** 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.
**
*************************************************************************
** $Id: btree.c,v 1.295 2006/01/13 04:31:58 drh Exp $
**
** 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.
................................................................................
** at most one effective restoreOrClearCursorPosition() call after each 
** saveCursorPosition().
**
** If the second argument argument - doSeek - is false, then instead of 
** returning the cursor to it's saved position, any saved position is deleted
** and the cursor state set to CURSOR_INVALID.
*/
static int restoreOrClearCursorPosition(BtCursor *pCur, int doSeek){
  int rc = SQLITE_OK;
  if( pCur->eState==CURSOR_REQUIRESEEK ){
    assert( sqlite3ThreadDataReadOnly()->useSharedData );

    if( doSeek ){
      rc = sqlite3BtreeMoveto(pCur, pCur->pKey, pCur->nKey, &pCur->skip);
    }else{
      pCur->eState = CURSOR_INVALID;
    }
    if( rc==SQLITE_OK ){
      sqliteFree(pCur->pKey);
      pCur->pKey = 0;
      assert( CURSOR_VALID==pCur->eState || CURSOR_INVALID==pCur->eState );
    }
  }
  return rc;
}




/*
** Query to see if btree handle p may obtain a lock of type eLock 
** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
** SQLITE_OK if the lock may be obtained (by calling lockTable()), or
** SQLITE_LOCKED if not.
*/
static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){

** 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.
**
*************************************************************************
** $Id: btree.c,v 1.296 2006/01/13 06:33:24 danielk1977 Exp $
**
** 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.
................................................................................
** at most one effective restoreOrClearCursorPosition() call after each 
** saveCursorPosition().
**
** If the second argument argument - doSeek - is false, then instead of 
** returning the cursor to it's saved position, any saved position is deleted
** and the cursor state set to CURSOR_INVALID.
*/
static int restoreOrClearCursorPositionX(BtCursor *pCur, int doSeek){
  int rc = SQLITE_OK;

  assert( sqlite3ThreadDataReadOnly()->useSharedData );
  assert( pCur->eState==CURSOR_REQUIRESEEK );
  if( doSeek ){
    rc = sqlite3BtreeMoveto(pCur, pCur->pKey, pCur->nKey, &pCur->skip);
  }else{
    pCur->eState = CURSOR_INVALID;
  }
  if( rc==SQLITE_OK ){
    sqliteFree(pCur->pKey);
    pCur->pKey = 0;
    assert( CURSOR_VALID==pCur->eState || CURSOR_INVALID==pCur->eState );

  }
  return rc;
}

#define restoreOrClearCursorPosition(p,x) \
  (p->eState==CURSOR_REQUIRESEEK?restoreOrClearCursorPositionX(p,x):SQLITE_OK)

/*
** Query to see if btree handle p may obtain a lock of type eLock 
** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
** SQLITE_OK if the lock may be obtained (by calling lockTable()), or
** SQLITE_LOCKED if not.
*/
static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.378 2006/01/12 01:56:44 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
  int i;

  if( (p = pParse->pNewTable)==0 ) return;
  i = p->nCol-1;

  if( sqlite3LocateCollSeq(pParse, zType, nType) ){
    Index *pIdx;
    p->aCol[i].zColl = sqlite3StrNDup(zType, nType);
  
    /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
    ** then an index may have been created on this column before the
    ** collation type was added. Correct this if it is the case.
    */
    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->nColumn==1 );
................................................................................
  if( pName1==0 || pName1->z==0 ){
    reindexDatabases(pParse, 0);
    return;
  }else if( pName2==0 || pName2->z==0 ){
    assert( pName1->z );
    pColl = sqlite3FindCollSeq(db, ENC(db), (char*)pName1->z, pName1->n, 0);
    if( pColl ){
      char *z = sqlite3StrNDup(pName1->z, pName1->n);
      if( z ){
        reindexDatabases(pParse, z);
        sqliteFree(z);
      }
      return;
    }
  }

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.379 2006/01/13 06:33:24 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
  int i;

  if( (p = pParse->pNewTable)==0 ) return;
  i = p->nCol-1;

  if( sqlite3LocateCollSeq(pParse, zType, nType) ){
    Index *pIdx;
    p->aCol[i].zColl = sqliteStrNDup(zType, nType);
  
    /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
    ** then an index may have been created on this column before the
    ** collation type was added. Correct this if it is the case.
    */
    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->nColumn==1 );
................................................................................
  if( pName1==0 || pName1->z==0 ){
    reindexDatabases(pParse, 0);
    return;
  }else if( pName2==0 || pName2->z==0 ){
    assert( pName1->z );
    pColl = sqlite3FindCollSeq(db, ENC(db), (char*)pName1->z, pName1->n, 0);
    if( pColl ){
      char *z = sqliteStrNDup(pName1->z, pName1->n);
      if( z ){
        reindexDatabases(pParse, z);
        sqliteFree(z);
      }
      return;
    }
  }

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.248 2006/01/11 21:41:22 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
        break;
      }
    }
    if( i>=pParse->nVarExpr ){
      pExpr->iTable = ++pParse->nVar;
      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
        sqlite3ReallocOrFree((void**)&pParse->apVarExpr,
                       pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0]) );
      }
      if( !sqlite3ThreadDataReadOnly()->mallocFailed ){
        assert( pParse->apVarExpr!=0 );
        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
      }
    }

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.249 2006/01/13 06:33:24 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
        break;
      }
    }
    if( i>=pParse->nVarExpr ){
      pExpr->iTable = ++pParse->nVar;
      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
        sqliteReallocOrFree((void**)&pParse->apVarExpr,
                       pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0]) );
      }
      if( !sqlite3ThreadDataReadOnly()->mallocFailed ){
        assert( pParse->apVarExpr!=0 );
        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
      }
    }

** sqlite3GenericOsFree
** sqlite3GenericAllocationSize
**
** Implementation of the os level dynamic memory allocation interface in terms
** of the standard malloc(), realloc() and free() found in many operating
** systems. No rocket science here.
*/

void *sqlite3GenericMalloc(int n){
  char *p = (char *)malloc(n+8);
  assert(n>0);
  assert(sizeof(int)<=8);
  if( p ){
    *(int *)p = n;
  }
................................................................................
void sqlite3GenericFree(void *p){
  assert(p);
  free((void *)((char *)p - 8));
}
int sqlite3GenericAllocationSize(void *p){
  return p ? *(int *)((char *)p - 8) : 0;
}

** sqlite3GenericOsFree
** sqlite3GenericAllocationSize
**
** Implementation of the os level dynamic memory allocation interface in terms
** of the standard malloc(), realloc() and free() found in many operating
** systems. No rocket science here.
*/
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
void *sqlite3GenericMalloc(int n){
  char *p = (char *)malloc(n+8);
  assert(n>0);
  assert(sizeof(int)<=8);
  if( p ){
    *(int *)p = n;
  }
................................................................................
void sqlite3GenericFree(void *p){
  assert(p);
  free((void *)((char *)p - 8));
}
int sqlite3GenericAllocationSize(void *p){
  return p ? *(int *)((char *)p - 8) : 0;
}
#else
void *sqlite3GenericMalloc(int n){
  char *p = (char *)malloc(n);
  return (void *)p;
}
void *sqlite3GenericRealloc(void *p, int n){
  assert(n>0);
  p = realloc(p, n);
  return p;
}
void sqlite3GenericFree(void *p){
  assert(p);
  free(p);
}
int sqlite3GenericAllocationSize(void *p){
  assert(0);
}
#endif

  int nByte;
  nByte = strlen(zRelative) + MAX_PATH + 1001;
  zFull = sqliteMalloc( nByte );
  if( zFull==0 ) return 0;
  if( cygwin_conv_to_full_win32_path(zRelative, zFull) ) return 0;
#elif OS_WINCE
  /* WinCE has no concept of a relative pathname, or so I am told. */
  zFull = sqlite3StrDup(zRelative);
#else
  char *zNotUsed;
  WCHAR *zWide;
  int nByte;
  zWide = utf8ToUnicode(zRelative);
  if( zWide ){
    WCHAR *zTemp, *zNotUsedW;

  int nByte;
  nByte = strlen(zRelative) + MAX_PATH + 1001;
  zFull = sqliteMalloc( nByte );
  if( zFull==0 ) return 0;
  if( cygwin_conv_to_full_win32_path(zRelative, zFull) ) return 0;
#elif OS_WINCE
  /* WinCE has no concept of a relative pathname, or so I am told. */
  zFull = sqliteStrDup(zRelative);
#else
  char *zNotUsed;
  WCHAR *zWide;
  int nByte;
  zWide = utf8ToUnicode(zRelative);
  if( zWide ){
    WCHAR *zTemp, *zNotUsedW;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
**
** $Id: prepare.c,v 1.21 2006/01/12 12:43:36 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates
................................................................................

/*
** Initialize all database files - the main database file, the file
** used to store temporary tables, and any additional database files
** created using ATTACH statements.  Return a success code.  If an
** error occurs, write an error message into *pzErrMsg.
**
** After the database is initialized, the SQLITE_Initialized
** bit is set in the flags field of the sqlite structure. 

*/
int sqlite3Init(sqlite3 *db, char **pzErrMsg){
  int i, rc;
  int called_initone = 0;
  
  if( db->init.busy ) return SQLITE_OK;
  rc = SQLITE_OK;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
**
** $Id: prepare.c,v 1.22 2006/01/13 06:33:24 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates
................................................................................

/*
** Initialize all database files - the main database file, the file
** used to store temporary tables, and any additional database files
** created using ATTACH statements.  Return a success code.  If an
** error occurs, write an error message into *pzErrMsg.
**
** After a database is initialized, the DB_SchemaLoaded bit is set
** bit is set in the flags field of the Db structure. If the database
** file was of zero-length, then the DB_Empty flag is also set.
*/
int sqlite3Init(sqlite3 *db, char **pzErrMsg){
  int i, rc;
  int called_initone = 0;
  
  if( db->init.busy ) return SQLITE_OK;
  rc = SQLITE_OK;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.293 2006/01/11 21:41:22 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
................................................................................
    memset(&sNC, 0, sizeof(sNC));
    sNC.pSrcList = pSelect->pSrc;
    zType = sqliteStrDup(columnType(&sNC, p));
    pCol->zType = zType;
    pCol->affinity = sqlite3ExprAffinity(p);
    pColl = sqlite3ExprCollSeq(pParse, p);
    if( pColl ){
      pCol->zColl = sqlite3StrDup(pColl->zName);
    }
  }
  pTab->iPKey = -1;
  return pTab;
}

/*

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.294 2006/01/13 06:33:24 danielk1977 Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
................................................................................
    memset(&sNC, 0, sizeof(sNC));
    sNC.pSrcList = pSelect->pSrc;
    zType = sqliteStrDup(columnType(&sNC, p));
    pCol->zType = zType;
    pCol->affinity = sqlite3ExprAffinity(p);
    pColl = sqlite3ExprCollSeq(pParse, p);
    if( pColl ){
      pCol->zColl = sqliteStrDup(pColl->zName);
    }
  }
  pTab->iPKey = -1;
  return pTab;
}

/*

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.466 2006/01/12 17:20:51 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/
................................................................................
#define sqliteStrNDup(x,y)       sqlite3StrNDup(x,y)
#define sqliteReallocOrFree(x,y) sqlite3ReallocOrFree(x,y)

#endif

#define sqliteFree(x)          sqlite3FreeX(x)
#define sqliteAllocSize(x)     sqlite3AllocSize(x)


/*
** An instance of this structure might be allocated to store information
** specific to a single thread.
**
** To avoid a memory leak on windows, the content of this structure is
** checked at the conclusion of each API call.  If it is all zero, it

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.467 2006/01/13 06:33:24 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/
................................................................................
#define sqliteStrNDup(x,y)       sqlite3StrNDup(x,y)
#define sqliteReallocOrFree(x,y) sqlite3ReallocOrFree(x,y)

#endif

#define sqliteFree(x)          sqlite3FreeX(x)
#define sqliteAllocSize(x)     sqlite3AllocSize(x)


/*
** An instance of this structure might be allocated to store information
** specific to a single thread.
**
** To avoid a memory leak on windows, the content of this structure is
** checked at the conclusion of each API call.  If it is all zero, it

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used to translate between UTF-8, 
** UTF-16, UTF-16BE, and UTF-16LE.
**
** $Id: utf.c,v 1.35 2005/12/15 22:34:01 drh Exp $
**
** Notes on UTF-8:
**
**   Byte-0    Byte-1    Byte-2    Byte-3    Value
**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx
................................................................................
char *sqlite3utf16to8(const void *z, int nByte){
  Mem m;
  memset(&m, 0, sizeof(m));
  sqlite3VdbeMemSetStr(&m, z, nByte, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);
  assert( m.flags & MEM_Term );
  assert( m.flags & MEM_Str );
  return (m.flags & MEM_Dyn)!=0 ? m.z : sqlite3StrDup(m.z);
}

/*
** pZ is a UTF-16 encoded unicode string. If nChar is less than zero,
** return the number of bytes up to (but not including), the first pair
** of consecutive 0x00 bytes in pZ. If nChar is not less than zero,
** then return the number of bytes in the first nChar unicode characters

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used to translate between UTF-8, 
** UTF-16, UTF-16BE, and UTF-16LE.
**
** $Id: utf.c,v 1.36 2006/01/13 06:33:24 danielk1977 Exp $
**
** Notes on UTF-8:
**
**   Byte-0    Byte-1    Byte-2    Byte-3    Value
**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx
................................................................................
char *sqlite3utf16to8(const void *z, int nByte){
  Mem m;
  memset(&m, 0, sizeof(m));
  sqlite3VdbeMemSetStr(&m, z, nByte, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);
  assert( m.flags & MEM_Term );
  assert( m.flags & MEM_Str );
  return (m.flags & MEM_Dyn)!=0 ? m.z : sqliteStrDup(m.z);
}

/*
** pZ is a UTF-16 encoded unicode string. If nChar is less than zero,
** return the number of bytes up to (but not including), the first pair
** of consecutive 0x00 bytes in pZ. If nChar is not less than zero,
** then return the number of bytes in the first nChar unicode characters

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.169 2006/01/12 01:25:18 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <stdarg.h>
#include <ctype.h>

/*
................................................................................
** sqlite3Malloc(), sqlite3Realloc() or sqlite3ReallocOrFree().
**
** The number of bytes allocated does not include any overhead inserted by 
** any malloc() wrapper functions that may be called. So the value returned
** is the number of bytes that were available to SQLite using pointer p, 
** regardless of how much memory was actually allocated.
*/

int sqlite3AllocSize(void *p){
  return OSSIZEOF(p);
}


/*
** Make a copy of a string in memory obtained from sqliteMalloc(). These 
** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
** is because when memory debugging is turned on, these two functions are 
** called via macros that record the current file and line number in the
** ThreadData structure.

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.170 2006/01/13 06:33:24 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <stdarg.h>
#include <ctype.h>

/*
................................................................................
** sqlite3Malloc(), sqlite3Realloc() or sqlite3ReallocOrFree().
**
** The number of bytes allocated does not include any overhead inserted by 
** any malloc() wrapper functions that may be called. So the value returned
** is the number of bytes that were available to SQLite using pointer p, 
** regardless of how much memory was actually allocated.
*/
#if 0          /* This is never actually used */
int sqlite3AllocSize(void *p){
  return OSSIZEOF(p);
}
#endif

/*
** Make a copy of a string in memory obtained from sqliteMalloc(). These 
** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
** is because when memory debugging is turned on, these two functions are 
** called via macros that record the current file and line number in the
** ThreadData structure.

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.526 2006/01/13 01:48:59 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  int i = p->contextStackTop++;
  Context *pContext;

  assert( i>=0 );
  /* FIX ME: This should be allocated as part of the vdbe at compile-time */
  if( i>=p->contextStackDepth ){
    p->contextStackDepth = i+1;
    sqlite3ReallocOrFree((void**)&p->contextStack, sizeof(Context)*(i+1));
    if( p->contextStack==0 ) goto no_mem;
  }
  pContext = &p->contextStack[i];
  pContext->lastRowid = db->lastRowid;
  pContext->nChange = p->nChange;
  pContext->sFifo = p->sFifo;
  sqlite3VdbeFifoInit(&p->sFifo);

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.527 2006/01/13 06:33:24 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  int i = p->contextStackTop++;
  Context *pContext;

  assert( i>=0 );
  /* FIX ME: This should be allocated as part of the vdbe at compile-time */
  if( i>=p->contextStackDepth ){
    p->contextStackDepth = i+1;
    sqliteReallocOrFree((void**)&p->contextStack, sizeof(Context)*(i+1));
    if( p->contextStack==0 ) goto no_mem;
  }
  pContext = &p->contextStack[i];
  pContext->lastRowid = db->lastRowid;
  pContext->nChange = p->nChange;
  pContext->sFifo = p->sFifo;
  sqlite3VdbeFifoInit(&p->sFifo);

*/
int sqlite3VdbeMakeLabel(Vdbe *p){
  int i;
  i = p->nLabel++;
  assert( p->magic==VDBE_MAGIC_INIT );
  if( i>=p->nLabelAlloc ){
    p->nLabelAlloc = p->nLabelAlloc*2 + 10;
    sqlite3ReallocOrFree((void**)&p->aLabel,
                          p->nLabelAlloc*sizeof(p->aLabel[0]));
  }
  if( p->aLabel ){
    p->aLabel[i] = -1;
  }
  return -1-i;
}

*/
int sqlite3VdbeMakeLabel(Vdbe *p){
  int i;
  i = p->nLabel++;
  assert( p->magic==VDBE_MAGIC_INIT );
  if( i>=p->nLabelAlloc ){
    p->nLabelAlloc = p->nLabelAlloc*2 + 10;
    sqliteReallocOrFree((void**)&p->aLabel,
                          p->nLabelAlloc*sizeof(p->aLabel[0]));
  }
  if( p->aLabel ){
    p->aLabel[i] = -1;
  }
  return -1-i;
}

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.194 2006/01/11 21:41:22 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
    Vdbe *v = pParse->pVdbe;

    sqlite3CodeSubselect(pParse, pX);
    iTab = pX->iTable;
    sqlite3VdbeAddOp(v, OP_Rewind, iTab, brk);
    VdbeComment((v, "# %.*s", pX->span.n, pX->span.z));
    pLevel->nIn++;
    sqlite3ReallocOrFree((void**)&pLevel->aInLoop,
                                 sizeof(pLevel->aInLoop[0])*3*pLevel->nIn);
    aIn = pLevel->aInLoop;
    if( aIn ){
      aIn += pLevel->nIn*3 - 3;
      aIn[0] = OP_Next;
      aIn[1] = iTab;
      aIn[2] = sqlite3VdbeAddOp(v, OP_Column, iTab, 0);

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.195 2006/01/13 06:33:25 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
    Vdbe *v = pParse->pVdbe;

    sqlite3CodeSubselect(pParse, pX);
    iTab = pX->iTable;
    sqlite3VdbeAddOp(v, OP_Rewind, iTab, brk);
    VdbeComment((v, "# %.*s", pX->span.n, pX->span.z));
    pLevel->nIn++;
    sqliteReallocOrFree((void**)&pLevel->aInLoop,
                                 sizeof(pLevel->aInLoop[0])*3*pLevel->nIn);
    aIn = pLevel->aInLoop;
    if( aIn ){
      aIn += pLevel->nIn*3 - 3;
      aIn[0] = OP_Next;
      aIn[1] = iTab;
      aIn[2] = sqlite3VdbeAddOp(v, OP_Column, iTab, 0);