**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that used to generate VDBE code
** that implements the ALTER TABLE command.
**
** $Id: alter.c,v 1.14 2006/01/05 11:34:33 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The code in this file only exists if we are not omitting the
** ALTER TABLE logic from the build.
................................................................................
** table pTab has no temporary triggers, or is itself stored in the 
** temporary database, NULL is returned.
*/
static char *whereTempTriggers(Parse *pParse, Table *pTab){
  Trigger *pTrig;
  char *zWhere = 0;
  char *tmp = 0;
  const DbSchema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */

  /* If the table is not located in the temp-db (in which case NULL is 
  ** returned, loop through the tables list of triggers. For each trigger
  ** that is not part of the temp-db schema, add a clause to the WHERE 
  ** expression being built up in zWhere.
  */
  if( pTab->pSchema!=pTempSchema ){
................................................................................
  char *zName = 0;          /* NULL-terminated version of pName */ 
  sqlite3 *db = pParse->db; /* Database connection */
  Vdbe *v;
#ifndef SQLITE_OMIT_TRIGGER
  char *zWhere = 0;         /* Where clause to locate temp triggers */
#endif
  
  if( sqlite3Tsd()->mallocFailed ) goto exit_rename_table;
  assert( pSrc->nSrc==1 );

  pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
  if( !pTab ) goto exit_rename_table;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  zDb = db->aDb[iDb].zName;

................................................................................
  Vdbe *v;
  int iDb;
  int i;
  int nAlloc;

  /* Look up the table being altered. */
  assert( pParse->pNewTable==0 );
  if( sqlite3Tsd()->mallocFailed ) goto exit_begin_add_column;
  pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
  if( !pTab ) goto exit_begin_add_column;

  /* Make sure this is not an attempt to ALTER a view. */
  if( pTab->pSelect ){
    sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
    goto exit_begin_add_column;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that used to generate VDBE code
** that implements the ALTER TABLE command.
**
** $Id: alter.c,v 1.15 2006/01/09 06:29:48 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The code in this file only exists if we are not omitting the
** ALTER TABLE logic from the build.
................................................................................
** table pTab has no temporary triggers, or is itself stored in the 
** temporary database, NULL is returned.
*/
static char *whereTempTriggers(Parse *pParse, Table *pTab){
  Trigger *pTrig;
  char *zWhere = 0;
  char *tmp = 0;
  const Schema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */

  /* If the table is not located in the temp-db (in which case NULL is 
  ** returned, loop through the tables list of triggers. For each trigger
  ** that is not part of the temp-db schema, add a clause to the WHERE 
  ** expression being built up in zWhere.
  */
  if( pTab->pSchema!=pTempSchema ){
................................................................................
  char *zName = 0;          /* NULL-terminated version of pName */ 
  sqlite3 *db = pParse->db; /* Database connection */
  Vdbe *v;
#ifndef SQLITE_OMIT_TRIGGER
  char *zWhere = 0;         /* Where clause to locate temp triggers */
#endif
  
  if( sqlite3ThreadData()->mallocFailed ) goto exit_rename_table;
  assert( pSrc->nSrc==1 );

  pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
  if( !pTab ) goto exit_rename_table;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  zDb = db->aDb[iDb].zName;

................................................................................
  Vdbe *v;
  int iDb;
  int i;
  int nAlloc;

  /* Look up the table being altered. */
  assert( pParse->pNewTable==0 );
  if( sqlite3ThreadData()->mallocFailed ) goto exit_begin_add_column;
  pTab = sqlite3LocateTable(pParse, pSrc->a[0].zName, pSrc->a[0].zDatabase);
  if( !pTab ) goto exit_begin_add_column;

  /* Make sure this is not an attempt to ALTER a view. */
  if( pTab->pSelect ){
    sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
    goto exit_begin_add_column;

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code associated with the ANALYZE command.
**
** @(#) $Id: analyze.c,v 1.14 2006/01/08 18:10:18 drh Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

/*
** This routine generates code that opens the sqlite_stat1 table on cursor
** iStatCur.
................................................................................
}

/*
** Generate code that will do an analysis of an entire database
*/
static void analyzeDatabase(Parse *pParse, int iDb){
  sqlite3 *db = pParse->db;
  DbSchema *pSchema = db->aDb[iDb].pSchema;    /* Schema of database iDb */
  HashElem *k;
  int iStatCur;
  int iMem;

  sqlite3BeginWriteOperation(pParse, 0, iDb);
  iStatCur = pParse->nTab++;
  openStatTable(pParse, iDb, iStatCur, 0);

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code associated with the ANALYZE command.
**
** @(#) $Id: analyze.c,v 1.15 2006/01/09 06:29:48 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

/*
** This routine generates code that opens the sqlite_stat1 table on cursor
** iStatCur.
................................................................................
}

/*
** Generate code that will do an analysis of an entire database
*/
static void analyzeDatabase(Parse *pParse, int iDb){
  sqlite3 *db = pParse->db;
  Schema *pSchema = db->aDb[iDb].pSchema;    /* Schema of database iDb */
  HashElem *k;
  int iStatCur;
  int iMem;

  sqlite3BeginWriteOperation(pParse, 0, iDb);
  iStatCur = pParse->nTab++;
  openStatTable(pParse, iDb, iStatCur, 0);

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.40 2006/01/06 21:52:50 drh Exp $
*/
#include "sqliteInt.h"

/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
** identifiers are treated as strings, not possible column names or aliases.
................................................................................
  int rc;
  NameContext sName;
  Vdbe *v;
  FuncDef *pFunc;
  sqlite3* db = pParse->db;

#ifndef SQLITE_OMIT_AUTHORIZATION
  assert( sqlite3Tsd()->mallocFailed || pAuthArg );
  if( pAuthArg ){
    char *zAuthArg = sqlite3NameFromToken(&pAuthArg->span);
    if( !zAuthArg ){
      goto attach_end;
    }
    rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0);
    sqliteFree(zAuthArg);
................................................................................
  }

  v = sqlite3GetVdbe(pParse);
  sqlite3ExprCode(pParse, pFilename);
  sqlite3ExprCode(pParse, pDbname);
  sqlite3ExprCode(pParse, pKey);

  assert(v || sqlite3Tsd()->mallocFailed);
  if( v ){
    sqlite3VdbeAddOp(v, OP_Function, 0, nFunc);
    pFunc = sqlite3FindFunction(db, zFunc, strlen(zFunc), nFunc, SQLITE_UTF8,0);
    sqlite3VdbeChangeP3(v, -1, (char *)pFunc, P3_FUNCDEF);

    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
    ** statement only). For DETACH, set it to false (expire all existing

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.41 2006/01/09 06:29:48 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
** identifiers are treated as strings, not possible column names or aliases.
................................................................................
  int rc;
  NameContext sName;
  Vdbe *v;
  FuncDef *pFunc;
  sqlite3* db = pParse->db;

#ifndef SQLITE_OMIT_AUTHORIZATION
  assert( sqlite3ThreadData()->mallocFailed || pAuthArg );
  if( pAuthArg ){
    char *zAuthArg = sqlite3NameFromToken(&pAuthArg->span);
    if( !zAuthArg ){
      goto attach_end;
    }
    rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0);
    sqliteFree(zAuthArg);
................................................................................
  }

  v = sqlite3GetVdbe(pParse);
  sqlite3ExprCode(pParse, pFilename);
  sqlite3ExprCode(pParse, pDbname);
  sqlite3ExprCode(pParse, pKey);

  assert(v || sqlite3ThreadData()->mallocFailed);
  if( v ){
    sqlite3VdbeAddOp(v, OP_Function, 0, nFunc);
    pFunc = sqlite3FindFunction(db, zFunc, strlen(zFunc), nFunc, SQLITE_UTF8,0);
    sqlite3VdbeChangeP3(v, -1, (char *)pFunc, P3_FUNCDEF);

    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
    ** statement only). For DETACH, set it to false (expire all existing

** 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 1.286 2006/01/09 05:36:27 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
  u16 usableSize;       /* Number of usable bytes on each page */
  int maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
  int minLocal;         /* Minimum local payload in non-LEAFDATA tables */
  int maxLeaf;          /* Maximum local payload in a LEAFDATA table */
  int minLeaf;          /* Minimum local payload in a LEAFDATA table */
  BusyHandler *pBusyHandler;   /* Callback for when there is lock contention */
  u8 inTransaction;     /* Transaction state */
  BtShared *pNext;      /* Next in SqliteTsd.pBtree linked list */
  int nRef;             /* Number of references to this structure */
  int nTransaction;     /* Number of open transactions (read + write) */
  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
#ifndef SQLITE_OMIT_SHARED_CACHE
  BtLock *pLock;        /* List of locks held on this shared-btree struct */

#endif
};

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
................................................................................
/*
** Save the positions of all cursors except pExcept open on the table 
** with root-page iRoot. Usually, this is called just before cursor
** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).
*/
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
  BtCursor *p;
  if( sqlite3Tsd()->useSharedData ){
    for(p=pBt->pCursor; p; p=p->pNext){
      if( p!=pExcept && p->pgnoRoot==iRoot && p->eState==CURSOR_VALID ){
        int rc = saveCursorPosition(p);
        if( SQLITE_OK!=rc ){
          return rc;
        }
      }
................................................................................
** If the second argument argument - doSeek - is false, then instead of 
** returning the cursor to it's saved position, any saved position is deleted
** and the cursor state set to CURSOR_INVALID.
*/
static int restoreCursorPosition(BtCursor *pCur, int doSeek){
  int rc = SQLITE_OK;
  if( pCur->eState==CURSOR_REQUIRESEEK ){
    assert( sqlite3Tsd()->useSharedData );
    if( doSeek ){
      rc = sqlite3BtreeMoveto(pCur, pCur->pKey, pCur->nKey, &pCur->skip);
    }else{
      pCur->eState = CURSOR_INVALID;
    }
    if( rc==SQLITE_OK ){
      sqliteFree(pCur->pKey);
................................................................................
** SQLITE_LOCKED if not.
*/
static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){
  BtShared *pBt = p->pBt;
  BtLock *pIter;

  /* This is a no-op if the shared-cache is not enabled */
  if( 0==sqlite3Tsd()->useSharedData ){
    return SQLITE_OK;
  }

  /* This (along with lockTable()) is where the ReadUncommitted flag is
  ** dealt with. If the caller is querying for a read-lock and the flag is
  ** set, it is unconditionally granted - even if there are write-locks
  ** on the table. If a write-lock is requested, the ReadUncommitted flag
................................................................................
*/
static int lockTable(Btree *p, Pgno iTable, u8 eLock){
  BtShared *pBt = p->pBt;
  BtLock *pLock = 0;
  BtLock *pIter;

  /* This is a no-op if the shared-cache is not enabled */
  if( 0==sqlite3Tsd()->useSharedData ){
    return SQLITE_OK;
  }

  assert( SQLITE_OK==queryTableLock(p, iTable, eLock) );

  /* If the read-uncommitted flag is set and a read-lock is requested,
  ** return early without adding an entry to the BtShared.pLock list. See
................................................................................
static void unlockAllTables(Btree *p){
  BtLock **ppIter = &p->pBt->pLock;

  /* If the shared-cache extension is not enabled, there should be no
  ** locks in the BtShared.pLock list, making this procedure a no-op. Assert
  ** that this is the case.
  */
  assert( sqlite3Tsd()->useSharedData || 0==*ppIter );

  while( *ppIter ){
    BtLock *pLock = *ppIter;
    if( pLock->pBtree==p ){
      *ppIter = pLock->pNext;
      sqliteFree(pLock);
    }else{
................................................................................
){
  BtShared *pBt;          /* Shared part of btree structure */
  Btree *p;               /* Handle to return */
  int rc;
  int nReserve;
  unsigned char zDbHeader[100];
#ifndef SQLITE_OMIT_SHARED_CACHE
  SqliteTsd *pTsd = sqlite3Tsd();
#endif

  /* Set the variable isMemdb to true for an in-memory database, or 
  ** false for a file-based database. This symbol is only required if
  ** either of the shared-data or autovacuum features are compiled 
  ** into the library.
  */
................................................................................
#endif
  }
  pBt->usableSize = pBt->pageSize - nReserve;
  assert( (pBt->pageSize & 7)==0 );  /* 8-byte alignment of pageSize */
  sqlite3pager_set_pagesize(pBt->pPager, pBt->pageSize);

#ifndef SQLITE_OMIT_SHARED_CACHE
  /* Add the new btree to the linked list starting at SqliteTsd.pBtree */
  if( pTsd->useSharedData && zFilename && !isMemdb ){
    pBt->pNext = pTsd->pBtree;
    pTsd->pBtree = pBt;
  }
#endif
  pBt->nRef = 1;
  *ppBtree = p;
................................................................................
** Close an open database and invalidate all cursors.
*/
int sqlite3BtreeClose(Btree *p){
  BtShared *pBt = p->pBt;
  BtCursor *pCur;

#ifndef SQLITE_OMIT_SHARED_CACHE
  SqliteTsd *pTsd = sqlite3Tsd();
#endif

  /* Drop any table-locks */
  unlockAllTables(p);

  /* Close all cursors opened via this handle.  */
  pCur = pBt->pCursor;
................................................................................

/*
** This routine is called prior to sqlite3pager_commit when a transaction
** is commited for an auto-vacuum database.
*/
static int autoVacuumCommit(BtShared *pBt, Pgno *nTrunc){
  Pager *pPager = pBt->pPager;
  Pgno nFreeList;   /* Number of pages remaining on the free-list. */
  int nPtrMap;      /* Number of pointer-map pages deallocated */
  Pgno origSize;  /* Pages in the database file */
  Pgno finSize;   /* Pages in the database file after truncation */
  int rc;           /* Return code */
  u8 eType;
  int pgsz = pBt->pageSize;  /* Page size for this database */
  Pgno iDbPage;              /* The database page to move */
  MemPage *pDbMemPage = 0;   /* "" */
  Pgno iPtrPage;             /* The page that contains a pointer to iDbPage */
  Pgno iFreePage;            /* The free-list page to move iDbPage to */
  MemPage *pFreeMemPage = 0; /* "" */
................................................................................
        goto autovacuum_out;
      }
      assert( iFreePage<=origSize );
    }while( iFreePage>finSize );
    releasePage(pFreeMemPage);
    pFreeMemPage = 0;







    rc = relocatePage(pBt, pDbMemPage, eType, iPtrPage, iFreePage);
    releasePage(pDbMemPage);
    if( rc!=SQLITE_OK ) goto autovacuum_out;
  }

  /* The entire free-list has been swapped to the end of the file. So
  ** truncate the database file to finSize pages and consider the
................................................................................
}

#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** Enable the shared pager and schema features.
*/
int sqlite3_enable_shared_cache(int enable){
  SqliteTsd *pTsd = sqlite3Tsd();
  if( pTsd->pPager ){
    return SQLITE_MISUSE;
  }
  pTsd->useSharedData = enable;
  return SQLITE_OK;
}
#endif

** 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 1.287 2006/01/09 06:29:48 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
  u16 usableSize;       /* Number of usable bytes on each page */
  int maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
  int minLocal;         /* Minimum local payload in non-LEAFDATA tables */
  int maxLeaf;          /* Maximum local payload in a LEAFDATA table */
  int minLeaf;          /* Minimum local payload in a LEAFDATA table */
  BusyHandler *pBusyHandler;   /* Callback for when there is lock contention */
  u8 inTransaction;     /* Transaction state */

  int nRef;             /* Number of references to this structure */
  int nTransaction;     /* Number of open transactions (read + write) */
  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
#ifndef SQLITE_OMIT_SHARED_CACHE
  BtLock *pLock;        /* List of locks held on this shared-btree struct */
  BtShared *pNext;      /* Next in ThreadData.pBtree linked list */
#endif
};

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
................................................................................
/*
** Save the positions of all cursors except pExcept open on the table 
** with root-page iRoot. Usually, this is called just before cursor
** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).
*/
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
  BtCursor *p;
  if( sqlite3ThreadData()->useSharedData ){
    for(p=pBt->pCursor; p; p=p->pNext){
      if( p!=pExcept && p->pgnoRoot==iRoot && p->eState==CURSOR_VALID ){
        int rc = saveCursorPosition(p);
        if( SQLITE_OK!=rc ){
          return rc;
        }
      }
................................................................................
** If the second argument argument - doSeek - is false, then instead of 
** returning the cursor to it's saved position, any saved position is deleted
** and the cursor state set to CURSOR_INVALID.
*/
static int restoreCursorPosition(BtCursor *pCur, int doSeek){
  int rc = SQLITE_OK;
  if( pCur->eState==CURSOR_REQUIRESEEK ){
    assert( sqlite3ThreadData()->useSharedData );
    if( doSeek ){
      rc = sqlite3BtreeMoveto(pCur, pCur->pKey, pCur->nKey, &pCur->skip);
    }else{
      pCur->eState = CURSOR_INVALID;
    }
    if( rc==SQLITE_OK ){
      sqliteFree(pCur->pKey);
................................................................................
** SQLITE_LOCKED if not.
*/
static int queryTableLock(Btree *p, Pgno iTab, u8 eLock){
  BtShared *pBt = p->pBt;
  BtLock *pIter;

  /* This is a no-op if the shared-cache is not enabled */
  if( 0==sqlite3ThreadData()->useSharedData ){
    return SQLITE_OK;
  }

  /* This (along with lockTable()) is where the ReadUncommitted flag is
  ** dealt with. If the caller is querying for a read-lock and the flag is
  ** set, it is unconditionally granted - even if there are write-locks
  ** on the table. If a write-lock is requested, the ReadUncommitted flag
................................................................................
*/
static int lockTable(Btree *p, Pgno iTable, u8 eLock){
  BtShared *pBt = p->pBt;
  BtLock *pLock = 0;
  BtLock *pIter;

  /* This is a no-op if the shared-cache is not enabled */
  if( 0==sqlite3ThreadData()->useSharedData ){
    return SQLITE_OK;
  }

  assert( SQLITE_OK==queryTableLock(p, iTable, eLock) );

  /* If the read-uncommitted flag is set and a read-lock is requested,
  ** return early without adding an entry to the BtShared.pLock list. See
................................................................................
static void unlockAllTables(Btree *p){
  BtLock **ppIter = &p->pBt->pLock;

  /* If the shared-cache extension is not enabled, there should be no
  ** locks in the BtShared.pLock list, making this procedure a no-op. Assert
  ** that this is the case.
  */
  assert( sqlite3ThreadData()->useSharedData || 0==*ppIter );

  while( *ppIter ){
    BtLock *pLock = *ppIter;
    if( pLock->pBtree==p ){
      *ppIter = pLock->pNext;
      sqliteFree(pLock);
    }else{
................................................................................
){
  BtShared *pBt;          /* Shared part of btree structure */
  Btree *p;               /* Handle to return */
  int rc;
  int nReserve;
  unsigned char zDbHeader[100];
#ifndef SQLITE_OMIT_SHARED_CACHE
  ThreadData *pTsd = sqlite3ThreadData();
#endif

  /* Set the variable isMemdb to true for an in-memory database, or 
  ** false for a file-based database. This symbol is only required if
  ** either of the shared-data or autovacuum features are compiled 
  ** into the library.
  */
................................................................................
#endif
  }
  pBt->usableSize = pBt->pageSize - nReserve;
  assert( (pBt->pageSize & 7)==0 );  /* 8-byte alignment of pageSize */
  sqlite3pager_set_pagesize(pBt->pPager, pBt->pageSize);

#ifndef SQLITE_OMIT_SHARED_CACHE
  /* Add the new btree to the linked list starting at ThreadData.pBtree */
  if( pTsd->useSharedData && zFilename && !isMemdb ){
    pBt->pNext = pTsd->pBtree;
    pTsd->pBtree = pBt;
  }
#endif
  pBt->nRef = 1;
  *ppBtree = p;
................................................................................
** Close an open database and invalidate all cursors.
*/
int sqlite3BtreeClose(Btree *p){
  BtShared *pBt = p->pBt;
  BtCursor *pCur;

#ifndef SQLITE_OMIT_SHARED_CACHE
  ThreadData *pTsd = sqlite3ThreadData();
#endif

  /* Drop any table-locks */
  unlockAllTables(p);

  /* Close all cursors opened via this handle.  */
  pCur = pBt->pCursor;
................................................................................

/*
** This routine is called prior to sqlite3pager_commit when a transaction
** is commited for an auto-vacuum database.
*/
static int autoVacuumCommit(BtShared *pBt, Pgno *nTrunc){
  Pager *pPager = pBt->pPager;
  Pgno nFreeList;            /* Number of pages remaining on the free-list. */
  int nPtrMap;               /* Number of pointer-map pages deallocated */
  Pgno origSize;             /* Pages in the database file */
  Pgno finSize;              /* Pages in the database file after truncation */
  int rc;                    /* Return code */
  u8 eType;
  int pgsz = pBt->pageSize;  /* Page size for this database */
  Pgno iDbPage;              /* The database page to move */
  MemPage *pDbMemPage = 0;   /* "" */
  Pgno iPtrPage;             /* The page that contains a pointer to iDbPage */
  Pgno iFreePage;            /* The free-list page to move iDbPage to */
  MemPage *pFreeMemPage = 0; /* "" */
................................................................................
        goto autovacuum_out;
      }
      assert( iFreePage<=origSize );
    }while( iFreePage>finSize );
    releasePage(pFreeMemPage);
    pFreeMemPage = 0;

    /* Relocate the page into the body of the file. Note that although the 
    ** page has moved within the database file, the pDbMemPage pointer 
    ** remains valid. This means that this function can run without
    ** invalidating cursors open on the btree. This is important in 
    ** shared-cache mode.
    */
    rc = relocatePage(pBt, pDbMemPage, eType, iPtrPage, iFreePage);
    releasePage(pDbMemPage);
    if( rc!=SQLITE_OK ) goto autovacuum_out;
  }

  /* The entire free-list has been swapped to the end of the file. So
  ** truncate the database file to finSize pages and consider the
................................................................................
}

#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** Enable the shared pager and schema features.
*/
int sqlite3_enable_shared_cache(int enable){
  ThreadData *pTsd = sqlite3ThreadData();
  if( pTsd->pPager ){
    return SQLITE_MISUSE;
  }
  pTsd->useSharedData = enable;
  return SQLITE_OK;
}
#endif

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.370 2006/01/09 05:36:27 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
  int iTab, 
  u8 isWriteLock,  
  const char *zName
){
  int i;
  int nBytes;
  TableLock *p;
  SqliteTsd *pTsd = sqlite3Tsd();

  if( 0==pTsd->useSharedData ){
    return;
  }

  for(i=0; i<pParse->nTableLock; i++){
    p = &pParse->aTableLock[i];
................................................................................
/*
** Code an OP_TableLock instruction for each table locked by the
** statement (configured by calls to sqlite3TableLock()).
*/
static void codeTableLocks(Parse *pParse){
  int i;
  Vdbe *pVdbe; 
  assert( sqlite3Tsd()->useSharedData || pParse->nTableLock==0 );

  if( 0==(pVdbe = sqlite3GetVdbe(pParse)) ){
    return;
  }

  for(i=0; i<pParse->nTableLock; i++){
    TableLock *p = &pParse->aTableLock[i];
................................................................................
** Note that if an error occurred, it might be the case that
** no VDBE code was generated.
*/
void sqlite3FinishCoding(Parse *pParse){
  sqlite3 *db;
  Vdbe *v;

  if( sqlite3Tsd()->mallocFailed ) return;
  if( pParse->nested ) return;
  if( !pParse->pVdbe ){
    if( pParse->rc==SQLITE_OK && pParse->nErr ){
      pParse->rc = SQLITE_ERROR;
    }
    return;
  }
................................................................................
*/
Index *sqlite3FindIndex(sqlite3 *db, const char *zName, const char *zDb){
  Index *p = 0;
  int i;
  assert( (db->flags & SQLITE_Initialized) || db->init.busy );
  for(i=OMIT_TEMPDB; i<db->nDb; i++){
    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
    DbSchema *pSchema = db->aDb[j].pSchema;
    if( zDb && sqlite3StrICmp(zDb, db->aDb[j].zName) ) continue;
    assert( pSchema || (j==1 && !db->aDb[1].pBt) );
    if( pSchema ){
      p = sqlite3HashFind(&pSchema->idxHash, zName, strlen(zName)+1);
    }
    if( p ) break;
  }
................................................................................
  Token *pEnd,            /* The final ')' token in the CREATE TABLE */
  Select *pSelect         /* Select from a "CREATE ... AS SELECT" */
){
  Table *p;
  sqlite3 *db = pParse->db;
  int iDb;

  if( (pEnd==0 && pSelect==0) || pParse->nErr || sqlite3Tsd()->mallocFailed ) {

    return;
  }
  p = pParse->pNewTable;
  if( p==0 ) return;

  assert( !db->init.busy || !pSelect );

................................................................................


  /* Add the table to the in-memory representation of the database.
  */
  if( db->init.busy && pParse->nErr==0 ){
    Table *pOld;
    FKey *pFKey; 
    DbSchema *pSchema = p->pSchema;
    pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName, strlen(p->zName)+1,p);
    if( pOld ){
      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
      return;
    }
#ifndef SQLITE_OMIT_FOREIGN_KEY
    for(pFKey=p->pFKey; pFKey; pFKey=pFKey->pNextFrom){
................................................................................
  /* Make a copy of the entire SELECT statement that defines the view.
  ** This will force all the Expr.token.z values to be dynamically
  ** allocated rather than point to the input string - which means that
  ** they will persist after the current sqlite3_exec() call returns.
  */
  p->pSelect = sqlite3SelectDup(pSelect);
  sqlite3SelectDelete(pSelect);
  if( sqlite3Tsd()->mallocFailed ){
    return;
  }
  if( !pParse->db->init.busy ){
    sqlite3ViewGetColumnNames(pParse, p);
  }

  /* Locate the end of the CREATE VIEW statement.  Make sEnd point to
................................................................................
*/
void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
  Table *pTab;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  if( pParse->nErr || sqlite3Tsd()->mallocFailed ) goto exit_drop_table;
  assert( pName->nSrc==1 );
  pTab = sqlite3LocateTable(pParse, pName->a[0].zName, pName->a[0].zDatabase);

  if( pTab==0 ){
    if( noErr ){
      sqlite3ErrorClear(pParse);
    }
................................................................................
  int sortOrderMask;   /* 1 to honor DESC in index.  0 to ignore. */
  sqlite3 *db = pParse->db;
  Db *pDb;             /* The specific table containing the indexed database */
  int iDb;             /* Index of the database that is being written */
  Token *pName = 0;    /* Unqualified name of the index to create */
  struct ExprList_item *pListItem; /* For looping over pList */


  if( pParse->nErr || sqlite3Tsd()->mallocFailed ) goto exit_create_index;


  /*
  ** Find the table that is to be indexed.  Return early if not found.
  */
  if( pTblName!=0 ){

    /* Use the two-part index name to determine the database 
................................................................................

  /* 
  ** Allocate the index structure. 
  */
  nName = strlen(zName);
  pIndex = sqliteMalloc( sizeof(Index) + nName + 2 + sizeof(int) +
                        (sizeof(int)*2 + sizeof(CollSeq*) + 1)*pList->nExpr );
  if( sqlite3Tsd()->mallocFailed ) goto exit_create_index;
  pIndex->aiColumn = (int*)&pIndex->keyInfo.aColl[pList->nExpr];
  pIndex->aiRowEst = (unsigned*)&pIndex->aiColumn[pList->nExpr];
  pIndex->zName = (char*)&pIndex->aiRowEst[pList->nExpr+1];
  pIndex->keyInfo.aSortOrder = &pIndex->zName[nName+1];
  strcpy(pIndex->zName, zName);
  pIndex->pTable = pTab;
  pIndex->nColumn = pList->nExpr;
................................................................................
*/
void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
  Index *pIndex;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  if( pParse->nErr || sqlite3Tsd()->mallocFailed ){
    goto exit_drop_index;
  }
  assert( pName->nSrc==1 );
  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    goto exit_drop_index;
  }
  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].zDatabase);
................................................................................

/*
** Assign cursors to all tables in a SrcList
*/
void sqlite3SrcListAssignCursors(Parse *pParse, SrcList *pList){
  int i;
  struct SrcList_item *pItem;
  assert(pList || sqlite3Tsd()->mallocFailed);
  if( pList ){
    for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
      if( pItem->iCursor>=0 ) break;
      pItem->iCursor = pParse->nTab++;
      if( pItem->pSelect ){
        sqlite3SrcListAssignCursors(pParse, pItem->pSelect->pSrc);
      }
................................................................................
*/
void sqlite3BeginTransaction(Parse *pParse, int type){
  sqlite3 *db;
  Vdbe *v;
  int i;

  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
  if( pParse->nErr || sqlite3Tsd()->mallocFailed ) return;
  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "BEGIN", 0, 0) ) return;

  v = sqlite3GetVdbe(pParse);
  if( !v ) return;
  if( type!=TK_DEFERRED ){
    for(i=0; i<db->nDb; i++){
      sqlite3VdbeAddOp(v, OP_Transaction, i, (type==TK_EXCLUSIVE)+1);
................................................................................
** Commit a transaction
*/
void sqlite3CommitTransaction(Parse *pParse){
  sqlite3 *db;
  Vdbe *v;

  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
  if( pParse->nErr || sqlite3Tsd()->mallocFailed ) return;
  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "COMMIT", 0, 0) ) return;

  v = sqlite3GetVdbe(pParse);
  if( v ){
    sqlite3VdbeAddOp(v, OP_AutoCommit, 1, 0);
  }
}
................................................................................
** Rollback a transaction
*/
void sqlite3RollbackTransaction(Parse *pParse){
  sqlite3 *db;
  Vdbe *v;

  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
  if( pParse->nErr || sqlite3Tsd()->mallocFailed ) return;
  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "ROLLBACK", 0, 0) ) return;

  v = sqlite3GetVdbe(pParse);
  if( v ){
    sqlite3VdbeAddOp(v, OP_AutoCommit, 1, 1);
  }
}

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.371 2006/01/09 06:29:48 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
  int iTab, 
  u8 isWriteLock,  
  const char *zName
){
  int i;
  int nBytes;
  TableLock *p;
  ThreadData *pTsd = sqlite3ThreadData();

  if( 0==pTsd->useSharedData ){
    return;
  }

  for(i=0; i<pParse->nTableLock; i++){
    p = &pParse->aTableLock[i];
................................................................................
/*
** Code an OP_TableLock instruction for each table locked by the
** statement (configured by calls to sqlite3TableLock()).
*/
static void codeTableLocks(Parse *pParse){
  int i;
  Vdbe *pVdbe; 
  assert( sqlite3ThreadData()->useSharedData || pParse->nTableLock==0 );

  if( 0==(pVdbe = sqlite3GetVdbe(pParse)) ){
    return;
  }

  for(i=0; i<pParse->nTableLock; i++){
    TableLock *p = &pParse->aTableLock[i];
................................................................................
** Note that if an error occurred, it might be the case that
** no VDBE code was generated.
*/
void sqlite3FinishCoding(Parse *pParse){
  sqlite3 *db;
  Vdbe *v;

  if( sqlite3ThreadData()->mallocFailed ) return;
  if( pParse->nested ) return;
  if( !pParse->pVdbe ){
    if( pParse->rc==SQLITE_OK && pParse->nErr ){
      pParse->rc = SQLITE_ERROR;
    }
    return;
  }
................................................................................
*/
Index *sqlite3FindIndex(sqlite3 *db, const char *zName, const char *zDb){
  Index *p = 0;
  int i;
  assert( (db->flags & SQLITE_Initialized) || db->init.busy );
  for(i=OMIT_TEMPDB; i<db->nDb; i++){
    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
    Schema *pSchema = db->aDb[j].pSchema;
    if( zDb && sqlite3StrICmp(zDb, db->aDb[j].zName) ) continue;
    assert( pSchema || (j==1 && !db->aDb[1].pBt) );
    if( pSchema ){
      p = sqlite3HashFind(&pSchema->idxHash, zName, strlen(zName)+1);
    }
    if( p ) break;
  }
................................................................................
  Token *pEnd,            /* The final ')' token in the CREATE TABLE */
  Select *pSelect         /* Select from a "CREATE ... AS SELECT" */
){
  Table *p;
  sqlite3 *db = pParse->db;
  int iDb;

  if( (pEnd==0 && pSelect==0) || 
      pParse->nErr || sqlite3ThreadData()->mallocFailed ) {
    return;
  }
  p = pParse->pNewTable;
  if( p==0 ) return;

  assert( !db->init.busy || !pSelect );

................................................................................


  /* Add the table to the in-memory representation of the database.
  */
  if( db->init.busy && pParse->nErr==0 ){
    Table *pOld;
    FKey *pFKey; 
    Schema *pSchema = p->pSchema;
    pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName, strlen(p->zName)+1,p);
    if( pOld ){
      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
      return;
    }
#ifndef SQLITE_OMIT_FOREIGN_KEY
    for(pFKey=p->pFKey; pFKey; pFKey=pFKey->pNextFrom){
................................................................................
  /* Make a copy of the entire SELECT statement that defines the view.
  ** This will force all the Expr.token.z values to be dynamically
  ** allocated rather than point to the input string - which means that
  ** they will persist after the current sqlite3_exec() call returns.
  */
  p->pSelect = sqlite3SelectDup(pSelect);
  sqlite3SelectDelete(pSelect);
  if( sqlite3ThreadData()->mallocFailed ){
    return;
  }
  if( !pParse->db->init.busy ){
    sqlite3ViewGetColumnNames(pParse, p);
  }

  /* Locate the end of the CREATE VIEW statement.  Make sEnd point to
................................................................................
*/
void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
  Table *pTab;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ) goto exit_drop_table;
  assert( pName->nSrc==1 );
  pTab = sqlite3LocateTable(pParse, pName->a[0].zName, pName->a[0].zDatabase);

  if( pTab==0 ){
    if( noErr ){
      sqlite3ErrorClear(pParse);
    }
................................................................................
  int sortOrderMask;   /* 1 to honor DESC in index.  0 to ignore. */
  sqlite3 *db = pParse->db;
  Db *pDb;             /* The specific table containing the indexed database */
  int iDb;             /* Index of the database that is being written */
  Token *pName = 0;    /* Unqualified name of the index to create */
  struct ExprList_item *pListItem; /* For looping over pList */

  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ){
    goto exit_create_index;
  }

  /*
  ** Find the table that is to be indexed.  Return early if not found.
  */
  if( pTblName!=0 ){

    /* Use the two-part index name to determine the database 
................................................................................

  /* 
  ** Allocate the index structure. 
  */
  nName = strlen(zName);
  pIndex = sqliteMalloc( sizeof(Index) + nName + 2 + sizeof(int) +
                        (sizeof(int)*2 + sizeof(CollSeq*) + 1)*pList->nExpr );
  if( sqlite3ThreadData()->mallocFailed ) goto exit_create_index;
  pIndex->aiColumn = (int*)&pIndex->keyInfo.aColl[pList->nExpr];
  pIndex->aiRowEst = (unsigned*)&pIndex->aiColumn[pList->nExpr];
  pIndex->zName = (char*)&pIndex->aiRowEst[pList->nExpr+1];
  pIndex->keyInfo.aSortOrder = &pIndex->zName[nName+1];
  strcpy(pIndex->zName, zName);
  pIndex->pTable = pTab;
  pIndex->nColumn = pList->nExpr;
................................................................................
*/
void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
  Index *pIndex;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ){
    goto exit_drop_index;
  }
  assert( pName->nSrc==1 );
  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    goto exit_drop_index;
  }
  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].zDatabase);
................................................................................

/*
** Assign cursors to all tables in a SrcList
*/
void sqlite3SrcListAssignCursors(Parse *pParse, SrcList *pList){
  int i;
  struct SrcList_item *pItem;
  assert(pList || sqlite3ThreadData()->mallocFailed);
  if( pList ){
    for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
      if( pItem->iCursor>=0 ) break;
      pItem->iCursor = pParse->nTab++;
      if( pItem->pSelect ){
        sqlite3SrcListAssignCursors(pParse, pItem->pSelect->pSrc);
      }
................................................................................
*/
void sqlite3BeginTransaction(Parse *pParse, int type){
  sqlite3 *db;
  Vdbe *v;
  int i;

  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ) return;
  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "BEGIN", 0, 0) ) return;

  v = sqlite3GetVdbe(pParse);
  if( !v ) return;
  if( type!=TK_DEFERRED ){
    for(i=0; i<db->nDb; i++){
      sqlite3VdbeAddOp(v, OP_Transaction, i, (type==TK_EXCLUSIVE)+1);
................................................................................
** Commit a transaction
*/
void sqlite3CommitTransaction(Parse *pParse){
  sqlite3 *db;
  Vdbe *v;

  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ) return;
  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "COMMIT", 0, 0) ) return;

  v = sqlite3GetVdbe(pParse);
  if( v ){
    sqlite3VdbeAddOp(v, OP_AutoCommit, 1, 0);
  }
}
................................................................................
** Rollback a transaction
*/
void sqlite3RollbackTransaction(Parse *pParse){
  sqlite3 *db;
  Vdbe *v;

  if( pParse==0 || (db=pParse->db)==0 || db->aDb[0].pBt==0 ) return;
  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ) return;
  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "ROLLBACK", 0, 0) ) return;

  v = sqlite3GetVdbe(pParse);
  if( v ){
    sqlite3VdbeAddOp(v, OP_AutoCommit, 1, 1);
  }
}

**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains functions used to access the internal hash tables
** of user defined functions and collation sequences.
**
** $Id: callback.c,v 1.7 2005/12/14 22:51:17 drh Exp $
*/

#include "sqliteInt.h"

/*
** Invoke the 'collation needed' callback to request a collation sequence
** in the database text encoding of name zName, length nName.
................................................................................
      pColl[0].zName[nName] = 0;
      pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, nName, pColl);

      /* If a malloc() failure occured in sqlite3HashInsert(), it will 
      ** return the pColl pointer to be deleted (because it wasn't added
      ** to the hash table).
      */
      assert( !pDel || (sqlite3Tsd()->mallocFailed && pDel==pColl) );
      sqliteFree(pDel);
    }
  }
  return pColl;
}

/*

**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains functions used to access the internal hash tables
** of user defined functions and collation sequences.
**
** $Id: callback.c,v 1.8 2006/01/09 06:29:48 danielk1977 Exp $
*/

#include "sqliteInt.h"

/*
** Invoke the 'collation needed' callback to request a collation sequence
** in the database text encoding of name zName, length nName.
................................................................................
      pColl[0].zName[nName] = 0;
      pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, nName, pColl);

      /* If a malloc() failure occured in sqlite3HashInsert(), it will 
      ** return the pColl pointer to be deleted (because it wasn't added
      ** to the hash table).
      */
      assert( !pDel || (sqlite3ThreadData()->mallocFailed && pDel==pColl) );
      sqliteFree(pDel);
    }
  }
  return pColl;
}

/*

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.115 2006/01/07 13:21:04 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  int triggers_exist = 0;      /* True if any triggers exist */
#endif

  sContext.pParse = 0;
  if( pParse->nErr || sqlite3Tsd()->mallocFailed ){
    goto delete_from_cleanup;
  }
  db = pParse->db;
  assert( pTabList->nSrc==1 );

  /* Locate the table which we want to delete.  This table has to be
  ** put in an SrcList structure because some of the subroutines we

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.116 2006/01/09 06:29:48 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  int triggers_exist = 0;      /* True if any triggers exist */
#endif

  sContext.pParse = 0;
  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ){
    goto delete_from_cleanup;
  }
  db = pParse->db;
  assert( pTabList->nSrc==1 );

  /* Locate the table which we want to delete.  This table has to be
  ** put in an SrcList structure because some of the subroutines we

**    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 1.244 2006/01/05 11:34:34 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
/*
** Set the Expr.span field of the given expression to span all
** text between the two given tokens.
*/
void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
  assert( pRight!=0 );
  assert( pLeft!=0 );
  if( !sqlite3Tsd()->mallocFailed && pRight->z && pLeft->z ){
    assert( pLeft->dyn==0 || pLeft->z[pLeft->n]==0 );
    if( pLeft->dyn==0 && pRight->dyn==0 ){
      pExpr->span.z = pLeft->z;
      pExpr->span.n = pRight->n + (pRight->z - pLeft->z);
    }else{
      pExpr->span.z = 0;
    }
................................................................................
    if( i>=pParse->nVarExpr ){
      pExpr->iTable = ++pParse->nVar;
      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
        sqlite3ReallocOrFree((void**)&pParse->apVarExpr,
                       pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0]) );
      }
      if( !sqlite3Tsd()->mallocFailed ){
        assert( pParse->apVarExpr!=0 );
        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
      }
    }
  } 
}

................................................................................
    if( pOldExpr->span.z!=0 && pNewExpr ){
      /* Always make a copy of the span for top-level expressions in the
      ** expression list.  The logic in SELECT processing that determines
      ** the names of columns in the result set needs this information */
      sqlite3TokenCopy(&pNewExpr->span, &pOldExpr->span);
    }
    assert( pNewExpr==0 || pNewExpr->span.z!=0 
            || pOldExpr->span.z==0 || sqlite3Tsd()->mallocFailed );
    pItem->zName = sqliteStrDup(pOldItem->zName);
    pItem->sortOrder = pOldItem->sortOrder;
    pItem->isAgg = pOldItem->isAgg;
    pItem->done = 0;
  }
  return pNew;
}
................................................................................
  struct SrcList_item *pMatch = 0;  /* The matching pSrcList item */
  NameContext *pTopNC = pNC;        /* First namecontext in the list */

  assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
  zDb = sqlite3NameFromToken(pDbToken);
  zTab = sqlite3NameFromToken(pTableToken);
  zCol = sqlite3NameFromToken(pColumnToken);
  if( sqlite3Tsd()->mallocFailed ){
    goto lookupname_end;
  }

  pExpr->iTable = -1;
  while( pNC && cnt==0 ){
    ExprList *pEList;
    SrcList *pSrcList = pNC->pSrcList;
................................................................................
  ** If all of the above are false, then we can run this code just once
  ** save the results, and reuse the same result on subsequent invocations.
  */
  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) && !pParse->trigStack ){
    int mem = pParse->nMem++;
    sqlite3VdbeAddOp(v, OP_MemLoad, mem, 0);
    testAddr = sqlite3VdbeAddOp(v, OP_If, 0, 0);
    assert( testAddr>0 || sqlite3Tsd()->mallocFailed );
    sqlite3VdbeAddOp(v, OP_MemInt, 1, mem);
  }

  switch( pExpr->op ){
    case TK_IN: {
      char affinity;
      KeyInfo keyInfo;

**    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 1.245 2006/01/09 06:29:48 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
/*
** Set the Expr.span field of the given expression to span all
** text between the two given tokens.
*/
void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
  assert( pRight!=0 );
  assert( pLeft!=0 );
  if( !sqlite3ThreadData()->mallocFailed && pRight->z && pLeft->z ){
    assert( pLeft->dyn==0 || pLeft->z[pLeft->n]==0 );
    if( pLeft->dyn==0 && pRight->dyn==0 ){
      pExpr->span.z = pLeft->z;
      pExpr->span.n = pRight->n + (pRight->z - pLeft->z);
    }else{
      pExpr->span.z = 0;
    }
................................................................................
    if( i>=pParse->nVarExpr ){
      pExpr->iTable = ++pParse->nVar;
      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
        sqlite3ReallocOrFree((void**)&pParse->apVarExpr,
                       pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0]) );
      }
      if( !sqlite3ThreadData()->mallocFailed ){
        assert( pParse->apVarExpr!=0 );
        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
      }
    }
  } 
}

................................................................................
    if( pOldExpr->span.z!=0 && pNewExpr ){
      /* Always make a copy of the span for top-level expressions in the
      ** expression list.  The logic in SELECT processing that determines
      ** the names of columns in the result set needs this information */
      sqlite3TokenCopy(&pNewExpr->span, &pOldExpr->span);
    }
    assert( pNewExpr==0 || pNewExpr->span.z!=0 
            || pOldExpr->span.z==0 || sqlite3ThreadData()->mallocFailed );
    pItem->zName = sqliteStrDup(pOldItem->zName);
    pItem->sortOrder = pOldItem->sortOrder;
    pItem->isAgg = pOldItem->isAgg;
    pItem->done = 0;
  }
  return pNew;
}
................................................................................
  struct SrcList_item *pMatch = 0;  /* The matching pSrcList item */
  NameContext *pTopNC = pNC;        /* First namecontext in the list */

  assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
  zDb = sqlite3NameFromToken(pDbToken);
  zTab = sqlite3NameFromToken(pTableToken);
  zCol = sqlite3NameFromToken(pColumnToken);
  if( sqlite3ThreadData()->mallocFailed ){
    goto lookupname_end;
  }

  pExpr->iTable = -1;
  while( pNC && cnt==0 ){
    ExprList *pEList;
    SrcList *pSrcList = pNC->pSrcList;
................................................................................
  ** If all of the above are false, then we can run this code just once
  ** save the results, and reuse the same result on subsequent invocations.
  */
  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) && !pParse->trigStack ){
    int mem = pParse->nMem++;
    sqlite3VdbeAddOp(v, OP_MemLoad, mem, 0);
    testAddr = sqlite3VdbeAddOp(v, OP_If, 0, 0);
    assert( testAddr>0 || sqlite3ThreadData()->mallocFailed );
    sqlite3VdbeAddOp(v, OP_MemInt, 1, mem);
  }

  switch( pExpr->op ){
    case TK_IN: {
      char affinity;
      KeyInfo keyInfo;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.154 2006/01/08 18:10:18 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
** Return non-zero if SELECT statement p opens the table with rootpage
** iTab in database iDb.  This is used to see if a statement of the form 
** "INSERT INTO <iDb, iTab> SELECT ..." can run without using temporary
** table for the results of the SELECT. 
**
** No checking is done for sub-selects that are part of expressions.
*/
static int selectReadsTable(Select *p, DbSchema *pSchema, int iTab){
  int i;
  struct SrcList_item *pItem;
  if( p->pSrc==0 ) return 0;
  for(i=0, pItem=p->pSrc->a; i<p->pSrc->nSrc; i++, pItem++){
    if( pItem->pSelect ){
      if( selectReadsTable(pItem->pSelect, pSchema, iTab) ) return 1;
    }else{
................................................................................
  int triggers_exist = 0;     /* True if there are FOR EACH ROW triggers */
#endif

#ifndef SQLITE_OMIT_AUTOINCREMENT
  int counterRowid;     /* Memory cell holding rowid of autoinc counter */
#endif

  if( pParse->nErr || sqlite3Tsd()->mallocFailed ) goto insert_cleanup;
  db = pParse->db;

  /* Locate the table into which we will be inserting new information.
  */
  assert( pTabList->nSrc==1 );
  zTab = pTabList->a[0].zName;
  if( zTab==0 ) goto insert_cleanup;
................................................................................
    int rc, iInitCode;
    iInitCode = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
    iSelectLoop = sqlite3VdbeCurrentAddr(v);
    iInsertBlock = sqlite3VdbeMakeLabel(v);

    /* Resolve the expressions in the SELECT statement and execute it. */
    rc = sqlite3Select(pParse, pSelect, SRT_Subroutine, iInsertBlock,0,0,0,0);
    if( rc || pParse->nErr || sqlite3Tsd()->mallocFailed ) goto insert_cleanup;

    iCleanup = sqlite3VdbeMakeLabel(v);
    sqlite3VdbeAddOp(v, OP_Goto, 0, iCleanup);
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;

    /* Set useTempTable to TRUE if the result of the SELECT statement

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.155 2006/01/09 06:29:48 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
** Return non-zero if SELECT statement p opens the table with rootpage
** iTab in database iDb.  This is used to see if a statement of the form 
** "INSERT INTO <iDb, iTab> SELECT ..." can run without using temporary
** table for the results of the SELECT. 
**
** No checking is done for sub-selects that are part of expressions.
*/
static int selectReadsTable(Select *p, Schema *pSchema, int iTab){
  int i;
  struct SrcList_item *pItem;
  if( p->pSrc==0 ) return 0;
  for(i=0, pItem=p->pSrc->a; i<p->pSrc->nSrc; i++, pItem++){
    if( pItem->pSelect ){
      if( selectReadsTable(pItem->pSelect, pSchema, iTab) ) return 1;
    }else{
................................................................................
  int triggers_exist = 0;     /* True if there are FOR EACH ROW triggers */
#endif

#ifndef SQLITE_OMIT_AUTOINCREMENT
  int counterRowid;     /* Memory cell holding rowid of autoinc counter */
#endif

  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ) goto insert_cleanup;
  db = pParse->db;

  /* Locate the table into which we will be inserting new information.
  */
  assert( pTabList->nSrc==1 );
  zTab = pTabList->a[0].zName;
  if( zTab==0 ) goto insert_cleanup;
................................................................................
    int rc, iInitCode;
    iInitCode = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
    iSelectLoop = sqlite3VdbeCurrentAddr(v);
    iInsertBlock = sqlite3VdbeMakeLabel(v);

    /* Resolve the expressions in the SELECT statement and execute it. */
    rc = sqlite3Select(pParse, pSelect, SRT_Subroutine, iInsertBlock,0,0,0,0);
    if( rc || pParse->nErr || sqlite3ThreadData()->mallocFailed ) goto insert_cleanup;

    iCleanup = sqlite3VdbeMakeLabel(v);
    sqlite3VdbeAddOp(v, OP_Goto, 0, iCleanup);
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;

    /* Set useTempTable to TRUE if the result of the SELECT statement

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: legacy.c,v 1.9 2005/12/12 06:53:04 danielk1977 Exp $
*/

#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
................................................................................
    azCols = 0;
  }

exec_out:
  if( pStmt ) sqlite3_finalize(pStmt);
  if( azCols ) sqliteFree(azCols);

  if( sqlite3Tsd()->mallocFailed ){
    rc = SQLITE_NOMEM;
    sqlite3MallocClearFailed();
  }

  if( rc!=SQLITE_OK && rc==sqlite3_errcode(db) && pzErrMsg ){
    *pzErrMsg = malloc(1+strlen(sqlite3_errmsg(db)));
    if( *pzErrMsg ){

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: legacy.c,v 1.10 2006/01/09 06:29:49 danielk1977 Exp $
*/

#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
................................................................................
    azCols = 0;
  }

exec_out:
  if( pStmt ) sqlite3_finalize(pStmt);
  if( azCols ) sqliteFree(azCols);

  if( sqlite3ThreadData()->mallocFailed ){
    rc = SQLITE_NOMEM;
    sqlite3MallocClearFailed();
  }

  if( rc!=SQLITE_OK && rc==sqlite3_errcode(db) && pzErrMsg ){
    *pzErrMsg = malloc(1+strlen(sqlite3_errmsg(db)));
    if( *pzErrMsg ){

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.318 2006/01/06 21:52:50 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and
................................................................................

/*
** Return UTF-8 encoded English language explanation of the most recent
** error.
*/
const char *sqlite3_errmsg(sqlite3 *db){
  const char *z;
  if( sqlite3Tsd()->mallocFailed ){
    return sqlite3ErrStr(SQLITE_NOMEM);
  }
  if( sqlite3SafetyCheck(db) || db->errCode==SQLITE_MISUSE ){
    return sqlite3ErrStr(SQLITE_MISUSE);
  }
  z = (char*)sqlite3_value_text(db->pErr);
  if( z==0 ){
................................................................................
    0, 'c', 0, 'a', 0, 'l', 0, 'l', 0, 'e', 0, 'd', 0, ' ', 
    0, 'o', 0, 'u', 0, 't', 0, ' ', 
    0, 'o', 0, 'f', 0, ' ', 
    0, 's', 0, 'e', 0, 'q', 0, 'u', 0, 'e', 0, 'n', 0, 'c', 0, 'e', 0, 0, 0
  };

  const void *z;
  if( sqlite3Tsd()->mallocFailed ){
    return (void *)(&outOfMemBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
  }
  if( sqlite3SafetyCheck(db) || db->errCode==SQLITE_MISUSE ){
    return (void *)(&misuseBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
  }
  z = sqlite3_value_text16(db->pErr);
  if( z==0 ){
................................................................................
#endif /* SQLITE_OMIT_UTF16 */

/*
** Return the most recent error code generated by an SQLite routine. If NULL is
** passed to this function, we assume a malloc() failed during sqlite3_open().
*/
int sqlite3_errcode(sqlite3 *db){
  if( !db || sqlite3Tsd()->mallocFailed ){
    return SQLITE_NOMEM;
  }
  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  return db->errCode;
}
................................................................................
  const char *zFilename, /* Database filename UTF-8 encoded */
  sqlite3 **ppDb         /* OUT: Returned database handle */
){
  sqlite3 *db;
  int rc;
  CollSeq *pColl;

  assert( !sqlite3Tsd()->mallocFailed );

  /* Allocate the sqlite data structure */
  db = sqliteMalloc( sizeof(sqlite3) );
  if( db==0 ) goto opendb_out;
  db->priorNewRowid = 0;
  db->magic = SQLITE_MAGIC_BUSY;
  db->nDb = 2;
................................................................................
  if( sqlite3_create_collation(db, "BINARY", SQLITE_UTF8, 0,binCollFunc) ||
      sqlite3_create_collation(db, "BINARY", SQLITE_UTF16, 0,binCollFunc) ||
      (db->pDfltColl = sqlite3FindCollSeq(db, db->enc, "BINARY", 6, 0))==0 
  ){
    /* sqlite3_create_collation() is an external API. So the mallocFailed flag
    ** will have been cleared before returning. So set it explicitly here.
    */
    sqlite3Tsd()->mallocFailed = 1;
    db->magic = SQLITE_MAGIC_CLOSED;
    goto opendb_out;
  }

  /* Also add a UTF-8 case-insensitive collation sequence. */
  sqlite3_create_collation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc);

................................................................................
  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zFilename8 ){
    rc = openDatabase(zFilename8, ppDb);
    if( rc==SQLITE_OK && *ppDb ){
      rc = sqlite3_exec(*ppDb, "PRAGMA encoding = 'UTF-16'", 0, 0, 0);
    }
  }else{
    assert( sqlite3Tsd()->mallocFailed );
    sqlite3MallocClearFailed();
  }
  sqlite3ValueFree(pVal);

  return rc;
}
#endif /* SQLITE_OMIT_UTF16 */

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.319 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and
................................................................................

/*
** Return UTF-8 encoded English language explanation of the most recent
** error.
*/
const char *sqlite3_errmsg(sqlite3 *db){
  const char *z;
  if( sqlite3ThreadData()->mallocFailed ){
    return sqlite3ErrStr(SQLITE_NOMEM);
  }
  if( sqlite3SafetyCheck(db) || db->errCode==SQLITE_MISUSE ){
    return sqlite3ErrStr(SQLITE_MISUSE);
  }
  z = (char*)sqlite3_value_text(db->pErr);
  if( z==0 ){
................................................................................
    0, 'c', 0, 'a', 0, 'l', 0, 'l', 0, 'e', 0, 'd', 0, ' ', 
    0, 'o', 0, 'u', 0, 't', 0, ' ', 
    0, 'o', 0, 'f', 0, ' ', 
    0, 's', 0, 'e', 0, 'q', 0, 'u', 0, 'e', 0, 'n', 0, 'c', 0, 'e', 0, 0, 0
  };

  const void *z;
  if( sqlite3ThreadData()->mallocFailed ){
    return (void *)(&outOfMemBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
  }
  if( sqlite3SafetyCheck(db) || db->errCode==SQLITE_MISUSE ){
    return (void *)(&misuseBe[SQLITE_UTF16NATIVE==SQLITE_UTF16LE?1:0]);
  }
  z = sqlite3_value_text16(db->pErr);
  if( z==0 ){
................................................................................
#endif /* SQLITE_OMIT_UTF16 */

/*
** Return the most recent error code generated by an SQLite routine. If NULL is
** passed to this function, we assume a malloc() failed during sqlite3_open().
*/
int sqlite3_errcode(sqlite3 *db){
  if( !db || sqlite3ThreadData()->mallocFailed ){
    return SQLITE_NOMEM;
  }
  if( sqlite3SafetyCheck(db) ){
    return SQLITE_MISUSE;
  }
  return db->errCode;
}
................................................................................
  const char *zFilename, /* Database filename UTF-8 encoded */
  sqlite3 **ppDb         /* OUT: Returned database handle */
){
  sqlite3 *db;
  int rc;
  CollSeq *pColl;

  assert( !sqlite3ThreadData()->mallocFailed );

  /* Allocate the sqlite data structure */
  db = sqliteMalloc( sizeof(sqlite3) );
  if( db==0 ) goto opendb_out;
  db->priorNewRowid = 0;
  db->magic = SQLITE_MAGIC_BUSY;
  db->nDb = 2;
................................................................................
  if( sqlite3_create_collation(db, "BINARY", SQLITE_UTF8, 0,binCollFunc) ||
      sqlite3_create_collation(db, "BINARY", SQLITE_UTF16, 0,binCollFunc) ||
      (db->pDfltColl = sqlite3FindCollSeq(db, db->enc, "BINARY", 6, 0))==0 
  ){
    /* sqlite3_create_collation() is an external API. So the mallocFailed flag
    ** will have been cleared before returning. So set it explicitly here.
    */
    sqlite3ThreadData()->mallocFailed = 1;
    db->magic = SQLITE_MAGIC_CLOSED;
    goto opendb_out;
  }

  /* Also add a UTF-8 case-insensitive collation sequence. */
  sqlite3_create_collation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc);

................................................................................
  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zFilename8 ){
    rc = openDatabase(zFilename8, ppDb);
    if( rc==SQLITE_OK && *ppDb ){
      rc = sqlite3_exec(*ppDb, "PRAGMA encoding = 'UTF-16'", 0, 0, 0);
    }
  }else{
    assert( sqlite3ThreadData()->mallocFailed );
    sqlite3MallocClearFailed();
  }
  sqlite3ValueFree(pVal);

  return rc;
}
#endif /* SQLITE_OMIT_UTF16 */

){
  int rc;
  struct lockKey key1;
  struct openKey key2;
  struct stat statbuf;
  struct lockInfo *pLock;
  struct openCnt *pOpen;
  SqliteTsd *pTsd = sqlite3Tsd();
  rc = fstat(fd, &statbuf);
  if( rc!=0 ) return 1;

  /* Disable the sqlite3_release_memory() function */
  assert( !pTsd->disableReleaseMemory );
  pTsd->disableReleaseMemory = 1;

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

/*
** Close a file.
*/
static int unixClose(OsFile **pId){
  SqliteTsd *pTsd = sqlite3Tsd();
  unixFile *id = (unixFile*)*pId;
  if( !id ) return SQLITE_OK;
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;
  unixUnlock(*pId, NO_LOCK);
  if( id->dirfd>=0 ) close(id->dirfd);
  id->dirfd = -1;
  sqlite3OsEnterMutex();
................................................................................
*/
int sqlite3UnixInMutex(){
  return inMutex;
}

/*
** This function is called automatically when a thread exists to delete
** the threads SqliteTsd structure. 
**
** Because the SqliteTsd structure is required by higher level routines
** such as sqliteMalloc() we use OsFree() and OsMalloc() directly to
** allocate the thread specific data.
*/
#ifdef SQLITE_UNIX_THREADS
static void deleteTsd(void *pTsd){
  sqlite3OsFree(pTsd);
}

){
  int rc;
  struct lockKey key1;
  struct openKey key2;
  struct stat statbuf;
  struct lockInfo *pLock;
  struct openCnt *pOpen;
  ThreadData *pTsd = sqlite3ThreadData();
  rc = fstat(fd, &statbuf);
  if( rc!=0 ) return 1;

  /* Disable the sqlite3_release_memory() function */
  assert( !pTsd->disableReleaseMemory );
  pTsd->disableReleaseMemory = 1;

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

/*
** Close a file.
*/
static int unixClose(OsFile **pId){
  ThreadData *pTsd = sqlite3ThreadData();
  unixFile *id = (unixFile*)*pId;
  if( !id ) return SQLITE_OK;
  if( CHECK_THREADID(id) ) return SQLITE_MISUSE;
  unixUnlock(*pId, NO_LOCK);
  if( id->dirfd>=0 ) close(id->dirfd);
  id->dirfd = -1;
  sqlite3OsEnterMutex();
................................................................................
*/
int sqlite3UnixInMutex(){
  return inMutex;
}

/*
** This function is called automatically when a thread exists to delete
** the threads ThreadData structure. 
**
** Because the ThreadData structure is required by higher level routines
** such as sqliteMalloc() we use OsFree() and OsMalloc() directly to
** allocate the thread specific data.
*/
#ifdef SQLITE_UNIX_THREADS
static void deleteTsd(void *pTsd){
  sqlite3OsFree(pTsd);
}

** 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 1.231 2006/01/06 14:32:20 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>
................................................................................
  int i;
  int tempFile = 0;
  int memDb = 0;
  int readOnly = 0;
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
  char zTemp[SQLITE_TEMPNAME_SIZE];
  SqliteTsd *pTsd = sqlite3Tsd();

  /* If malloc() has already failed return SQLITE_NOMEM. Before even
  ** testing for this, set *ppPager to NULL so the caller knows the pager
  ** structure was never allocated. 
  */
  *ppPager = 0;
  if( sqlite3Tsd()->mallocFailed ){
    return SQLITE_NOMEM;
  }
  memset(&fd, 0, sizeof(fd));

  /* Open the pager file and set zFullPathname to point at malloc()ed 
  ** memory containing the complete filename (i.e. including the directory).
  */
................................................................................
** is made to roll it back. If an error occurs during the rollback 
** a hot journal may be left in the filesystem but no error is returned
** to the caller.
*/
int sqlite3pager_close(Pager *pPager){
  PgHdr *pPg, *pNext;
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  SqliteTsd *pTsd = sqlite3Tsd();
#endif

  switch( pPager->state ){
    case PAGER_RESERVED:
    case PAGER_SYNCED: 
    case PAGER_EXCLUSIVE: {
      /* We ignore any IO errors that occur during the rollback
................................................................................
  ** if( pPager->tempFile ){
  **   sqlite3OsDelete(pPager->zFilename);
  ** }
  */

#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  /* Remove the pager from the linked list of pagers starting at 
  ** SqliteTsd.pPager.
  */
  if( pPager==pTsd->pPager ){
    pTsd->pPager = pPager->pNext;
  }else{
    Pager *pTmp;
    for(pTmp = pTsd->pPager; pTmp->pNext!=pPager; pTmp=pTmp->pNext);
    pTmp->pNext = pPager->pNext;
................................................................................
** nReq is the number of bytes of memory required. Once this much has
** been released, the function returns. A negative value for nReq means
** free as much memory as possible. The return value is the total number 
** of bytes of memory released.
*/
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
int sqlite3pager_release_memory(int nReq){
  SqliteTsd *pTsd = sqlite3Tsd();
  Pager *p;
  int nReleased = 0;
  int i;

  /* If the disableReleaseMemory memory flag is set, this operation is
  ** a no-op; zero bytes of memory are freed. The flag is set before
  ** malloc() is called while the global mutex (see sqlite3OsEnterMutex) 

** 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 1.232 2006/01/09 06:29:49 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>
................................................................................
  int i;
  int tempFile = 0;
  int memDb = 0;
  int readOnly = 0;
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
  char zTemp[SQLITE_TEMPNAME_SIZE];
  ThreadData *pTsd = sqlite3ThreadData();

  /* If malloc() has already failed return SQLITE_NOMEM. Before even
  ** testing for this, set *ppPager to NULL so the caller knows the pager
  ** structure was never allocated. 
  */
  *ppPager = 0;
  if( sqlite3ThreadData()->mallocFailed ){
    return SQLITE_NOMEM;
  }
  memset(&fd, 0, sizeof(fd));

  /* Open the pager file and set zFullPathname to point at malloc()ed 
  ** memory containing the complete filename (i.e. including the directory).
  */
................................................................................
** is made to roll it back. If an error occurs during the rollback 
** a hot journal may be left in the filesystem but no error is returned
** to the caller.
*/
int sqlite3pager_close(Pager *pPager){
  PgHdr *pPg, *pNext;
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  ThreadData *pTsd = sqlite3ThreadData();
#endif

  switch( pPager->state ){
    case PAGER_RESERVED:
    case PAGER_SYNCED: 
    case PAGER_EXCLUSIVE: {
      /* We ignore any IO errors that occur during the rollback
................................................................................
  ** if( pPager->tempFile ){
  **   sqlite3OsDelete(pPager->zFilename);
  ** }
  */

#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  /* Remove the pager from the linked list of pagers starting at 
  ** ThreadData.pPager.
  */
  if( pPager==pTsd->pPager ){
    pTsd->pPager = pPager->pNext;
  }else{
    Pager *pTmp;
    for(pTmp = pTsd->pPager; pTmp->pNext!=pPager; pTmp=pTmp->pNext);
    pTmp->pNext = pPager->pNext;
................................................................................
** nReq is the number of bytes of memory required. Once this much has
** been released, the function returns. A negative value for nReq means
** free as much memory as possible. The return value is the total number 
** of bytes of memory released.
*/
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
int sqlite3pager_release_memory(int nReq){
  ThreadData *pTsd = sqlite3ThreadData();
  Pager *p;
  int nReleased = 0;
  int i;

  /* If the disableReleaseMemory memory flag is set, this operation is
  ** a no-op; zero bytes of memory are freed. The flag is set before
  ** malloc() is called while the global mutex (see sqlite3OsEnterMutex) 

**    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 1.15 2006/01/06 21:52:50 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates
** that the database is corrupt.
*/
static void corruptSchema(InitData *pData, const char *zExtra){
  if( !sqlite3Tsd()->mallocFailed ){
    sqlite3SetString(pData->pzErrMsg, "malformed database schema",
       zExtra!=0 && zExtra[0]!=0 ? " - " : (char*)0, zExtra, (char*)0);
  }
}

/*
** This is the callback routine for the code that initializes the
................................................................................
**
*/
int sqlite3InitCallback(void *pInit, int argc, char **argv, char **azColName){
  InitData *pData = (InitData*)pInit;
  sqlite3 *db = pData->db;
  int iDb;

  if( sqlite3Tsd()->mallocFailed ){
    return SQLITE_NOMEM;
  }

  assert( argc==4 );
  if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
  if( argv[1]==0 || argv[3]==0 ){
    corruptSchema(pData, 0);
................................................................................
    assert( db->init.busy );
    db->init.iDb = iDb;
    db->init.newTnum = atoi(argv[1]);
    rc = sqlite3_exec(db, argv[2], 0, 0, &zErr);
    db->init.iDb = 0;
    if( SQLITE_OK!=rc ){
      if( rc==SQLITE_NOMEM ){
          sqlite3Tsd()->mallocFailed = 1;
      }else{
          corruptSchema(pData, zErr);
      }
      sqlite3_free(zErr);
      return rc;
    }
  }else{
................................................................................
#else
  #define temp_master_schema 0
#endif

  assert( iDb>=0 && iDb<db->nDb );

  if( 0==db->aDb[iDb].pSchema ){
    DbSchema *pS = sqlite3BtreeSchema(db->aDb[iDb].pBt, sizeof(DbSchema), 
        sqlite3SchemaFree);
    db->aDb[iDb].pSchema = pS;
    if( !pS ){
      return SQLITE_NOMEM;
    }else if( pS->file_format!=0 ){
      return SQLITE_OK;
    }else{
................................................................................
#ifndef SQLITE_OMIT_ANALYZE
    if( rc==SQLITE_OK ){
      sqlite3AnalysisLoad(db, iDb);
    }
#endif
    sqlite3BtreeCloseCursor(curMain);
  }
  if( sqlite3Tsd()->mallocFailed ){
    sqlite3SetString(pzErrMsg, "out of memory", (char*)0);
    rc = SQLITE_NOMEM;
    sqlite3ResetInternalSchema(db, 0);
  }
  if( rc==SQLITE_OK ){
    DbSetProperty(db, iDb, DB_SchemaLoaded);
  }else{
................................................................................
    }
  }
  return allOk;
}

/*
** Free all resources held by the schema structure. The void* argument points
** at a DbSchema struct. This function does not call sqliteFree() on the 
** pointer itself, it just cleans up subsiduary resources (i.e. the contents
** of the schema hash tables).
*/
void sqlite3SchemaFree(void *p){
  Hash temp1;
  Hash temp2;
  HashElem *pElem;
  DbSchema *pSchema = (DbSchema *)p;

  temp1 = pSchema->tblHash;
  temp2 = pSchema->trigHash;
  sqlite3HashInit(&pSchema->trigHash, SQLITE_HASH_STRING, 0);
  sqlite3HashClear(&pSchema->aFKey);
  sqlite3HashClear(&pSchema->idxHash);
  for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
................................................................................
    sqlite3DeleteTable(0, pTab);
  }
  sqlite3HashClear(&temp1);
  pSchema->pSeqTab = 0;
  pSchema->flags &= ~DB_SchemaLoaded;
}

DbSchema *sqlite3SchemaGet(Btree *pBt){
  DbSchema * p;
  if( pBt ){
    p = (DbSchema *)sqlite3BtreeSchema(pBt,sizeof(DbSchema),sqlite3SchemaFree);
  }else{
    p = (DbSchema *)sqliteMalloc(sizeof(DbSchema));
  }
  if( p && 0==p->file_format ){
    sqlite3HashInit(&p->tblHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->idxHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->trigHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->aFKey, SQLITE_HASH_STRING, 1);
  }
  return p;
}

int sqlite3SchemaToIndex(sqlite3 *db, DbSchema *pSchema){
  int i = -1000000;

  /* If pSchema is NULL, then return -1000000. This happens when code in 
  ** expr.c is trying to resolve a reference to a transient table (i.e. one
  ** created by a sub-select). In this case the return value of this 
  ** function should never be used.
  **
................................................................................
  const char** pzTail       /* OUT: End of parsed string */
){
  Parse sParse;
  char *zErrMsg = 0;
  int rc = SQLITE_OK;
  int i;

  assert( !sqlite3Tsd()->mallocFailed );

  assert( ppStmt );
  *ppStmt = 0;
  if( sqlite3SafetyOn(db) ){
    return SQLITE_MISUSE;
  }

................................................................................
    }
  }
  
  memset(&sParse, 0, sizeof(sParse));
  sParse.db = db;
  sqlite3RunParser(&sParse, zSql, &zErrMsg);

  if( sqlite3Tsd()->mallocFailed ){
    sParse.rc = SQLITE_NOMEM;
  }
  if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
  if( sParse.checkSchema && !schemaIsValid(db) ){
    sParse.rc = SQLITE_SCHEMA;
  }
  if( sParse.rc==SQLITE_SCHEMA ){
................................................................................
  }else{
    sqlite3Error(db, rc, 0);
  }

  /* We must check for malloc failure last of all, in case malloc() failed
  ** inside of the sqlite3Error() call above or something.
  */
  if( sqlite3Tsd()->mallocFailed ){
    rc = SQLITE_NOMEM;
    sqlite3Error(db, rc, 0);
  }

  sqlite3MallocClearFailed();
  return rc;
}

**    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 1.16 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates
** that the database is corrupt.
*/
static void corruptSchema(InitData *pData, const char *zExtra){
  if( !sqlite3ThreadData()->mallocFailed ){
    sqlite3SetString(pData->pzErrMsg, "malformed database schema",
       zExtra!=0 && zExtra[0]!=0 ? " - " : (char*)0, zExtra, (char*)0);
  }
}

/*
** This is the callback routine for the code that initializes the
................................................................................
**
*/
int sqlite3InitCallback(void *pInit, int argc, char **argv, char **azColName){
  InitData *pData = (InitData*)pInit;
  sqlite3 *db = pData->db;
  int iDb;

  if( sqlite3ThreadData()->mallocFailed ){
    return SQLITE_NOMEM;
  }

  assert( argc==4 );
  if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
  if( argv[1]==0 || argv[3]==0 ){
    corruptSchema(pData, 0);
................................................................................
    assert( db->init.busy );
    db->init.iDb = iDb;
    db->init.newTnum = atoi(argv[1]);
    rc = sqlite3_exec(db, argv[2], 0, 0, &zErr);
    db->init.iDb = 0;
    if( SQLITE_OK!=rc ){
      if( rc==SQLITE_NOMEM ){
          sqlite3ThreadData()->mallocFailed = 1;
      }else{
          corruptSchema(pData, zErr);
      }
      sqlite3_free(zErr);
      return rc;
    }
  }else{
................................................................................
#else
  #define temp_master_schema 0
#endif

  assert( iDb>=0 && iDb<db->nDb );

  if( 0==db->aDb[iDb].pSchema ){
    Schema *pS = sqlite3BtreeSchema(db->aDb[iDb].pBt, sizeof(Schema), 
        sqlite3SchemaFree);
    db->aDb[iDb].pSchema = pS;
    if( !pS ){
      return SQLITE_NOMEM;
    }else if( pS->file_format!=0 ){
      return SQLITE_OK;
    }else{
................................................................................
#ifndef SQLITE_OMIT_ANALYZE
    if( rc==SQLITE_OK ){
      sqlite3AnalysisLoad(db, iDb);
    }
#endif
    sqlite3BtreeCloseCursor(curMain);
  }
  if( sqlite3ThreadData()->mallocFailed ){
    sqlite3SetString(pzErrMsg, "out of memory", (char*)0);
    rc = SQLITE_NOMEM;
    sqlite3ResetInternalSchema(db, 0);
  }
  if( rc==SQLITE_OK ){
    DbSetProperty(db, iDb, DB_SchemaLoaded);
  }else{
................................................................................
    }
  }
  return allOk;
}

/*
** Free all resources held by the schema structure. The void* argument points
** at a Schema struct. This function does not call sqliteFree() on the 
** pointer itself, it just cleans up subsiduary resources (i.e. the contents
** of the schema hash tables).
*/
void sqlite3SchemaFree(void *p){
  Hash temp1;
  Hash temp2;
  HashElem *pElem;
  Schema *pSchema = (Schema *)p;

  temp1 = pSchema->tblHash;
  temp2 = pSchema->trigHash;
  sqlite3HashInit(&pSchema->trigHash, SQLITE_HASH_STRING, 0);
  sqlite3HashClear(&pSchema->aFKey);
  sqlite3HashClear(&pSchema->idxHash);
  for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
................................................................................
    sqlite3DeleteTable(0, pTab);
  }
  sqlite3HashClear(&temp1);
  pSchema->pSeqTab = 0;
  pSchema->flags &= ~DB_SchemaLoaded;
}

Schema *sqlite3SchemaGet(Btree *pBt){
  Schema * p;
  if( pBt ){
    p = (Schema *)sqlite3BtreeSchema(pBt,sizeof(Schema),sqlite3SchemaFree);
  }else{
    p = (Schema *)sqliteMalloc(sizeof(Schema));
  }
  if( p && 0==p->file_format ){
    sqlite3HashInit(&p->tblHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->idxHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->trigHash, SQLITE_HASH_STRING, 0);
    sqlite3HashInit(&p->aFKey, SQLITE_HASH_STRING, 1);
  }
  return p;
}

int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){
  int i = -1000000;

  /* If pSchema is NULL, then return -1000000. This happens when code in 
  ** expr.c is trying to resolve a reference to a transient table (i.e. one
  ** created by a sub-select). In this case the return value of this 
  ** function should never be used.
  **
................................................................................
  const char** pzTail       /* OUT: End of parsed string */
){
  Parse sParse;
  char *zErrMsg = 0;
  int rc = SQLITE_OK;
  int i;

  assert( !sqlite3ThreadData()->mallocFailed );

  assert( ppStmt );
  *ppStmt = 0;
  if( sqlite3SafetyOn(db) ){
    return SQLITE_MISUSE;
  }

................................................................................
    }
  }
  
  memset(&sParse, 0, sizeof(sParse));
  sParse.db = db;
  sqlite3RunParser(&sParse, zSql, &zErrMsg);

  if( sqlite3ThreadData()->mallocFailed ){
    sParse.rc = SQLITE_NOMEM;
  }
  if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
  if( sParse.checkSchema && !schemaIsValid(db) ){
    sParse.rc = SQLITE_SCHEMA;
  }
  if( sParse.rc==SQLITE_SCHEMA ){
................................................................................
  }else{
    sqlite3Error(db, rc, 0);
  }

  /* We must check for malloc failure last of all, in case malloc() failed
  ** inside of the sqlite3Error() call above or something.
  */
  if( sqlite3ThreadData()->mallocFailed ){
    rc = SQLITE_NOMEM;
    sqlite3Error(db, rc, 0);
  }

  sqlite3MallocClearFailed();
  return rc;
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.289 2006/01/09 00:09:02 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
................................................................................
  /* If this is an EXPLAIN, skip this step */
  if( pParse->explain ){
    return;
  }
#endif

  assert( v!=0 );
  if( pParse->colNamesSet || v==0 || sqlite3Tsd()->mallocFailed ) return;
  pParse->colNamesSet = 1;
  fullNames = (db->flags & SQLITE_FullColNames)!=0;
  shortNames = (db->flags & SQLITE_ShortColNames)!=0;
  sqlite3VdbeSetNumCols(v, pEList->nExpr);
  for(i=0; i<pEList->nExpr; i++){
    Expr *p;
    p = pEList->a[i].pExpr;
................................................................................
      /* Use the original text of the column expression as its name */
      zName = sqlite3MPrintf("%T", &p->span);
    }else{
      /* If all else fails, make up a name */
      zName = sqlite3MPrintf("column%d", i+1);
    }
    sqlite3Dequote(zName);
    if( sqlite3Tsd()->mallocFailed ){
      sqliteFree(zName);
      sqlite3DeleteTable(0, pTab);
      return 0;
    }

    /* Make sure the column name is unique.  If the name is not unique,
    ** append a integer to the name so that it becomes unique.
................................................................................
static int prepSelectStmt(Parse *pParse, Select *p){
  int i, j, k, rc;
  SrcList *pTabList;
  ExprList *pEList;
  Table *pTab;
  struct SrcList_item *pFrom;

  if( p==0 || p->pSrc==0 || sqlite3Tsd()->mallocFailed ) return 1;
  pTabList = p->pSrc;
  pEList = p->pEList;

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, p->pSrc);
................................................................................
  int isDistinct;        /* True if the DISTINCT keyword is present */
  int distinct;          /* Table to use for the distinct set */
  int rc = 1;            /* Value to return from this function */
  int addrSortIndex;     /* Address of an OP_OpenVirtual instruction */
  AggInfo sAggInfo;      /* Information used by aggregate queries */
  int iEnd;              /* Address of the end of the query */

  if( sqlite3Tsd()->mallocFailed || pParse->nErr || p==0 ) return 1;
  if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
  memset(&sAggInfo, 0, sizeof(sAggInfo));

#ifndef SQLITE_OMIT_COMPOUND_SELECT
  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){
................................................................................
    }
    sAggInfo.nAccumulator = sAggInfo.nColumn;
    for(i=0; i<sAggInfo.nFunc; i++){
      if( sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList) ){
        goto select_end;
      }
    }
    if( sqlite3Tsd()->mallocFailed ) goto select_end;

    /* Processing for aggregates with GROUP BY is very different and
    ** much more complex tha aggregates without a GROUP BY.
    */
    if( pGroupBy ){
      KeyInfo *pKeyInfo;  /* Keying information for the group by clause */

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.290 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
................................................................................
  /* If this is an EXPLAIN, skip this step */
  if( pParse->explain ){
    return;
  }
#endif

  assert( v!=0 );
  if( pParse->colNamesSet || v==0 || sqlite3ThreadData()->mallocFailed ) return;
  pParse->colNamesSet = 1;
  fullNames = (db->flags & SQLITE_FullColNames)!=0;
  shortNames = (db->flags & SQLITE_ShortColNames)!=0;
  sqlite3VdbeSetNumCols(v, pEList->nExpr);
  for(i=0; i<pEList->nExpr; i++){
    Expr *p;
    p = pEList->a[i].pExpr;
................................................................................
      /* Use the original text of the column expression as its name */
      zName = sqlite3MPrintf("%T", &p->span);
    }else{
      /* If all else fails, make up a name */
      zName = sqlite3MPrintf("column%d", i+1);
    }
    sqlite3Dequote(zName);
    if( sqlite3ThreadData()->mallocFailed ){
      sqliteFree(zName);
      sqlite3DeleteTable(0, pTab);
      return 0;
    }

    /* Make sure the column name is unique.  If the name is not unique,
    ** append a integer to the name so that it becomes unique.
................................................................................
static int prepSelectStmt(Parse *pParse, Select *p){
  int i, j, k, rc;
  SrcList *pTabList;
  ExprList *pEList;
  Table *pTab;
  struct SrcList_item *pFrom;

  if( p==0 || p->pSrc==0 || sqlite3ThreadData()->mallocFailed ) return 1;
  pTabList = p->pSrc;
  pEList = p->pEList;

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, p->pSrc);
................................................................................
  int isDistinct;        /* True if the DISTINCT keyword is present */
  int distinct;          /* Table to use for the distinct set */
  int rc = 1;            /* Value to return from this function */
  int addrSortIndex;     /* Address of an OP_OpenVirtual instruction */
  AggInfo sAggInfo;      /* Information used by aggregate queries */
  int iEnd;              /* Address of the end of the query */

  if( sqlite3ThreadData()->mallocFailed || pParse->nErr || p==0 ) return 1;
  if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
  memset(&sAggInfo, 0, sizeof(sAggInfo));

#ifndef SQLITE_OMIT_COMPOUND_SELECT
  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){
................................................................................
    }
    sAggInfo.nAccumulator = sAggInfo.nColumn;
    for(i=0; i<sAggInfo.nFunc; i++){
      if( sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList) ){
        goto select_end;
      }
    }
    if( sqlite3ThreadData()->mallocFailed ) goto select_end;

    /* Processing for aggregates with GROUP BY is very different and
    ** much more complex tha aggregates without a GROUP BY.
    */
    if( pGroupBy ){
      KeyInfo *pKeyInfo;  /* Keying information for the group by clause */

**    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 1.453 2006/01/07 13:21:04 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/
................................................................................
** only.  They only work if SQLITE_MEMDEBUG is defined.
*/
extern int sqlite3_nMalloc;      /* Number of sqliteMalloc() calls */
extern int sqlite3_nFree;        /* Number of sqliteFree() calls */
extern int sqlite3_iMallocFail;  /* Fail sqliteMalloc() after this many calls */
extern int sqlite3_iMallocReset; /* Set iMallocFail to this when it reaches 0 */
#define ENTER_MALLOC (\
  sqlite3Tsd()->zFile = __FILE__, sqlite3Tsd()->iLine = __LINE__ \
)
#define sqliteMalloc(x)          (ENTER_MALLOC, sqlite3Malloc(x))
#define sqliteMallocRaw(x)       (ENTER_MALLOC, sqlite3MallocRaw(x))
#define sqliteRealloc(x,y)       (ENTER_MALLOC, sqlite3Realloc(x,y))
#define sqliteStrDup(x)          (ENTER_MALLOC, sqlite3StrDup(x))
#define sqliteStrNDup(x,y)       (ENTER_MALLOC, sqlite3StrNDup(x,y))
#define sqliteReallocOrFree(x,y) (ENTER_MALLOC, sqlite3ReallocOrFree(x,y))
................................................................................

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

/*
** An instance of this structure is allocated for each thread that uses SQLite.
*/
struct SqliteTsd {
  u8 isInit;               /* True if structure has been initialised */
  u8 mallocFailed;         /* True after a malloc() has failed */
  u8 disableReleaseMemory; /* True to make sqlite3_release_memory() a no-op */

#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  i64 nSoftHeapLimit;      /* Suggested max mem allocation.  No limit if <0 */
  i64 nAlloc;              /* Number of bytes currently allocated */
................................................................................

#ifndef SQLITE_OMIT_SHARED_CACHE
  u8 useSharedData;        /* True if shared pagers and schemas are enabled */
  BtShared *pBtree;        /* Linked list of all currently open BTrees */
#endif

#ifdef SQLITE_MEMDEBUG
  i64 nMaxAlloc;           /* High water mark of SqliteTsd.nAlloc */
  int mallocAllowed;       /* assert() in sqlite3Malloc() if not set */
  int isFail;              /* True if all malloc() calls should fail */
  const char *zFile;       /* Filename to associate debugging info with */
  int iLine;               /* Line number to associate debugging info with */
  void *pFirst;            /* Pointer to linked list of allocations */
#endif
};
................................................................................
** Forward references to structures
*/
typedef struct AggInfo AggInfo;
typedef struct AuthContext AuthContext;
typedef struct CollSeq CollSeq;
typedef struct Column Column;
typedef struct Db Db;
typedef struct DbSchema DbSchema;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct FKey FKey;
typedef struct FuncDef FuncDef;
typedef struct IdList IdList;
typedef struct Index Index;
typedef struct KeyClass KeyClass;
typedef struct KeyInfo KeyInfo;
typedef struct NameContext NameContext;
typedef struct Parse Parse;
typedef struct Select Select;
typedef struct SrcList SrcList;
typedef struct SqliteTsd SqliteTsd;
typedef struct Table Table;
typedef struct TableLock TableLock;
typedef struct Token Token;
typedef struct TriggerStack TriggerStack;
typedef struct TriggerStep TriggerStep;
typedef struct Trigger Trigger;
typedef struct WhereInfo WhereInfo;
................................................................................
  char *zName;         /* Name of this database */
  Btree *pBt;          /* The B*Tree structure for this database file */
  u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
  u8 safety_level;     /* How aggressive at synching data to disk */
  int cache_size;      /* Number of pages to use in the cache */
  void *pAux;               /* Auxiliary data.  Usually NULL */
  void (*xFreeAux)(void*);  /* Routine to free pAux */
  DbSchema *pSchema;   /* Pointer to database schema (possibly shared) */
};

/*
** An instance of the following structure stores a database schema.
*/
struct DbSchema {
  int schema_cookie;   /* Database schema version number for this file */
  Hash tblHash;        /* All tables indexed by name */
  Hash idxHash;        /* All (named) indices indexed by name */
  Hash trigHash;       /* All triggers indexed by name */
  Hash aFKey;          /* Foreign keys indexed by to-table */
  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
  u8 file_format;      /* Schema format version for this file */
................................................................................
  char *zColAff;     /* String defining the affinity of each column */
#ifndef SQLITE_OMIT_CHECK
  Expr *pCheck;      /* The AND of all CHECK constraints */
#endif
#ifndef SQLITE_OMIT_ALTERTABLE
  int addColOffset;  /* Offset in CREATE TABLE statement to add a new column */
#endif
  DbSchema *pSchema;
};

/*
** Each foreign key constraint is an instance of the following structure.
**
** A foreign key is associated with two tables.  The "from" table is
** the table that contains the REFERENCES clause that creates the foreign
................................................................................
  Table *pTable;   /* The SQL table being indexed */
  int tnum;        /* Page containing root of this index in database file */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
  // u8 iDb;          /* Index in sqlite.aDb[] of where this index is stored */
  char *zColAff;   /* String defining the affinity of each column */
  Index *pNext;    /* The next index associated with the same table */
  DbSchema *pSchema;
  KeyInfo keyInfo; /* Info on how to order keys.  MUST BE LAST */
};

/*
** Each token coming out of the lexer is an instance of
** this structure.  Tokens are also used as part of an expression.
**
................................................................................
                         ** iColumn-th field of the iTable-th table. */
  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
  int iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
  int iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
  Select *pSelect;       /* When the expression is a sub-select.  Also the
                         ** right side of "<expr> IN (<select>)" */
  Table *pTab;           /* Table for OP_Column expressions. */
  DbSchema *pSchema;
};

/*
** The following are the meanings of bits in the Expr.flags field.
*/
#define EP_FromJoin     0x01  /* Originated in ON or USING clause of a join */
#define EP_Agg          0x02  /* Contains one or more aggregate functions */
................................................................................
  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
  u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
  Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */
  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
                             the <column-list> is stored here */
  int foreach;            /* One of TK_ROW or TK_STATEMENT */
  Token nameToken;        /* Token containing zName. Use during parsing only */
  DbSchema *pSchema;      /* Schema containing the trigger */
  DbSchema *pTabSchema;   /* Schema containing the table */
  TriggerStep *step_list; /* Link list of trigger program steps             */
  Trigger *pNext;         /* Next trigger associated with the table */
};

/*
** A trigger is either a BEFORE or an AFTER trigger.  The following constants
** determine which. 
................................................................................
void sqlite3Analyze(Parse*, Token*, Token*);
int sqlite3InvokeBusyHandler(BusyHandler*);
int sqlite3FindDb(sqlite3*, Token*);
void sqlite3AnalysisLoad(sqlite3*,int iDB);
void sqlite3DefaultRowEst(Index*);
void sqlite3RegisterLikeFunctions(sqlite3*, int);
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
SqliteTsd *sqlite3Tsd();
void sqlite3AttachFunctions(sqlite3 *);
void sqlite3MinimumFileFormat(Parse*, int, int);
void sqlite3SchemaFree(void *);
DbSchema *sqlite3SchemaGet(Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, DbSchema *);

#ifndef SQLITE_OMIT_SHARED_CACHE
  void sqlite3TableLock(Parse *, int, int, u8, const char *);
#else
  #define sqlite3TableLock(v,w,x,y,z)
#endif

**    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 1.454 2006/01/09 06:29:49 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/
................................................................................
** only.  They only work if SQLITE_MEMDEBUG is defined.
*/
extern int sqlite3_nMalloc;      /* Number of sqliteMalloc() calls */
extern int sqlite3_nFree;        /* Number of sqliteFree() calls */
extern int sqlite3_iMallocFail;  /* Fail sqliteMalloc() after this many calls */
extern int sqlite3_iMallocReset; /* Set iMallocFail to this when it reaches 0 */
#define ENTER_MALLOC (\
  sqlite3ThreadData()->zFile = __FILE__, sqlite3ThreadData()->iLine = __LINE__ \
)
#define sqliteMalloc(x)          (ENTER_MALLOC, sqlite3Malloc(x))
#define sqliteMallocRaw(x)       (ENTER_MALLOC, sqlite3MallocRaw(x))
#define sqliteRealloc(x,y)       (ENTER_MALLOC, sqlite3Realloc(x,y))
#define sqliteStrDup(x)          (ENTER_MALLOC, sqlite3StrDup(x))
#define sqliteStrNDup(x,y)       (ENTER_MALLOC, sqlite3StrNDup(x,y))
#define sqliteReallocOrFree(x,y) (ENTER_MALLOC, sqlite3ReallocOrFree(x,y))
................................................................................

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

/*
** An instance of this structure is allocated for each thread that uses SQLite.
*/
struct ThreadData {
  u8 isInit;               /* True if structure has been initialised */
  u8 mallocFailed;         /* True after a malloc() has failed */
  u8 disableReleaseMemory; /* True to make sqlite3_release_memory() a no-op */

#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  i64 nSoftHeapLimit;      /* Suggested max mem allocation.  No limit if <0 */
  i64 nAlloc;              /* Number of bytes currently allocated */
................................................................................

#ifndef SQLITE_OMIT_SHARED_CACHE
  u8 useSharedData;        /* True if shared pagers and schemas are enabled */
  BtShared *pBtree;        /* Linked list of all currently open BTrees */
#endif

#ifdef SQLITE_MEMDEBUG
  i64 nMaxAlloc;           /* High water mark of ThreadData.nAlloc */
  int mallocAllowed;       /* assert() in sqlite3Malloc() if not set */
  int isFail;              /* True if all malloc() calls should fail */
  const char *zFile;       /* Filename to associate debugging info with */
  int iLine;               /* Line number to associate debugging info with */
  void *pFirst;            /* Pointer to linked list of allocations */
#endif
};
................................................................................
** Forward references to structures
*/
typedef struct AggInfo AggInfo;
typedef struct AuthContext AuthContext;
typedef struct CollSeq CollSeq;
typedef struct Column Column;
typedef struct Db Db;
typedef struct Schema Schema;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct FKey FKey;
typedef struct FuncDef FuncDef;
typedef struct IdList IdList;
typedef struct Index Index;
typedef struct KeyClass KeyClass;
typedef struct KeyInfo KeyInfo;
typedef struct NameContext NameContext;
typedef struct Parse Parse;
typedef struct Select Select;
typedef struct SrcList SrcList;
typedef struct ThreadData ThreadData;
typedef struct Table Table;
typedef struct TableLock TableLock;
typedef struct Token Token;
typedef struct TriggerStack TriggerStack;
typedef struct TriggerStep TriggerStep;
typedef struct Trigger Trigger;
typedef struct WhereInfo WhereInfo;
................................................................................
  char *zName;         /* Name of this database */
  Btree *pBt;          /* The B*Tree structure for this database file */
  u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
  u8 safety_level;     /* How aggressive at synching data to disk */
  int cache_size;      /* Number of pages to use in the cache */
  void *pAux;               /* Auxiliary data.  Usually NULL */
  void (*xFreeAux)(void*);  /* Routine to free pAux */
  Schema *pSchema;     /* Pointer to database schema (possibly shared) */
};

/*
** An instance of the following structure stores a database schema.
*/
struct Schema {
  int schema_cookie;   /* Database schema version number for this file */
  Hash tblHash;        /* All tables indexed by name */
  Hash idxHash;        /* All (named) indices indexed by name */
  Hash trigHash;       /* All triggers indexed by name */
  Hash aFKey;          /* Foreign keys indexed by to-table */
  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
  u8 file_format;      /* Schema format version for this file */
................................................................................
  char *zColAff;     /* String defining the affinity of each column */
#ifndef SQLITE_OMIT_CHECK
  Expr *pCheck;      /* The AND of all CHECK constraints */
#endif
#ifndef SQLITE_OMIT_ALTERTABLE
  int addColOffset;  /* Offset in CREATE TABLE statement to add a new column */
#endif
  Schema *pSchema;
};

/*
** Each foreign key constraint is an instance of the following structure.
**
** A foreign key is associated with two tables.  The "from" table is
** the table that contains the REFERENCES clause that creates the foreign
................................................................................
  Table *pTable;   /* The SQL table being indexed */
  int tnum;        /* Page containing root of this index in database file */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
  // u8 iDb;          /* Index in sqlite.aDb[] of where this index is stored */
  char *zColAff;   /* String defining the affinity of each column */
  Index *pNext;    /* The next index associated with the same table */
  Schema *pSchema;
  KeyInfo keyInfo; /* Info on how to order keys.  MUST BE LAST */
};

/*
** Each token coming out of the lexer is an instance of
** this structure.  Tokens are also used as part of an expression.
**
................................................................................
                         ** iColumn-th field of the iTable-th table. */
  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
  int iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
  int iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
  Select *pSelect;       /* When the expression is a sub-select.  Also the
                         ** right side of "<expr> IN (<select>)" */
  Table *pTab;           /* Table for OP_Column expressions. */
  Schema *pSchema;
};

/*
** The following are the meanings of bits in the Expr.flags field.
*/
#define EP_FromJoin     0x01  /* Originated in ON or USING clause of a join */
#define EP_Agg          0x02  /* Contains one or more aggregate functions */
................................................................................
  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
  u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
  Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */
  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
                             the <column-list> is stored here */
  int foreach;            /* One of TK_ROW or TK_STATEMENT */
  Token nameToken;        /* Token containing zName. Use during parsing only */
  Schema *pSchema;        /* Schema containing the trigger */
  Schema *pTabSchema;     /* Schema containing the table */
  TriggerStep *step_list; /* Link list of trigger program steps             */
  Trigger *pNext;         /* Next trigger associated with the table */
};

/*
** A trigger is either a BEFORE or an AFTER trigger.  The following constants
** determine which. 
................................................................................
void sqlite3Analyze(Parse*, Token*, Token*);
int sqlite3InvokeBusyHandler(BusyHandler*);
int sqlite3FindDb(sqlite3*, Token*);
void sqlite3AnalysisLoad(sqlite3*,int iDB);
void sqlite3DefaultRowEst(Index*);
void sqlite3RegisterLikeFunctions(sqlite3*, int);
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
ThreadData *sqlite3ThreadData();
void sqlite3AttachFunctions(sqlite3 *);
void sqlite3MinimumFileFormat(Parse*, int, int);
void sqlite3SchemaFree(void *);
Schema *sqlite3SchemaGet(Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, Schema *);

#ifndef SQLITE_OMIT_SHARED_CACHE
  void sqlite3TableLock(Parse *, int, int, u8, const char *);
#else
  #define sqlite3TableLock(v,w,x,y,z)
#endif

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the printf() interface to SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.183 2006/01/07 16:06:07 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
**
** Rig sqliteMalloc() to fail on the N-th call and every REPEAT-INTERVAL call
** after that.  If REPEAT-INTERVAL is 0 or is omitted, then only a single
** malloc will fail.  If REPEAT-INTERVAL is 1 then all mallocs after the
** first failure will continue to fail on every call.  If REPEAT-INTERVAL is
** 2 then every other malloc will fail.  And so forth.
**
** Turn off this mechanism and reset the sqlite3Tsd()->mallocFailed variable is N==0.
*/
#ifdef SQLITE_MEMDEBUG
static int sqlite_malloc_fail(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
................................................................................
    Tcl_WrongNumArgs(interp, 1, objv, "?-bytes?");
    return TCL_ERROR;
  }

  if( objc==2 ){
    const char *zArg = Tcl_GetString(objv[1]);
    if( 0==strcmp(zArg, "-bytes") ){
      Tcl_SetObjResult(interp, Tcl_NewIntObj(sqlite3Tsd()->nAlloc));
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
    }else if( 0==strcmp(zArg, "-maxbytes") ){
      Tcl_SetObjResult(interp, Tcl_NewWideIntObj(sqlite3Tsd()->nMaxAlloc));
    }else if( 0==strcmp(zArg, "-clearmaxbytes") ){
      sqlite3Tsd()->nMaxAlloc = sqlite3Tsd()->nAlloc;
#endif
    }else{
      Tcl_AppendResult(interp, "bad option \"", zArg, 
        "\": must be -bytes, -maxbytes or -clearmaxbytes", 0
      );
      return TCL_ERROR;
    }
................................................................................
  ClientData clientData,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int objc,              /* Number of arguments */
  Tcl_Obj *CONST objv[]  /* Command arguments */
){
  int rc;
  int enable;
  SqliteTsd *pTsd = sqlite3Tsd();
  Tcl_SetObjResult(interp, Tcl_NewBooleanObj(pTsd->useSharedData));

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "BOOLEAN");
    return TCL_ERROR;
  }
  if( Tcl_GetBooleanFromObj(interp, objv[1], &enable) ){
................................................................................
){
#if !defined(SQLITE_OMIT_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
  int amt;
  if( objc!=1 && objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?N?");
    return TCL_ERROR;
  }
  amt = sqlite3Tsd()->nSoftHeapLimit;
  if( objc==2 ){
    int N;
    if( Tcl_GetIntFromObj(interp, objv[1], &N) ) return TCL_ERROR;
    sqlite3_soft_heap_limit(N);
  }
  Tcl_SetObjResult(interp, Tcl_NewIntObj(amt));
#endif

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the printf() interface to SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.184 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
**
** Rig sqliteMalloc() to fail on the N-th call and every REPEAT-INTERVAL call
** after that.  If REPEAT-INTERVAL is 0 or is omitted, then only a single
** malloc will fail.  If REPEAT-INTERVAL is 1 then all mallocs after the
** first failure will continue to fail on every call.  If REPEAT-INTERVAL is
** 2 then every other malloc will fail.  And so forth.
**
** Turn off this mechanism and reset the sqlite3ThreadData()->mallocFailed variable is N==0.
*/
#ifdef SQLITE_MEMDEBUG
static int sqlite_malloc_fail(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
................................................................................
    Tcl_WrongNumArgs(interp, 1, objv, "?-bytes?");
    return TCL_ERROR;
  }

  if( objc==2 ){
    const char *zArg = Tcl_GetString(objv[1]);
    if( 0==strcmp(zArg, "-bytes") ){
      Tcl_SetObjResult(interp, Tcl_NewIntObj(sqlite3ThreadData()->nAlloc));
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
    }else if( 0==strcmp(zArg, "-maxbytes") ){
      Tcl_SetObjResult(interp, Tcl_NewWideIntObj(sqlite3ThreadData()->nMaxAlloc));
    }else if( 0==strcmp(zArg, "-clearmaxbytes") ){
      sqlite3ThreadData()->nMaxAlloc = sqlite3ThreadData()->nAlloc;
#endif
    }else{
      Tcl_AppendResult(interp, "bad option \"", zArg, 
        "\": must be -bytes, -maxbytes or -clearmaxbytes", 0
      );
      return TCL_ERROR;
    }
................................................................................
  ClientData clientData,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int objc,              /* Number of arguments */
  Tcl_Obj *CONST objv[]  /* Command arguments */
){
  int rc;
  int enable;
  ThreadData *pTsd = sqlite3ThreadData();
  Tcl_SetObjResult(interp, Tcl_NewBooleanObj(pTsd->useSharedData));

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "BOOLEAN");
    return TCL_ERROR;
  }
  if( Tcl_GetBooleanFromObj(interp, objv[1], &enable) ){
................................................................................
){
#if !defined(SQLITE_OMIT_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
  int amt;
  if( objc!=1 && objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?N?");
    return TCL_ERROR;
  }
  amt = sqlite3ThreadData()->nSoftHeapLimit;
  if( objc==2 ){
    int N;
    if( Tcl_GetIntFromObj(interp, objv[1], &N) ) return TCL_ERROR;
    sqlite3_soft_heap_limit(N);
  }
  Tcl_SetObjResult(interp, Tcl_NewIntObj(amt));
#endif

*************************************************************************
** An tokenizer for SQL
**
** This file contains C code that splits an SQL input string up into
** individual tokens and sends those tokens one-by-one over to the
** parser for analysis.
**
** $Id: tokenize.c,v 1.111 2006/01/07 13:21:04 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include <stdlib.h>

/*
................................................................................
  assert( pParse->pNewTable==0 );
  assert( pParse->pNewTrigger==0 );
  assert( pParse->nVar==0 );
  assert( pParse->nVarExpr==0 );
  assert( pParse->nVarExprAlloc==0 );
  assert( pParse->apVarExpr==0 );
  pParse->zTail = pParse->zSql = zSql;
  while( sqlite3Tsd()->mallocFailed==0 && zSql[i]!=0 ){
    assert( i>=0 );
    pParse->sLastToken.z = (u8*)&zSql[i];
    assert( pParse->sLastToken.dyn==0 );
    pParse->sLastToken.n = getToken((unsigned char*)&zSql[i],&tokenType);
    i += pParse->sLastToken.n;
    switch( tokenType ){
      case TK_SPACE:
................................................................................
    if( lastTokenParsed!=TK_SEMI ){
      sqlite3Parser(pEngine, TK_SEMI, pParse->sLastToken, pParse);
      pParse->zTail = &zSql[i];
    }
    sqlite3Parser(pEngine, 0, pParse->sLastToken, pParse);
  }
  sqlite3ParserFree(pEngine, sqlite3FreeX);
  if( sqlite3Tsd()->mallocFailed ){
    pParse->rc = SQLITE_NOMEM;
  }
  if( pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE && pParse->zErrMsg==0 ){
    sqlite3SetString(&pParse->zErrMsg, sqlite3ErrStr(pParse->rc), (char*)0);
  }
  if( pParse->zErrMsg ){
    if( pzErrMsg && *pzErrMsg==0 ){

*************************************************************************
** An tokenizer for SQL
**
** This file contains C code that splits an SQL input string up into
** individual tokens and sends those tokens one-by-one over to the
** parser for analysis.
**
** $Id: tokenize.c,v 1.112 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include <stdlib.h>

/*
................................................................................
  assert( pParse->pNewTable==0 );
  assert( pParse->pNewTrigger==0 );
  assert( pParse->nVar==0 );
  assert( pParse->nVarExpr==0 );
  assert( pParse->nVarExprAlloc==0 );
  assert( pParse->apVarExpr==0 );
  pParse->zTail = pParse->zSql = zSql;
  while( sqlite3ThreadData()->mallocFailed==0 && zSql[i]!=0 ){
    assert( i>=0 );
    pParse->sLastToken.z = (u8*)&zSql[i];
    assert( pParse->sLastToken.dyn==0 );
    pParse->sLastToken.n = getToken((unsigned char*)&zSql[i],&tokenType);
    i += pParse->sLastToken.n;
    switch( tokenType ){
      case TK_SPACE:
................................................................................
    if( lastTokenParsed!=TK_SEMI ){
      sqlite3Parser(pEngine, TK_SEMI, pParse->sLastToken, pParse);
      pParse->zTail = &zSql[i];
    }
    sqlite3Parser(pEngine, 0, pParse->sLastToken, pParse);
  }
  sqlite3ParserFree(pEngine, sqlite3FreeX);
  if( sqlite3ThreadData()->mallocFailed ){
    pParse->rc = SQLITE_NOMEM;
  }
  if( pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE && pParse->zErrMsg==0 ){
    sqlite3SetString(&pParse->zErrMsg, sqlite3ErrStr(pParse->rc), (char*)0);
  }
  if( pParse->zErrMsg ){
    if( pzErrMsg && *pzErrMsg==0 ){

  }

  /* If the trigger name was unqualified, and the table is a temp table,
  ** then set iDb to 1 to create the trigger in the temporary database.
  ** If sqlite3SrcListLookup() returns 0, indicating the table does not
  ** exist, the error is caught by the block below.
  */
  if( !pTableName || sqlite3Tsd()->mallocFailed ) goto trigger_cleanup;
  pTab = sqlite3SrcListLookup(pParse, pTableName);
  if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
    iDb = 1;
  }

  /* Ensure the table name matches database name and that the table exists */
  if( sqlite3Tsd()->mallocFailed ) goto trigger_cleanup;
  assert( pTableName->nSrc==1 );
  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) && 
      sqlite3FixSrcList(&sFix, pTableName) ){
    goto trigger_cleanup;
  }
  pTab = sqlite3SrcListLookup(pParse, pTableName);
  if( !pTab ){
................................................................................
  if( db->init.busy ){
    int n;
    Table *pTab;
    Trigger *pDel;
    pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash, 
                     pTrig->name, strlen(pTrig->name)+1, pTrig);
    if( pDel ){
      assert( sqlite3Tsd()->mallocFailed && pDel==pTrig );
      goto triggerfinish_cleanup;
    }
    n = strlen(pTrig->table) + 1;
    pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
    assert( pTab!=0 );
    pTrig->pNext = pTab->pTrigger;
    pTab->pTrigger = pTrig;
................................................................................
  Trigger *pTrigger = 0;
  int i;
  const char *zDb;
  const char *zName;
  int nName;
  sqlite3 *db = pParse->db;

  if( sqlite3Tsd()->mallocFailed ) goto drop_trigger_cleanup;
  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    goto drop_trigger_cleanup;
  }

  assert( pName->nSrc==1 );
  zDb = pName->a[0].zDatabase;
  zName = pName->a[0].zName;

  }

  /* If the trigger name was unqualified, and the table is a temp table,
  ** then set iDb to 1 to create the trigger in the temporary database.
  ** If sqlite3SrcListLookup() returns 0, indicating the table does not
  ** exist, the error is caught by the block below.
  */
  if( !pTableName || sqlite3ThreadData()->mallocFailed ) goto trigger_cleanup;
  pTab = sqlite3SrcListLookup(pParse, pTableName);
  if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
    iDb = 1;
  }

  /* Ensure the table name matches database name and that the table exists */
  if( sqlite3ThreadData()->mallocFailed ) goto trigger_cleanup;
  assert( pTableName->nSrc==1 );
  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) && 
      sqlite3FixSrcList(&sFix, pTableName) ){
    goto trigger_cleanup;
  }
  pTab = sqlite3SrcListLookup(pParse, pTableName);
  if( !pTab ){
................................................................................
  if( db->init.busy ){
    int n;
    Table *pTab;
    Trigger *pDel;
    pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash, 
                     pTrig->name, strlen(pTrig->name)+1, pTrig);
    if( pDel ){
      assert( sqlite3ThreadData()->mallocFailed && pDel==pTrig );
      goto triggerfinish_cleanup;
    }
    n = strlen(pTrig->table) + 1;
    pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n);
    assert( pTab!=0 );
    pTrig->pNext = pTab->pTrigger;
    pTab->pTrigger = pTrig;
................................................................................
  Trigger *pTrigger = 0;
  int i;
  const char *zDb;
  const char *zName;
  int nName;
  sqlite3 *db = pParse->db;

  if( sqlite3ThreadData()->mallocFailed ) goto drop_trigger_cleanup;
  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    goto drop_trigger_cleanup;
  }

  assert( pName->nSrc==1 );
  zDb = pName->a[0].zDatabase;
  zName = pName->a[0].zName;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.116 2006/01/07 13:21:04 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.
................................................................................
  int triggers_exist = 0;      /* True if any row triggers exist */
#endif

  int newIdx      = -1;  /* index of trigger "new" temp table       */
  int oldIdx      = -1;  /* index of trigger "old" temp table       */

  sContext.pParse = 0;
  if( pParse->nErr || sqlite3Tsd()->mallocFailed ) goto update_cleanup;
  db = pParse->db;
  assert( pTabList->nSrc==1 );

  /* Locate the table which we want to update. 
  */
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ) goto update_cleanup;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.117 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.
................................................................................
  int triggers_exist = 0;      /* True if any row triggers exist */
#endif

  int newIdx      = -1;  /* index of trigger "new" temp table       */
  int oldIdx      = -1;  /* index of trigger "old" temp table       */

  sContext.pParse = 0;
  if( pParse->nErr || sqlite3ThreadData()->mallocFailed ) goto update_cleanup;
  db = pParse->db;
  assert( pTabList->nSrc==1 );

  /* Locate the table which we want to update. 
  */
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ) goto update_cleanup;

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.162 2006/01/06 21:52:50 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <stdarg.h>
#include <ctype.h>

/*
................................................................................

#if !defined(SQLITE_OMIT_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
/*
** Set the soft heap-size limit for the current thread. Passing a negative
** value indicates no limit.
*/
void sqlite3_soft_heap_limit(sqlite_int64 n){
  sqlite3Tsd()->nSoftHeapLimit = n;
}

/*
** Release memory held by SQLite instances created by the current thread.
*/
int sqlite3_release_memory(int n){
  return sqlite3pager_release_memory(n);
................................................................................
int sqlite3_iMallocReset = -1; /* When iMallocFail reaches 0, set to this */

/*
** Check for a simulated memory allocation failure.  Return true if
** the failure should be simulated.  Return false to proceed as normal.
*/
static int failMalloc(){
  SqliteTsd *pTsd = sqlite3Tsd();
  if( pTsd->isFail ){
    return 1;
  }
  if( sqlite3_iMallocFail>=0 ){
    sqlite3_iMallocFail--;
    if( sqlite3_iMallocFail==0 ){
      sqlite3_iMallocFail = sqlite3_iMallocReset;
................................................................................
    static const int guard = 0xdead3344;
    memcpy(&z[i*sizeof(u32)], &guard, sizeof(u32));
  }

  /* Line number */
  z = &((char *)z)[TESTALLOC_NGUARD*sizeof(u32)];             /* Guard words */
  z = &zAlloc[TESTALLOC_OFFSET_LINENUMBER(p)];
  memcpy(z, &sqlite3Tsd()->iLine, sizeof(u32));

  /* File name */
  z = &zAlloc[TESTALLOC_OFFSET_FILENAME(p)];
  strncpy(z, sqlite3Tsd()->zFile, TESTALLOC_FILESIZE);
  z[TESTALLOC_FILESIZE - 1] = '\0';

  /* User string */
  z = &zAlloc[TESTALLOC_OFFSET_USER(p)];
  z[0] = 0;
  if( sqlite3_malloc_id ){
    strncpy(z, sqlite3_malloc_id, TESTALLOC_USERSIZE);
................................................................................

#if SQLITE_MEMDEBUG>1
/*
** The argument points to an Os level allocation. Link it into the threads list
** of allocations.
*/
static void linkAlloc(void *p){
  SqliteTsd *pTsd = sqlite3Tsd();
  void **pp = (void **)p;
  pp[0] = 0;
  pp[1] = pTsd->pFirst;
  if( pTsd->pFirst ){
    ((void **)pTsd->pFirst)[0] = p;
  }
  pTsd->pFirst = p;
................................................................................

/*
** The argument points to an Os level allocation. Unlinke it from the threads
** list of allocations.
*/
static void unlinkAlloc(void *p)
{
  SqliteTsd *pTsd = sqlite3Tsd();
  void **pp = (void **)p;
  if( p==pTsd->pFirst ){
    assert(!pp[0]);
    assert(!pp[1] || ((void **)(pp[1]))[0]==p);
    pTsd->pFirst = pp[1];
    if( pTsd->pFirst ){
      ((void **)pTsd->pFirst)[0] = 0;
................................................................................
*/
static void relinkAlloc(void *p)
{
  void **pp = (void **)p;
  if( pp[0] ){
    ((void **)(pp[0]))[1] = p;
  }else{
    SqliteTsd *pTsd = sqlite3Tsd();
    pTsd->pFirst = p;
  }
  if( pp[1] ){
    ((void **)(pp[1]))[0] = p;
  }
}
#else
................................................................................
** Todo: We could have a version of this function that outputs to stdout, 
** to debug memory leaks when Tcl is not available.
*/
#ifdef TCLSH
#include <tcl.h>
int sqlite3OutstandingMallocs(Tcl_Interp *interp){
  void *p;
  SqliteTsd *pTsd = sqlite3Tsd();
  Tcl_Obj *pRes = Tcl_NewObj();
  Tcl_IncrRefCount(pRes);

  for(p=pTsd->pFirst; p; p=((void **)p)[1]){
    Tcl_Obj *pEntry = Tcl_NewObj();
    Tcl_Obj *pStack = Tcl_NewObj();
    char *z;
................................................................................
#endif

/*
** This is the test layer's wrapper around sqlite3OsMalloc().
*/
static void * OSMALLOC(int n){
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  SqliteTsd *pTsd = sqlite3Tsd();
  pTsd->nMaxAlloc = MAX(pTsd->nMaxAlloc, pTsd->nAlloc);
#endif
  if( !failMalloc() ){
    u32 *p;
    p = (u32 *)sqlite3OsMalloc(n + TESTALLOC_OVERHEAD);
    assert(p);
    sqlite3_nMalloc++;
................................................................................
}

/*
** This is the test layer's wrapper around sqlite3OsRealloc().
*/
void * OSREALLOC(void *pRealloc, int n){
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  SqliteTsd *pTsd = sqlite3Tsd();
  pTsd->nMaxAlloc = MAX(pTsd->nMaxAlloc, pTsd->nAlloc);
#endif
  if( !failMalloc() ){
    u32 *p = (u32 *)getOsPointer(pRealloc);
    checkGuards(p);
    p = sqlite3OsRealloc(p, n + TESTALLOC_OVERHEAD);
    applyGuards(p);
................................................................................
    relinkAlloc(p);
    return (void *)(&p[TESTALLOC_NGUARD + 2*sizeof(void *)/sizeof(u32)]);
  }
  return 0;
}

void OSMALLOC_FAILED(){
  sqlite3Tsd()->isFail = 0;
}

int OSSIZEOF(void *p){
  if( p ){
    u32 *pOs = (u32 *)getOsPointer(p);
    return sqlite3OsAllocationSize(pOs) - TESTALLOC_OVERHEAD;
  }
................................................................................
** called to try to avoid this. No indication of whether or not this is
** successful is returned to the caller.
**
** If SQLITE_OMIT_MEMORY_MANAGEMENT is defined, this function is a no-op.
*/
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
static void handleSoftLimit(int n){
  SqliteTsd *pTsd = sqlite3Tsd();
  pTsd->nAlloc += (i64)n;
  if( n>0 && pTsd->nSoftHeapLimit>0 ){
    while( pTsd->nAlloc>pTsd->nSoftHeapLimit && sqlite3_release_memory(n) );
  }
}
#else
#define handleSoftLimit()
................................................................................

/*
** Allocate and return N bytes of uninitialised memory by calling
** sqlite3OsMalloc(). If the Malloc() call fails, attempt to free memory 
** by calling sqlite3_release_memory().
*/
void *sqlite3MallocRaw(int n){
  SqliteTsd *pTsd = sqlite3Tsd();
  void *p = 0;
  if( n>0 && !pTsd->mallocFailed ){
    handleSoftLimit(n);
    while( !(p = OSMALLOC(n)) && sqlite3_release_memory(n) );
    if( !p ){
      /* If the allocation failed, call handleSoftLimit() again, this time
      ** with the additive inverse of the argument passed to 
      ** handleSoftLimit() above. This is so the SqliteTsd.nAlloc variable is
      ** still correct after a malloc() failure. 
      */
      handleSoftLimit(n * -1);
      sqlite3Tsd()->mallocFailed = 1;
      OSMALLOC_FAILED();
    }
  }
  return p;
}

/*
** Resize the allocation at p to n bytes by calling sqlite3OsRealloc(). The
** pointer to the new allocation is returned.  If the Realloc() call fails,
** attempt to free memory by calling sqlite3_release_memory().
*/
void *sqlite3Realloc(void *p, int n){
  SqliteTsd *pTsd = sqlite3Tsd();
  if( pTsd->mallocFailed ){
    return 0;
  }

  if( !p ){
    return sqlite3Malloc(n);
  }else{
    void *np = 0;
    handleSoftLimit(n - OSSIZEOF(p));
    while( !(np = OSREALLOC(p, n)) && sqlite3_release_memory(n) );
    if( !np ){
      /* If the allocation failed, call handleSoftLimit() again, this time
      ** with the additive inverse of the argument passed to 
      ** handleSoftLimit() above. This is so the SqliteTsd.nAlloc variable is
      ** still correct after a malloc() failure. 
      */
      handleSoftLimit(OSSIZEOF(p) - n);
      pTsd->mallocFailed = 1;
      OSMALLOC_FAILED();
    }
    return np;
................................................................................
}

/*
** Make a copy of a string in memory obtained from sqliteMalloc(). These 
** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
** is because when memory debugging is turned on, these two functions are 
** called via macros that record the current file and line number in the
** SqliteTsd structure.
*/
char *sqlite3StrDup(const char *z){
  char *zNew;
  if( z==0 ) return 0;
  zNew = sqlite3MallocRaw(strlen(z)+1);
  if( zNew ) strcpy(zNew, z);
  return zNew;
................................................................................
    p = *(void**)&v2;
  }
  return p;
}
#endif

/*
** Return a pointer to the SqliteTsd associated with the calling thread.
*/
SqliteTsd *sqlite3Tsd(){
  SqliteTsd *pTsd = sqlite3OsThreadSpecificData(sizeof(SqliteTsd));
  if( pTsd && !pTsd->isInit ){
    pTsd->nSoftHeapLimit = -1;
#ifndef NDEBUG
    pTsd->mallocAllowed = 1;
#endif
    pTsd->isInit = 1;
  }
................................................................................
}

/*
** Clear the "mallocFailed" flag. This should be invoked before exiting any
** entry points that may have called sqliteMalloc().
*/
void sqlite3MallocClearFailed(){
  sqlite3Tsd()->mallocFailed = 0;
}


#ifndef NDEBUG
/*
** This function sets a flag in the thread-specific-data structure that will
** cause an assert to fail if sqliteMalloc() or sqliteRealloc() is called.
*/
void sqlite3MallocDisallow(){
  assert(sqlite3Tsd()->mallocAllowed);
  sqlite3Tsd()->mallocAllowed = 0;
}

/*
** This function clears the flag set in the thread-specific-data structure set
** by sqlite3MallocDisallow().
*/
void sqlite3MallocAllow(){
  assert(!sqlite3Tsd()->mallocAllowed);
  sqlite3Tsd()->mallocAllowed = 1;
}
#endif

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.163 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <stdarg.h>
#include <ctype.h>

/*
................................................................................

#if !defined(SQLITE_OMIT_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
/*
** Set the soft heap-size limit for the current thread. Passing a negative
** value indicates no limit.
*/
void sqlite3_soft_heap_limit(sqlite_int64 n){
  sqlite3ThreadData()->nSoftHeapLimit = n;
}

/*
** Release memory held by SQLite instances created by the current thread.
*/
int sqlite3_release_memory(int n){
  return sqlite3pager_release_memory(n);
................................................................................
int sqlite3_iMallocReset = -1; /* When iMallocFail reaches 0, set to this */

/*
** Check for a simulated memory allocation failure.  Return true if
** the failure should be simulated.  Return false to proceed as normal.
*/
static int failMalloc(){
  ThreadData *pTsd = sqlite3ThreadData();
  if( pTsd->isFail ){
    return 1;
  }
  if( sqlite3_iMallocFail>=0 ){
    sqlite3_iMallocFail--;
    if( sqlite3_iMallocFail==0 ){
      sqlite3_iMallocFail = sqlite3_iMallocReset;
................................................................................
    static const int guard = 0xdead3344;
    memcpy(&z[i*sizeof(u32)], &guard, sizeof(u32));
  }

  /* Line number */
  z = &((char *)z)[TESTALLOC_NGUARD*sizeof(u32)];             /* Guard words */
  z = &zAlloc[TESTALLOC_OFFSET_LINENUMBER(p)];
  memcpy(z, &sqlite3ThreadData()->iLine, sizeof(u32));

  /* File name */
  z = &zAlloc[TESTALLOC_OFFSET_FILENAME(p)];
  strncpy(z, sqlite3ThreadData()->zFile, TESTALLOC_FILESIZE);
  z[TESTALLOC_FILESIZE - 1] = '\0';

  /* User string */
  z = &zAlloc[TESTALLOC_OFFSET_USER(p)];
  z[0] = 0;
  if( sqlite3_malloc_id ){
    strncpy(z, sqlite3_malloc_id, TESTALLOC_USERSIZE);
................................................................................

#if SQLITE_MEMDEBUG>1
/*
** The argument points to an Os level allocation. Link it into the threads list
** of allocations.
*/
static void linkAlloc(void *p){
  ThreadData *pTsd = sqlite3ThreadData();
  void **pp = (void **)p;
  pp[0] = 0;
  pp[1] = pTsd->pFirst;
  if( pTsd->pFirst ){
    ((void **)pTsd->pFirst)[0] = p;
  }
  pTsd->pFirst = p;
................................................................................

/*
** The argument points to an Os level allocation. Unlinke it from the threads
** list of allocations.
*/
static void unlinkAlloc(void *p)
{
  ThreadData *pTsd = sqlite3ThreadData();
  void **pp = (void **)p;
  if( p==pTsd->pFirst ){
    assert(!pp[0]);
    assert(!pp[1] || ((void **)(pp[1]))[0]==p);
    pTsd->pFirst = pp[1];
    if( pTsd->pFirst ){
      ((void **)pTsd->pFirst)[0] = 0;
................................................................................
*/
static void relinkAlloc(void *p)
{
  void **pp = (void **)p;
  if( pp[0] ){
    ((void **)(pp[0]))[1] = p;
  }else{
    ThreadData *pTsd = sqlite3ThreadData();
    pTsd->pFirst = p;
  }
  if( pp[1] ){
    ((void **)(pp[1]))[0] = p;
  }
}
#else
................................................................................
** Todo: We could have a version of this function that outputs to stdout, 
** to debug memory leaks when Tcl is not available.
*/
#ifdef TCLSH
#include <tcl.h>
int sqlite3OutstandingMallocs(Tcl_Interp *interp){
  void *p;
  ThreadData *pTsd = sqlite3ThreadData();
  Tcl_Obj *pRes = Tcl_NewObj();
  Tcl_IncrRefCount(pRes);

  for(p=pTsd->pFirst; p; p=((void **)p)[1]){
    Tcl_Obj *pEntry = Tcl_NewObj();
    Tcl_Obj *pStack = Tcl_NewObj();
    char *z;
................................................................................
#endif

/*
** This is the test layer's wrapper around sqlite3OsMalloc().
*/
static void * OSMALLOC(int n){
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  ThreadData *pTsd = sqlite3ThreadData();
  pTsd->nMaxAlloc = MAX(pTsd->nMaxAlloc, pTsd->nAlloc);
#endif
  if( !failMalloc() ){
    u32 *p;
    p = (u32 *)sqlite3OsMalloc(n + TESTALLOC_OVERHEAD);
    assert(p);
    sqlite3_nMalloc++;
................................................................................
}

/*
** This is the test layer's wrapper around sqlite3OsRealloc().
*/
void * OSREALLOC(void *pRealloc, int n){
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
  ThreadData *pTsd = sqlite3ThreadData();
  pTsd->nMaxAlloc = MAX(pTsd->nMaxAlloc, pTsd->nAlloc);
#endif
  if( !failMalloc() ){
    u32 *p = (u32 *)getOsPointer(pRealloc);
    checkGuards(p);
    p = sqlite3OsRealloc(p, n + TESTALLOC_OVERHEAD);
    applyGuards(p);
................................................................................
    relinkAlloc(p);
    return (void *)(&p[TESTALLOC_NGUARD + 2*sizeof(void *)/sizeof(u32)]);
  }
  return 0;
}

void OSMALLOC_FAILED(){
  sqlite3ThreadData()->isFail = 0;
}

int OSSIZEOF(void *p){
  if( p ){
    u32 *pOs = (u32 *)getOsPointer(p);
    return sqlite3OsAllocationSize(pOs) - TESTALLOC_OVERHEAD;
  }
................................................................................
** called to try to avoid this. No indication of whether or not this is
** successful is returned to the caller.
**
** If SQLITE_OMIT_MEMORY_MANAGEMENT is defined, this function is a no-op.
*/
#ifndef SQLITE_OMIT_MEMORY_MANAGEMENT
static void handleSoftLimit(int n){
  ThreadData *pTsd = sqlite3ThreadData();
  pTsd->nAlloc += (i64)n;
  if( n>0 && pTsd->nSoftHeapLimit>0 ){
    while( pTsd->nAlloc>pTsd->nSoftHeapLimit && sqlite3_release_memory(n) );
  }
}
#else
#define handleSoftLimit()
................................................................................

/*
** Allocate and return N bytes of uninitialised memory by calling
** sqlite3OsMalloc(). If the Malloc() call fails, attempt to free memory 
** by calling sqlite3_release_memory().
*/
void *sqlite3MallocRaw(int n){
  ThreadData *pTsd = sqlite3ThreadData();
  void *p = 0;
  if( n>0 && !pTsd->mallocFailed ){
    handleSoftLimit(n);
    while( !(p = OSMALLOC(n)) && sqlite3_release_memory(n) );
    if( !p ){
      /* If the allocation failed, call handleSoftLimit() again, this time
      ** with the additive inverse of the argument passed to 
      ** handleSoftLimit() above. This is so the ThreadData.nAlloc variable is
      ** still correct after a malloc() failure. 
      */
      handleSoftLimit(n * -1);
      sqlite3ThreadData()->mallocFailed = 1;
      OSMALLOC_FAILED();
    }
  }
  return p;
}

/*
** Resize the allocation at p to n bytes by calling sqlite3OsRealloc(). The
** pointer to the new allocation is returned.  If the Realloc() call fails,
** attempt to free memory by calling sqlite3_release_memory().
*/
void *sqlite3Realloc(void *p, int n){
  ThreadData *pTsd = sqlite3ThreadData();
  if( pTsd->mallocFailed ){
    return 0;
  }

  if( !p ){
    return sqlite3Malloc(n);
  }else{
    void *np = 0;
    handleSoftLimit(n - OSSIZEOF(p));
    while( !(np = OSREALLOC(p, n)) && sqlite3_release_memory(n) );
    if( !np ){
      /* If the allocation failed, call handleSoftLimit() again, this time
      ** with the additive inverse of the argument passed to 
      ** handleSoftLimit() above. This is so the ThreadData.nAlloc variable is
      ** still correct after a malloc() failure. 
      */
      handleSoftLimit(OSSIZEOF(p) - n);
      pTsd->mallocFailed = 1;
      OSMALLOC_FAILED();
    }
    return np;
................................................................................
}

/*
** Make a copy of a string in memory obtained from sqliteMalloc(). These 
** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
** is because when memory debugging is turned on, these two functions are 
** called via macros that record the current file and line number in the
** ThreadData structure.
*/
char *sqlite3StrDup(const char *z){
  char *zNew;
  if( z==0 ) return 0;
  zNew = sqlite3MallocRaw(strlen(z)+1);
  if( zNew ) strcpy(zNew, z);
  return zNew;
................................................................................
    p = *(void**)&v2;
  }
  return p;
}
#endif

/*
** Return a pointer to the ThreadData associated with the calling thread.
*/
ThreadData *sqlite3ThreadData(){
  ThreadData *pTsd = sqlite3OsThreadSpecificData(sizeof(ThreadData));
  if( pTsd && !pTsd->isInit ){
    pTsd->nSoftHeapLimit = -1;
#ifndef NDEBUG
    pTsd->mallocAllowed = 1;
#endif
    pTsd->isInit = 1;
  }
................................................................................
}

/*
** Clear the "mallocFailed" flag. This should be invoked before exiting any
** entry points that may have called sqliteMalloc().
*/
void sqlite3MallocClearFailed(){
  sqlite3ThreadData()->mallocFailed = 0;
}


#ifndef NDEBUG
/*
** This function sets a flag in the thread-specific-data structure that will
** cause an assert to fail if sqliteMalloc() or sqliteRealloc() is called.
*/
void sqlite3MallocDisallow(){
  assert(sqlite3ThreadData()->mallocAllowed);
  sqlite3ThreadData()->mallocAllowed = 0;
}

/*
** This function clears the flag set in the thread-specific-data structure set
** by sqlite3MallocDisallow().
*/
void sqlite3MallocAllow(){
  assert(!sqlite3ThreadData()->mallocAllowed);
  sqlite3ThreadData()->mallocAllowed = 1;
}
#endif

**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.54 2006/01/06 14:32:20 drh Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"
#include "os.h"

#ifndef SQLITE_OMIT_VACUUM
/*
................................................................................
  ** by manually setting the autoCommit flag to true and detaching the
  ** vacuum database. The vacuum_db journal file is deleted when the pager
  ** is closed by the DETACH.
  */
  db->autoCommit = 1;

  if( pDetach ){
    int mf = sqlite3Tsd()->mallocFailed;
    sqlite3Tsd()->mallocFailed = 0;
    sqlite3MallocDisallow();
    ((Vdbe *)pDetach)->expired = 0;
    sqlite3_step(pDetach);
    rc2 = sqlite3_finalize(pDetach);
    if( rc==SQLITE_OK ){
      rc = rc2;
    }
    sqlite3MallocAllow();
    sqlite3Tsd()->mallocFailed = mf;
  }

  /* If one of the execSql() calls above returned SQLITE_NOMEM, then the
  ** mallocFailed flag will be clear (because execSql() calls sqlite3_exec()).
  ** Fix this so the flag and return code match.
  */
  if( rc==SQLITE_NOMEM ){
    sqlite3Tsd()->mallocFailed = 1;
  }

  if( zTemp ){
    sqlite3OsDelete(zTemp);
    sqliteFree(zTemp);
  }
  sqliteFree( zSql );
  sqlite3ResetInternalSchema(db, 0);
#endif

  return rc;
}

**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.55 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"
#include "os.h"

#ifndef SQLITE_OMIT_VACUUM
/*
................................................................................
  ** by manually setting the autoCommit flag to true and detaching the
  ** vacuum database. The vacuum_db journal file is deleted when the pager
  ** is closed by the DETACH.
  */
  db->autoCommit = 1;

  if( pDetach ){
    int mf = sqlite3ThreadData()->mallocFailed;
    sqlite3ThreadData()->mallocFailed = 0;
    sqlite3MallocDisallow();
    ((Vdbe *)pDetach)->expired = 0;
    sqlite3_step(pDetach);
    rc2 = sqlite3_finalize(pDetach);
    if( rc==SQLITE_OK ){
      rc = rc2;
    }
    sqlite3MallocAllow();
    sqlite3ThreadData()->mallocFailed = mf;
  }

  /* If one of the execSql() calls above returned SQLITE_NOMEM, then the
  ** mallocFailed flag will be clear (because execSql() calls sqlite3_exec()).
  ** Fix this so the flag and return code match.
  */
  if( rc==SQLITE_NOMEM ){
    sqlite3ThreadData()->mallocFailed = 1;
  }

  if( zTemp ){
    sqlite3OsDelete(zTemp);
    sqliteFree(zTemp);
  }
  sqliteFree( zSql );
  sqlite3ResetInternalSchema(db, 0);
#endif

  return rc;
}

**
** 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 1.518 2006/01/08 18:10:18 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  }
  p->resOnStack = 0;
  db->busyHandler.nBusy = 0;
  CHECK_FOR_INTERRUPT;
  for(pc=p->pc; rc==SQLITE_OK; pc++){
    assert( pc>=0 && pc<p->nOp );
    assert( pTos<=&p->aStack[pc] );
    if( sqlite3Tsd()->mallocFailed ) goto no_mem;
#ifdef VDBE_PROFILE
    origPc = pc;
    start = hwtime();
#endif
    pOp = &p->aOp[pc];

    /* Only allow tracing if SQLITE_DEBUG is defined.
................................................................................
    assert( pOp[-1].p3type==P3_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = (CollSeq *)pOp[-1].p3;
  }
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  (*ctx.pFunc->xFunc)(&ctx, n, apVal);
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  if( sqlite3Tsd()->mallocFailed ) goto no_mem;
  popStack(&pTos, n);

  /* If any auxilary data functions have been called by this user function,
  ** immediately call the destructor for any non-static values.
  */
  if( ctx.pVdbeFunc ){
    sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p1);
................................................................................
  zSql = sqlite3MPrintf(
     "SELECT name, rootpage, sql, %d FROM '%q'.%s WHERE %s",
     pOp->p1, db->aDb[iDb].zName, zMaster, pOp->p3);
  if( zSql==0 ) goto no_mem;
  sqlite3SafetyOff(db);
  assert( db->init.busy==0 );
  db->init.busy = 1;
  assert(0==sqlite3Tsd()->mallocFailed);
  rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
  sqliteFree(zSql);
  db->init.busy = 0;
  sqlite3SafetyOn(db);
  if( rc==SQLITE_NOMEM ){
    sqlite3Tsd()->mallocFailed = 1;
    goto no_mem;
  }
  break;  
}

#ifndef SQLITE_OMIT_ANALYZE
/* Opcode: LoadAnalysis P1 * *
................................................................................
  /* Fall thru into abort_due_to_error */

  /* Jump to here for any other kind of fatal error.  The "rc" variable
  ** should hold the error number.
  */
abort_due_to_error:
  if( p->zErrMsg==0 ){
    if( sqlite3Tsd()->mallocFailed ) rc = SQLITE_NOMEM;
    sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(rc), (char*)0);
  }
  goto vdbe_halt;

  /* Jump to here if the sqlite3_interrupt() API sets the interrupt
  ** flag.
  */

**
** 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 1.519 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  }
  p->resOnStack = 0;
  db->busyHandler.nBusy = 0;
  CHECK_FOR_INTERRUPT;
  for(pc=p->pc; rc==SQLITE_OK; pc++){
    assert( pc>=0 && pc<p->nOp );
    assert( pTos<=&p->aStack[pc] );
    if( sqlite3ThreadData()->mallocFailed ) goto no_mem;
#ifdef VDBE_PROFILE
    origPc = pc;
    start = hwtime();
#endif
    pOp = &p->aOp[pc];

    /* Only allow tracing if SQLITE_DEBUG is defined.
................................................................................
    assert( pOp[-1].p3type==P3_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = (CollSeq *)pOp[-1].p3;
  }
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  (*ctx.pFunc->xFunc)(&ctx, n, apVal);
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  if( sqlite3ThreadData()->mallocFailed ) goto no_mem;
  popStack(&pTos, n);

  /* If any auxilary data functions have been called by this user function,
  ** immediately call the destructor for any non-static values.
  */
  if( ctx.pVdbeFunc ){
    sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p1);
................................................................................
  zSql = sqlite3MPrintf(
     "SELECT name, rootpage, sql, %d FROM '%q'.%s WHERE %s",
     pOp->p1, db->aDb[iDb].zName, zMaster, pOp->p3);
  if( zSql==0 ) goto no_mem;
  sqlite3SafetyOff(db);
  assert( db->init.busy==0 );
  db->init.busy = 1;
  assert(0==sqlite3ThreadData()->mallocFailed);
  rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
  sqliteFree(zSql);
  db->init.busy = 0;
  sqlite3SafetyOn(db);
  if( rc==SQLITE_NOMEM ){
    sqlite3ThreadData()->mallocFailed = 1;
    goto no_mem;
  }
  break;  
}

#ifndef SQLITE_OMIT_ANALYZE
/* Opcode: LoadAnalysis P1 * *
................................................................................
  /* Fall thru into abort_due_to_error */

  /* Jump to here for any other kind of fatal error.  The "rc" variable
  ** should hold the error number.
  */
abort_due_to_error:
  if( p->zErrMsg==0 ){
    if( sqlite3ThreadData()->mallocFailed ) rc = SQLITE_NOMEM;
    sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(rc), (char*)0);
  }
  goto vdbe_halt;

  /* Jump to here if the sqlite3_interrupt() API sets the interrupt
  ** flag.
  */

** statement is completely executed or an error occurs.
*/
int sqlite3_step(sqlite3_stmt *pStmt){
  Vdbe *p = (Vdbe*)pStmt;
  sqlite3 *db;
  int rc;

  assert(!sqlite3Tsd()->mallocFailed);

  if( p==0 || p->magic!=VDBE_MAGIC_RUN ){
    return SQLITE_MISUSE;
  }
  if( p->aborted ){
    return SQLITE_ABORT;
  }
................................................................................
static void columnMallocFailure(sqlite3_stmt *pStmt)
{
  /* If malloc() failed during an encoding conversion within an
  ** sqlite3_column_XXX API, then set the return code of the statement to
  ** SQLITE_NOMEM. The next call to _step() (if any) will return SQLITE_ERROR
  ** and _finalize() will return NOMEM.
  */
  if( sqlite3Tsd()->mallocFailed ){
    ((Vdbe *)pStmt)->rc = SQLITE_NOMEM;
    sqlite3MallocClearFailed();
  }
}

/**************************** sqlite3_column_  *******************************
** The following routines are used to access elements of the current row

** statement is completely executed or an error occurs.
*/
int sqlite3_step(sqlite3_stmt *pStmt){
  Vdbe *p = (Vdbe*)pStmt;
  sqlite3 *db;
  int rc;

  assert(!sqlite3ThreadData()->mallocFailed);

  if( p==0 || p->magic!=VDBE_MAGIC_RUN ){
    return SQLITE_MISUSE;
  }
  if( p->aborted ){
    return SQLITE_ABORT;
  }
................................................................................
static void columnMallocFailure(sqlite3_stmt *pStmt)
{
  /* If malloc() failed during an encoding conversion within an
  ** sqlite3_column_XXX API, then set the return code of the statement to
  ** SQLITE_NOMEM. The next call to _step() (if any) will return SQLITE_ERROR
  ** and _finalize() will return NOMEM.
  */
  if( sqlite3ThreadData()->mallocFailed ){
    ((Vdbe *)pStmt)->rc = SQLITE_NOMEM;
    sqlite3MallocClearFailed();
  }
}

/**************************** sqlite3_column_  *******************************
** The following routines are used to access elements of the current row

  int i;
  VdbeOp *pOp;

  i = p->nOp;
  p->nOp++;
  assert( p->magic==VDBE_MAGIC_INIT );
  resizeOpArray(p, i+1);
  if( sqlite3Tsd()->mallocFailed ){
    return 0;
  }
  pOp = &p->aOp[i];
  pOp->opcode = op;
  pOp->p1 = p1;
  pOp->p2 = p2;
  pOp->p3 = 0;
................................................................................
** Add a whole list of operations to the operation stack.  Return the
** address of the first operation added.
*/
int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp){
  int addr;
  assert( p->magic==VDBE_MAGIC_INIT );
  resizeOpArray(p, p->nOp + nOp);
  if( sqlite3Tsd()->mallocFailed ){
    return 0;
  }
  addr = p->nOp;
  if( nOp>0 ){
    int i;
    VdbeOpList const *pIn = aOp;
    for(i=0; i<nOp; i++, pIn++){
................................................................................
** the Vdbe. In these cases we can just copy the pointer.
**
** If addr<0 then change P3 on the most recently inserted instruction.
*/
void sqlite3VdbeChangeP3(Vdbe *p, int addr, const char *zP3, int n){
  Op *pOp;
  assert( p->magic==VDBE_MAGIC_INIT );
  if( p==0 || p->aOp==0 || sqlite3Tsd()->mallocFailed ){
    if (n != P3_KEYINFO) {
      freeP3(n, (void*)*(char**)&zP3);
    }
    return;
  }
  if( addr<0 || addr>=p->nOp ){
    addr = p->nOp - 1;
................................................................................
/*
** Replace the P3 field of the most recently coded instruction with
** comment text.
*/
void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
  va_list ap;
  assert( p->nOp>0 );
  assert( p->aOp==0 || p->aOp[p->nOp-1].p3==0 || sqlite3Tsd()->mallocFailed );
  va_start(ap, zFormat);
  sqlite3VdbeChangeP3(p, -1, sqlite3VMPrintf(zFormat, ap), P3_DYNAMIC);
  va_end(ap);
}
#endif

/*
................................................................................
        nStack*sizeof(p->aStack[0])    /* aStack */
      + nArg*sizeof(Mem*)              /* apArg */
      + nVar*sizeof(Mem)               /* aVar */
      + nVar*sizeof(char*)             /* azVar */
      + nMem*sizeof(Mem)               /* aMem */
      + nCursor*sizeof(Cursor*)        /* apCsr */
    );
    if( !sqlite3Tsd()->mallocFailed ){
      p->aMem = &p->aStack[nStack];
      p->nMem = nMem;
      p->aVar = &p->aMem[nMem];
      p->nVar = nVar;
      p->okVar = 0;
      p->apArg = (Mem**)&p->aVar[nVar];
      p->azVar = (char**)&p->apArg[nArg];
................................................................................
** the string is freed using sqliteFree() when the vdbe is finished with
** it. Otherwise, N bytes of zName are copied.
*/
int sqlite3VdbeSetColName(Vdbe *p, int idx, const char *zName, int N){
  int rc;
  Mem *pColName;
  assert( idx<(2*p->nResColumn) );
  if( sqlite3Tsd()->mallocFailed ) return SQLITE_NOMEM;
  assert( p->aColName!=0 );
  pColName = &(p->aColName[idx]);
  if( N==P3_DYNAMIC || N==P3_STATIC ){
    rc = sqlite3VdbeMemSetStr(pColName, zName, -1, SQLITE_UTF8, SQLITE_STATIC);
  }else{
    rc = sqlite3VdbeMemSetStr(pColName, zName, N, SQLITE_UTF8,SQLITE_TRANSIENT);
  }
................................................................................
** means the close did not happen and needs to be repeated.
*/
int sqlite3VdbeHalt(Vdbe *p){
  sqlite3 *db = p->db;
  int i;
  int (*xFunc)(Btree *pBt) = 0;  /* Function to call on each btree backend */

  if( sqlite3Tsd()->mallocFailed ){
    p->rc = SQLITE_NOMEM;
  }

  if( p->magic!=VDBE_MAGIC_RUN ){
    /* Already halted.  Nothing to do. */
    assert( p->magic==VDBE_MAGIC_HALT );
    return SQLITE_OK;

  int i;
  VdbeOp *pOp;

  i = p->nOp;
  p->nOp++;
  assert( p->magic==VDBE_MAGIC_INIT );
  resizeOpArray(p, i+1);
  if( sqlite3ThreadData()->mallocFailed ){
    return 0;
  }
  pOp = &p->aOp[i];
  pOp->opcode = op;
  pOp->p1 = p1;
  pOp->p2 = p2;
  pOp->p3 = 0;
................................................................................
** Add a whole list of operations to the operation stack.  Return the
** address of the first operation added.
*/
int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp){
  int addr;
  assert( p->magic==VDBE_MAGIC_INIT );
  resizeOpArray(p, p->nOp + nOp);
  if( sqlite3ThreadData()->mallocFailed ){
    return 0;
  }
  addr = p->nOp;
  if( nOp>0 ){
    int i;
    VdbeOpList const *pIn = aOp;
    for(i=0; i<nOp; i++, pIn++){
................................................................................
** the Vdbe. In these cases we can just copy the pointer.
**
** If addr<0 then change P3 on the most recently inserted instruction.
*/
void sqlite3VdbeChangeP3(Vdbe *p, int addr, const char *zP3, int n){
  Op *pOp;
  assert( p->magic==VDBE_MAGIC_INIT );
  if( p==0 || p->aOp==0 || sqlite3ThreadData()->mallocFailed ){
    if (n != P3_KEYINFO) {
      freeP3(n, (void*)*(char**)&zP3);
    }
    return;
  }
  if( addr<0 || addr>=p->nOp ){
    addr = p->nOp - 1;
................................................................................
/*
** Replace the P3 field of the most recently coded instruction with
** comment text.
*/
void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
  va_list ap;
  assert( p->nOp>0 );
  assert( p->aOp==0 || p->aOp[p->nOp-1].p3==0 || sqlite3ThreadData()->mallocFailed );
  va_start(ap, zFormat);
  sqlite3VdbeChangeP3(p, -1, sqlite3VMPrintf(zFormat, ap), P3_DYNAMIC);
  va_end(ap);
}
#endif

/*
................................................................................
        nStack*sizeof(p->aStack[0])    /* aStack */
      + nArg*sizeof(Mem*)              /* apArg */
      + nVar*sizeof(Mem)               /* aVar */
      + nVar*sizeof(char*)             /* azVar */
      + nMem*sizeof(Mem)               /* aMem */
      + nCursor*sizeof(Cursor*)        /* apCsr */
    );
    if( !sqlite3ThreadData()->mallocFailed ){
      p->aMem = &p->aStack[nStack];
      p->nMem = nMem;
      p->aVar = &p->aMem[nMem];
      p->nVar = nVar;
      p->okVar = 0;
      p->apArg = (Mem**)&p->aVar[nVar];
      p->azVar = (char**)&p->apArg[nArg];
................................................................................
** the string is freed using sqliteFree() when the vdbe is finished with
** it. Otherwise, N bytes of zName are copied.
*/
int sqlite3VdbeSetColName(Vdbe *p, int idx, const char *zName, int N){
  int rc;
  Mem *pColName;
  assert( idx<(2*p->nResColumn) );
  if( sqlite3ThreadData()->mallocFailed ) return SQLITE_NOMEM;
  assert( p->aColName!=0 );
  pColName = &(p->aColName[idx]);
  if( N==P3_DYNAMIC || N==P3_STATIC ){
    rc = sqlite3VdbeMemSetStr(pColName, zName, -1, SQLITE_UTF8, SQLITE_STATIC);
  }else{
    rc = sqlite3VdbeMemSetStr(pColName, zName, N, SQLITE_UTF8,SQLITE_TRANSIENT);
  }
................................................................................
** means the close did not happen and needs to be repeated.
*/
int sqlite3VdbeHalt(Vdbe *p){
  sqlite3 *db = p->db;
  int i;
  int (*xFunc)(Btree *pBt) = 0;  /* Function to call on each btree backend */

  if( sqlite3ThreadData()->mallocFailed ){
    p->rc = SQLITE_NOMEM;
  }

  if( p->magic!=VDBE_MAGIC_RUN ){
    /* Already halted.  Nothing to do. */
    assert( p->magic==VDBE_MAGIC_HALT );
    return SQLITE_OK;

    return 0;
  }
  if( pVal->flags&MEM_Str ){
    sqlite3VdbeChangeEncoding(pVal, enc);
  }else if( !(pVal->flags&MEM_Blob) ){
    sqlite3VdbeMemStringify(pVal, enc);
  }
  assert(pVal->enc==enc || sqlite3Tsd()->mallocFailed);
  return (const void *)(pVal->enc==enc ? (pVal->z) : 0);
}

/*
** Create a new sqlite3_value object.
*/
sqlite3_value* sqlite3ValueNew(void){

    return 0;
  }
  if( pVal->flags&MEM_Str ){
    sqlite3VdbeChangeEncoding(pVal, enc);
  }else if( !(pVal->flags&MEM_Blob) ){
    sqlite3VdbeMemStringify(pVal, enc);
  }
  assert(pVal->enc==enc || sqlite3ThreadData()->mallocFailed);
  return (const void *)(pVal->enc==enc ? (pVal->z) : 0);
}

/*
** Create a new sqlite3_value object.
*/
sqlite3_value* sqlite3ValueNew(void){

** 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 1.191 2006/01/07 13:21:04 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
  WhereTerm *pTerm = &pWC->a[idxTerm];
  Expr *pExpr = pTerm->pExpr;
  Bitmask prereqLeft;
  Bitmask prereqAll;
  int nPattern;
  int isComplete;

  if( sqlite3Tsd()->mallocFailed ) return;
  prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  if( pExpr->op==TK_IN ){
    assert( pExpr->pRight==0 );
    pTerm->prereqRight = exprListTableUsage(pMaskSet, pExpr->pList)
                          | exprSelectTableUsage(pMaskSet, pExpr->pSelect);
  }else{
    pTerm->prereqRight = exprTableUsage(pMaskSet, pExpr->pRight);
................................................................................
  whereClauseInit(&wc, pParse);
  whereSplit(&wc, pWhere, TK_AND);
    
  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value.
  */
  pWInfo = sqliteMalloc( sizeof(WhereInfo) + pTabList->nSrc*sizeof(WhereLevel));
  if( sqlite3Tsd()->mallocFailed ){
    goto whereBeginNoMem;
  }
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->iBreak = sqlite3VdbeMakeLabel(v);

  /* Special case: a WHERE clause that is constant.  Evaluate the
................................................................................
  ** want to analyze these virtual terms, so start analyzing at the end
  ** and work forward so that the added virtual terms are never processed.
  */
  for(i=0; i<pTabList->nSrc; i++){
    createMask(&maskSet, pTabList->a[i].iCursor);
  }
  exprAnalyzeAll(pTabList, &maskSet, &wc);
  if( sqlite3Tsd()->mallocFailed ){
    goto whereBeginNoMem;
  }

  /* Chose the best index to use for each table in the FROM clause.
  **
  ** This loop fills in the following fields:
  **

** 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 1.192 2006/01/09 06:29:49 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
  WhereTerm *pTerm = &pWC->a[idxTerm];
  Expr *pExpr = pTerm->pExpr;
  Bitmask prereqLeft;
  Bitmask prereqAll;
  int nPattern;
  int isComplete;

  if( sqlite3ThreadData()->mallocFailed ) return;
  prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  if( pExpr->op==TK_IN ){
    assert( pExpr->pRight==0 );
    pTerm->prereqRight = exprListTableUsage(pMaskSet, pExpr->pList)
                          | exprSelectTableUsage(pMaskSet, pExpr->pSelect);
  }else{
    pTerm->prereqRight = exprTableUsage(pMaskSet, pExpr->pRight);
................................................................................
  whereClauseInit(&wc, pParse);
  whereSplit(&wc, pWhere, TK_AND);
    
  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value.
  */
  pWInfo = sqliteMalloc( sizeof(WhereInfo) + pTabList->nSrc*sizeof(WhereLevel));
  if( sqlite3ThreadData()->mallocFailed ){
    goto whereBeginNoMem;
  }
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->iBreak = sqlite3VdbeMakeLabel(v);

  /* Special case: a WHERE clause that is constant.  Evaluate the
................................................................................
  ** want to analyze these virtual terms, so start analyzing at the end
  ** and work forward so that the added virtual terms are never processed.
  */
  for(i=0; i<pTabList->nSrc; i++){
    createMask(&maskSet, pTabList->a[i].iCursor);
  }
  exprAnalyzeAll(pTabList, &maskSet, &wc);
  if( sqlite3ThreadData()->mallocFailed ){
    goto whereBeginNoMem;
  }

  /* Chose the best index to use for each table in the FROM clause.
  **
  ** This loop fills in the following fields:
  **

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the SELECT statement.
#
# $Id: shared.test,v 1.6 2006/01/07 13:21:04 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl
db close

ifcapable !shared_cache {
  finish_test
................................................................................
#             write-transaction, including a simple test to ensure the 
#             external locking protocol is still working.
# shared-3.*: Simple test of read-uncommitted mode.
# shared-4.*: Check that the schema is locked and unlocked correctly.
# shared-5.*: Test that creating/dropping schema items works when databases
#             are attached in different orders to different handles.
# shared-6.*: Locking, UNION ALL queries and sub-queries.

#

do_test shared-1.1 {
  # Open a second database on the file test.db. It should use the same pager
  # cache and schema as the original connection. Verify that only 1 file is 
  # opened.
  sqlite3 db2 test.db
................................................................................
      lappend ret $d
    }
  }
  set ret
} {}

catch {db1 close}
catch {db2 close}








































































finish_test
sqlite3_enable_shared_cache $::enable_shared_cache

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the SELECT statement.
#
# $Id: shared.test,v 1.7 2006/01/09 06:29:49 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl
db close

ifcapable !shared_cache {
  finish_test
................................................................................
#             write-transaction, including a simple test to ensure the 
#             external locking protocol is still working.
# shared-3.*: Simple test of read-uncommitted mode.
# shared-4.*: Check that the schema is locked and unlocked correctly.
# shared-5.*: Test that creating/dropping schema items works when databases
#             are attached in different orders to different handles.
# shared-6.*: Locking, UNION ALL queries and sub-queries.
# shared-6.*: Autovacuum and shared-cache.
#

do_test shared-1.1 {
  # Open a second database on the file test.db. It should use the same pager
  # cache and schema as the original connection. Verify that only 1 file is 
  # opened.
  sqlite3 db2 test.db
................................................................................
      lappend ret $d
    }
  }
  set ret
} {}

catch {db1 close}
catch {db2 close}
foreach f [list test.db test2.db] {
  file delete -force $f ${f}-journal
}

#--------------------------------------------------------------------------
# Tests shared-7.* test auto-vacuum does not invalidate cursors from
# other shared-cache users when it reorganizes the database on 
# COMMIT.
#
do_test shared-7.1 {
  sqlite3 db test.db
  sqlite3 db2 test.db
  execsql {
    PRAGMA auto_vacuum = 1;
    BEGIN;
    CREATE TABLE t1(a PRIMARY KEY, b);
    CREATE TABLE t2(a PRIMARY KEY, b);
  }
  for {set i 0} {$i < 100} {incr i} {
    set a [string repeat "$i " 20]
    set b [string repeat "$i " 20]
    db eval {
      INSERT INTO t1 VALUES($a, $b);
    }
    lappend ::contents [list [expr $i+1] $a $b]
  }
  execsql {
    INSERT INTO t2 SELECT * FROM t1;
    COMMIT;
  }
  execsql {
    PRAGMA auto_vacuum;
  }
} {1}
do_test shared-7.2 {
  proc lockrow {db tbl oids body} {
    set ret [list]
    db eval "SELECT oid AS i, a, b FROM $tbl ORDER BY a" {
      if {$i==[lindex $oids 0]} {
        set noids [lrange $oids 1 end]
        if {[llength $noids]==0} {
          set subret [eval $body]
        } else {
          set subret [lockrow $db $tbl $noids $body]
        }
      }
      lappend ret [list $i $a $b]
    }
    return [linsert $subret 0 $ret]
  }
  proc locktblrows {db tbl body} {
    set oids [db eval "SELECT oid FROM $tbl"]
    lockrow $db $tbl $oids $body
  }

  set scans [locktblrows db t2 {
    execsql {
      DELETE FROM t1;
    } db2
  }]
  set error 0
  foreach s $scans {
    if {[lsort -integer -index 0 $s]!=$::contents} {
      set error 1
    }
  }
  set error
} {0}

catch {db close}
catch {db2 close}

finish_test
sqlite3_enable_shared_cache $::enable_shared_cache