
}

# define expensive_assert(X)  assert(X)
#else
# define expensive_assert(X)
#endif

/********************************** Linked List Management ********************/

#if !defined(NDEBUG) && defined(SQLITE_ENABLE_EXPENSIVE_ASSERT)
/*
** Check that the pCache->pSynced variable is set correctly. If it
** is not, either fail an assert or return zero. Otherwise, return
** non-zero. This is only used in debugging builds, as follows:
**
**   expensive_assert( pcacheCheckSynced(pCache) );
*/
static int pcacheCheckSynced(PCache *pCache){
  PgHdr *p;
  for(p=pCache->pDirtyTail; p!=pCache->pSynced; p=p->pDirtyPrev){
    assert( p->nRef || (p->flags&PGHDR_NEED_SYNC) );
  }
  return (p==0 || p->nRef || (p->flags&PGHDR_NEED_SYNC)==0);
}
#endif /* !NDEBUG && SQLITE_ENABLE_EXPENSIVE_ASSERT */

/* Allowed values for second argument to pcacheManageDirtyList() */
#define PCACHE_DIRTYLIST_REMOVE   1    /* Remove pPage from dirty list */
#define PCACHE_DIRTYLIST_ADD      2    /* Add pPage to the dirty list */
#define PCACHE_DIRTYLIST_FRONT    3    /* Move pPage to the front of the list */

/*
** Manage pPage's participation on the dirty list.  Bits of the addRemove
................................................................................
      if( p->pDirty==0 && p->bPurgeable ){
        assert( p->eCreate==1 );
        p->eCreate = 2;
      }
    }
    pPage->pDirtyNext = 0;
    pPage->pDirtyPrev = 0;
    expensive_assert( pcacheCheckSynced(p) );
  }
  if( addRemove & PCACHE_DIRTYLIST_ADD ){
    assert( pPage->pDirtyNext==0 && pPage->pDirtyPrev==0 && p->pDirty!=pPage );
  
    pPage->pDirtyNext = p->pDirty;
    if( pPage->pDirtyNext ){
      assert( pPage->pDirtyNext->pDirtyPrev==0 );
      pPage->pDirtyNext->pDirtyPrev = pPage;


    }else if( p->bPurgeable ){
      assert( p->eCreate==2 );
      p->eCreate = 1;
    }
    p->pDirty = pPage;
    if( !p->pDirtyTail ){
      p->pDirtyTail = pPage;
    }

    if( !p->pSynced && 0==(pPage->flags&PGHDR_NEED_SYNC) ){
      p->pSynced = pPage;
    }
    expensive_assert( pcacheCheckSynced(p) );
  }
}

/*
** Wrapper around the pluggable caches xUnpin method. If the cache is
** being used for an in-memory database, this function is a no-op.
*/
................................................................................


  /* Find a dirty page to write-out and recycle. First try to find a 
  ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
  ** cleared), but if that is not possible settle for any other 
  ** unreferenced dirty page.
  */
  expensive_assert( pcacheCheckSynced(pCache) );
  for(pPg=pCache->pSynced; 
      pPg && (pPg->nRef || (pPg->flags&PGHDR_NEED_SYNC)); 
      pPg=pPg->pDirtyPrev
  );
  pCache->pSynced = pPg;
  if( !pPg ){
    for(pPg=pCache->pDirtyTail; pPg && pPg->nRef; pPg=pPg->pDirtyPrev);
................................................................................
    pCache->pPage1 = pPgHdr;
  }
  return pPgHdr;
}

/*
** Decrement the reference count on a page. If the page is clean and the
** reference count drops to 0, then it is made elible for recycling.
*/
void SQLITE_NOINLINE sqlite3PcacheRelease(PgHdr *p){
  assert( p->nRef>0 );
  p->nRef--;
  if( p->nRef==0 ){
    p->pCache->nRef--;
    if( (p->flags&PGHDR_DIRTY)==0 ){
      pcacheUnpin(p);
    }else{
      /* Move the page to the head of the dirty list. */
      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
    }
  }
}

/*
................................................................................
/*
** Free up as much memory as possible from the page cache.
*/
void sqlite3PcacheShrink(PCache *pCache){
  assert( pCache->pCache!=0 );
  sqlite3GlobalConfig.pcache2.xShrink(pCache->pCache);
}








#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
/*
** For all dirty pages currently in the cache, invoke the specified
** callback. This is only used if the SQLITE_CHECK_PAGES macro is
** defined.
*/

# define expensive_assert(X)  assert(X)
#else
# define expensive_assert(X)
#endif

/********************************** Linked List Management ********************/


















/* Allowed values for second argument to pcacheManageDirtyList() */
#define PCACHE_DIRTYLIST_REMOVE   1    /* Remove pPage from dirty list */
#define PCACHE_DIRTYLIST_ADD      2    /* Add pPage to the dirty list */
#define PCACHE_DIRTYLIST_FRONT    3    /* Move pPage to the front of the list */

/*
** Manage pPage's participation on the dirty list.  Bits of the addRemove
................................................................................
      if( p->pDirty==0 && p->bPurgeable ){
        assert( p->eCreate==1 );
        p->eCreate = 2;
      }
    }
    pPage->pDirtyNext = 0;
    pPage->pDirtyPrev = 0;

  }
  if( addRemove & PCACHE_DIRTYLIST_ADD ){
    assert( pPage->pDirtyNext==0 && pPage->pDirtyPrev==0 && p->pDirty!=pPage );
  
    pPage->pDirtyNext = p->pDirty;
    if( pPage->pDirtyNext ){
      assert( pPage->pDirtyNext->pDirtyPrev==0 );
      pPage->pDirtyNext->pDirtyPrev = pPage;
    }else{
      p->pDirtyTail = pPage;
      if( p->bPurgeable ){
        assert( p->eCreate==2 );
        p->eCreate = 1;
      }



    }
    p->pDirty = pPage;
    if( !p->pSynced && 0==(pPage->flags&PGHDR_NEED_SYNC) ){
      p->pSynced = pPage;
    }

  }
}

/*
** Wrapper around the pluggable caches xUnpin method. If the cache is
** being used for an in-memory database, this function is a no-op.
*/
................................................................................


  /* Find a dirty page to write-out and recycle. First try to find a 
  ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
  ** cleared), but if that is not possible settle for any other 
  ** unreferenced dirty page.
  */

  for(pPg=pCache->pSynced; 
      pPg && (pPg->nRef || (pPg->flags&PGHDR_NEED_SYNC)); 
      pPg=pPg->pDirtyPrev
  );
  pCache->pSynced = pPg;
  if( !pPg ){
    for(pPg=pCache->pDirtyTail; pPg && pPg->nRef; pPg=pPg->pDirtyPrev);
................................................................................
    pCache->pPage1 = pPgHdr;
  }
  return pPgHdr;
}

/*
** Decrement the reference count on a page. If the page is clean and the
** reference count drops to 0, then it is made eligible for recycling.
*/
void SQLITE_NOINLINE sqlite3PcacheRelease(PgHdr *p){
  assert( p->nRef>0 );
  p->nRef--;
  if( p->nRef==0 ){
    p->pCache->nRef--;
    if( (p->flags&PGHDR_DIRTY)==0 ){
      pcacheUnpin(p);
    }else if( p->pDirtyPrev!=0 ){
      /* Move the page to the head of the dirty list. */
      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
    }
  }
}

/*
................................................................................
/*
** Free up as much memory as possible from the page cache.
*/
void sqlite3PcacheShrink(PCache *pCache){
  assert( pCache->pCache!=0 );
  sqlite3GlobalConfig.pcache2.xShrink(pCache->pCache);
}

/*
** Return the size of the header added by this middleware layer
** in the page-cache hierarchy.
*/
int sqlite3HeaderSizePcache(void){ return sizeof(PgHdr); }


#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
/*
** For all dirty pages currently in the cache, invoke the specified
** callback. This is only used if the SQLITE_CHECK_PAGES macro is
** defined.
*/

#ifdef SQLITE_TEST
void sqlite3PcacheStats(int*,int*,int*,int*);
#endif

void sqlite3PCacheSetDefault(void);





#endif /* _PCACHE_H_ */

#ifdef SQLITE_TEST
void sqlite3PcacheStats(int*,int*,int*,int*);
#endif

void sqlite3PCacheSetDefault(void);

/* Return the header size */
int sqlite3HeaderSizePcache(void);
int sqlite3HeaderSizePcache1(void);

#endif /* _PCACHE_H_ */

**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file implements the default page cache implementation (the
** sqlite3_pcache interface). It also contains part of the implementation
** of the SQLITE_CONFIG_PAGECACHE and sqlite3_release_memory() features.
** If the default page cache implementation is overriden, then neither of
** these two features are available.
*/

#include "sqliteInt.h"

typedef struct PCache1 PCache1;
typedef struct PgHdr1 PgHdr1;
typedef struct PgFreeslot PgFreeslot;
typedef struct PGroup PGroup;

/* Each page cache (or PCache) belongs to a PGroup.  A PGroup is a set 
** of one or more PCaches that are able to recycle each others unpinned
** pages when they are under memory pressure.  A PGroup is an instance of
** the following object.
**
** This page cache implementation works in one of two modes:
**
**   (1)  Every PCache is the sole member of its own PGroup.  There is
**        one PGroup per PCache.
................................................................................
  assert( pCache->nPage >= pCache->nRecyclable );
  nPinned = pCache->nPage - pCache->nRecyclable;
  assert( pGroup->mxPinned == pGroup->nMaxPage + 10 - pGroup->nMinPage );
  assert( pCache->n90pct == pCache->nMax*9/10 );
  if( createFlag==1 && (
        nPinned>=pGroup->mxPinned
     || nPinned>=pCache->n90pct
     || pcache1UnderMemoryPressure(pCache)
  )){
    return 0;
  }

  if( pCache->nPage>=pCache->nHash ) pcache1ResizeHash(pCache);
  assert( pCache->nHash>0 && pCache->apHash );

................................................................................
    pcache1Truncate,         /* xTruncate */
    pcache1Destroy,          /* xDestroy */
    pcache1Shrink            /* xShrink */
  };
  sqlite3_config(SQLITE_CONFIG_PCACHE2, &defaultMethods);
}






#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** This function is called to free superfluous dynamically allocated memory
** held by the pager system. Memory in use by any SQLite pager allocated
** by the current thread may be sqlite3_free()ed.
**
** nReq is the number of bytes of memory required. Once this much has

**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file implements the default page cache implementation (the
** sqlite3_pcache interface). It also contains part of the implementation
** of the SQLITE_CONFIG_PAGECACHE and sqlite3_release_memory() features.
** If the default page cache implementation is overridden, then neither of
** these two features are available.
*/

#include "sqliteInt.h"

typedef struct PCache1 PCache1;
typedef struct PgHdr1 PgHdr1;
typedef struct PgFreeslot PgFreeslot;
typedef struct PGroup PGroup;

/* Each page cache (or PCache) belongs to a PGroup.  A PGroup is a set 
** of one or more PCaches that are able to recycle each other's unpinned
** pages when they are under memory pressure.  A PGroup is an instance of
** the following object.
**
** This page cache implementation works in one of two modes:
**
**   (1)  Every PCache is the sole member of its own PGroup.  There is
**        one PGroup per PCache.
................................................................................
  assert( pCache->nPage >= pCache->nRecyclable );
  nPinned = pCache->nPage - pCache->nRecyclable;
  assert( pGroup->mxPinned == pGroup->nMaxPage + 10 - pGroup->nMinPage );
  assert( pCache->n90pct == pCache->nMax*9/10 );
  if( createFlag==1 && (
        nPinned>=pGroup->mxPinned
     || nPinned>=pCache->n90pct
     || (pcache1UnderMemoryPressure(pCache) && pCache->nRecyclable<nPinned)
  )){
    return 0;
  }

  if( pCache->nPage>=pCache->nHash ) pcache1ResizeHash(pCache);
  assert( pCache->nHash>0 && pCache->apHash );

................................................................................
    pcache1Truncate,         /* xTruncate */
    pcache1Destroy,          /* xDestroy */
    pcache1Shrink            /* xShrink */
  };
  sqlite3_config(SQLITE_CONFIG_PCACHE2, &defaultMethods);
}

/*
** Return the size of the header on each page of this PCACHE implementation.
*/
int sqlite3HeaderSizePcache1(void){ return sizeof(PgHdr1); }

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** This function is called to free superfluous dynamically allocated memory
** held by the pager system. Memory in use by any SQLite pager allocated
** by the current thread may be sqlite3_free()ed.
**
** nReq is the number of bytes of memory required. Once this much has

#define PragTyp_SHRINK_MEMORY                 26
#define PragTyp_SOFT_HEAP_LIMIT               27
#define PragTyp_STATS                         28
#define PragTyp_SYNCHRONOUS                   29
#define PragTyp_TABLE_INFO                    30
#define PragTyp_TEMP_STORE                    31
#define PragTyp_TEMP_STORE_DIRECTORY          32

#define PragTyp_WAL_AUTOCHECKPOINT            33
#define PragTyp_WAL_CHECKPOINT                34
#define PragTyp_ACTIVATE_EXTENSIONS           35
#define PragTyp_HEXKEY                        36
#define PragTyp_KEY                           37
#define PragTyp_REKEY                         38
#define PragTyp_LOCK_STATUS                   39
#define PragTyp_PARSER_TRACE                  40
#define PragFlag_NeedSchema           0x01
static const struct sPragmaNames {
  const char *const zName;  /* Name of pragma */
  u8 ePragTyp;              /* PragTyp_XXX value */
  u8 mPragFlag;             /* Zero or more PragFlag_XXX values */
  u32 iArg;                 /* Extra argument */
} aPragmaNames[] = {
................................................................................
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
  { /* zName:     */ "temp_store_directory",
    /* ePragTyp:  */ PragTyp_TEMP_STORE_DIRECTORY,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif




#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "user_version",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
................................................................................
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
  { /* zName:     */ "writable_schema",
    /* ePragTyp:  */ PragTyp_FLAG,
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_WriteSchema|SQLITE_RecoveryMode },
#endif
};
/* Number of pragmas: 56 on by default, 69 total. */
/* End of the automatically generated pragma table.
***************************************************************************/

/*
** Interpret the given string as a safety level.  Return 0 for OFF,
** 1 for ON or NORMAL and 2 for FULL.  Return 1 for an empty or 
** unrecognized string argument.  The FULL option is disallowed
................................................................................
    }else{
      int mask = aPragmaNames[mid].iArg;    /* Mask of