SQLite

# build on the target system.  Some of the C source code and header
# files are automatically generated.  This target takes care of
# all that automatic generation.
#
target_source:	$(SRC)
	rm -rf tsrc
	mkdir tsrc
	cp $(SRC) $(TOP)/src/*.h tsrc
	rm tsrc/sqlite.h.in tsrc/parse.y

# Rules to build the LEMON compiler generator
#
lemon:	$(TOP)/tool/lemon.c $(TOP)/tool/lempar.c
	$(BCC) -o lemon $(TOP)/tool/lemon.c
	cp $(TOP)/tool/lempar.c .

/*
** 2004 April 6
**
** 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.
**
*************************************************************************
** $Id: btree.c,v 1.342 2007/03/26 22:05:01 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.

      rc = ptrmapPut(pBt, iFreePage, eType, iPtrPage);
    }
  }
  return rc;
}

/* Forward declaration required by autoVacuumCommit(). */
static int allocateBtreePage(BtShared *, MemPage **, Pgno *, Pgno, u8);

/*
** This routine is called prior to sqlite3PagerCommit when a transaction
** is commited for an auto-vacuum database.
*/
static int autoVacuumCommit(BtShared *pBt, Pgno *nTrunc){
  Pager *pPager = pBt->pPager;

      continue;
    }
    rc = getPage(pBt, iDbPage, &pDbMemPage, 0);
    if( rc!=SQLITE_OK ) goto autovacuum_out;

    /* Find the next page in the free-list that is not already at the end 
    ** of the file. A page can be pulled off the free list using the 
    ** allocateBtreePage() routine.
    */
    do{
      if( pFreeMemPage ){
        releasePage(pFreeMemPage);
        pFreeMemPage = 0;
      }
      rc = allocateBtreePage(pBt, &pFreeMemPage, &iFreePage, 0, 0);
      if( rc!=SQLITE_OK ){
        releasePage(pDbMemPage);
        goto autovacuum_out;
      }
      assert( iFreePage<=origSize );
    }while( iFreePage>finSize );
    releasePage(pFreeMemPage);

** attempt to keep related pages close to each other in the database file,
** which in turn can make database access faster.
**
** If the "exact" parameter is not 0, and the page-number nearby exists 
** anywhere on the free-list, then it is guarenteed to be returned. This
** is only used by auto-vacuum databases when allocating a new table.
*/
static int allocateBtreePage(
  BtShared *pBt, 
  MemPage **ppPage, 
  Pgno *pPgno, 
  Pgno nearby,
  u8 exact
){
  MemPage *pPage1;

  pPrior = &pCell[info.iOverflow];

  while( nPayload>0 ){
    if( spaceLeft==0 ){
#ifndef SQLITE_OMIT_AUTOVACUUM
      Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
#endif
      rc = allocateBtreePage(pBt, &pOvfl, &pgnoOvfl, pgnoOvfl, 0);
#ifndef SQLITE_OMIT_AUTOVACUUM
      /* If the database supports auto-vacuum, and the second or subsequent
      ** overflow page is being allocated, add an entry to the pointer-map
      ** for that page now. The entry for the first overflow page will be
      ** added later, by the insertCell() routine.
      */
      if( pBt->autoVacuum && pgnoPtrmap!=0 && rc==SQLITE_OK ){

  int parentIdx = pParent->nCell;   /* pParent new divider cell index */
  int parentSize;                   /* Size of new divider cell */
  u8 parentCell[64];                /* Space for the new divider cell */

  /* Allocate a new page. Insert the overflow cell from pPage
  ** into it. Then remove the overflow cell from pPage.
  */
  rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  pCell = pPage->aOvfl[0].pCell;
  szCell = cellSizePtr(pPage, pCell);
  zeroPage(pNew, pPage->aData[0]);
  assemblePage(pNew, 1, &pCell, &szCell);

      pNew = apNew[i] = apOld[i];
      pgnoNew[i] = pgnoOld[i];
      apOld[i] = 0;
      rc = sqlite3PagerWrite(pNew->pDbPage);
      if( rc ) goto balance_cleanup;
    }else{
      assert( i>0 );
      rc = allocateBtreePage(pBt, &pNew, &pgnoNew[i], pgnoNew[i-1], 0);
      if( rc ) goto balance_cleanup;
      apNew[i] = pNew;
    }
    nNew++;
    zeroPage(pNew, pageFlags);
  }

  u8 *cdata;          /* Content of the child page */
  int hdr;            /* Offset to page header in parent */
  int brk;            /* Offset to content of first cell in parent */

  assert( pPage->pParent==0 );
  assert( pPage->nOverflow>0 );
  pBt = pPage->pBt;
  rc = allocateBtreePage(pBt, &pChild, &pgnoChild, pPage->pgno, 0);
  if( rc ) return rc;
  assert( sqlite3PagerIswriteable(pChild->pDbPage) );
  usableSize = pBt->usableSize;
  data = pPage->aData;
  hdr = pPage->hdrOffset;
  brk = get2byte(&data[hdr+5]);
  cdata = pChild->aData;

  ** If an open cursor was using the page a problem would occur.
  */
  if( pBt->pCursor ){
    return SQLITE_LOCKED;
  }

#ifdef SQLITE_OMIT_AUTOVACUUM
  rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
  if( rc ) return rc;
#else
  if( pBt->autoVacuum ){
    Pgno pgnoMove;      /* Move a page here to make room for the root-page */
    MemPage *pPageMove; /* The page to move to. */

    /* Read the value of meta[3] from the database to determine where the

    }
    assert( pgnoRoot>=3 );

    /* Allocate a page. The page that currently resides at pgnoRoot will
    ** be moved to the allocated page (unless the allocated page happens
    ** to reside at pgnoRoot).
    */
    rc = allocateBtreePage(pBt, &pPageMove, &pgnoMove, pgnoRoot, 1);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    if( pgnoMove!=pgnoRoot ){
      u8 eType;
      Pgno iPtrPage;

    rc = sqlite3BtreeUpdateMeta(p, 4, pgnoRoot);
    if( rc ){
      releasePage(pRoot);
      return rc;
    }

  }else{
    rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
    if( rc ) return rc;
  }
#endif
  assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
  zeroPage(pRoot, flags | PTF_LEAF);
  sqlite3PagerUnref(pRoot->pDbPage);
  *piTable = (int)pgnoRoot;

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.416 2007/03/26 22:05:01 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.

    if( p->iDb==iDb && p->iTab==iTab ){
      p->isWriteLock = (p->isWriteLock || isWriteLock);
      return;
    }
  }

  nBytes = sizeof(TableLock) * (pParse->nTableLock+1);
  sqliteReallocOrFree(&pParse->aTableLock, nBytes);
  if( pParse->aTableLock ){
    p = &pParse->aTableLock[pParse->nTableLock++];
    p->iDb = iDb;
    p->iTab = iTab;
    p->isWriteLock = isWriteLock;
    p->zName = zName;
  }

**
** This routine allocates a new slot in the array, zeros it out,
** and returns its index.  If malloc fails a negative number is returned.
**
** szEntry is the sizeof of a single array entry.  initSize is the 
** number of array entries allocated on the initial allocation.
*/
int sqlite3ArrayAllocate(void *ppArray, int szEntry, int initSize){
  char *p;
  void **pp = (void**)ppArray;
  int *an = (int*)&pp[1];
  if( an[0]>=an[1] ){
    void *pNew;
    int newSize;
    newSize = an[1]*2 + initSize;
    pNew = sqliteRealloc(*pp, newSize*szEntry);
    if( pNew==0 ){
      return -1;
    }
    an[1] = newSize;
    *pp = pNew;
  }
  p = *pp;
  memset(&p[an[0]*szEntry], 0, szEntry);
  return an[0]++;
}

/*
** Append a new element to the given IdList.  Create a new IdList if
** need be.
**
** A new IdList is returned, or NULL if malloc() fails.
*/
IdList *sqlite3IdListAppend(IdList *pList, Token *pToken){
  int i;
  if( pList==0 ){
    pList = sqliteMalloc( sizeof(IdList) );
    if( pList==0 ) return 0;
    pList->nAlloc = 0;
  }
  i = sqlite3ArrayAllocate(&pList->a, sizeof(pList->a[0]), 5);
  if( i<0 ){
    sqlite3IdListDelete(pList);
    return 0;
  }
  pList->a[i].zName = sqlite3NameFromToken(pToken);
  return pList;
}

**    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 1.282 2007/03/26 22:05:01 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;
        sqliteReallocOrFree(&pParse->apVarExpr,
                       pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0]) );
      }
      if( !sqlite3MallocFailed() ){
        assert( pParse->apVarExpr!=0 );
        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
      }
    }

/*
** Add a new element to the pAggInfo->aCol[] array.  Return the index of
** the new element.  Return a negative number if malloc fails.
*/
static int addAggInfoColumn(AggInfo *pInfo){
  int i;
  i = sqlite3ArrayAllocate(&pInfo->aCol, sizeof(pInfo->aCol[0]), 3);
  if( i<0 ){
    return -1;
  }
  return i;
}    

/*
** Add a new element to the pAggInfo->aFunc[] array.  Return the index of
** the new element.  Return a negative number if malloc fails.
*/
static int addAggInfoFunc(AggInfo *pInfo){
  int i;
  i = sqlite3ArrayAllocate(&pInfo->aFunc, sizeof(pInfo->aFunc[0]), 2);
  if( i<0 ){
    return -1;
  }
  return i;
}    

/*

unsigned int sqlite3_pending_byte = 0x40000000;
#endif

int sqlite3_os_trace = 0;
#ifdef SQLITE_DEBUG
static int last_page = 0;
#define SEEK(X)           last_page=(X)
#define OSTRACE1(X)         if( sqlite3_os_trace ) sqlite3DebugPrintf(X)
#define OSTRACE2(X,Y)       if( sqlite3_os_trace ) sqlite3DebugPrintf(X,Y)
#define OSTRACE3(X,Y,Z)     if( sqlite3_os_trace ) sqlite3DebugPrintf(X,Y,Z)
#define OSTRACE4(X,Y,Z,A)   if( sqlite3_os_trace ) sqlite3DebugPrintf(X,Y,Z,A)
#define OSTRACE5(X,Y,Z,A,B) if( sqlite3_os_trace ) sqlite3DebugPrintf(X,Y,Z,A,B)
#define OSTRACE6(X,Y,Z,A,B,C) \
    if(sqlite3_os_trace) sqlite3DebugPrintf(X,Y,Z,A,B,C)
#define OSTRACE7(X,Y,Z,A,B,C,D) \
    if(sqlite3_os_trace) sqlite3DebugPrintf(X,Y,Z,A,B,C,D)
#else
#define SEEK(X)
#define OSTRACE1(X)
#define OSTRACE2(X,Y)
#define OSTRACE3(X,Y,Z)
#define OSTRACE4(X,Y,Z,A)
#define OSTRACE5(X,Y,Z,A,B)
#define OSTRACE6(X,Y,Z,A,B,C)
#define OSTRACE7(X,Y,Z,A,B,C,D)
#endif

/*
** Macros for performance tracing.  Normally turned off.  Only works
** on i486 hardware.
*/
#ifdef SQLITE_PERFORMANCE_TRACE

/*
** The default size of a disk sector
*/
#ifndef PAGER_SECTOR_SIZE
# define PAGER_SECTOR_SIZE 512
#endif

/*
** Delete the named file
*/
int sqlite3Os2Delete( const char *zFilename ){
  APIRET rc = NO_ERROR;

  rc = DosDelete( (PSZ)zFilename );
  OSTRACE2( "DELETE \"%s\"\n", zFilename );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
}

/*
** Return TRUE if the named file exists.
*/
int sqlite3Os2FileExists( const char *zFilename ){

    *pReadonly = 0;
  }
  f.h = hf;
  f.locktype = NO_LOCK;
  f.delOnClose = 0;
  f.pathToDel = NULL;
  OpenCounter(+1);
  OSTRACE3( "OPEN R/W %d \"%s\"\n", hf, zFilename );
  return allocateOs2File( &f, pld );
}


/*
** Attempt to open a new file for exclusive access by this process.
** The file will be opened for both reading and writing.  To avoid

  f.h = hf;
  f.locktype = NO_LOCK;
  f.delOnClose = delFlag ? 1 : 0;
  f.pathToDel = delFlag ? sqlite3OsFullPathname( zFilename ) : NULL;
  OpenCounter( +1 );
  if( delFlag ) DosForceDelete( sqlite3OsFullPathname( zFilename ) );
  OSTRACE3( "OPEN EX %d \"%s\"\n", hf, sqlite3OsFullPathname ( zFilename ) );
  return allocateOs2File( &f, pld );
}

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.

    return SQLITE_CANTOPEN;
  }
  f.h = hf;
  f.locktype = NO_LOCK;
  f.delOnClose = 0;
  f.pathToDel = NULL;
  OpenCounter( +1 );
  OSTRACE3( "OPEN RO %d \"%s\"\n", hf, zFilename );
  return allocateOs2File( &f, pld );
}

/*
** Attempt to open a file descriptor for the directory that contains a
** file.  This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written

      sqlite3Randomness( 15, &zBuf[j] );
      for( i = 0; i < 15; i++, j++ ){
        zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
      }
      zBuf[j] = 0;
      if( !sqlite3OsFileExists( zBuf ) ) break;
  }
  OSTRACE2( "TEMP FILENAME: %s\n", zBuf );
  return SQLITE_OK;
}

/*
** Close a file.
*/
int os2Close( OsFile **pld ){
  os2File *pFile;
  APIRET rc = NO_ERROR;
  if( pld && (pFile = (os2File*)*pld) != 0 ){
    OSTRACE2( "CLOSE %d\n", pFile->h );
    rc = DosClose( pFile->h );
    pFile->locktype = NO_LOCK;
    if( pFile->delOnClose != 0 ){
        rc = DosForceDelete( pFile->pathToDel );
    }
    *pld = 0;
    OpenCounter( -1 );

** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
int os2Read( OsFile *id, void *pBuf, int amt ){
  ULONG got;
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR );
  OSTRACE3( "READ %d lock=%d\n", ((os2File*)id)->h, ((os2File*)id)->locktype );
  DosRead( ((os2File*)id)->h, pBuf, amt, &got );
  if (got == (ULONG)amt)
    return SQLITE_OK;
  else if (got < 0)
    return SQLITE_IOERR_READ;
  else {
    memset(&((char*)pBuf)[got], 0, amt-got);

*/
int os2Write( OsFile *id, const void *pBuf, int amt ){
  APIRET rc = NO_ERROR;
  ULONG wrote;
  assert( id!=0 );
  SimulateIOError( return SQLITE_IOERR );
  SimulateDiskfullError( return SQLITE_FULL );
  OSTRACE3( "WRITE %d lock=%d\n", ((os2File*)id)->h, ((os2File*)id)->locktype );
  while( amt > 0 &&
      (rc = DosWrite( ((os2File*)id)->h, (PVOID)pBuf, amt, &wrote )) && wrote > 0 ){
      amt -= wrote;
      pBuf = &((char*)pBuf)[wrote];
  }

  return ( rc != NO_ERROR || amt > (int)wrote ) ? SQLITE_FULL : SQLITE_OK;
}

/*
** Move the read/write pointer in a file.
*/
int os2Seek( OsFile *id, i64 offset ){
  APIRET rc = NO_ERROR;
  ULONG filePointer = 0L;
  assert( id!=0 );
  rc = DosSetFilePtr( ((os2File*)id)->h, offset, FILE_BEGIN, &filePointer );
  OSTRACE3( "SEEK %d %lld\n", ((os2File*)id)->h, offset );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
}

/*
** Make sure all writes to a particular file are committed to disk.
*/
int os2Sync( OsFile *id, int dataOnly ){
  assert( id!=0 );
  OSTRACE3( "SYNC %d lock=%d\n", ((os2File*)id)->h, ((os2File*)id)->locktype );
  return DosResetBuffer( ((os2File*)id)->h ) == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;
}

/*
** Sync the directory zDirname. This is a no-op on operating systems other
** than UNIX.
*/
int sqlite3Os2SyncDirectory( const char *zDirname ){
  SimulateIOError( return SQLITE_IOERR );
  return SQLITE_OK;
}

/*
** Truncate an open file to a specified size
*/
int os2Truncate( OsFile *id, i64 nByte ){
  APIRET rc = NO_ERROR;
  ULONG upperBits = nByte>>32;
  assert( id!=0 );
  OSTRACE3( "TRUNCATE %d %lld\n", ((os2File*)id)->h, nByte );
  SimulateIOError( return SQLITE_IOERR );
  rc = DosSetFilePtr( ((os2File*)id)->h, nByte, FILE_BEGIN, &upperBits );
  if( rc != NO_ERROR ){
    return SQLITE_IOERR;
  }
  rc = DosSetFilePtr( ((os2File*)id)->h, 0L, FILE_END, &upperBits );
  return rc == NO_ERROR ? SQLITE_OK : SQLITE_IOERR;

  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
  FILELOCK  LockArea,
            UnlockArea;
  os2File *pFile = (os2File*)id;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  assert( pFile!=0 );
  OSTRACE4( "LOCK %d %d was %d\n", pFile->h, locktype, pFile->locktype );

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3OsEnterMutex() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    return SQLITE_OK;

    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;

    while( cnt-->0 && (res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 2000L, 1L) )!=NO_ERROR ){
      /* Try 3 times to get the pending lock.  The pending lock might be
      ** held by another reader process who will release it momentarily.
      */
      OSTRACE2( "could not get a PENDING lock. cnt=%d\n", cnt );
      DosSleep(1);
    }
    gotPendingLock = res;
  }

  /* Acquire a shared lock
  */

  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE2( "unreadlock = %d\n", res );
    LockArea.lOffset = SHARED_FIRST;
    LockArea.lRange = SHARED_SIZE;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    res = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 2000L, 1L );
    if( res == NO_ERROR ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      OSTRACE2( "error-code = %d\n", res );
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = PENDING_BYTE;
    UnlockArea.lRange = 1L;
    DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 2000L, 1L );
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res == NO_ERROR ){
    rc = SQLITE_OK;
  }else{
    OSTRACE4( "LOCK FAILED %d trying for %d but got %d\n", pFile->h,
           locktype, newLocktype );
    rc = SQLITE_BUSY;
  }
  pFile->locktype = newLocktype;
  return rc;
}

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, return
** non-zero, otherwise zero.
*/
int os2CheckReservedLock( OsFile *id ){
  APIRET rc = NO_ERROR;
  os2File *pFile = (os2File*)id;
  assert( pFile!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    rc = 1;
    OSTRACE3( "TEST WR-LOCK %d %d (local)\n", pFile->h, rc );
  }else{
    FILELOCK  LockArea,
              UnlockArea;
    memset(&LockArea, 0, sizeof(LockArea));
    memset(&UnlockArea, 0, sizeof(UnlockArea));
    LockArea.lOffset = RESERVED_BYTE;
    LockArea.lRange = 1L;
    UnlockArea.lOffset = 0L;
    UnlockArea.lRange = 0L;
    rc = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 2000L, 1L );
    if( rc == NO_ERROR ){
      LockArea.lOffset = 0L;
      LockArea.lRange = 0L;
      UnlockArea.lOffset = RESERVED_BYTE;
      UnlockArea.lRange = 1L;
      rc = DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 2000L, 1L );
    }
    OSTRACE3( "TEST WR-LOCK %d %d (remote)\n", pFile->h, rc );
  }
  return rc;
}

/*
** Lower the locking level on file descriptor id to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.

  os2File *pFile = (os2File*)id;
  FILELOCK  LockArea,
            UnlockArea;
  memset(&LockArea, 0, sizeof(LockArea));
  memset(&UnlockArea, 0, sizeof(UnlockArea));
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE4( "UNLOCK %d to %d was %d\n", pFile->h, locktype, pFile->locktype );
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    LockArea.lOffset = 0L;
    LockArea.lRange = 0L;
    UnlockArea.lOffset = SHARED_FIRST;
    UnlockArea.lRange = SHARED_SIZE;
    DosSetFileLocks( pFile->h, &UnlockArea, &LockArea, 2000L, 1L );

  if( threadsOverrideEachOthersLocks ){
    /* Ownership transfers not needed on this system */
    return SQLITE_OK;
  }
  hSelf = pthread_self();
  if( pthread_equal(pFile->tid, hSelf) ){
    /* We are still in the same thread */
    OSTRACE1("No-transfer, same thread\n");
    return SQLITE_OK;
  }
  if( pFile->locktype!=NO_LOCK ){
    /* We cannot change ownership while we are holding a lock! */
    return SQLITE_MISUSE;
  }
  OSTRACE4("Transfer ownership of %d from %d to %d\n",
            pFile->h, pFile->tid, hSelf);
  pFile->tid = hSelf;
  if (pFile->pLock != NULL) {
    releaseLockInfo(pFile->pLock);
    rc = findLockInfo(pFile->h, &pFile->pLock, 0);
    OSTRACE5("LOCK    %d is now %s(%s,%d)\n", pFile->h,
           locktypeName(pFile->locktype),
           locktypeName(pFile->pLock->locktype), pFile->pLock->cnt);
    return rc;
  } else {
    return SQLITE_OK;
  }
}

  }
  SET_THREADID(pFile);
  assert( pFile->dirfd<0 );
  pFile->dirfd = open(zDirname, O_RDONLY|O_BINARY, 0);
  if( pFile->dirfd<0 ){
    return SQLITE_CANTOPEN; 
  }
  OSTRACE3("OPENDIR %-3d %s\n", pFile->dirfd, zDirname);
  return SQLITE_OK;
}

/*
** If the following global variable points to a string which is the
** name of a directory, then that directory will be used to store
** temporary files.

  newOffset = lseek(id->h, id->offset, SEEK_SET);
  if( newOffset!=id->offset ){
    return -1;
  }
  got = read(id->h, pBuf, cnt);
#endif
  TIMER_END;
  OSTRACE5("READ    %-3d %5d %7lld %d\n", id->h, got, id->offset, TIMER_ELAPSED);
  if( got>0 ){
    id->offset += got;
  }
  return got;
}

/*

  newOffset = lseek(id->h, id->offset, SEEK_SET);
  if( newOffset!=id->offset ){
    return -1;
  }
  got = write(id->h, pBuf, cnt);
#endif
  TIMER_END;
  OSTRACE5("WRITE   %-3d %5d %7lld %d\n", id->h, got, id->offset, TIMER_ELAPSED);
  if( got>0 ){
    id->offset += got;
  }
  return got;
}

** the directory entry for the journal was never created) and the transaction
** will not roll back - possibly leading to database corruption.
*/
static int unixSync(OsFile *id, int dataOnly){
  int rc;
  unixFile *pFile = (unixFile*)id;
  assert( pFile );
  OSTRACE2("SYNC    %-3d\n", pFile->h);
  rc = full_fsync(pFile->h, pFile->fullSync, dataOnly);
  SimulateIOError( rc=1 );
  if( rc ){
    return SQLITE_IOERR_FSYNC;
  }
  if( pFile->dirfd>=0 ){
    OSTRACE4("DIRSYNC %-3d (have_fullfsync=%d fullsync=%d)\n", pFile->dirfd,
            HAVE_FULLFSYNC, pFile->fullSync);
#ifndef SQLITE_DISABLE_DIRSYNC
    /* The directory sync is only attempted if full_fsync is
    ** turned off or unavailable.  If a full_fsync occurred above,
    ** then the directory sync is superfluous.
    */
    if( (!HAVE_FULLFSYNC || !pFile->fullSync) && full_fsync(pFile->dirfd,0,0) ){

int sqlite3UnixSyncDirectory(const char *zDirname){
#ifdef SQLITE_DISABLE_DIRSYNC
  return SQLITE_OK;
#else
  int fd;
  int r;
  fd = open(zDirname, O_RDONLY|O_BINARY, 0);
  OSTRACE3("DIRSYNC %-3d (%s)\n", fd, zDirname);
  if( fd<0 ){
    return SQLITE_CANTOPEN; 
  }
  r = fsync(fd);
  close(fd);
  SimulateIOError( r=1 );
  if( r ){

    fcntl(pFile->h, F_GETLK, &lock);
    if( lock.l_type!=F_UNLCK ){
      r = 1;
    }
  }
  
  sqlite3OsLeaveMutex();
  OSTRACE3("TEST WR-LOCK %d %d\n", pFile->h, r);

  return r;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:

  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  struct lockInfo *pLock = pFile->pLock;
  struct flock lock;
  int s;

  assert( pFile );
  OSTRACE7("LOCK    %d %s was %s(%s,%d) pid=%d\n", pFile->h,
      locktypeName(locktype), locktypeName(pFile->locktype),
      locktypeName(pLock->locktype), pLock->cnt , getpid());

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3OsEnterMutex() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    OSTRACE3("LOCK    %d %s ok (already held)\n", pFile->h,
            locktypeName(locktype));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct
  */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );

  }else if( locktype==EXCLUSIVE_LOCK ){
    pFile->locktype = PENDING_LOCK;
    pLock->locktype = PENDING_LOCK;
  }

end_lock:
  sqlite3OsLeaveMutex();
  OSTRACE4("LOCK    %d %s %s\n", pFile->h, locktypeName(locktype), 
      rc==SQLITE_OK ? "ok" : "failed");
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int unixUnlock(OsFile *id, int locktype){
  struct lockInfo *pLock;
  struct flock lock;
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;

  assert( pFile );
  OSTRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d\n", pFile->h, locktype,
      pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());

  assert( locktype<=SHARED_LOCK );
  if( pFile->locktype<=locktype ){
    return SQLITE_OK;
  }
  if( CHECK_THREADID(pFile) ){

    close(id->h);
  }
  releaseLockInfo(id->pLock);
  releaseOpenCnt(id->pOpen);

  sqlite3OsLeaveMutex();
  id->isOpen = 0;
  OSTRACE2("CLOSE   %-3d\n", id->h);
  OpenCounter(-1);
  sqlite3ThreadSafeFree(id);
  *pId = 0;
  return SQLITE_OK;
}

  int                     err;
  
  pb.unLockFlag = setLockFlag ? 0 : 1;
  pb.startEndFlag = 0;
  pb.offset = offset;
  pb.length = length; 
  pb.fd = fd;
  OSTRACE5("AFPLOCK setting lock %s for %d in range %llx:%llx\n", 
    (setLockFlag?"ON":"OFF"), fd, offset, length);
  err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
  if ( err==-1 ) {
    OSTRACE4("AFPLOCK failed to fsctl() '%s' %d %s\n", path, errno, 
      strerror(errno));
    return 1; // error
  } else {
    return 0;
  }
}

      r = 1;
    } else {
      /* if we succeeded in taking the reserved lock, unlock it to restore
      ** the original state */
      _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1, 0);
    }
  }
  OSTRACE3("TEST WR-LOCK %d %d\n", pFile->h, r);
  
  return r;
}

/* AFP-style locking following the behavior of unixLock, see the unixLock 
** function comments for details of lock management. */
static int afpUnixLock(OsFile *id, int locktype)
{
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  int gotPendingLock = 0;
  
  assert( pFile );
  OSTRACE5("LOCK    %d %s was %s pid=%d\n", pFile->h,
         locktypeName(locktype), locktypeName(pFile->locktype), getpid());  
  /* If there is already a lock of this type or more restrictive on the
    ** OsFile, do nothing. Don't use the afp_end_lock: exit path, as
    ** sqlite3OsEnterMutex() hasn't been called yet.
    */
  if( pFile->locktype>=locktype ){
    OSTRACE3("LOCK    %d %s ok (already held)\n", pFile->h,
           locktypeName(locktype));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct
    */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );

    pFile->locktype = locktype;
  }else if( locktype==EXCLUSIVE_LOCK ){
    pFile->locktype = PENDING_LOCK;
  }
  
afp_end_lock:
    sqlite3OsLeaveMutex();
  OSTRACE4("LOCK    %d %s %s\n", pFile->h, locktypeName(locktype), 
         rc==SQLITE_OK ? "ok" : "failed");
  return rc;
}

/*
 ** Lower the locking level on file descriptor pFile to locktype.  locktype
 ** must be either NO_LOCK or SHARED_LOCK.
 **
 ** If the locking level of the file descriptor is already at or below
 ** the requested locking level, this routine is a no-op.
 */
static int afpUnixUnlock(OsFile *id, int locktype) {
  struct flock lock;
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;

  assert( pFile );
  OSTRACE5("UNLOCK  %d %d was %d pid=%d\n", pFile->h, locktype,
         pFile->locktype, getpid());
  
  assert( locktype<=SHARED_LOCK );
  if( pFile->locktype<=locktype ){
    return SQLITE_OK;
  }
  if( CHECK_THREADID(pFile) ){

    sqlite3ThreadSafeFree(id->lockingContext);
  }
  
  if( id->dirfd>=0 ) close(id->dirfd);
  id->dirfd = -1;
  close(id->h);
  id->isOpen = 0;
  OSTRACE2("CLOSE   %-3d\n", id->h);
  OpenCounter(-1);
  sqlite3ThreadSafeFree(id);
  *pId = 0;
  return SQLITE_OK;
}

  if( id->dirfd>=0 ) close(id->dirfd);
  id->dirfd = -1;
  sqlite3OsEnterMutex();
  
  close(id->h);  
  sqlite3OsLeaveMutex();
  id->isOpen = 0;
  OSTRACE2("CLOSE   %-3d\n", id->h);
  OpenCounter(-1);
  sqlite3ThreadSafeFree(id);
  *pId = 0;
  return SQLITE_OK;
}

#pragma mark Old-School .lock file based locking

  id->dirfd = -1;
  sqlite3OsEnterMutex();
  
  close(id->h);
  
  sqlite3OsLeaveMutex();
  id->isOpen = 0;
  OSTRACE2("CLOSE   %-3d\n", id->h);
  OpenCounter(-1);
  sqlite3ThreadSafeFree(id);
  *pId = 0;
  return SQLITE_OK;
}

  id->dirfd = -1;
  sqlite3OsEnterMutex();
  
  close(id->h);
  
  sqlite3OsLeaveMutex();
  id->isOpen = 0;
  OSTRACE2("CLOSE   %-3d\n", id->h);
  OpenCounter(-1);
  sqlite3ThreadSafeFree(id);
  *pId = 0;
  return SQLITE_OK;
}

#endif /* SQLITE_ENABLE_LOCKING_STYLE */

  if( delFlag ){
    unlink(zFilename);
  }
  if( rc ){
    close(h);
    return SQLITE_NOMEM;
  }
  OSTRACE3("OPEN    %-3d %s\n", h, zFilename);
  f.dirfd = -1;
  f.fullSync = 0;
  f.locktype = 0;
  f.offset = 0;
  f.h = h;
  SET_THREADID(&f);
  pNew = sqlite3ThreadSafeMalloc( sizeof(unixFile) );

    do{
      rc = DeleteFileA(zConverted);
    }while( rc==0 && GetFileAttributesA(zConverted)!=0xffffffff
            && cnt++ < MX_DELETION_ATTEMPTS && (Sleep(100), 1) );
#endif
  }
  sqliteFree(zConverted);
  OSTRACE2("DELETE \"%s\"\n", zFilename);
  return rc!=0 ? SQLITE_OK : SQLITE_IOERR;
}

/*
** Return TRUE if the named file exists.
*/
int sqlite3WinFileExists(const char *zFilename){

  sqliteFree(zConverted);

  f.h = h;
#if OS_WINCE
  f.zDeleteOnClose = 0;
#endif
  OSTRACE3("OPEN R/W %d \"%s\"\n", h, zFilename);
  return allocateWinFile(&f, pId);
}


/*
** Attempt to open a new file for exclusive access by this process.
** The file will be opened for both reading and writing.  To avoid

  f.hMutex = NULL;
#endif
  sqliteFree(zConverted);
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  f.h = h;
  OSTRACE3("OPEN EX %d \"%s\"\n", h, zFilename);
  return allocateWinFile(&f, pId);
}

/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.

    return SQLITE_CANTOPEN;
  }
  f.h = h;
#if OS_WINCE
  f.zDeleteOnClose = 0;
  f.hMutex = NULL;
#endif
  OSTRACE3("OPEN RO %d \"%s\"\n", h, zFilename);
  return allocateWinFile(&f, pId);
}

/*
** Attempt to open a file descriptor for the directory that contains a
** file.  This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written

    sqlite3Randomness(15, &zBuf[j]);
    for(i=0; i<15; i++, j++){
      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
    }
    zBuf[j] = 0;
    if( !sqlite3OsFileExists(zBuf) ) break;
  }
  OSTRACE2("TEMP FILENAME: %s\n", zBuf);
  return SQLITE_OK; 
}

/*
** Close a file.
**
** It is reported that an attempt to close a handle might sometimes
** fail.  This is a very unreasonable result, but windows is notorious
** for being unreasonable so I do not doubt that it might happen.  If
** the close fails, we pause for 100 milliseconds and try again.  As
** many as MX_CLOSE_ATTEMPT attempts to close the handle are made before
** giving up and returning an error.
*/
#define MX_CLOSE_ATTEMPT 3
static int winClose(OsFile **pId){
  winFile *pFile;
  int rc = 1;
  if( pId && (pFile = (winFile*)*pId)!=0 ){
    int rc, cnt = 0;
    OSTRACE2("CLOSE %d\n", pFile->h);
    do{
      rc = CloseHandle(pFile->h);
    }while( rc==0 && cnt++ < MX_CLOSE_ATTEMPT && (Sleep(100), 1) );
#if OS_WINCE
    winceDestroyLock(pFile);
    if( pFile->zDeleteOnClose ){
      DeleteFileW(pFile->zDeleteOnClose);

** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
static int winRead(OsFile *id, void *pBuf, int amt){
  DWORD got;
  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_READ);
  OSTRACE3("READ %d lock=%d\n", ((winFile*)id)->h, ((winFile*)id)->locktype);
  if( !ReadFile(((winFile*)id)->h, pBuf, amt, &got, 0) ){
    return SQLITE_IOERR_READ;
  }
  if( got==(DWORD)amt ){
    return SQLITE_OK;
  }else{
    memset(&((char*)pBuf)[got], 0, amt-got);

*/
static int winWrite(OsFile *id, const void *pBuf, int amt){
  int rc = 0;
  DWORD wrote;
  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_READ);
  SimulateDiskfullError(return SQLITE_FULL);
  OSTRACE3("WRITE %d lock=%d\n", ((winFile*)id)->h, ((winFile*)id)->locktype);
  assert( amt>0 );
  while( amt>0 && (rc = WriteFile(((winFile*)id)->h, pBuf, amt, &wrote, 0))!=0
         && wrote>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
  }
  if( !rc || amt>(int)wrote ){

  DWORD rc;
  assert( id!=0 );
#ifdef SQLITE_TEST
  if( offset ) SimulateDiskfullError(return SQLITE_FULL);
#endif
  SEEK(offset/1024 + 1);
  rc = SetFilePointer(((winFile*)id)->h, lowerBits, &upperBits, FILE_BEGIN);
  OSTRACE3("SEEK %d %lld\n", ((winFile*)id)->h, offset);
  if( rc==INVALID_SET_FILE_POINTER && GetLastError()!=NO_ERROR ){
    return SQLITE_FULL;
  }
  return SQLITE_OK;
}

/*
** Make sure all writes to a particular file are committed to disk.
*/
static int winSync(OsFile *id, int dataOnly){
  assert( id!=0 );
  OSTRACE3("SYNC %d lock=%d\n", ((winFile*)id)->h, ((winFile*)id)->locktype);
  if( FlushFileBuffers(((winFile*)id)->h) ){
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR;
  }
}

/*
** Truncate an open file to a specified size
*/
static int winTruncate(OsFile *id, i64 nByte){
  LONG upperBits = nByte>>32;
  assert( id!=0 );
  OSTRACE3("TRUNCATE %d %lld\n", ((winFile*)id)->h, nByte);
  SimulateIOError(return SQLITE_IOERR_TRUNCATE);
  SetFilePointer(((winFile*)id)->h, nByte, &upperBits, FILE_BEGIN);
  SetEndOfFile(((winFile*)id)->h);
  return SQLITE_OK;
}

/*

  int rc = SQLITE_OK;    /* Return code from subroutines */
  int res = 1;           /* Result of a windows lock call */
  int newLocktype;       /* Set id->locktype to this value before exiting */
  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
  winFile *pFile = (winFile*)id;

  assert( pFile!=0 );
  OSTRACE5("LOCK %d %d was %d(%d)\n",
          pFile->h, locktype, pFile->locktype, pFile->sharedLockByte);

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3OsEnterMutex() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){

   || (locktype==EXCLUSIVE_LOCK && pFile->locktype==RESERVED_LOCK)
  ){
    int cnt = 3;
    while( cnt-->0 && (res = LockFile(pFile->h, PENDING_BYTE, 0, 1, 0))==0 ){
      /* Try 3 times to get the pending lock.  The pending lock might be
      ** held by another reader process who will release it momentarily.
      */
      OSTRACE2("could not get a PENDING lock. cnt=%d\n", cnt);
      Sleep(1);
    }
    gotPendingLock = res;
  }

  /* Acquire a shared lock
  */

  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE2("unreadlock = %d\n", res);
    res = LockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( res ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      OSTRACE2("error-code = %d\n", GetLastError());
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    UnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res ){
    rc = SQLITE_OK;
  }else{
    OSTRACE4("LOCK FAILED %d trying for %d but got %d\n", pFile->h,
           locktype, newLocktype);
    rc = SQLITE_BUSY;
  }
  pFile->locktype = newLocktype;
  return rc;
}

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, return
** non-zero, otherwise zero.
*/
static int winCheckReservedLock(OsFile *id){
  int rc;
  winFile *pFile = (winFile*)id;
  assert( pFile!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    rc = 1;
    OSTRACE3("TEST WR-LOCK %d %d (local)\n", pFile->h, rc);
  }else{
    rc = LockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    if( rc ){
      UnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    }
    rc = !rc;
    OSTRACE3("TEST WR-LOCK %d %d (remote)\n", pFile->h, rc);
  }
  return rc;
}

/*
** Lower the locking level on file descriptor id to locktype.  locktype
** must be either NO_LOCK or SHARED_LOCK.

*/
static int winUnlock(OsFile *id, int locktype){
  int type;
  int rc = SQLITE_OK;
  winFile *pFile = (winFile*)id;
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE5("UNLOCK %d to %d was %d(%d)\n", pFile->h, locktype,
          pFile->locktype, pFile->sharedLockByte);
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    UnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !getReadLock(pFile) ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.300 2007/03/26 22:05:02 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

/*
** Macros for troubleshooting.  Normally turned off
*/
#if 0
#define sqlite3DebugPrintf printf
#define PAGERTRACE1(X)       sqlite3DebugPrintf(X)
#define PAGERTRACE2(X,Y)     sqlite3DebugPrintf(X,Y)
#define PAGERTRACE3(X,Y,Z)   sqlite3DebugPrintf(X,Y,Z)
#define PAGERTRACE4(X,Y,Z,W) sqlite3DebugPrintf(X,Y,Z,W)
#define PAGERTRACE5(X,Y,Z,W,V) sqlite3DebugPrintf(X,Y,Z,W,V)
#else
#define PAGERTRACE1(X)
#define PAGERTRACE2(X,Y)
#define PAGERTRACE3(X,Y,Z)
#define PAGERTRACE4(X,Y,Z,W)
#define PAGERTRACE5(X,Y,Z,W,V)
#endif

/*
** The following two macros are used within the PAGERTRACEX() macros above
** to print out file-descriptors. 
**
** PAGERID() takes a pointer to a Pager struct as it's argument. The
** associated file-descriptor is returned. FILEHANDLEID() takes an OsFile
** struct as it's argument.
*/
#define PAGERID(p) ((int)(p->fd))

  ** content.  Two conditions must be met before writing to the database
  ** files. (1) the database must be locked.  (2) we know that the original
  ** page content is in the main journal either because the page is not in
  ** cache or else it is marked as needSync==0.
  */
  pPg = pager_lookup(pPager, pgno);
  assert( pPager->state>=PAGER_EXCLUSIVE || pPg!=0 );
  PAGERTRACE3("PLAYBACK %d page %d\n", PAGERID(pPager), pgno);
  if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0) ){
    rc = sqlite3OsSeek(pPager->fd, (pgno-1)*(i64)pPager->pageSize);
    if( rc==SQLITE_OK ){
      rc = sqlite3OsWrite(pPager->fd, aData, pPager->pageSize);
    }
    if( pPg ){
      makeClean(pPg);

    char *zBuf = pPager->pTmpSpace;        /* Temp storage for one page */
    if( !pPg->dirty ) continue;
    if( (int)pPg->pgno <= pPager->origDbSize ){
      rc = sqlite3OsSeek(pPager->fd, pPager->pageSize*(i64)(pPg->pgno-1));
      if( rc==SQLITE_OK ){
        rc = sqlite3OsRead(pPager->fd, zBuf, pPager->pageSize);
      }
      PAGERTRACE3("REFETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      if( rc ) break;
      CODEC1(pPager, zBuf, pPg->pgno, 2);
    }else{
      memset(zBuf, 0, pPager->pageSize);
    }
    if( pPg->nRef==0 || memcmp(zBuf, PGHDR_TO_DATA(pPg), pPager->pageSize) ){
      memcpy(PGHDR_TO_DATA(pPg), zBuf, pPager->pageSize);

  if( !pPager || !zFullPathname || !pPager->pTmpSpace || rc!=SQLITE_OK ){
    sqlite3OsClose(&fd);
    sqliteFree(zFullPathname);
    sqliteFree(pPager);
    return ((rc==SQLITE_OK)?SQLITE_NOMEM:rc);
  }

  PAGERTRACE3("OPEN %d %s\n", FILEHANDLEID(fd), zFullPathname);
  IOTRACE(("OPEN %p %s\n", pPager, zFullPathname))
  pPager->zFilename = (char*)&pPager[1];
  pPager->zDirectory = &pPager->zFilename[nameLen+1];
  pPager->zJournal = &pPager->zDirectory[nameLen+1];
  strcpy(pPager->zFilename, zFullPathname);
  strcpy(pPager->zDirectory, zFullPathname);

** and returned.
*/
int sqlite3PagerSetPagesize(Pager *pPager, int pageSize){
  assert( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE );
  if( !pPager->memDb && pPager->nRef==0 ){
    pager_reset(pPager);
    pPager->pageSize = pageSize;
    sqlite3ReallocOrFree(&pPager->pTmpSpace, pageSize);
  }
  return pPager->pageSize;
}

/*
** The following set of routines are used to disable the simulated
** I/O error mechanism.  These routines are used to avoid simulated

  disable_simulated_io_errors();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
  pager_reset(pPager);
  pagerUnlockAndRollback(pPager);
  enable_simulated_io_errors();
  PAGERTRACE2("CLOSE %d\n", PAGERID(pPager));
  IOTRACE(("CLOSE %p\n", pPager))
  assert( pPager->errCode || (pPager->journalOpen==0 && pPager->stmtOpen==0) );
  if( pPager->journalOpen ){
    sqlite3OsClose(&pPager->jfd);
  }
  sqliteFree(pPager->aInJournal);
  if( pPager->stmtOpen ){

      {
        /* Write the nRec value into the journal file header. If in
        ** full-synchronous mode, sync the journal first. This ensures that
        ** all data has really hit the disk before nRec is updated to mark
        ** it as a candidate for rollback. 
        */
        if( pPager->fullSync ){
          PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
          IOTRACE(("JSYNC %p\n", pPager))
          rc = sqlite3OsSync(pPager->jfd, 0);
          if( rc!=0 ) return rc;
        }
        rc = sqlite3OsSeek(pPager->jfd,
                           pPager->journalHdr + sizeof(aJournalMagic));
        if( rc ) return rc;
        IOTRACE(("JHDR %p %lld %d\n", pPager,
                  pPager->journalHdr + sizeof(aJournalMagic), 4))
        rc = write32bits(pPager->jfd, pPager->nRec);
        if( rc ) return rc;

        rc = sqlite3OsSeek(pPager->jfd, pPager->journalOff);
        if( rc ) return rc;
      }
      PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
      IOTRACE(("JSYNC %d\n", pPager))
      rc = sqlite3OsSync(pPager->jfd, pPager->full_fsync);
      if( rc!=0 ) return rc;
      pPager->journalStarted = 1;
    }
    pPager->needSync = 0;

    /* If there are dirty pages in the page cache with page numbers greater
    ** than Pager.dbSize, this means sqlite3PagerTruncate() was called to
    ** make the file smaller (presumably by auto-vacuum code). Do not write
    ** any such pages to the file.
    */
    if( pList->pgno<=pPager->dbSize ){
      char *pData = CODEC2(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
      PAGERTRACE3("STORE %d page %d\n", PAGERID(pPager), pList->pgno);
      IOTRACE(("PGOUT %p %d\n", pPager, pList->pgno))
      rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize);
      TEST_INCR(pPager->nWrite);
    }
#ifndef NDEBUG
    else{
      PAGERTRACE3("NOSTORE %d page %d\n", PAGERID(pPager), pList->pgno);
    }
#endif
    if( rc ) return rc;
    pList->dirty = 0;
#ifdef SQLITE_CHECK_PAGES
    pList->pageHash = pager_pagehash(pList);
#endif

      assert( MEMDB==0 );
      rc = sqlite3OsSeek(pPager->fd, (pgno-1)*(i64)pPager->pageSize);
      if( rc==SQLITE_OK ){
        rc = sqlite3OsRead(pPager->fd, PGHDR_TO_DATA(pPg),
                              pPager->pageSize);
      }
      IOTRACE(("PGIN %p %d\n", pPager, pgno))
      PAGERTRACE3("FETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      CODEC1(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
      if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
        pPg->pgno = 0;
        sqlite3PagerUnref(pPg);
        return rc;
      }else{
        TEST_INCR(pPager->nRead);

          rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
        }
      }
      if( rc!=SQLITE_OK ){
        return rc;
      }
      pPager->dirtyCache = 0;
      PAGERTRACE2("TRANSACTION %d\n", PAGERID(pPager));
      if( pPager->useJournal && !pPager->tempFile ){
        rc = pager_open_journal(pPager);
      }
    }
  }else if( pPager->journalOpen && pPager->journalOff==0 ){
    /* This happens when the pager was in exclusive-access mode last
    ** time a (read or write) transaction was successfully concluded

    ** the transaction journal if it is not there already.
    */
    if( !pPg->inJournal && (pPager->useJournal || MEMDB) ){
      if( (int)pPg->pgno <= pPager->origDbSize ){
        int szPg;
        if( MEMDB ){
          PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
          PAGERTRACE3("JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
          assert( pHist->pOrig==0 );
          pHist->pOrig = sqliteMallocRaw( pPager->pageSize );
          if( pHist->pOrig ){
            memcpy(pHist->pOrig, PGHDR_TO_DATA(pPg), pPager->pageSize);
          }
        }else{
          u32 cksum, saved;

          put32bits(pEnd, cksum);
          szPg = pPager->pageSize+8;
          put32bits(pData2, pPg->pgno);
          rc = sqlite3OsWrite(pPager->jfd, pData2, szPg);
          IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno,
                   pPager->journalOff, szPg))
          pPager->journalOff += szPg;
          PAGERTRACE4("JOURNAL %d page %d needSync=%d\n",
                  PAGERID(pPager), pPg->pgno, pPg->needSync);
          *(u32*)pEnd = saved;

	  /* An error has occured writing to the journal file. The 
          ** transaction will be rolled back by the layer above.
          */
          if( rc!=SQLITE_OK ){

          if( pPager->stmtInUse ){
            pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
            page_add_to_stmt_list(pPg);
          }
        }
      }else{
        pPg->needSync = !pPager->journalStarted && !pPager->noSync;
        PAGERTRACE4("APPEND %d page %d needSync=%d\n",
                PAGERID(pPager), pPg->pgno, pPg->needSync);
      }
      if( pPg->needSync ){
        pPager->needSync = 1;
      }
      pPg->inJournal = 1;
    }

      if( MEMDB ){
        PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
        assert( pHist->pStmt==0 );
        pHist->pStmt = sqliteMallocRaw( pPager->pageSize );
        if( pHist->pStmt ){
          memcpy(pHist->pStmt, PGHDR_TO_DATA(pPg), pPager->pageSize);
        }
        PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
      }else{
        char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7)-4;
        put32bits(pData2, pPg->pgno);
        rc = sqlite3OsWrite(pPager->stfd, pData2, pPager->pageSize+4);
        PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
        if( rc!=SQLITE_OK ){
          return rc;
        }
        pPager->stmtNRec++;
        assert( pPager->aInStmt!=0 );
        pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
      }

      ** When the database file grows, we must make sure that the last page
      ** gets written at least once so that the disk file will be the correct
      ** size. If you do not write this page and the size of the file
      ** on the disk ends up being too small, that can lead to database
      ** corruption during the next transaction.
      */
    }else{
      PAGERTRACE3("DONT_WRITE page %d of %d\n", pgno, PAGERID(pPager));
      IOTRACE(("CLEAN %p %d\n", pPager, pgno))
      makeClean(pPg);
#ifdef SQLITE_CHECK_PAGES
      pPg->pageHash = pager_pagehash(pPg);
#endif
    }
  }

    assert( pPager->aInJournal!=0 );
    pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    pPg->inJournal = 1;
    if( pPager->stmtInUse ){
      pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
      page_add_to_stmt_list(pPg);
    }
    PAGERTRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager));
    IOTRACE(("GARBAGE %p %d\n", pPager, pPg->pgno))
  }
  if( pPager->stmtInUse && !pPg->inStmt && (int)pPg->pgno<=pPager->stmtSize ){
    assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
    assert( pPager->aInStmt!=0 );
    pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    page_add_to_stmt_list(pPg);

  if( pPager->errCode ){
    return pPager->errCode;
  }
  if( pPager->state<PAGER_RESERVED ){
    return SQLITE_ERROR;
  }
  PAGERTRACE2("COMMIT %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPg = pager_get_all_dirty_pages(pPager);
    while( pPg ){
      clearHistory(PGHDR_TO_HIST(pPg, pPager));
      pPg->dirty = 0;
      pPg->inJournal = 0;
      pPg->inStmt = 0;

** process is writing trash into the journal file (SQLITE_CORRUPT) or
** unless a prior malloc() failed (SQLITE_NOMEM).  Appropriate error
** codes are returned for all these occasions.  Otherwise,
** SQLITE_OK is returned.
*/
int sqlite3PagerRollback(Pager *pPager){
  int rc;
  PAGERTRACE2("ROLLBACK %d\n", PAGERID(pPager));
  if( MEMDB ){
    PgHdr *p;
    for(p=pPager->pAll; p; p=p->pNextAll){
      PgHistory *pHist;
      assert( !p->alwaysRollback );
      if( !p->dirty ){
        assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pOrig );
        assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pStmt );
        continue;
      }

      pHist = PGHDR_TO_HIST(p, pPager);
      if( pHist->pOrig ){
        memcpy(PGHDR_TO_DATA(p), pHist->pOrig, pPager->pageSize);
        PAGERTRACE3("ROLLBACK-PAGE %d of %d\n", p->pgno, PAGERID(pPager));
      }else{
        PAGERTRACE3("PAGE %d is clean on %d\n", p->pgno, PAGERID(pPager));
      }
      clearHistory(pHist);
      p->dirty = 0;
      p->inJournal = 0;
      p->inStmt = 0;
      p->pPrevStmt = p->pNextStmt = 0;
      if( pPager->xReiniter ){

** changes of a single SQL command within a larger transaction.
*/
int sqlite3PagerStmtBegin(Pager *pPager){
  int rc;
  assert( !pPager->stmtInUse );
  assert( pPager->state>=PAGER_SHARED );
  assert( pPager->dbSize>=0 );
  PAGERTRACE2("STMT-BEGIN %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPager->stmtInUse = 1;
    pPager->stmtSize = pPager->dbSize;
    return SQLITE_OK;
  }
  if( !pPager->journalOpen ){
    pPager->stmtAutoopen = 1;

/*
** Commit a statement.
*/
int sqlite3PagerStmtCommit(Pager *pPager){
  if( pPager->stmtInUse ){
    PgHdr *pPg, *pNext;
    PAGERTRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
    if( !MEMDB ){
      sqlite3OsSeek(pPager->stfd, 0);
      /* sqlite3OsTruncate(pPager->stfd, 0); */
      sqliteFree( pPager->aInStmt );
      pPager->aInStmt = 0;
    }
    for(pPg=pPager->pStmt; pPg; pPg=pNext){

/*
** Rollback a statement.
*/
int sqlite3PagerStmtRollback(Pager *pPager){
  int rc;
  if( pPager->stmtInUse ){
    PAGERTRACE2("STMT-ROLLBACK %d\n", PAGERID(pPager));
    if( MEMDB ){
      PgHdr *pPg;
      for(pPg=pPager->pStmt; pPg; pPg=pPg->pNextStmt){
        PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
        if( pHist->pStmt ){
          memcpy(PGHDR_TO_DATA(pPg), pHist->pStmt, pPager->pageSize);
          sqliteFree(pHist->pStmt);

**
** If parameter nTrunc is non-zero, then the pager file is truncated to
** nTrunc pages (this is used by auto-vacuum databases).
*/
int sqlite3PagerSync(Pager *pPager, const char *zMaster, Pgno nTrunc){
  int rc = SQLITE_OK;

  PAGERTRACE4("DATABASE SYNC: File=%s zMaster=%s nTrunc=%d\n", 
      pPager->zFilename, zMaster, nTrunc);

  /* If this is an in-memory db, or no pages have been written to, or this
  ** function has already been called, it is a no-op.
  */
  if( pPager->state!=PAGER_SYNCED && !MEMDB && pPager->dirtyCache ){
    PgHdr *pPg;

int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
  PgHdr *pPgOld; 
  int h;
  Pgno needSyncPgno = 0;

  assert( pPg->nRef>0 );

  PAGERTRACE5("MOVE %d page %d (needSync=%d) moves to %d\n", 
      PAGERID(pPager), pPg->pgno, pPg->needSync, pgno);
  IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))

  if( pPg->needSync ){
    needSyncPgno = pPg->pgno;
    assert( pPg->inJournal );
    assert( pPg->dirty );

**    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 1.45 2007/03/26 22:05:02 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

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

/*
** Rerun the compilation of a statement after a schema change.
** Return true if the statement was recompiled successfully.
** Return false if there is an error of some kind.
*/
int sqlite3Reprepare(Vdbe *p){
  int rc;
  sqlite3_stmt *pNew;
  const char *zSql;
  sqlite3 *db;
  
  zSql = sqlite3VdbeGetSql(p);
  if( zSql==0 ){
    return 0;
  }
  db = sqlite3VdbeDb(p);
  rc = sqlite3Prepare(db, zSql, -1, 0, &pNew, 0);
  if( rc ){
    assert( pNew==0 );
    return 0;
  }else{
    assert( pNew!=0 );
  }
  sqlite3VdbeSwap((Vdbe*)pNew, p);
  sqlite3_transfer_bindings(pNew, (sqlite3_stmt*)p);
  sqlite3VdbeResetStepResult((Vdbe*)pNew);
  sqlite3VdbeFinalize((Vdbe*)pNew);
  return 1;
}


/*
** Two versions of the official API.  Legacy and new use.  In the legacy
** version, the original SQL text is not saved in the prepared statement

/*
** 2001 September 15
**
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.544 2007/03/26 22:05:02 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_




#if defined(SQLITE_TCL) || defined(TCLSH)
# include <tcl.h>
#endif

/*
** Many people are failing to set -DNDEBUG=1 when compiling SQLite.
** Setting NDEBUG makes the code smaller and run faster.  So the following
** lines are added to automatically set NDEBUG unless the -DSQLITE_DEBUG=1
** option is set.  Thus NDEBUG becomes an opt-in rather than an opt-out

void *sqlite3Malloc(int,int);
void *sqlite3MallocRaw(int,int);
void sqlite3Free(void*);
void *sqlite3Realloc(void*,int);
char *sqlite3StrDup(const char*);
char *sqlite3StrNDup(const char*, int);
# define sqlite3CheckMemory(a,b)
void sqlite3ReallocOrFree(void*,int);
void sqlite3FreeX(void*);
void *sqlite3MallocX(int);
int sqlite3AllocSize(void *);

char *sqlite3MPrintf(const char*, ...);
char *sqlite3VMPrintf(const char*, va_list);
void sqlite3DebugPrintf(const char*, ...);

#else
# define sqlite3ViewGetColumnNames(A,B) 0
#endif

void sqlite3DropTable(Parse*, SrcList*, int, int);
void sqlite3DeleteTable(sqlite3*, Table*);
void sqlite3Insert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
int sqlite3ArrayAllocate(void*,int,int);
IdList *sqlite3IdListAppend(IdList*, Token*);
int sqlite3IdListIndex(IdList*,const char*);
SrcList *sqlite3SrcListAppend(SrcList*, Token*, Token*);
SrcList *sqlite3SrcListAppendFromTerm(SrcList*, Token*, Token*, Token*,
                                      Select*, Expr*, IdList*);
void sqlite3SrcListShiftJoinType(SrcList*);
void sqlite3SrcListAssignCursors(Parse*, SrcList*);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing all sorts of SQLite interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.230 2007/03/26 22:05:02 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

    case SQLITE_ROW:        zName = "SQLITE_ROW";         break;
    case SQLITE_DONE:       zName = "SQLITE_DONE";        break;
    case SQLITE_NOTADB:     zName = "SQLITE_NOTADB";      break;
    default:                zName = "SQLITE_Unknown";     break;
  }
  return zName;
}
#define t1ErrorName sqlite3TestErrorName

/*
** Convert an sqlite3_stmt* into an sqlite3*.  This depends on the
** fact that the sqlite3* is the first field in the Vdbe structure.
*/
#define StmtToDb(X)   sqlite3_db_handle(X)

/*
** Check a return value to make sure it agrees with the results
** from sqlite3_errcode.
*/
int sqlite3TestErrCode(Tcl_Interp *interp, sqlite3 *db, int rc){
  if( rc!=SQLITE_MISUSE && rc!=SQLITE_OK && sqlite3_errcode(db)!=rc ){
    char zBuf[200];
    int r2 = sqlite3_errcode(db);
    sprintf(zBuf, "error code %s (%d) does not match sqlite3_errcode %s (%d)",
       t1ErrorName(rc), rc, t1ErrorName(r2), r2);
    Tcl_ResetResult(interp);
    Tcl_AppendResult(interp, zBuf, 0);
    return 1;
  }
  return 0;
}

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME\"", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite3_close(db);
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
  return TCL_OK;
}

/*
** Implementation of the x_coalesce() function.
** Return the first argument non-NULL argument.
*/
static void t1_ifnullFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int i;
  for(i=0; i<argc; i++){
    if( SQLITE_NULL!=sqlite3_value_type(argv[i]) ){
      sqlite3_result_text(context, (char*)sqlite3_value_text(argv[i]),
          sqlite3_value_bytes(argv[i]), SQLITE_TRANSIENT);
      break;
    }

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " DB\"", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite3_create_function(db, "x_coalesce", -1, SQLITE_ANY, 0, 
        t1_ifnullFunc, 0, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "hex8", 1, SQLITE_ANY, 0, 
          hex8Func, 0, 0);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "hex16", 1, SQLITE_ANY, 0, 
          hex16Func, 0, 0);

              sqlite3ValueText(pVal, SQLITE_UTF16NATIVE),
              1, SQLITE_UTF16, db, sqlite3ExecFunc, 0, 0);
    sqlite3ValueFree(pVal);
  }
#endif

  if( sqlite3TestErrCode(interp, db, rc) ) return TCL_ERROR;
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), 0);
  return TCL_OK;
}

/*
** Routines to implement the x_count() aggregate function.
**
** x_count() counts the number of non-null arguments.  But there are
** some twists for testing purposes.
**
** If the argument to x_count() is 40 then a UTF-8 error is reported
** on the step function.  If x_count(41) is seen, then a UTF-16 error
** is reported on the step function.  If the total count is 42, then
** a UTF-8 error is reported on the finalize function.
*/
typedef struct t1CountCtx t1CountCtx;
struct t1CountCtx {
  int n;
};
static void t1CountStep(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  t1CountCtx *p;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  if( (argc==0 || SQLITE_NULL!=sqlite3_value_type(argv[0]) ) && p ){
    p->n++;
  }
  if( argc>0 ){
    int v = sqlite3_value_int(argv[0]);
    if( v==40 ){
      sqlite3_result_error(context, "value of 40 handed to x_count", -1);
#ifndef SQLITE_OMIT_UTF16
    }else if( v==41 ){
      const char zUtf16ErrMsg[] = { 0, 0x61, 0, 0x62, 0, 0x63, 0, 0, 0};
      sqlite3_result_error16(context, &zUtf16ErrMsg[1-SQLITE_BIGENDIAN], -1);
#endif
    }
  }
}   
static void t1CountFinalize(sqlite3_context *context){
  t1CountCtx *p;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  if( p ){
    if( p->n==42 ){
      sqlite3_result_error(context, "x_count totals to 42", -1);
    }else{
      sqlite3_result_int(context, p ? p->n : 0);
    }

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME\"", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite3_create_function(db, "x_count", 0, SQLITE_UTF8, 0, 0,
      t1CountStep,t1CountFinalize);
  if( rc==SQLITE_OK ){
    sqlite3_create_function(db, "x_count", 1, SQLITE_UTF8, 0, 0,
        t1CountStep,t1CountFinalize);
  }
  if( sqlite3TestErrCode(interp, db, rc) ) return TCL_ERROR;
  return TCL_OK;
}


/*

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;

  if( pStmt ){
    db = StmtToDb(pStmt);
  }
  rc = sqlite3_finalize(pStmt);
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
  if( db && sqlite3TestErrCode(interp, db, rc) ) return TCL_ERROR;
  return TCL_OK;
}

/*
** Usage:  sqlite3_reset  STMT 
**

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;

  rc = sqlite3_reset(pStmt);
  if( pStmt && sqlite3TestErrCode(interp, StmtToDb(pStmt), rc) ){
    return TCL_ERROR;
  }
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
/*
  if( rc ){
    return TCL_ERROR;
  }
*/
  return TCL_OK;
}

  int i;
  if( objc!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv, "<error code>");
  }

  zCode = Tcl_GetString(objv[1]);
  for(i=0; i<200; i++){
    if( 0==strcmp(t1ErrorName(i), zCode) ) break;
  }
  Tcl_SetResult(interp, (char *)sqlite3ErrStr(i), 0);
  return TCL_OK;
}

/*
** Usage:    breakpoint

  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  rc = sqlite3_errcode(db);
  if( (rc&0xff)==rc ){
    zBuf[0] = 0;
  }else{
    sprintf(zBuf,"+%d", rc>>8);
  }
  Tcl_AppendResult(interp, (char *)t1ErrorName(rc), zBuf, 0);
  return TCL_OK;
}

/*
** Usage:   test_errmsg DB
**
** Returns the UTF-8 representation of the error message string for the

    return TCL_ERROR;
  }

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;
  rc = sqlite3_step(pStmt);

  /* if( rc!=SQLITE_DONE && rc!=SQLITE_ROW ) return TCL_ERROR; */
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), 0);
  return TCL_OK;
}

/*
** Usage: sqlite3_column_count STMT 
**
** Return the number of columns returned by the sql statement STMT.

#ifndef SQLITE_OMIT_GLOBALRECOVER
  int rc;
  if( objc!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv, "");
    return TCL_ERROR;
  }
  rc = sqlite3_global_recover();
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
#endif
  return TCL_OK;
}

/*
** Usage: sqlite3_column_text STMT column
**

    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filename", 0);
    return TCL_ERROR;
  }

  rc = sqlite3OsOpenReadWrite(Tcl_GetString(objv[1]), &pFile, &dummy);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  sqlite3TestMakePointerStr(interp, zBuf, pFile);
  Tcl_SetResult(interp, zBuf, 0);
  return TCL_ERROR;
}

  }

  if( getFilePointer(interp, Tcl_GetString(objv[1]), &pFile) ){
    return TCL_ERROR;
  }
  rc = sqlite3OsClose(&pFile);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:  sqlite3OsLock <file handle> <locktype>

    Tcl_AppendResult(interp, "wrong # args: should be \"", 
        Tcl_GetString(objv[0]), 
        " filehandle (SHARED|RESERVED|PENDING|EXCLUSIVE)", 0);
    return TCL_ERROR;
  }

  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:  sqlite3OsUnlock <file handle>

  }

  if( getFilePointer(interp, Tcl_GetString(objv[1]), &pFile) ){
    return TCL_ERROR;
  }
  rc = sqlite3OsUnlock(pFile, NO_LOCK);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:  sqlite3OsTempFileName
*/
static int test_sqlite3OsTempFileName(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  char zFile[SQLITE_TEMPNAME_SIZE];
  int rc;

  rc = sqlite3OsTempFileName(zFile);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  Tcl_AppendResult(interp, zFile, 0);
  return TCL_OK;
}
#endif

  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0], 
        " DB function-name", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite3_create_function(db, argv[2], -1, SQLITE_UTF8, 0, 0, 0, 0);
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
  return TCL_OK;
}

/*
** Usage: sqlite_delete_collation DB collation-name
**
** Delete the collation sequence 'collation-name' from database handle 

  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0], 
        " DB function-name", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  rc = sqlite3_create_collation(db, argv[2], SQLITE_UTF8, 0, 0);
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
  return TCL_OK;
}

/*
** Usage: sqlite3_get_autocommit DB
**
** Return true if the database DB is currently in auto-commit mode.

  static int bitmask_size = sizeof(Bitmask)*8;
  int i;
  extern int sqlite3_os_trace;
  extern int sqlite3_where_trace;
  extern int sqlite3_sync_count, sqlite3_fullsync_count;
  extern int sqlite3_opentemp_count;
  extern int sqlite3_memUsed;
  extern char *sqlite3_malloc_id;
  extern int sqlite3_memMax;
  extern int sqlite3_like_count;
  extern int sqlite3_tsd_count;
  extern int sqlite3_xferopt_count;
#if OS_UNIX && defined(SQLITE_TEST) && defined(THREADSAFE) && THREADSAFE
  extern int threadsOverrideEachOthersLocks;
#endif

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the btree.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test3.c,v 1.72 2007/03/26 22:05:02 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

  Tcl_AppendResult(interp, &zBuf[1], 0);
  return SQLITE_OK;
}

/*
** Copied from btree.c:
*/
static u32 t4Get4byte(unsigned char *p){
  return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
}

/*
**   btree_ovfl_info  BTREE  CURSOR
**
** Given a cursor, return the sequence of pages number that form the

    Tcl_DStringAppendElement(&str, zElem);
    if( sqlite3PagerGet(pPager, pgno, &pDbPage)!=SQLITE_OK ){
      Tcl_DStringFree(&str);
      Tcl_AppendResult(interp, "unable to get page ", zElem, 0);
      return TCL_ERROR;
    }
    pPage = sqlite3PagerGetData(pDbPage);
    pgno = t4Get4byte((unsigned char*)pPage);
    sqlite3PagerUnref(pDbPage);
  }
  Tcl_DStringResult(interp, &str);
  return SQLITE_OK;
}

/*

/* Forward references */
typedef struct AsyncWrite AsyncWrite;
typedef struct AsyncFile AsyncFile;

/* Enable for debugging */
static int sqlite3async_trace = 0;
# define ASYNC_TRACE(X) if( sqlite3async_trace ) asyncTrace X
static void asyncTrace(const char *zFormat, ...){
  char *z;
  va_list ap;
  va_start(ap, zFormat);
  z = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
  fprintf(stderr, "[%d] %s", (int)pthread_self(), z);

  if( async.pQueueLast ){
    assert( async.pQueueFirst );
    async.pQueueLast->pNext = pWrite;
  }else{
    async.pQueueFirst = pWrite;
  }
  async.pQueueLast = pWrite;
  ASYNC_TRACE(("PUSH %p (%s %s %d)\n", pWrite, azOpcodeName[pWrite->op],
         pWrite->pFile ? pWrite->pFile->zName : "-", pWrite->iOffset));

  if( pWrite->op==ASYNC_CLOSE ){
    async.nFile--;
    if( async.nFile==0 ){
      async.ioError = SQLITE_OK;
    }

    rc = sqlite3OsSeek(pBase, pFile->iOffset);
    if( rc!=SQLITE_OK ){
      goto asyncread_out;
    }
    nRead = MIN(filesize - pFile->iOffset, amt);
    if( nRead>0 ){
      rc = sqlite3OsRead(pBase, obuf, nRead);
      ASYNC_TRACE(("READ %s %d bytes at %d\n", pFile->zName, nRead, pFile->iOffset));
    }
  }

  if( rc==SQLITE_OK ){
    AsyncWrite *p;
    i64 iOffset = pFile->iOffset;           /* Current seek offset */

    for(p=async.pQueueFirst; p; p = p->pNext){
      if( p->pFile==pFile && p->op==ASYNC_WRITE ){
        int iBeginOut = (p->iOffset - iOffset);
        int iBeginIn = -iBeginOut;
        int nCopy;

        if( iBeginIn<0 ) iBeginIn = 0;
        if( iBeginOut<0 ) iBeginOut = 0;
        nCopy = MIN(p->nByte-iBeginIn, amt-iBeginOut);

        if( nCopy>0 ){
          memcpy(&((char *)obuf)[iBeginOut], &p->zBuf[iBeginIn], nCopy);
          ASYNC_TRACE(("OVERREAD %d bytes at %d\n", nCopy, iBeginOut+iOffset));
        }
      }
    }

    pFile->iOffset += (i64)amt;
  }

** as with standard (unmodified) SQLite as long as all connections 
** come from this one process.  Connections from external processes
** cannot see our internal hash table (obviously) and will thus not
** honor our locks.
*/
static int asyncLock(OsFile *id, int lockType){
  AsyncFile *pFile = (AsyncFile*)id;
  ASYNC_TRACE(("LOCK %d (%s)\n", lockType, pFile->zName));
  pthread_mutex_lock(&async.lockMutex);
  sqlite3HashInsert(&async.aLock, pFile->zName, pFile->nName, (void*)lockType);
  pthread_mutex_unlock(&async.lockMutex);
  return SQLITE_OK;
}
static int asyncUnlock(OsFile *id, int lockType){
  return asyncLock(id, lockType);
}

/*
** This function is called when the pager layer first opens a database file
** and is checking for a hot-journal.
*/
static int asyncCheckReservedLock(OsFile *id){
  AsyncFile *pFile = (AsyncFile*)id;
  int rc;
  pthread_mutex_lock(&async.lockMutex);
  rc = (int)sqlite3HashFind(&async.aLock, pFile->zName, pFile->nName);
  pthread_mutex_unlock(&async.lockMutex);
  ASYNC_TRACE(("CHECK-LOCK %d (%s)\n", rc, pFile->zName));
  return rc>SHARED_LOCK;
}

static int asyncSectorSize(OsFile *id){
  /* TODO: This is tricky to implement, as this backend might not have
  ** an open file handle at this point.
  */

    if( p->op==ASYNC_DELETE && 0==strcmp(p->zBuf, z) ){
      ret = 0;
    }else if( p->op==ASYNC_OPENEXCLUSIVE && 0==strcmp(p->zBuf, z) ){
      ret = 1;
    }
  }

  ASYNC_TRACE(("EXISTS: %s = %d\n", z, ret));
  pthread_mutex_unlock(&async.queueMutex);
  return ret;
}

/*
** Call this routine to enable or disable the
** asynchronous IO features implemented in this file. 

    }
    while( (p = async.pQueueFirst)==0 ){
      pthread_cond_broadcast(&async.emptySignal);
      if( async.writerHaltWhenIdle ){
        pthread_mutex_unlock(&async.queueMutex);
        break;
      }else{
        ASYNC_TRACE(("IDLE\n"));
        pthread_cond_wait(&async.queueSignal, &async.queueMutex);
        ASYNC_TRACE(("WAKEUP\n"));
      }
    }
    if( p==0 ) break;
    holdingMutex = 1;

    /* Right now this thread is holding the mutex on the write-op queue.
    ** Variable 'p' points to the first entry in the write-op queue. In

    switch( p->op ){
      case ASYNC_NOOP:
        break;

      case ASYNC_WRITE:
        assert( pBase );
        ASYNC_TRACE(("WRITE %s %d bytes at %d\n",
                p->pFile->zName, p->nByte, p->iOffset));
        rc = sqlite3OsSeek(pBase, p->iOffset);
        if( rc==SQLITE_OK ){
          rc = sqlite3OsWrite(pBase, (const void *)(p->zBuf), p->nByte);
        }
        break;

      case ASYNC_SYNC:
        assert( pBase );
        ASYNC_TRACE(("SYNC %s\n", p->pFile->zName));
        rc = sqlite3OsSync(pBase, p->nByte);
        break;

      case ASYNC_TRUNCATE:
        assert( pBase );
        ASYNC_TRACE(("TRUNCATE %s to %d bytes\n", p->pFile->zName, p->iOffset));
        rc = sqlite3OsTruncate(pBase, p->iOffset);
        break;

      case ASYNC_CLOSE:
        ASYNC_TRACE(("CLOSE %s\n", p->pFile->zName));
        sqlite3OsClose(&p->pFile->pBaseWrite);
        sqlite3OsClose(&p->pFile->pBaseRead);
        sqlite3OsFree(p->pFile);
        break;

      case ASYNC_OPENDIRECTORY:
        assert( pBase );
        ASYNC_TRACE(("OPENDIR %s\n", p->zBuf));
        sqlite3OsOpenDirectory(pBase, p->zBuf);
        break;

      case ASYNC_SETFULLSYNC:
        assert( pBase );
        ASYNC_TRACE(("SETFULLSYNC %s %d\n", p->pFile->zName, p->nByte));
        sqlite3OsSetFullSync(pBase, p->nByte);
        break;

      case ASYNC_DELETE:
        ASYNC_TRACE(("DELETE %s\n", p->zBuf));
        rc = xOrigDelete(p->zBuf);
        break;

      case ASYNC_SYNCDIRECTORY:
        ASYNC_TRACE(("SYNCDIR %s\n", p->zBuf));
        rc = xOrigSyncDirectory(p->zBuf);
        break;

      case ASYNC_OPENEXCLUSIVE: {
        AsyncFile *pFile = p->pFile;
        int delFlag = ((p->iOffset)?1:0);
        OsFile *pBase = 0;
        ASYNC_TRACE(("OPEN %s delFlag=%d\n", p->zBuf, delFlag));
        assert(pFile->pBaseRead==0 && pFile->pBaseWrite==0);
        rc = xOrigOpenExclusive(p->zBuf, &pBase, delFlag);
        assert( holdingMutex==0 );
        pthread_mutex_lock(&async.queueMutex);
        holdingMutex = 1;
        if( rc==SQLITE_OK ){
          pFile->pBaseRead = pBase;

    ** so that the AsyncWrite structure can be safely removed from the 
    ** global write-op queue.
    */
    if( !holdingMutex ){
      pthread_mutex_lock(&async.queueMutex);
      holdingMutex = 1;
    }
    /* ASYNC_TRACE(("UNLINK %p\n", p)); */
    if( p==async.pQueueLast ){
      async.pQueueLast = 0;
    }
    async.pQueueFirst = p->pNext;
    sqlite3OsFree(p);
    assert( holdingMutex );

  }

  while( cnt-- && !pthread_mutex_trylock(&async.writerMutex) ){
    pthread_mutex_unlock(&async.writerMutex);
    sched_yield();
  }
  if( cnt>=0 ){
    ASYNC_TRACE(("WAIT\n"));
    pthread_mutex_lock(&async.queueMutex);
    pthread_cond_broadcast(&async.queueSignal);
    pthread_mutex_unlock(&async.queueMutex);
    pthread_mutex_lock(&async.writerMutex);
    pthread_mutex_unlock(&async.writerMutex);
  }else{
    ASYNC_TRACE(("NO-WAIT\n"));
  }
  return TCL_OK;
}


#endif  /* OS_UNIX and THREADSAFE and defined(SQLITE_ENABLE_REDEF_IO) */

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.196 2007/03/26 22:05:02 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <stdarg.h>
#include <ctype.h>

/*

void *sqlite3Malloc(int n, int doMemManage){
  void *p = sqlite3MallocRaw(n, doMemManage);
  if( p ){
    memset(p, 0, n);
  }
  return p;
}
void sqlite3ReallocOrFree(void *pp, int n){
  char **x = (char**)pp;
  void *p = sqlite3Realloc(*x, n);
  if( !p ){
    sqlite3FreeX(*x);
  }
  *x = p;
}

/*
** sqlite3ThreadSafeMalloc() and sqlite3ThreadSafeFree() are used in those
** rare scenarios where sqlite may allocate memory in one thread and free
** it in another. They are exactly the same as sqlite3Malloc() and 
** sqlite3Free() except that:

  }
  v = 0;
  while( *z ){
    v = (v<<4) + hexToInt(*z);
    z++;
  }
  if( sizeof(p)==sizeof(v) ){
    memcpy(&p, &v, sizeof(p));
  }else{
    assert( sizeof(p)==sizeof(v2) );
    v2 = (u32)v;
    memcpy(&p, &v2, sizeof(p));
  }
  return p;
}
#endif

/*
** Return a pointer to the ThreadData associated with the calling thread.

**
** 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 1.592 2007/03/26 22:05:02 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;
    sqliteReallocOrFree(&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);

/*
** The makefile scans the vdbe.c source file and creates the following
** array of string constants which are the names of all VDBE opcodes.  This
** array is defined in a separate source code file named opcode.c which is
** automatically generated by the makefile.
*/
extern const char *const sqlite3OpcodeNames[];

/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine.  Each instruction is an instance
** of the following structure.
*/
typedef struct VdbeOp Op;

**
** Each value has a manifest type. The manifest type of the value stored
** in a Mem struct is returned by the MemType(Mem*) macro. The type is
** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or
** SQLITE_BLOB.
*/
struct Mem {
  union {
    i64 i;              /* Integer value. Or FuncDef* when flags==MEM_Agg */
    FuncDef *pDef;
  };
  double r;           /* Real value */
  char *z;            /* String or BLOB value */
  int n;              /* Number of characters in string value, including '\0' */
  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  u8  type;           /* One of MEM_Null, MEM_Str, etc. */
  u8  enc;            /* TEXT_Utf8, TEXT_Utf16le, or TEXT_Utf16be */
  void (*xDel)(void *);  /* If not null, call this function to delete Mem.z */

  if( (pMem->flags & MEM_Agg)==0 ){
    if( nByte==0 ){
      assert( pMem->flags==MEM_Null );
      pMem->z = 0;
    }else{
      pMem->flags = MEM_Agg;
      pMem->xDel = sqlite3FreeX;
      pMem->pDef = p->pFunc;
      if( nByte<=NBFS ){
        pMem->z = pMem->zShort;
        memset(pMem->z, 0, nByte);
      }else{
        pMem->z = sqliteMalloc( nByte );
      }
    }

** If iCol is not valid, return a pointer to a Mem which has a value
** of NULL.
*/
static Mem *columnMem(sqlite3_stmt *pStmt, int i){
  Vdbe *pVm = (Vdbe *)pStmt;
  int vals = sqlite3_data_count(pStmt);
  if( i>=vals || i<0 ){
    static const Mem nullMem = {{0,}, 0.0, "", 0, MEM_Null, MEM_Null };
    sqlite3Error(pVm->db, SQLITE_RANGE, 0);
    return (Mem*)&nullMem;
  }
  return &pVm->pTos[(1-vals)+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(&p->aLabel, p->nLabelAlloc*sizeof(p->aLabel[0]));
  }
  if( p->aLabel ){
    p->aLabel[i] = -1;
  }
  return -1-i;
}

    Mem *pMem = p->aStack;
    pMem->flags = MEM_Int;
    pMem->type = SQLITE_INTEGER;
    pMem->i = i;                                /* Program counter */
    pMem++;

    pMem->flags = MEM_Static|MEM_Str|MEM_Term;
    pMem->z = (char*)sqlite3OpcodeNames[pOp->opcode];  /* Opcode */
    assert( pMem->z!=0 );
    pMem->n = strlen(pMem->z);
    pMem->type = SQLITE_TEXT;
    pMem->enc = SQLITE_UTF8;
    pMem++;

    pMem->flags = MEM_Int;

  int len;

  /* Integer and Real */
  if( serial_type<=7 && serial_type>0 ){
    u64 v;
    int i;
    if( serial_type==7 ){
      assert( sizeof(v)==sizeof(pMem->r) );
      memcpy(&v, &pMem->r, sizeof(v));
    }else{
      v = pMem->i;
    }
    len = i = sqlite3VdbeSerialTypeLen(serial_type);
    while( i-- ){
      buf[i] = (v&0xFF);
      v >>= 8;
    }
    return len;

      u64 x;
      u32 y;
#if !defined(NDEBUG) && !defined(SQLITE_OMIT_FLOATING_POINT)
      /* Verify that integers and floating point values use the same
      ** byte order.  The byte order differs on some (broken) architectures.
      */
      static const u64 t1 = ((u64)0x3ff00000)<<32;
      static const double r1 = 1.0;
      assert( sizeof(r1)==sizeof(t1) && memcmp(&r1, &t1, sizeof(r1))==0 );
#endif

      x = (buf[0]<<24) | (buf[1]<<16) | (buf[2]<<8) | buf[3];
      y = (buf[4]<<24) | (buf[5]<<16) | (buf[6]<<8) | buf[7];
      x = (x<<32) | y;
      if( serial_type==6 ){
        pMem->i = *(i64*)&x;
        pMem->flags = MEM_Int;
      }else{
        assert( sizeof(x)==8 && sizeof(pMem->r)==8 );
        memcpy(&pMem->r, &x, sizeof(x));
        /* pMem->r = *(double*)&x; */
        pMem->flags = MEM_Real;
      }
      return 8;
    }
    case 8:    /* Integer 0 */
    case 9: {  /* Integer 1 */
      pMem->i = serial_type-8;

#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** Allocate a new FifoPage and return a pointer to it.  Return NULL if
** we run out of memory.  Leave space on the page for nEntry entries.
*/
static FifoPage *allocateFifoPage(int nEntry){
  FifoPage *pPage;
  if( nEntry>32767 ){
    nEntry = 32767;
  }
  pPage = sqliteMallocRaw( sizeof(FifoPage) + sizeof(i64)*(nEntry-1) );
  if( pPage ){
    pPage->nSlot = nEntry;

** normally.   SQLITE_NOMEM is returned if we are unable to allocate
** memory.
*/
int sqlite3VdbeFifoPush(Fifo *pFifo, i64 val){
  FifoPage *pPage;
  pPage = pFifo->pLast;
  if( pPage==0 ){
    pPage = pFifo->pLast = pFifo->pFirst = allocateFifoPage(20);
    if( pPage==0 ){
      return SQLITE_NOMEM;
    }
  }else if( pPage->iWrite>=pPage->nSlot ){
    pPage->pNext = allocateFifoPage(pFifo->nEntry);
    if( pPage->pNext==0 ){
      return SQLITE_NOMEM;
    }
    pPage = pFifo->pLast = pPage->pNext;
  }
  pPage->aSlot[pPage->iWrite++] = val;
  pFifo->nEntry++;

** Return SQLITE_ERROR if the finalizer reports an error.  SQLITE_OK
** otherwise.
*/
int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
  int rc = SQLITE_OK;
  if( pFunc && pFunc->xFinalize ){
    sqlite3_context ctx;
    assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->pDef );
    ctx.s.flags = MEM_Null;
    ctx.s.z = pMem->zShort;
    ctx.pMem = pMem;
    ctx.pFunc = pFunc;
    ctx.isError = 0;
    pFunc->xFinalize(&ctx);
    if( pMem->z && pMem->z!=pMem->zShort ){

** inconsistent state, for example with (Mem.z==0) and
** (Mem.type==SQLITE_TEXT).
*/
void sqlite3VdbeMemRelease(Mem *p){
  if( p->flags & (MEM_Dyn|MEM_Agg) ){
    if( p->xDel ){
      if( p->flags & MEM_Agg ){
        sqlite3VdbeMemFinalize(p, p->pDef);
        assert( (p->flags & MEM_Agg)==0 );
        sqlite3VdbeMemRelease(p);
      }else{
        p->xDel((void *)p->z);
      }
    }else{
      sqliteFree(p->z);

** 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 1.240 2007/03/26 22:05:02 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)

/*
** Determine the number of elements in an array.
*/
#define ARRAYSIZE(X)  (sizeof(X)/sizeof(X[0]))

/*
** Trace output macros
*/
#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
int sqlite3_where_trace = 0;
# define WHERETRACE(X)  if(sqlite3_where_trace) sqlite3DebugPrintf X
#else
# define WHERETRACE(X)
#endif

/* Forward reference
*/
typedef struct WhereClause WhereClause;
typedef struct ExprMaskSet ExprMaskSet;

  ** allocated and initialized for this virtual table, then allocate
  ** and initialize it now
  */
  pIdxInfo = *ppIdxInfo;
  if( pIdxInfo==0 ){
    WhereTerm *pTerm;
    int nTerm;
    WHERETRACE(("Recomputing index info for %s...\n", pTab->zName));

    /* Count the number of possible WHERE clause constraints referring
    ** to this virtual table */
    for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
      if( pTerm->leftCursor != pSrc->iCursor ) continue;
      if( pTerm->eOperator==WO_IN ) continue;
      nTerm++;

  pIdxInfo->estimatedCost = SQLITE_BIG_DBL / 2.0;
  nOrderBy = pIdxInfo->nOrderBy;
  if( pIdxInfo->nOrderBy && !orderByUsable ){
    *(int*)&pIdxInfo->nOrderBy = 0;
  }

  sqlite3SafetyOff(pParse->db);
  WHERETRACE(("xBestIndex for %s\n", pTab->zName));
  TRACE_IDX_INPUTS(pIdxInfo);
  rc = pTab->pVtab->pModule->xBestIndex(pTab->pVtab, pIdxInfo);
  TRACE_IDX_OUTPUTS(pIdxInfo);
  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM ){
      sqlite3FailedMalloc();
    }else {

  Index *pProbe;              /* An index we are evaluating */
  int rev;                    /* True to scan in reverse order */
  int flags;                  /* Flags associated with pProbe */
  int nEq;                    /* Number of == or IN constraints */
  int eqTermMask;             /* Mask of valid equality operators */
  double cost;                /* Cost of using pProbe */

  WHERETRACE(("bestIndex: tbl=%s notReady=%x\n", pSrc->pTab->zName, notReady));
  lowestCost = SQLITE_BIG_DBL;
  pProbe = pSrc->pTab->pIndex;

  /* If the table has no indices and there are no terms in the where
  ** clause that refer to the ROWID, then we will never be able to do
  ** anything other than a full table scan on this table.  We might as
  ** well put it first in the join order.  That way, perhaps it can be

    *ppIndex = 0;
    bestFlags = WHERE_ROWID_EQ;
    if( pTerm->eOperator & WO_EQ ){
      /* Rowid== is always the best pick.  Look no further.  Because only
      ** a single row is generated, output is always in sorted order */
      *pFlags = WHERE_ROWID_EQ | WHERE_UNIQUE;
      *pnEq = 1;
      WHERETRACE(("... best is rowid\n"));
      return 0.0;
    }else if( (pExpr = pTerm->pExpr)->pList!=0 ){
      /* Rowid IN (LIST): cost is NlogN where N is the number of list
      ** elements.  */
      lowestCost = pExpr->pList->nExpr;
      lowestCost *= estLog(lowestCost);
    }else{
      /* Rowid IN (SELECT): cost is NlogN where N is the number of rows
      ** in the result of the inner select.  We have no way to estimate
      ** that value so make a wild guess. */
      lowestCost = 200;
    }
    WHERETRACE(("... rowid IN cost: %.9g\n", lowestCost));
  }

  /* Estimate the cost of a table scan.  If we do not know how many
  ** entries are in the table, use 1 million as a guess.
  */
  cost = pProbe ? pProbe->aiRowEst[0] : 1000000;
  WHERETRACE(("... table scan base cost: %.9g\n", cost));
  flags = WHERE_ROWID_RANGE;

  /* Check for constraints on a range of rowids in a table scan.
  */
  pTerm = findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE|WO_GT|WO_GE, 0);
  if( pTerm ){
    if( findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE, 0) ){
      flags |= WHERE_TOP_LIMIT;
      cost /= 3;  /* Guess that rowid<EXPR eliminates two-thirds or rows */
    }
    if( findTerm(pWC, iCur, -1, notReady, WO_GT|WO_GE, 0) ){
      flags |= WHERE_BTM_LIMIT;
      cost /= 3;  /* Guess that rowid>EXPR eliminates two-thirds of rows */
    }
    WHERETRACE(("... rowid range reduces cost to %.9g\n", cost));
  }else{
    flags = 0;
  }

  /* If the table scan does not satisfy the ORDER BY clause, increase
  ** the cost by NlogN to cover the expense of sorting. */
  if( pOrderBy ){
    if( sortableByRowid(iCur, pOrderBy, pWC->pMaskSet, &rev) ){
      flags |= WHERE_ORDERBY|WHERE_ROWID_RANGE;
      if( rev ){
        flags |= WHERE_REVERSE;
      }
    }else{
      cost += cost*estLog(cost);
      WHERETRACE(("... sorting increases cost to %.9g\n", cost));
    }
  }
  if( cost<lowestCost ){
    lowestCost = cost;
    bestFlags = flags;
  }

  /* Look at each index.
  */
  for(; pProbe; pProbe=pProbe->pNext){
    int i;                       /* Loop counter */
    double inMultiplier = 1;

    WHERETRACE(("... index %s:\n", pProbe->zName));

    /* Count the number of columns in the index that are satisfied
    ** by x=EXPR constraints or x IN (...) constraints.
    */
    flags = 0;
    for(i=0; i<pProbe->nColumn; i++){
      int j = pProbe->aiColumn[i];

    }
    cost = pProbe->aiRowEst[i] * inMultiplier * estLog(inMultiplier);
    nEq = i;
    if( pProbe->onError!=OE_None && (flags & WHERE_COLUMN_IN)==0
         && nEq==pProbe->nColumn ){
      flags |= WHERE_UNIQUE;
    }
    WHERETRACE(("...... nEq=%d inMult=%.9g cost=%.9g\n", nEq, inMultiplier, cost));

    /* Look for range constraints
    */
    if( nEq<pProbe->nColumn ){
      int j = pProbe->aiColumn[nEq];
      pTerm = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pProbe);
      if( pTerm ){
        flags |= WHERE_COLUMN_RANGE;
        if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pProbe) ){
          flags |= WHERE_TOP_LIMIT;
          cost /= 3;
        }
        if( findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pProbe) ){
          flags |= WHERE_BTM_LIMIT;
          cost /= 3;
        }
        WHERETRACE(("...... range reduces cost to %.9g\n", cost));
      }
    }

    /* Add the additional cost of sorting if that is a factor.
    */
    if( pOrderBy ){
      if( (flags & WHERE_COLUMN_IN)==0 &&
           isSortingIndex(pParse,pWC->pMaskSet,pProbe,iCur,pOrderBy,nEq,&rev) ){
        if( flags==0 ){
          flags = WHERE_COLUMN_RANGE;
        }
        flags |= WHERE_ORDERBY;
        if( rev ){
          flags |= WHERE_REVERSE;
        }
      }else{
        cost += cost*estLog(cost);
        WHERETRACE(("...... orderby increases cost to %.9g\n", cost));
      }
    }

    /* Check to see if we can get away with using just the index without
    ** ever reading the table.  If that is the case, then halve the
    ** cost of this index.
    */
    if( flags && pSrc->colUsed < (((Bitmask)1)<<(BMS-1)) ){
      Bitmask m = pSrc->colUsed;
      int j;
      for(j=0; j<pProbe->nColumn; j++){
        int x = pProbe->aiColumn[j];
        if( x<BMS-1 ){
          m &= ~(((Bitmask)1)<<x);
        }
      }
      if( m==0 ){
        flags |= WHERE_IDX_ONLY;
        cost /= 2;
        WHERETRACE(("...... idx-only reduces cost to %.9g\n", cost));
      }
    }

    /* If this index has achieved the lowest cost so far, then use it.
    */
    if( cost < lowestCost ){
      bestIdx = pProbe;
      lowestCost = cost;
      assert( flags!=0 );
      bestFlags = flags;
      bestNEq = nEq;
    }
  }

  /* Report the best result
  */
  *ppIndex = bestIdx;
  WHERETRACE(("best index is %s, cost=%.9g, flags=%x, nEq=%d\n",
        bestIdx ? bestIdx->zName : "(none)", lowestCost, bestFlags, bestNEq));
  *pFlags = bestFlags | eqTermMask;
  *pnEq = bestNEq;
  return lowestCost;
}

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

  ** This loop also figures out the nesting order of tables in the FROM
  ** clause.
  */
  notReady = ~(Bitmask)0;
  pTabItem = pTabList->a;
  pLevel = pWInfo->a;
  andFlags = ~0;
  WHERETRACE(("*** Optimizer Start ***\n"));
  for(i=iFrom=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
    Index *pIdx;                /* Index for FROM table at pTabItem */
    int flags;                  /* Flags asssociated with pIdx */
    int nEq;                    /* Number of == or IN constraints */
    double cost;                /* The cost for pIdx */
    int j;                      /* For looping over FROM tables */
    Index *pBest = 0;           /* The best index seen so far */

        bestFlags = flags;
        bestNEq = nEq;
        bestJ = j;
        pLevel->pBestIdx = pIndex;
      }
      if( doNotReorder ) break;
    }
    WHERETRACE(("*** Optimizer choose table %d for loop %d\n", bestJ,
           pLevel-pWInfo->a));
    if( (bestFlags & WHERE_ORDERBY)!=0 ){
      *ppOrderBy = 0;
    }
    andFlags &= bestFlags;
    pLevel->flags = bestFlags;
    pLevel->pIdx = pBest;
    pLevel->nEq = bestNEq;
    pLevel->aInLoop = 0;
    pLevel->nIn = 0;
    if( pBest ){
      pLevel->iIdxCur = pParse->nTab++;
    }else{
      pLevel->iIdxCur = -1;
    }
    notReady &= ~getMask(&maskSet, pTabList->a[bestJ].iCursor);
    pLevel->iFrom = bestJ;
  }
  WHERETRACE(("*** Optimizer Finished ***\n"));

  /* If the total query only selects a single row, then the ORDER BY
  ** clause is irrelevant.
  */
  if( (andFlags & WHERE_UNIQUE)!=0 && ppOrderBy ){
    *ppOrderBy = 0;
  }