#define SPELLFIX_COL_TOP             7
#define SPELLFIX_COL_SCOPE           8
#define SPELLFIX_COL_SRCHCNT         9
#define SPELLFIX_COL_SOUNDSLIKE     10
#define SPELLFIX_COL_COMMAND        11
    }
    if( rc==SQLITE_OK && isCreate ){
      sqlite3_uint64 r;
      spellfix1DbExec(&rc, db,
         "CREATE TABLE IF NOT EXISTS \"%w\".\"%w_vocab\"(\n"
         "  id INTEGER PRIMARY KEY,\n"
         "  rank INT,\n"
         "  langid INT,\n"
         "  word TEXT,\n"
         "  k1 TEXT,\n"
         "  k2 TEXT\n"
         ");\n",
         zDbName, zTableName
      );
      sqlite3_randomness(sizeof(r), &r);
      spellfix1DbExec(&rc, db,
         "CREATE INDEX IF NOT EXISTS \"%w\".\"%w_index_%llx\" "
            "ON \"%w_vocab\"(langid,k2);",
         zDbName, zModule, r, zTableName
      );
    }
    for(i=3; rc==SQLITE_OK && i<argc; i++){
      if( strncmp(argv[i],"edit_cost_table=",16)==0 && pNew->zCostTable==0 ){
        pNew->zCostTable = spellfix1Dequote(&argv[i][16]);
        if( pNew->zCostTable==0 ) rc = SQLITE_NOMEM;
        continue;

#define SPELLFIX_COL_TOP             7
#define SPELLFIX_COL_SCOPE           8
#define SPELLFIX_COL_SRCHCNT         9
#define SPELLFIX_COL_SOUNDSLIKE     10
#define SPELLFIX_COL_COMMAND        11
    }
    if( rc==SQLITE_OK && isCreate ){

      spellfix1DbExec(&rc, db,
         "CREATE TABLE IF NOT EXISTS \"%w\".\"%w_vocab\"(\n"
         "  id INTEGER PRIMARY KEY,\n"
         "  rank INT,\n"
         "  langid INT,\n"
         "  word TEXT,\n"
         "  k1 TEXT,\n"
         "  k2 TEXT\n"
         ");\n",
         zDbName, zTableName
      );

      spellfix1DbExec(&rc, db,
         "CREATE INDEX IF NOT EXISTS \"%w\".\"%w_vocab_index_langid_k2\" "
            "ON \"%w_vocab\"(langid,k2);",
         zDbName, zModule, zTableName
      );
    }
    for(i=3; rc==SQLITE_OK && i<argc; i++){
      if( strncmp(argv[i],"edit_cost_table=",16)==0 && pNew->zCostTable==0 ){
        pNew->zCostTable = spellfix1Dequote(&argv[i][16]);
        if( pNew->zCostTable==0 ) rc = SQLITE_NOMEM;
        continue;

** See comments in the body of this function for details.
*/
static int sessionBindValue(
  sqlite3_stmt *pStmt,            /* Statement to bind value to */
  int i,                          /* Parameter number to bind to */
  sqlite3_value *pVal             /* Value to bind */
){
  if( (pVal->type==SQLITE_TEXT || pVal->type==SQLITE_BLOB) && pVal->z==0 ){

    /* This condition occurs when an earlier OOM in a call to
    ** sqlite3_value_text() or sqlite3_value_blob() (perhaps from within
    ** a conflict-hanler) has zeroed the pVal->z pointer. Return NOMEM. */
    return SQLITE_NOMEM;
  }
  return sqlite3_bind_value(pStmt, i, pVal);
}

** See comments in the body of this function for details.
*/
static int sessionBindValue(
  sqlite3_stmt *pStmt,            /* Statement to bind value to */
  int i,                          /* Parameter number to bind to */
  sqlite3_value *pVal             /* Value to bind */
){
  int eType = sqlite3_value_type(pVal);
  if( (eType==SQLITE_TEXT || eType==SQLITE_BLOB) && pVal->z==0 ){
    /* This condition occurs when an earlier OOM in a call to
    ** sqlite3_value_text() or sqlite3_value_blob() (perhaps from within
    ** a conflict-hanler) has zeroed the pVal->z pointer. Return NOMEM. */
    return SQLITE_NOMEM;
  }
  return sqlite3_bind_value(pStmt, i, pVal);
}

    pVTab = sqlite3GetVTable(db, pTab);
    if( pVTab->pVtab->pModule->xRename==0 ){
      pVTab = 0;
    }
  }
#endif

  /* Begin a transaction and code the VerifyCookie for database iDb. 
  ** Then modify the schema cookie (since the ALTER TABLE modifies the
  ** schema). Open a statement transaction if the table is a virtual
  ** table.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    goto exit_rename_table;

    pVTab = sqlite3GetVTable(db, pTab);
    if( pVTab->pVtab->pModule->xRename==0 ){
      pVTab = 0;
    }
  }
#endif

  /* Begin a transaction for database iDb. 
  ** Then modify the schema cookie (since the ALTER TABLE modifies the
  ** schema). Open a statement transaction if the table is a virtual
  ** table.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    goto exit_rename_table;

}

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









*/
int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
  int rc;
  int idx;
  MemPage *pPage;

  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );

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


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









*/
int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
  int rc;
  MemPage *pPage;

  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );

  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  pCur->atLast = 0;
  if( pCur->eState!=CURSOR_VALID ){
    if( ALWAYS(pCur->eState>=CURSOR_REQUIRESEEK) ){
      rc = btreeRestoreCursorPosition(pCur);
      if( rc!=SQLITE_OK ){
        *pRes = 0;
................................................................................
  ** the cursor to the largest entry in the tree that is smaller than
  ** the entry being deleted. This cell will replace the cell being deleted
  ** from the internal node. The 'previous' entry is used for this instead
  ** of the 'next' entry, as the previous entry is always a part of the
  ** sub-tree headed by the child page of the cell being deleted. This makes
  ** balancing the tree following the delete operation easier.  */
  if( !pPage->leaf ){
    int notUsed;
    rc = sqlite3BtreePrevious(pCur, &notUsed);
    if( rc ) return rc;
  }

  /* Save the positions of any other cursors open on this table before
  ** making any modifications. Make the page containing the entry to be 
  ** deleted writable. Then free any overflow pages associated with the 

}

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

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


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

  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 || *pRes==1 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  pCur->atLast = 0;
  if( pCur->eState!=CURSOR_VALID ){
    if( ALWAYS(pCur->eState>=CURSOR_REQUIRESEEK) ){
      rc = btreeRestoreCursorPosition(pCur);
      if( rc!=SQLITE_OK ){
        *pRes = 0;
................................................................................
  ** the cursor to the largest entry in the tree that is smaller than
  ** the entry being deleted. This cell will replace the cell being deleted
  ** from the internal node. The 'previous' entry is used for this instead
  ** of the 'next' entry, as the previous entry is always a part of the
  ** sub-tree headed by the child page of the cell being deleted. This makes
  ** balancing the tree following the delete operation easier.  */
  if( !pPage->leaf ){
    int notUsed = 0;
    rc = sqlite3BtreePrevious(pCur, &notUsed);
    if( rc ) return rc;
  }

  /* Save the positions of any other cursors open on this table before
  ** making any modifications. Make the page containing the entry to be 
  ** deleted writable. Then free any overflow pages associated with the 

    /* The cookie mask contains one bit for each database file open.
    ** (Bit 0 is for main, bit 1 is for temp, and so forth.)  Bits are
    ** set for each database that is used.  Generate code to start a
    ** transaction on each used database and to verify the schema cookie
    ** on each used database.
    */
    if( pParse->cookieGoto>0 ){
      yDbMask mask;
      int iDb, i, addr;

      sqlite3VdbeJumpHere(v, pParse->cookieGoto-1);
      for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
        if( (mask & pParse->cookieMask)==0 ) continue;
        sqlite3VdbeUsesBtree(v, iDb);
        sqlite3VdbeAddOp2(v,OP_Transaction, iDb, (mask & pParse->writeMask)!=0);
        if( db->init.busy==0 ){
          assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
          sqlite3VdbeAddOp3(v, OP_VerifyCookie,
                            iDb, pParse->cookieValue[iDb],
                            db->aDb[iDb].pSchema->iGeneration);
        }


      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      for(i=0; i<pParse->nVtabLock; i++){
        char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
        sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
      }
      pParse->nVtabLock = 0;
................................................................................
      codeTableLocks(pParse);

      /* Initialize any AUTOINCREMENT data structures required.
      */
      sqlite3AutoincrementBegin(pParse);

      /* Code constant expressions that where factored out of inner loops */
      addr = pParse->cookieGoto;
      if( pParse->pConstExpr ){
        ExprList *pEL = pParse->pConstExpr;
        pParse->cookieGoto = 0;

        for(i=0; i<pEL->nExpr; i++){
          sqlite3ExprCode(pParse, pEL->a[i].pExpr, pEL->a[i].u.iConstExprReg);
        }
      }

      /* Finally, jump back to the beginning of the executable code. */
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
    }
  }


  /* Get the VDBE program ready for execution
  */
  if( v && ALWAYS(pParse->nErr==0) && !db->mallocFailed ){
................................................................................
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;
  pParse->nSet = 0;
  pParse->nVar = 0;
  pParse->cookieMask = 0;
  pParse->cookieGoto = 0;
}

/*
** Run the parser and code generator recursively in order to generate
** code for the SQL statement given onto the end of the pParse context
** currently under construction.  When the parser is run recursively
** this way, the final OP_Halt is not appended and other initialization
................................................................................
      return 1;
    }
  }
  return 0;
}

/*
** Generate VDBE code that will verify the schema cookie and start
** a read-transaction for all named database files.
**
** It is important that all schema cookies be verified and all
** read transactions be started before anything else happens in
** the VDBE program.  But this routine can be called after much other
** code has been generated.  So here is what we do:
**
** The first time this routine is called, we code an OP_Goto that
** will jump to a subroutine at the end of the program.  Then we
** record every database that needs its schema verified in the
** pParse->cookieMask field.  Later, after all other code has been
** generated, the subroutine that does the cookie verifications and
** starts the transactions will be coded and the OP_Goto P2 value
** will be made to point to that subroutine.  The generation of the
** cookie verification subroutine code happens in sqlite3FinishCoding().
**
** If iDb<0 then code the OP_Goto only - don't set flag to verify the
** schema on any databases.  This can be used to position the OP_Goto
** early in the code, before we know if any database tables will be used.
*/
void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
  Parse *pToplevel = sqlite3ParseToplevel(pParse);

#ifndef SQLITE_OMIT_TRIGGER
  if( pToplevel!=pParse ){
    /* This branch is taken if a trigger is currently being coded. In this
    ** case, set cookieGoto to a non-zero value to show that this function
    ** has been called. This is used by the sqlite3ExprCodeConstants()
    ** function. */
    pParse->cookieGoto = -1;
  }
#endif
  if( pToplevel->cookieGoto==0 ){
    Vdbe *v = sqlite3GetVdbe(pToplevel);
    if( v==0 ) return;  /* This only happens if there was a prior error */
    pToplevel->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
  }
  if( iDb>=0 ){
    sqlite3 *db = pToplevel->db;
    yDbMask mask;

    assert( iDb<db->nDb );
    assert( db->aDb[iDb].pBt!=0 || iDb==1 );
    assert( iDb<SQLITE_MAX_ATTACHED+2 );
    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
    mask = ((yDbMask)1)<<iDb;
    if( (pToplevel->cookieMask & mask)==0 ){
      pToplevel->cookieMask |= mask;
      pToplevel->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
      if( !OMIT_TEMPDB && iDb==1 ){
        sqlite3OpenTempDatabase(pToplevel);
      }
    }
  }
}

/*
** If argument zDb is NULL, then call sqlite3CodeVerifySchema() for each 
** attached database. Otherwise, invoke it for the database named zDb only.

    /* The cookie mask contains one bit for each database file open.
    ** (Bit 0 is for main, bit 1 is for temp, and so forth.)  Bits are
    ** set for each database that is used.  Generate code to start a
    ** transaction on each used database and to verify the schema cookie
    ** on each used database.
    */
    if( db->mallocFailed==0 && (pParse->cookieMask || pParse->pConstExpr) ){
      yDbMask mask;
      int iDb, i;
      assert( sqlite3VdbeGetOp(v, 0)->opcode==OP_Init );
      sqlite3VdbeJumpHere(v, 0);
      for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
        if( (mask & pParse->cookieMask)==0 ) continue;
        sqlite3VdbeUsesBtree(v, iDb);
        sqlite3VdbeAddOp4Int(v,
          OP_Transaction,                    /* Opcode */
          iDb,                               /* P1 */
          (mask & pParse->writeMask)!=0,     /* P2 */
          pParse->cookieValue[iDb],          /* P3 */
          db->aDb[iDb].pSchema->iGeneration  /* P4 */

        );
        if( db->init.busy==0 ) sqlite3VdbeChangeP5(v, 1);
      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      for(i=0; i<pParse->nVtabLock; i++){
        char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
        sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
      }
      pParse->nVtabLock = 0;
................................................................................
      codeTableLocks(pParse);

      /* Initialize any AUTOINCREMENT data structures required.
      */
      sqlite3AutoincrementBegin(pParse);

      /* Code constant expressions that where factored out of inner loops */

      if( pParse->pConstExpr ){
        ExprList *pEL = pParse->pConstExpr;

        pParse->okConstFactor = 0;
        for(i=0; i<pEL->nExpr; i++){
          sqlite3ExprCode(pParse, pEL->a[i].pExpr, pEL->a[i].u.iConstExprReg);
        }
      }

      /* Finally, jump back to the beginning of the executable code. */
      sqlite3VdbeAddOp2(v, OP_Goto, 0, 1);
    }
  }


  /* Get the VDBE program ready for execution
  */
  if( v && ALWAYS(pParse->nErr==0) && !db->mallocFailed ){
................................................................................
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;
  pParse->nSet = 0;
  pParse->nVar = 0;
  pParse->cookieMask = 0;

}

/*
** Run the parser and code generator recursively in order to generate
** code for the SQL statement given onto the end of the pParse context
** currently under construction.  When the parser is run recursively
** this way, the final OP_Halt is not appended and other initialization
................................................................................
      return 1;
    }
  }
  return 0;
}

/*
** Record the fact that the schema cookie will need to be verified
** for database iDb.  The code to actually verify the schema cookie
** will occur at the end of the top-level VDBE and will be generated












** later, by sqlite3FinishCoding().




*/
void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
  Parse *pToplevel = sqlite3ParseToplevel(pParse);
















  sqlite3 *db = pToplevel->db;
  yDbMask mask;

  assert( iDb>=0 && iDb<db->nDb );
  assert( db->aDb[iDb].pBt!=0 || iDb==1 );
  assert( iDb<SQLITE_MAX_ATTACHED+2 );
  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
  mask = ((yDbMask)1)<<iDb;
  if( (pToplevel->cookieMask & mask)==0 ){
    pToplevel->cookieMask |= mask;
    pToplevel->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
    if( !OMIT_TEMPDB && iDb==1 ){
      sqlite3OpenTempDatabase(pToplevel);

    }
  }
}

/*
** If argument zDb is NULL, then call sqlite3CodeVerifySchema() for each 
** attached database. Otherwise, invoke it for the database named zDb only.

  int iCur             /* Cursor number for ephemerial table */
){
  SelectDest dest;
  Select *pSel;
  SrcList *pFrom;
  sqlite3 *db = pParse->db;
  int iDb = sqlite3SchemaToIndex(db, pView->pSchema);

  pWhere = sqlite3ExprDup(db, pWhere, 0);
  pFrom = sqlite3SrcListAppend(db, 0, 0, 0);

  if( pFrom ){
    assert( pFrom->nSrc==1 );
    pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
    pFrom->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zName);
    assert( pFrom->a[0].pOn==0 );
    assert( pFrom->a[0].pUsing==0 );
  }

  pSel = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
  if( pSel ) pSel->selFlags |= SF_Materialize;

  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
  sqlite3Select(pParse, pSel, &dest);
  sqlite3SelectDelete(db, pSel);
}
#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */

#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)

  int iCur             /* Cursor number for ephemerial table */
){
  SelectDest dest;
  Select *pSel;
  SrcList *pFrom;
  sqlite3 *db = pParse->db;
  int iDb = sqlite3SchemaToIndex(db, pView->pSchema);

  pWhere = sqlite3ExprDup(db, pWhere, 0);
  pFrom = sqlite3SrcListAppend(db, 0, 0, 0);

  if( pFrom ){
    assert( pFrom->nSrc==1 );
    pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
    pFrom->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zName);
    assert( pFrom->a[0].pOn==0 );
    assert( pFrom->a[0].pUsing==0 );
  }

  pSel = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);


  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
  sqlite3Select(pParse, pSel, &dest);
  sqlite3SelectDelete(db, pSel);
}
#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */

#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)

  if( pPrior ) pPrior->pNext = pNew;
  pNew->pNext = 0;
  pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
  pNew->pOffset = sqlite3ExprDup(db, p->pOffset, flags);
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
  pNew->pRightmost = 0;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->addrOpenEphm[2] = -1;
  pNew->nSelectRow = p->nSelectRow;
  pNew->pWith = withDup(db, p->pWith);
  return pNew;
}
................................................................................
    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
    pTab = p->pSrc->a[0].pTab;
    pExpr = p->pEList->a[0].pExpr;
    iCol = (i16)pExpr->iColumn;
   
    /* Code an OP_VerifyCookie and OP_TableLock for <table>. */
    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
    sqlite3CodeVerifySchema(pParse, iDb);
    sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);

    /* This function is only called from two places. In both cases the vdbe
    ** has already been allocated. So assume sqlite3GetVdbe() is always
    ** successful here.
................................................................................
      ** SELECT... statement are columns, then numeric affinity is used
      ** if either column has NUMERIC or INTEGER affinity. If neither
      ** 'x' nor the SELECT... statement are columns, then numeric affinity
      ** is used.
      */
      pExpr->iTable = pParse->nTab++;
      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pExpr->iTable, !isRowid);
      if( rMayHaveNull==0 ) sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
      pKeyInfo = isRowid ? 0 : sqlite3KeyInfoAlloc(pParse->db, 1, 1);

      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        /* Case 1:     expr IN (SELECT ...)
        **
        ** Generate code to write the results of the select into the temporary
        ** table allocated and opened above.

  if( pPrior ) pPrior->pNext = pNew;
  pNew->pNext = 0;
  pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
  pNew->pOffset = sqlite3ExprDup(db, p->pOffset, flags);
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;

  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->addrOpenEphm[2] = -1;
  pNew->nSelectRow = p->nSelectRow;
  pNew->pWith = withDup(db, p->pWith);
  return pNew;
}
................................................................................
    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
    pTab = p->pSrc->a[0].pTab;
    pExpr = p->pEList->a[0].pExpr;
    iCol = (i16)pExpr->iColumn;
   
    /* Code an OP_Transaction and OP_TableLock for <table>. */
    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
    sqlite3CodeVerifySchema(pParse, iDb);
    sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);

    /* This function is only called from two places. In both cases the vdbe
    ** has already been allocated. So assume sqlite3GetVdbe() is always
    ** successful here.
................................................................................
      ** SELECT... statement are columns, then numeric affinity is used
      ** if either column has NUMERIC or INTEGER affinity. If neither
      ** 'x' nor the SELECT... statement are columns, then numeric affinity
      ** is used.
      */
      pExpr->iTable = pParse->nTab++;
      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pExpr->iTable, !isRowid);

      pKeyInfo = isRowid ? 0 : sqlite3KeyInfoAlloc(pParse->db, 1, 1);

      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        /* Case 1:     expr IN (SELECT ...)
        **
        ** Generate code to write the results of the select into the temporary
        ** table allocated and opened above.

**
** Registers are allocated as follows:
**
**   pDest->iSDParm      The register holding the next entry-point of the
**                       co-routine.  Run the co-routine to its next breakpoint
**                       by calling "OP_Yield $X" where $X is pDest->iSDParm.
**
**   pDest->iSDParm+1    The register holding the "completed" flag for the
**                       co-routine. This register is 0 if the previous Yield
**                       generated a new result row, or 1 if the subquery
**                       has completed.  If the Yield is called again
**                       after this register becomes 1, then the VDBE will
**                       halt with an SQLITE_INTERNAL error.
**
**   pDest->iSdst        First result register.
**
**   pDest->nSdst        Number of result registers.



**
** This routine handles all of the register allocation and fills in the
** pDest structure appropriately.
**
** Here is a schematic of the generated code assuming that X is the 
** co-routine entry-point register reg[pDest->iSDParm], that EOF is the
** completed flag reg[pDest->iSDParm+1], and R and S are the range of
** registers that hold the result set, reg[pDest->iSdst] through
** reg[pDest->iSdst+pDest->nSdst-1]:
**
**         X <- A
**         EOF <- 0
**         goto B
**      A: setup for the SELECT
**         loop rows in the SELECT
**           load results into registers R..S
**           yield X
**         end loop
**         cleanup after the SELECT
**         EOF <- 1
**         yield X
**         halt-error
**      B:
**
** To use this subroutine, the caller generates code as follows:
**
**         [ Co-routine generated by this subroutine, shown above ]
**      S: yield X
**         if EOF goto E
**         if skip this row, goto C
**         if terminate loop, goto E
**         deal with this row
**      C: goto S
**      E:
*/
int sqlite3CodeCoroutine(Parse *pParse, Select *pSelect, SelectDest *pDest){
  int regYield;       /* Register holding co-routine entry-point */
  int regEof;         /* Register holding co-routine completion flag */
  int addrTop;        /* Top of the co-routine */
  int j1;             /* Jump instruction */
  int rc;             /* Result code */
  Vdbe *v;            /* VDBE under construction */

  regYield = ++pParse->nMem;
  regEof = ++pParse->nMem;
  v = sqlite3GetVdbe(pParse);
  addrTop = sqlite3VdbeCurrentAddr(v);
  sqlite3VdbeAddOp2(v, OP_Integer, addrTop+2, regYield); /* X <- A */
  VdbeComment((v, "Co-routine entry point"));
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regEof);           /* EOF <- 0 */
  VdbeComment((v, "Co-routine completion flag"));

  sqlite3SelectDestInit(pDest, SRT_Coroutine, regYield);
  j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
  rc = sqlite3Select(pParse, pSelect, pDest);
  assert( pParse->nErr==0 || rc );
  if( pParse->db->mallocFailed && rc==SQLITE_OK ) rc = SQLITE_NOMEM;
  if( rc ) return rc;
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof);            /* EOF <- 1 */
  sqlite3VdbeAddOp1(v, OP_Yield, regYield);   /* yield X */
  sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
  VdbeComment((v, "End of coroutine"));
  sqlite3VdbeJumpHere(v, j1);                             /* label B: */
  return rc;
}



/* Forward declaration */
static int xferOptimization(
................................................................................
**           close cursors
**         end foreach
**
** The 3rd template is for when the second template does not apply
** and the SELECT clause does not read from <table> at any time.
** The generated code follows this template:
**
**         EOF <- 0
**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the rows in the SELECT
**           load values into registers R..R+n
**           yield X
**         end loop
**         cleanup after the SELECT
**         EOF <- 1
**         yield X
**         goto A
**      B: open write cursor to <table> and its indices
**      C: yield X
**         if EOF goto D
**         insert the select result into <table> from R..R+n
**         goto C
**      D: cleanup
**
** The 4th template is used if the insert statement takes its
** values from a SELECT but the data is being inserted into a table
** that is also read as part of the SELECT.  In the third form,
** we have to use a intermediate table to store the results of
** the select.  The template is like this:
**
**         EOF <- 0
**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the tables in the SELECT
**           load value into register R..R+n
**           yield X
**         end loop
**         cleanup after the SELECT
**         EOF <- 1
**         yield X
**         halt-error
**      B: open temp table
**      L: yield X
**         if EOF goto M
**         insert row from R..R+n into temp table
**         goto L
**      M: open write cursor to <table> and its indices
**         rewind temp table
**      C: loop over rows of intermediate table
**           transfer values form intermediate table into <table>
**         end loop
................................................................................
  /* Register allocations */
  int regFromSelect = 0;/* Base register for data coming from SELECT */
  int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
  int regRowCount = 0;  /* Memory cell used for the row counter */
  int regIns;           /* Block of regs holding rowid+data being inserted */
  int regRowid;         /* registers holding insert rowid */
  int regData;          /* register holding first column to insert */
  int regEof = 0;       /* Register recording end of SELECT data */
  int *aRegIdx = 0;     /* One register allocated to each index */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                 /* True if attempting to insert into a view */
  Trigger *pTrigger;          /* List of triggers on pTab, if required */
  int tmask;                  /* Mask of trigger times */
#endif
................................................................................
  ** co-routine is the common header to the 3rd and 4th templates.
  */
  if( pSelect ){
    /* Data is coming from a SELECT.  Generate a co-routine to run the SELECT */
    int rc = sqlite3CodeCoroutine(pParse, pSelect, &dest);
    if( rc ) goto insert_cleanup;

    regEof = dest.iSDParm + 1;
    regFromSelect = dest.iSdst;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;
    assert( dest.nSdst==nColumn );

    /* Set useTempTable to TRUE if the result of the SELECT statement
    ** should be written into a temporary table (template 4).  Set to
................................................................................

    if( useTempTable ){
      /* Invoke the coroutine to extract information from the SELECT
      ** and add it to a transient table srcTab.  The code generated
      ** here is from the 4th template:
      **
      **      B: open temp table
      **      L: yield X
      **         if EOF goto M
      **         insert row from R..R+n into temp table
      **         goto L
      **      M: ...
      */
      int regRec;          /* Register to hold packed record */
      int regTempRowid;    /* Register to hold temp table ROWID */
      int addrTop;         /* Label "L" */
      int addrIf;          /* Address of jump to M */

      srcTab = pParse->nTab++;
      regRec = sqlite3GetTempReg(pParse);
      regTempRowid = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
      addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
      addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
      sqlite3VdbeJumpHere(v, addrIf);
      sqlite3ReleaseTempReg(pParse, regRec);
      sqlite3ReleaseTempReg(pParse, regTempRowid);
    }
  }else{
    /* This is the case if the data for the INSERT is coming from a VALUES
    ** clause
    */
................................................................................
  }

  /* This is the top of the main insertion loop */
  if( useTempTable ){
    /* This block codes the top of loop only.  The complete loop is the
    ** following pseudocode (template 4):
    **
    **         rewind temp table
    **      C: loop over rows of intermediate table
    **           transfer values form intermediate table into <table>
    **         end loop
    **      D: ...
    */
    addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab);
    addrCont = sqlite3VdbeCurrentAddr(v);
  }else if( pSelect ){
    /* This block codes the top of loop only.  The complete loop is the
    ** following pseudocode (template 3):
    **
    **      C: yield X
    **         if EOF goto D
    **         insert the select result into <table> from R..R+n
    **         goto C
    **      D: ...
    */
    addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
    addrInsTop = sqlite3VdbeAddOp1(v, OP_If, regEof);
  }

  /* Allocate registers for holding the rowid of the new row,
  ** the content of the new row, and the assemblied row record.
  */
  regRowid = regIns = pParse->nMem+1;
  pParse->nMem += pTab->nCol + 1;
................................................................................
    sqlite3VdbeAddOp2(v, OP_RowKey, iSrc, regData);
    sqlite3VdbeAddOp3(v, OP_IdxInsert, iDest, regData, 1);
    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
  }
  sqlite3VdbeJumpHere(v, emptySrcTest);
  sqlite3ReleaseTempReg(pParse, regRowid);
  sqlite3ReleaseTempReg(pParse, regData);
  if( emptyDestTest ){
    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
    sqlite3VdbeJumpHere(v, emptyDestTest);
    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
    return 0;
  }else{
    return 1;
  }
}
#endif /* SQLITE_OMIT_XFER_OPT */

**
** Registers are allocated as follows:
**
**   pDest->iSDParm      The register holding the next entry-point of the
**                       co-routine.  Run the co-routine to its next breakpoint
**                       by calling "OP_Yield $X" where $X is pDest->iSDParm.
**







**   pDest->iSdst        First result register.
**
**   pDest->nSdst        Number of result registers.
**
** At EOF the first result register will be marked as "undefined" so that
** the caller can know when to stop reading results.
**
** This routine handles all of the register allocation and fills in the
** pDest structure appropriately.
**
** Here is a schematic of the generated code assuming that X is the 
** co-routine entry-point register reg[pDest->iSDParm], that EOF is the
** completed flag reg[pDest->iSDParm+1], and R and S are the range of
** registers that hold the result set, reg[pDest->iSdst] through
** reg[pDest->iSdst+pDest->nSdst-1]:
**
**         X <- A

**         goto B
**      A: setup for the SELECT
**         loop rows in the SELECT
**           load results into registers R..S
**           yield X
**         end loop
**         cleanup after the SELECT

**         end co-routine R

**      B:
**
** To use this subroutine, the caller generates code as follows:
**
**         [ Co-routine generated by this subroutine, shown above ]
**      S: yield X, at EOF goto E

**         if skip this row, goto C
**         if terminate loop, goto E
**         deal with this row
**      C: goto S
**      E:
*/
int sqlite3CodeCoroutine(Parse *pParse, Select *pSelect, SelectDest *pDest){
  int regYield;       /* Register holding co-routine entry-point */

  int addrTop;        /* Top of the co-routine */

  int rc;             /* Result code */
  Vdbe *v;            /* VDBE under construction */

  regYield = ++pParse->nMem;

  v = sqlite3GetVdbe(pParse);
  addrTop = sqlite3VdbeCurrentAddr(v) + 1;




  sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
  sqlite3SelectDestInit(pDest, SRT_Coroutine, regYield);

  rc = sqlite3Select(pParse, pSelect, pDest);
  assert( pParse->nErr==0 || rc );
  if( pParse->db->mallocFailed && rc==SQLITE_OK ) rc = SQLITE_NOMEM;
  if( rc ) return rc;

  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regYield);


  sqlite3VdbeJumpHere(v, addrTop - 1);                       /* label B: */
  return rc;
}



/* Forward declaration */
static int xferOptimization(
................................................................................
**           close cursors
**         end foreach
**
** The 3rd template is for when the second template does not apply
** and the SELECT clause does not read from <table> at any time.
** The generated code follows this template:
**

**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the rows in the SELECT
**           load values into registers R..R+n
**           yield X
**         end loop
**         cleanup after the SELECT


**         end-coroutine X
**      B: open write cursor to <table> and its indices
**      C: yield X, at EOF goto D

**         insert the select result into <table> from R..R+n
**         goto C
**      D: cleanup
**
** The 4th template is used if the insert statement takes its
** values from a SELECT but the data is being inserted into a table
** that is also read as part of the SELECT.  In the third form,
** we have to use a intermediate table to store the results of
** the select.  The template is like this:
**

**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the tables in the SELECT
**           load value into register R..R+n
**           yield X
**         end loop
**         cleanup after the SELECT

**         end co-routine R

**      B: open temp table
**      L: yield X, at EOF goto M

**         insert row from R..R+n into temp table
**         goto L
**      M: open write cursor to <table> and its indices
**         rewind temp table
**      C: loop over rows of intermediate table
**           transfer values form intermediate table into <table>
**         end loop
................................................................................
  /* Register allocations */
  int regFromSelect = 0;/* Base register for data coming from SELECT */
  int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
  int regRowCount = 0;  /* Memory cell used for the row counter */
  int regIns;           /* Block of regs holding rowid+data being inserted */
  int regRowid;         /* registers holding insert rowid */
  int regData;          /* register holding first column to insert */

  int *aRegIdx = 0;     /* One register allocated to each index */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                 /* True if attempting to insert into a view */
  Trigger *pTrigger;          /* List of triggers on pTab, if required */
  int tmask;                  /* Mask of trigger times */
#endif
................................................................................
  ** co-routine is the common header to the 3rd and 4th templates.
  */
  if( pSelect ){
    /* Data is coming from a SELECT.  Generate a co-routine to run the SELECT */
    int rc = sqlite3CodeCoroutine(pParse, pSelect, &dest);
    if( rc ) goto insert_cleanup;


    regFromSelect = dest.iSdst;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;
    assert( dest.nSdst==nColumn );

    /* Set useTempTable to TRUE if the result of the SELECT statement
    ** should be written into a temporary table (template 4).  Set to
................................................................................

    if( useTempTable ){
      /* Invoke the coroutine to extract information from the SELECT
      ** and add it to a transient table srcTab.  The code generated
      ** here is from the 4th template:
      **
      **      B: open temp table
      **      L: yield X, goto M at EOF

      **         insert row from R..R+n into temp table
      **         goto L
      **      M: ...
      */
      int regRec;          /* Register to hold packed record */
      int regTempRowid;    /* Register to hold temp table ROWID */
      int addrTop;         /* Label "L" */


      srcTab = pParse->nTab++;
      regRec = sqlite3GetTempReg(pParse);
      regTempRowid = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
      addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);

      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
      sqlite3VdbeJumpHere(v, addrTop);
      sqlite3ReleaseTempReg(pParse, regRec);
      sqlite3ReleaseTempReg(pParse, regTempRowid);
    }
  }else{
    /* This is the case if the data for the INSERT is coming from a VALUES
    ** clause
    */
................................................................................
  }

  /* This is the top of the main insertion loop */
  if( useTempTable ){
    /* This block codes the top of loop only.  The complete loop is the
    ** following pseudocode (template 4):
    **
    **         rewind temp table, if empty goto D
    **      C: loop over rows of intermediate table
    **           transfer values form intermediate table into <table>
    **         end loop
    **      D: ...
    */
    addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab);
    addrCont = sqlite3VdbeCurrentAddr(v);
  }else if( pSelect ){
    /* This block codes the top of loop only.  The complete loop is the
    ** following pseudocode (template 3):
    **
    **      C: yield X, at EOF goto D

    **         insert the select result into <table> from R..R+n
    **         goto C
    **      D: ...
    */
    addrInsTop = addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);

  }

  /* Allocate registers for holding the rowid of the new row,
  ** the content of the new row, and the assemblied row record.
  */
  regRowid = regIns = pParse->nMem+1;
  pParse->nMem += pTab->nCol + 1;
................................................................................
    sqlite3VdbeAddOp2(v, OP_RowKey, iSrc, regData);
    sqlite3VdbeAddOp3(v, OP_IdxInsert, iDest, regData, 1);
    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
  }
  if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
  sqlite3ReleaseTempReg(pParse, regRowid);
  sqlite3ReleaseTempReg(pParse, regData);
  if( emptyDestTest ){
    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
    sqlite3VdbeJumpHere(v, emptyDestTest);
    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
    return 0;
  }else{
    return 1;
  }
}
#endif /* SQLITE_OMIT_XFER_OPT */

#  if defined(__RTP__) || defined(_WRS_KERNEL)
#    define OS_VXWORKS 1
#  else
#    define OS_VXWORKS 0
#  endif
#endif

/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks
** large file support, these should be no-ops.
**
** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
** on the compiler command line.  This is necessary if you are compiling
** on a recent machine (ex: RedHat 7.2) but you want your code to work
** on an older machine (ex: RedHat 6.0).  If you compile on RedHat 7.2
** without this option, LFS is enable.  But LFS does not exist in the kernel
** in RedHat 6.0, so the code won't work.  Hence, for maximum binary
** portability you should omit LFS.
**
** The previous paragraph was written in 2005.  (This paragraph is written
** on 2008-11-28.) These days, all Linux kernels support large files, so
** you should probably leave LFS enabled.  But some embedded platforms might
** lack LFS in which case the SQLITE_DISABLE_LFS macro might still be useful.
*/
#ifndef SQLITE_DISABLE_LFS
# define _LARGE_FILE       1
# ifndef _FILE_OFFSET_BITS
#   define _FILE_OFFSET_BITS 64
# endif
# define _LARGEFILE_SOURCE 1
#endif

/*
** standard include files.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#  if defined(__RTP__) || defined(_WRS_KERNEL)
#    define OS_VXWORKS 1
#  else
#    define OS_VXWORKS 0
#  endif
#endif



























/*
** standard include files.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

/* 
** Windows will only let you create file view mappings
** on allocation size granularity boundaries.
** During sqlite3_os_init() we do a GetSystemInfo()
** to get the granularity size.
*/
SYSTEM_INFO winSysInfo;

#ifndef SQLITE_OMIT_WAL

/*
** Helper functions to obtain and relinquish the global mutex. The
** global mutex is used to protect the winLockInfo objects used by 
** this file, all of which may be shared by multiple threads.

/* 
** Windows will only let you create file view mappings
** on allocation size granularity boundaries.
** During sqlite3_os_init() we do a GetSystemInfo()
** to get the granularity size.
*/
static SYSTEM_INFO winSysInfo;

#ifndef SQLITE_OMIT_WAL

/*
** Helper functions to obtain and relinquish the global mutex. The
** global mutex is used to protect the winLockInfo objects used by 
** this file, all of which may be shared by multiple threads.

/*
** Find a page in the hash table given its page number. Return
** a pointer to the page or NULL if the requested page is not 
** already in memory.
*/
static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
  PgHdr *p;                         /* Return value */

  /* It is not possible for a call to PcacheFetch() with createFlag==0 to
  ** fail, since no attempt to allocate dynamic memory will be made.
  */
  (void)sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &p);
  return p;
}

/*
** Find a page in the hash table given its page number. Return
** a pointer to the page or NULL if the requested page is not 
** already in memory.
*/
static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
  PgHdr *p = 0;                     /* Return value */

  /* It is not possible for a call to PcacheFetch() with createFlag==0 to
  ** fail, since no attempt to allocate dynamic memory will be made.
  */
  (void)sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &p);
  return p;
}

%type select {Select*}
%destructor select {sqlite3SelectDelete(pParse->db, $$);}
%type selectnowith {Select*}
%destructor selectnowith {sqlite3SelectDelete(pParse->db, $$);}
%type oneselect {Select*}
%destructor oneselect {sqlite3SelectDelete(pParse->db, $$);}

select(A) ::= with(W) selectnowith(X). { 

  if( X ){

    X->pWith = W; 











  }else{
    sqlite3WithDelete(pParse->db, W);
  }
  A = X; 
}

selectnowith(A) ::= oneselect(X).                      {A = X;}
%ifndef SQLITE_OMIT_COMPOUND_SELECT
selectnowith(A) ::= selectnowith(X) multiselect_op(Y) oneselect(Z).  {
  if( Z ){
    Z->op = (u8)Y;

%type select {Select*}
%destructor select {sqlite3SelectDelete(pParse->db, $$);}
%type selectnowith {Select*}
%destructor selectnowith {sqlite3SelectDelete(pParse->db, $$);}
%type oneselect {Select*}
%destructor oneselect {sqlite3SelectDelete(pParse->db, $$);}

select(A) ::= with(W) selectnowith(X). {
  Select *p = X, *pNext, *pLoop;
  if( p ){
    int cnt = 0, mxSelect;
    p->pWith = W;
    if( p->pPrior ){
      pNext = 0;
      for(pLoop=p; pLoop; pNext=pLoop, pLoop=pLoop->pPrior, cnt++){
        pLoop->pNext = pNext;
        pLoop->selFlags |= SF_Compound;
      }
      mxSelect = pParse->db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
      if( mxSelect && cnt>mxSelect ){
        sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
      }
    }
  }else{
    sqlite3WithDelete(pParse->db, W);
  }
  A = p;
}

selectnowith(A) ::= oneselect(X).                      {A = X;}
%ifndef SQLITE_OMIT_COMPOUND_SELECT
selectnowith(A) ::= selectnowith(X) multiselect_op(Y) oneselect(Z).  {
  if( Z ){
    Z->op = (u8)Y;

struct PCache {
  PgHdr *pDirty, *pDirtyTail;         /* List of dirty pages in LRU order */
  PgHdr *pSynced;                     /* Last synced page in dirty page list */
  int nRef;                           /* Number of referenced pages */
  int szCache;                        /* Configured cache size */
  int szPage;                         /* Size of every page in this cache */
  int szExtra;                        /* Size of extra space for each page */
  int bPurgeable;                     /* True if pages are on backing store */

  int (*xStress)(void*,PgHdr*);       /* Call to try make a page clean */
  void *pStress;                      /* Argument to xStress */
  sqlite3_pcache *pCache;             /* Pluggable cache module */
  PgHdr *pPage1;                      /* Reference to page 1 */
};

/*
................................................................................
    p->pDirtyTail = pPage->pDirtyPrev;
  }
  if( pPage->pDirtyPrev ){
    pPage->pDirtyPrev->pDirtyNext = pPage->pDirtyNext;
  }else{
    assert( pPage==p->pDirty );
    p->pDirty = pPage->pDirtyNext;




  }
  pPage->pDirtyNext = 0;
  pPage->pDirtyPrev = 0;

  expensive_assert( pcacheCheckSynced(p) );
}

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

  assert( pPage->pDirtyNext==0 && pPage->pDirtyPrev==0 && p->pDirty!=pPage );

  pPage->pDirtyNext = p->pDirty;
  if( pPage->pDirtyNext ){
    assert( pPage->pDirtyNext->pDirtyPrev==0 );
    pPage->pDirtyNext->pDirtyPrev = pPage;



  }
  p->pDirty = pPage;
  if( !p->pDirtyTail ){
    p->pDirtyTail = pPage;
  }
  if( !p->pSynced && 0==(pPage->flags&PGHDR_NEED_SYNC) ){
    p->pSynced = pPage;
................................................................................
  void *pStress,               /* Argument to xStress */
  PCache *p                    /* Preallocated space for the PCache */
){
  memset(p, 0, sizeof(PCache));
  p->szPage = szPage;
  p->szExtra = szExtra;
  p->bPurgeable = bPurgeable;

  p->xStress = xStress;
  p->pStress = pStress;
  p->szCache = 100;
}

/*
** Change the page size for PCache object. The caller must ensure that there
................................................................................
*/
int sqlite3PcacheFetch(
  PCache *pCache,       /* Obtain the page from this cache */
  Pgno pgno,            /* Page number to obtain */
  int createFlag,       /* If true, create page if it does not exist already */
  PgHdr **ppPage        /* Write the page here */
){
  sqlite3_pcache_page *pPage = 0;
  PgHdr *pPgHdr = 0;
  int eCreate;

  assert( pCache!=0 );
  assert( createFlag==1 || createFlag==0 );
  assert( pgno>0 );

  /* If the pluggable cache (sqlite3_pcache*) has not been allocated,
  ** allocate it now.
  */
  if( !pCache->pCache && createFlag ){
    sqlite3_pcache *p;




    p = sqlite3GlobalConfig.pcache2.xCreate(
        pCache->szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable
    );
    if( !p ){
      return SQLITE_NOMEM;
    }
    sqlite3GlobalConfig.pcache2.xCachesize(p, numberOfCachePages(pCache));
    pCache->pCache = p;
  }

  eCreate = createFlag * (1 + (!pCache->bPurgeable || !pCache->pDirty));
  if( pCache->pCache ){







    pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
  }

  if( !pPage && eCreate==1 ){
    PgHdr *pPg;

    /* Find a dirty page to write-out and recycle. First try to find a 
    ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
    ** cleared), but if that is not possible settle for any other 
    ** unreferenced dirty page.

struct PCache {
  PgHdr *pDirty, *pDirtyTail;         /* List of dirty pages in LRU order */
  PgHdr *pSynced;                     /* Last synced page in dirty page list */
  int nRef;                           /* Number of referenced pages */
  int szCache;                        /* Configured cache size */
  int szPage;                         /* Size of every page in this cache */
  int szExtra;                        /* Size of extra space for each page */
  u8 bPurgeable;                      /* True if pages are on backing store */
  u8 eCreate;                         /* eCreate value for for xFetch() */
  int (*xStress)(void*,PgHdr*);       /* Call to try make a page clean */
  void *pStress;                      /* Argument to xStress */
  sqlite3_pcache *pCache;             /* Pluggable cache module */
  PgHdr *pPage1;                      /* Reference to page 1 */
};

/*
................................................................................
    p->pDirtyTail = pPage->pDirtyPrev;
  }
  if( pPage->pDirtyPrev ){
    pPage->pDirtyPrev->pDirtyNext = pPage->pDirtyNext;
  }else{
    assert( pPage==p->pDirty );
    p->pDirty = pPage->pDirtyNext;
    if( p->pDirty==0 && p->bPurgeable ){
      assert( p->eCreate==1 );
      p->eCreate = 2;
    }
  }
  pPage->pDirtyNext = 0;
  pPage->pDirtyPrev = 0;

  expensive_assert( pcacheCheckSynced(p) );
}

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

  assert( pPage->pDirtyNext==0 && pPage->pDirtyPrev==0 && p->pDirty!=pPage );

  pPage->pDirtyNext = p->pDirty;
  if( pPage->pDirtyNext ){
    assert( pPage->pDirtyNext->pDirtyPrev==0 );
    pPage->pDirtyNext->pDirtyPrev = pPage;
  }else if( p->bPurgeable ){
    assert( p->eCreate==2 );
    p->eCreate = 1;
  }
  p->pDirty = pPage;
  if( !p->pDirtyTail ){
    p->pDirtyTail = pPage;
  }
  if( !p->pSynced && 0==(pPage->flags&PGHDR_NEED_SYNC) ){
    p->pSynced = pPage;
................................................................................
  void *pStress,               /* Argument to xStress */
  PCache *p                    /* Preallocated space for the PCache */
){
  memset(p, 0, sizeof(PCache));
  p->szPage = szPage;
  p->szExtra = szExtra;
  p->bPurgeable = bPurgeable;
  p->eCreate = 2;
  p->xStress = xStress;
  p->pStress = pStress;
  p->szCache = 100;
}

/*
** Change the page size for PCache object. The caller must ensure that there
................................................................................
*/
int sqlite3PcacheFetch(
  PCache *pCache,       /* Obtain the page from this cache */
  Pgno pgno,            /* Page number to obtain */
  int createFlag,       /* If true, create page if it does not exist already */
  PgHdr **ppPage        /* Write the page here */
){
  sqlite3_pcache_page *pPage;
  PgHdr *pPgHdr = 0;
  int eCreate;

  assert( pCache!=0 );
  assert( createFlag==1 || createFlag==0 );
  assert( pgno>0 );

  /* If the pluggable cache (sqlite3_pcache*) has not been allocated,
  ** allocate it now.
  */
  if( !pCache->pCache ){
    sqlite3_pcache *p;
    if( !createFlag ){
      *ppPage = 0;
      return SQLITE_OK;
    }
    p = sqlite3GlobalConfig.pcache2.xCreate(
        pCache->szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable
    );
    if( !p ){
      return SQLITE_NOMEM;
    }
    sqlite3GlobalConfig.pcache2.xCachesize(p, numberOfCachePages(pCache));
    pCache->pCache = p;
  }

  /* eCreate defines what to do if the page does not exist.
  **    0     Do not allocate a new page.  (createFlag==0)
  **    1     Allocate a new page if doing so is inexpensive.
  **          (createFlag==1 AND bPurgeable AND pDirty)
  **    2     Allocate a new page even it doing so is difficult.
  **          (createFlag==1 AND !(bPurgeable AND pDirty)
  */
  eCreate = createFlag==0 ? 0 : pCache->eCreate;
  assert( (createFlag*(1+(!pCache->bPurgeable||!pCache->pDirty)))==eCreate );
  pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);


  if( !pPage && eCreate==1 ){
    PgHdr *pPg;

    /* Find a dirty page to write-out and recycle. First try to find a 
    ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
    ** cleared), but if that is not possible settle for any other 
    ** unreferenced dirty page.

*/
void sqlite3SelectDelete(sqlite3 *db, Select *p){
  if( p ){
    clearSelect(db, p);
    sqlite3DbFree(db, p);
  }
}









/*
** Given 1 to 3 identifiers preceding the JOIN keyword, determine the
** type of join.  Return an integer constant that expresses that type
** in terms of the following bit values:
**
**     JT_INNER
................................................................................
        sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
        /* The LIMIT clause will jump out of the loop for us */
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* Send the data to the callback function or to a subroutine.  In the
    ** case of a subroutine, the subroutine itself is responsible for
    ** popping the data from the stack.
    */
    case SRT_Coroutine:
    case SRT_Output: {
      testcase( eDest==SRT_Coroutine );
      testcase( eDest==SRT_Output );
      if( pOrderBy ){
        int r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1);
        pushOntoSorter(pParse, pOrderBy, p, r1);
        sqlite3ReleaseTempReg(pParse, r1);
................................................................................
** Get a VDBE for the given parser context.  Create a new one if necessary.
** If an error occurs, return NULL and leave a message in pParse.
*/
Vdbe *sqlite3GetVdbe(Parse *pParse){
  Vdbe *v = pParse->pVdbe;
  if( v==0 ){
    v = pParse->pVdbe = sqlite3VdbeCreate(pParse);
#ifndef SQLITE_OMIT_TRACE
    if( v ){
      sqlite3VdbeAddOp0(v, OP_Trace);




    }
#endif

  }
  return v;
}


/*
** Compute the iLimit and iOffset fields of the SELECT based on the
................................................................................
    p->selFlags |= SF_UsesEphemeral;
  }

  /* Detach the ORDER BY clause from the compound SELECT */
  p->pOrderBy = 0;

  /* Store the results of the setup-query in Queue. */

  rc = sqlite3Select(pParse, pSetup, &destQueue);

  if( rc ) goto end_of_recursive_query;

  /* Find the next row in the Queue and output that row */
  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iQueue, addrBreak);

  /* Transfer the next row in Queue over to Current */
  sqlite3VdbeAddOp1(v, OP_NullRow, iCurrent); /* To reset column cache */
................................................................................
  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
  */
  assert( p && p->pPrior );  /* Calling function guarantees this much */
  assert( (p->selFlags & SF_Recursive)==0 || p->op==TK_ALL || p->op==TK_UNION );
  db = pParse->db;
  pPrior = p->pPrior;
  assert( pPrior->pRightmost!=pPrior );
  assert( pPrior->pRightmost==p->pRightmost );
  dest = *pDest;
  if( pPrior->pOrderBy ){
    sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
      selectOpName(p->op));
    rc = 1;
    goto multi_select_end;
  }
................................................................................
      Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
      int addr;
      SelectDest uniondest;

      testcase( p->op==TK_EXCEPT );
      testcase( p->op==TK_UNION );
      priorOp = SRT_Union;
      if( dest.eDest==priorOp && ALWAYS(!p->pLimit &&!p->pOffset) ){
        /* We can reuse a temporary table generated by a SELECT to our
        ** right.
        */
        assert( p->pRightmost!=p );  /* Can only happen for leftward elements
                                     ** of a 3-way or more compound */
        assert( p->pLimit==0 );      /* Not allowed on leftward elements */
        assert( p->pOffset==0 );     /* Not allowed on leftward elements */
        unionTab = dest.iSDParm;
      }else{
        /* We will need to create our own temporary table to hold the
        ** intermediate results.
        */
        unionTab = pParse->nTab++;
        assert( p->pOrderBy==0 );
        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
        assert( p->addrOpenEphm[0] == -1 );
        p->addrOpenEphm[0] = addr;
        p->pRightmost->selFlags |= SF_UsesEphemeral;
        assert( p->pEList );
      }

      /* Code the SELECT statements to our left
      */
      assert( !pPrior->pOrderBy );
      sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
................................................................................
      tab1 = pParse->nTab++;
      tab2 = pParse->nTab++;
      assert( p->pOrderBy==0 );

      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
      assert( p->addrOpenEphm[0] == -1 );
      p->addrOpenEphm[0] = addr;
      p->pRightmost->selFlags |= SF_UsesEphemeral;
      assert( p->pEList );

      /* Code the SELECTs to our left into temporary table "tab1".
      */
      sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
      explainSetInteger(iSub1, pParse->iNextSelectId);
      rc = sqlite3Select(pParse, pPrior, &intersectdest);
................................................................................
  if( p->selFlags & SF_UsesEphemeral ){
    int i;                        /* Loop counter */
    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
    Select *pLoop;                /* For looping through SELECT statements */
    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */
    int nCol;                     /* Number of columns in result set */

    assert( p->pRightmost==p );
    nCol = p->pEList->nExpr;
    pKeyInfo = sqlite3KeyInfoAlloc(db, nCol, 1);
    if( !pKeyInfo ){
      rc = SQLITE_NOMEM;
      goto multi_select_end;
    }
    for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
................................................................................
){
  int i, j;             /* Loop counters */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  SelectDest destA;     /* Destination for coroutine A */
  SelectDest destB;     /* Destination for coroutine B */
  int regAddrA;         /* Address register for select-A coroutine */
  int regEofA;          /* Flag to indicate when select-A is complete */
  int regAddrB;         /* Address register for select-B coroutine */
  int regEofB;          /* Flag to indicate when select-B is complete */
  int addrSelectA;      /* Address of the select-A coroutine */
  int addrSelectB;      /* Address of the select-B coroutine */
  int regOutA;          /* Address register for the output-A subroutine */
  int regOutB;          /* Address register for the output-B subroutine */
  int addrOutA;         /* Address of the output-A subroutine */
  int addrOutB = 0;     /* Address of the output-B subroutine */
  int addrEofA;         /* Address of the select-A-exhausted subroutine */

  int addrEofB;         /* Address of the select-B-exhausted subroutine */
  int addrAltB;         /* Address of the A<B subroutine */
  int addrAeqB;         /* Address of the A==B subroutine */
  int addrAgtB;         /* Address of the A>B subroutine */
  int regLimitA;        /* Limit register for select-A */
  int regLimitB;        /* Limit register for select-A */
  int regPrev;          /* A range of registers to hold previous output */
................................................................................
      }
    }
  }
 
  /* Separate the left and the right query from one another
  */
  p->pPrior = 0;

  sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
  if( pPrior->pPrior==0 ){
    sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
  }

  /* Compute the limit registers */
  computeLimitRegisters(pParse, p, labelEnd);
................................................................................
  }
  sqlite3ExprDelete(db, p->pLimit);
  p->pLimit = 0;
  sqlite3ExprDelete(db, p->pOffset);
  p->pOffset = 0;

  regAddrA = ++pParse->nMem;
  regEofA = ++pParse->nMem;
  regAddrB = ++pParse->nMem;
  regEofB = ++pParse->nMem;
  regOutA = ++pParse->nMem;
  regOutB = ++pParse->nMem;
  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);

  /* Jump past the various subroutines and coroutines to the main
  ** merge loop
  */
  j1 = sqlite3VdbeAddOp0(v, OP_Goto);
  addrSelectA = sqlite3VdbeCurrentAddr(v);


  /* Generate a coroutine to evaluate the SELECT statement to the
  ** left of the compound operator - the "A" select.
  */
  VdbeNoopComment((v, "Begin coroutine for left SELECT"));


  pPrior->iLimit = regLimitA;
  explainSetInteger(iSub1, pParse->iNextSelectId);
  sqlite3Select(pParse, pPrior, &destA);
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  VdbeNoopComment((v, "End coroutine for left SELECT"));

  /* Generate a coroutine to evaluate the SELECT statement on 
  ** the right - the "B" select
  */
  addrSelectB = sqlite3VdbeCurrentAddr(v);
  VdbeNoopComment((v, "Begin coroutine for right SELECT"));

  savedLimit = p->iLimit;
  savedOffset = p->iOffset;
  p->iLimit = regLimitB;
  p->iOffset = 0;  
  explainSetInteger(iSub2, pParse->iNextSelectId);
  sqlite3Select(pParse, p, &destB);
  p->iLimit = savedLimit;
  p->iOffset = savedOffset;
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  VdbeNoopComment((v, "End coroutine for right SELECT"));

  /* Generate a subroutine that outputs the current row of the A
  ** select as the next output row of the compound select.
  */
  VdbeNoopComment((v, "Output routine for A"));
  addrOutA = generateOutputSubroutine(pParse,
                 p, &destA, pDest, regOutA,
................................................................................
                 regPrev, pKeyDup, labelEnd);
  }
  sqlite3KeyInfoUnref(pKeyDup);

  /* Generate a subroutine to run when the results from select A
  ** are exhausted and only data in select B remains.
  */
  VdbeNoopComment((v, "eof-A subroutine"));
  if( op==TK_EXCEPT || op==TK_INTERSECT ){
    addrEofA = sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
  }else{  
    addrEofA = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
    sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
    p->nSelectRow += pPrior->nSelectRow;
  }

  /* Generate a subroutine to run when the results from select B
  ** are exhausted and only data in select A remains.
  */
  if( op==TK_INTERSECT ){
    addrEofB = addrEofA;
    if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
  }else{  
    VdbeNoopComment((v, "eof-B subroutine"));
    addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
    sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
  }

  /* Generate code to handle the case of A<B
  */
  VdbeNoopComment((v, "A-lt-B subroutine"));
  addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);

  /* Generate code to handle the case of A==B
  */
  if( op==TK_ALL ){
    addrAeqB = addrAltB;
  }else if( op==TK_INTERSECT ){
    addrAeqB = addrAltB;
    addrAltB++;
  }else{
    VdbeNoopComment((v, "A-eq-B subroutine"));
    addrAeqB =
    sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
    sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
  }

  /* Generate code to handle the case of A>B
  */
  VdbeNoopComment((v, "A-gt-B subroutine"));
  addrAgtB = sqlite3VdbeCurrentAddr(v);
  if( op==TK_ALL || op==TK_UNION ){
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
  }
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);

  /* This code runs once to initialize everything.
  */
  sqlite3VdbeJumpHere(v, j1);
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofA);
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofB);
  sqlite3VdbeAddOp2(v, OP_Gosub, regAddrA, addrSelectA);
  sqlite3VdbeAddOp2(v, OP_Gosub, regAddrB, addrSelectB);
  sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
  sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);

  /* Implement the main merge loop
  */
  sqlite3VdbeResolveLabel(v, labelCmpr);
  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
  sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy,
                         (char*)pKeyMerge, P4_KEYINFO);
................................................................................

  /* Reassembly the compound query so that it will be freed correctly
  ** by the calling function */
  if( p->pPrior ){
    sqlite3SelectDelete(db, p->pPrior);
  }
  p->pPrior = pPrior;


  /*** TBD:  Insert subroutine calls to close cursors on incomplete
  **** subqueries ****/
  explainComposite(pParse, p->op, iSub1, iSub2, 0);
  return SQLITE_OK;
}
#endif
................................................................................
  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
  ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
  ** because they could be computed at compile-time.  But when LIMIT and OFFSET
  ** became arbitrary expressions, we were forced to add restrictions (13)
  ** and (14). */
  if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
  if( pSub->pOffset ) return 0;                          /* Restriction (14) */
  if( p->pRightmost && pSub->pLimit ){
    return 0;                                            /* Restriction (15) */
  }
  if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
  if( pSub->selFlags & SF_Distinct ) return 0;           /* Restriction (5)  */
  if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
     return 0;         /* Restrictions (8)(9) */
  }
................................................................................
    p->pOffset = 0;
    pNew = sqlite3SelectDup(db, p, 0);
    p->pOffset = pOffset;
    p->pLimit = pLimit;
    p->pOrderBy = pOrderBy;
    p->pSrc = pSrc;
    p->op = TK_ALL;
    p->pRightmost = 0;
    if( pNew==0 ){
      pNew = pPrior;
    }else{
      pNew->pPrior = pPrior;

      pNew->pRightmost = 0;
    }
    p->pPrior = pNew;

    if( db->mallocFailed ) return 1;
  }

  /* Begin flattening the iFrom-th entry of the FROM clause 
  ** in the outer query.
  */
  pSub = pSub1 = pSubitem->pSelect;
................................................................................
  p->pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ALL, 0));
  p->op = TK_SELECT;
  p->pWhere = 0;
  pNew->pGroupBy = 0;
  pNew->pHaving = 0;
  pNew->pOrderBy = 0;
  p->pPrior = 0;




  pNew->pLimit = 0;
  pNew->pOffset = 0;
  return WRC_Continue;
}

#ifndef SQLITE_OMIT_CTE
/*
................................................................................
**
** This function is used as the xSelectCallback2() callback by
** sqlite3SelectExpand() when walking a SELECT tree to resolve table
** names and other FROM clause elements. 
*/
static void selectPopWith(Walker *pWalker, Select *p){
  Parse *pParse = pWalker->pParse;
  if( p->pWith ){

    assert( pParse->pWith==p->pWith );
    pParse->pWith = p->pWith->pOuter;
  }
}
#else
#define selectPopWith 0
#endif

/*
................................................................................
    return WRC_Abort;
  }
  if( NEVER(p->pSrc==0) || (selFlags & SF_Expanded)!=0 ){
    return WRC_Prune;
  }
  pTabList = p->pSrc;
  pEList = p->pEList;
  sqlite3WithPush(pParse, p->pWith, 0);

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, pTabList);

  /* Look up every table named in the FROM clause of the select.  If
................................................................................
    if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
      /* This subquery can be absorbed into its parent. */
      if( isAggSub ){
        isAgg = 1;
        p->selFlags |= SF_Aggregate;
      }
      i = -1;
    }else if( pTabList->nSrc==1 && (p->selFlags & SF_Materialize)==0
      && OptimizationEnabled(db, SQLITE_SubqCoroutine)
    ){
      /* Implement a co-routine that will return a single row of the result
      ** set on each invocation.
      */
      int addrTop;
      int addrEof;
      pItem->regReturn = ++pParse->nMem;
      addrEof = ++pParse->nMem;
      /* Before coding the OP_Goto to jump to the start of the main routine,
      ** ensure that the jump to the verify-schema routine has already
      ** been coded. Otherwise, the verify-schema would likely be coded as 
      ** part of the co-routine. If the main routine then accessed the 
      ** database before invoking the co-routine for the first time (for 
      ** example to initialize a LIMIT register from a sub-select), it would 
      ** be doing so without having verified the schema version and obtained 
      ** the required db locks. See ticket d6b36be38.  */
      sqlite3CodeVerifySchema(pParse, -1);
      sqlite3VdbeAddOp0(v, OP_Goto);
      addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor);
      sqlite3VdbeChangeP5(v, 1);

      VdbeComment((v, "coroutine for %s", pItem->pTab->zName));
      pItem->addrFillSub = addrTop;
      sqlite3VdbeAddOp2(v, OP_Integer, 0, addrEof);
      sqlite3VdbeChangeP5(v, 1);
      sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn);
      explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
      sqlite3Select(pParse, pSub, &dest);
      pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
      pItem->viaCoroutine = 1;
      sqlite3VdbeChangeP2(v, addrTop, dest.iSdst);
      sqlite3VdbeChangeP3(v, addrTop, dest.nSdst);
      sqlite3VdbeAddOp2(v, OP_Integer, 1, addrEof);
      sqlite3VdbeAddOp1(v, OP_Yield, pItem->regReturn);
      VdbeComment((v, "end %s", pItem->pTab->zName));
      sqlite3VdbeJumpHere(v, addrTop-1);
      sqlite3ClearTempRegCache(pParse);
    }else{
      /* Generate a subroutine that will fill an ephemeral table with
      ** the content of this subquery.  pItem->addrFillSub will point
      ** to the address of the generated subroutine.  pItem->regReturn
      ** is a register allocated to hold the subroutine return address
................................................................................
      int topAddr;
      int onceAddr = 0;
      int retAddr;
      assert( pItem->addrFillSub==0 );
      pItem->regReturn = ++pParse->nMem;
      topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn);
      pItem->addrFillSub = topAddr+1;
      VdbeNoopComment((v, "materialize %s", pItem->pTab->zName));
      if( pItem->isCorrelated==0 ){
        /* If the subquery is not correlated and if we are not inside of
        ** a trigger, then we only need to compute the value of the subquery
        ** once. */
        onceAddr = sqlite3CodeOnce(pParse);



      }
      sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
      explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
      sqlite3Select(pParse, pSub, &dest);
      pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
      if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
      retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
................................................................................
  pHaving = p->pHaving;
  sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0;

#ifndef SQLITE_OMIT_COMPOUND_SELECT
  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){
    if( p->pRightmost==0 ){
      Select *pLoop, *pRight = 0;
      int cnt = 0;
      int mxSelect;
      for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
        pLoop->pRightmost = p;
        pLoop->pNext = pRight;
        pRight = pLoop;
      }
      mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
      if( mxSelect && cnt>mxSelect ){
        sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
        goto select_end;
      }
    }
    rc = multiSelect(pParse, p, pDest);
    explainSetInteger(pParse->iSelectId, iRestoreSelectId);
    return rc;
  }
#endif

  /* If there is both a GROUP BY and an ORDER BY clause and they are
................................................................................
  }
}
void sqlite3ExplainSelect(Vdbe *pVdbe, Select *p){
  if( p==0 ){
    sqlite3ExplainPrintf(pVdbe, "(null-select)");
    return;
  }
  while( p->pPrior ){
    p->pPrior->pNext = p;
    p = p->pPrior;
  }
  sqlite3ExplainPush(pVdbe);
  while( p ){
    explainOneSelect(pVdbe, p);
    p = p->pNext;
    if( p==0 ) break;
    sqlite3ExplainNL(pVdbe);
    sqlite3ExplainPrintf(pVdbe, "%s\n", selectOpName(p->op));

*/
void sqlite3SelectDelete(sqlite3 *db, Select *p){
  if( p ){
    clearSelect(db, p);
    sqlite3DbFree(db, p);
  }
}

/*
** Return a pointer to the right-most SELECT statement in a compound.
*/
static Select *findRightmost(Select *p){
  while( p->pNext ) p = p->pNext;
  return p;
}

/*
** Given 1 to 3 identifiers preceding the JOIN keyword, determine the
** type of join.  Return an integer constant that expresses that type
** in terms of the following bit values:
**
**     JT_INNER
................................................................................
        sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
        /* The LIMIT clause will jump out of the loop for us */
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */





    case SRT_Coroutine:       /* Send data to a co-routine */
    case SRT_Output: {        /* Return the results */
      testcase( eDest==SRT_Coroutine );
      testcase( eDest==SRT_Output );
      if( pOrderBy ){
        int r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1);
        pushOntoSorter(pParse, pOrderBy, p, r1);
        sqlite3ReleaseTempReg(pParse, r1);
................................................................................
** Get a VDBE for the given parser context.  Create a new one if necessary.
** If an error occurs, return NULL and leave a message in pParse.
*/
Vdbe *sqlite3GetVdbe(Parse *pParse){
  Vdbe *v = pParse->pVdbe;
  if( v==0 ){
    v = pParse->pVdbe = sqlite3VdbeCreate(pParse);


    if( v ) sqlite3VdbeAddOp0(v, OP_Init);
    if( pParse->pToplevel==0
     && OptimizationEnabled(pParse->db,SQLITE_FactorOutConst)
    ){
      pParse->okConstFactor = 1;
    }


  }
  return v;
}


/*
** Compute the iLimit and iOffset fields of the SELECT based on the
................................................................................
    p->selFlags |= SF_UsesEphemeral;
  }

  /* Detach the ORDER BY clause from the compound SELECT */
  p->pOrderBy = 0;

  /* Store the results of the setup-query in Queue. */
  pSetup->pNext = 0;
  rc = sqlite3Select(pParse, pSetup, &destQueue);
  pSetup->pNext = p;
  if( rc ) goto end_of_recursive_query;

  /* Find the next row in the Queue and output that row */
  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iQueue, addrBreak);

  /* Transfer the next row in Queue over to Current */
  sqlite3VdbeAddOp1(v, OP_NullRow, iCurrent); /* To reset column cache */
................................................................................
  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
  */
  assert( p && p->pPrior );  /* Calling function guarantees this much */
  assert( (p->selFlags & SF_Recursive)==0 || p->op==TK_ALL || p->op==TK_UNION );
  db = pParse->db;
  pPrior = p->pPrior;


  dest = *pDest;
  if( pPrior->pOrderBy ){
    sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
      selectOpName(p->op));
    rc = 1;
    goto multi_select_end;
  }
................................................................................
      Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
      int addr;
      SelectDest uniondest;

      testcase( p->op==TK_EXCEPT );
      testcase( p->op==TK_UNION );
      priorOp = SRT_Union;
      if( dest.eDest==priorOp ){
        /* We can reuse a temporary table generated by a SELECT to our
        ** right.
        */


        assert( p->pLimit==0 );      /* Not allowed on leftward elements */
        assert( p->pOffset==0 );     /* Not allowed on leftward elements */
        unionTab = dest.iSDParm;
      }else{
        /* We will need to create our own temporary table to hold the
        ** intermediate results.
        */
        unionTab = pParse->nTab++;
        assert( p->pOrderBy==0 );
        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
        assert( p->addrOpenEphm[0] == -1 );
        p->addrOpenEphm[0] = addr;
        findRightmost(p)->selFlags |= SF_UsesEphemeral;
        assert( p->pEList );
      }

      /* Code the SELECT statements to our left
      */
      assert( !pPrior->pOrderBy );
      sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
................................................................................
      tab1 = pParse->nTab++;
      tab2 = pParse->nTab++;
      assert( p->pOrderBy==0 );

      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
      assert( p->addrOpenEphm[0] == -1 );
      p->addrOpenEphm[0] = addr;
      findRightmost(p)->selFlags |= SF_UsesEphemeral;
      assert( p->pEList );

      /* Code the SELECTs to our left into temporary table "tab1".
      */
      sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
      explainSetInteger(iSub1, pParse->iNextSelectId);
      rc = sqlite3Select(pParse, pPrior, &intersectdest);
................................................................................
  if( p->selFlags & SF_UsesEphemeral ){
    int i;                        /* Loop counter */
    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
    Select *pLoop;                /* For looping through SELECT statements */
    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */
    int nCol;                     /* Number of columns in result set */

    assert( p->pNext==0 );
    nCol = p->pEList->nExpr;
    pKeyInfo = sqlite3KeyInfoAlloc(db, nCol, 1);
    if( !pKeyInfo ){
      rc = SQLITE_NOMEM;
      goto multi_select_end;
    }
    for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
................................................................................
){
  int i, j;             /* Loop counters */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  SelectDest destA;     /* Destination for coroutine A */
  SelectDest destB;     /* Destination for coroutine B */
  int regAddrA;         /* Address register for select-A coroutine */

  int regAddrB;         /* Address register for select-B coroutine */

  int addrSelectA;      /* Address of the select-A coroutine */
  int addrSelectB;      /* Address of the select-B coroutine */
  int regOutA;          /* Address register for the output-A subroutine */
  int regOutB;          /* Address register for the output-B subroutine */
  int addrOutA;         /* Address of the output-A subroutine */
  int addrOutB = 0;     /* Address of the output-B subroutine */
  int addrEofA;         /* Address of the select-A-exhausted subroutine */
  int addrEofA_noB;     /* Alternate addrEofA if B is uninitialized */
  int addrEofB;         /* Address of the select-B-exhausted subroutine */
  int addrAltB;         /* Address of the A<B subroutine */
  int addrAeqB;         /* Address of the A==B subroutine */
  int addrAgtB;         /* Address of the A>B subroutine */
  int regLimitA;        /* Limit register for select-A */
  int regLimitB;        /* Limit register for select-A */
  int regPrev;          /* A range of registers to hold previous output */
................................................................................
      }
    }
  }
 
  /* Separate the left and the right query from one another
  */
  p->pPrior = 0;
  pPrior->pNext = 0;
  sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
  if( pPrior->pPrior==0 ){
    sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
  }

  /* Compute the limit registers */
  computeLimitRegisters(pParse, p, labelEnd);
................................................................................
  }
  sqlite3ExprDelete(db, p->pLimit);
  p->pLimit = 0;
  sqlite3ExprDelete(db, p->pOffset);
  p->pOffset = 0;

  regAddrA = ++pParse->nMem;

  regAddrB = ++pParse->nMem;

  regOutA = ++pParse->nMem;
  regOutB = ++pParse->nMem;
  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);








  /* Generate a coroutine to evaluate the SELECT statement to the
  ** left of the compound operator - the "A" select.
  */
  addrSelectA = sqlite3VdbeCurrentAddr(v) + 1;
  j1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrA, 0, addrSelectA);
  VdbeComment((v, "left SELECT"));
  pPrior->iLimit = regLimitA;
  explainSetInteger(iSub1, pParse->iNextSelectId);
  sqlite3Select(pParse, pPrior, &destA);
  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regAddrA);
  sqlite3VdbeJumpHere(v, j1);


  /* Generate a coroutine to evaluate the SELECT statement on 
  ** the right - the "B" select
  */
  addrSelectB = sqlite3VdbeCurrentAddr(v) + 1;
  j1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrB, 0, addrSelectB);
  VdbeComment((v, "right SELECT"));
  savedLimit = p->iLimit;
  savedOffset = p->iOffset;
  p->iLimit = regLimitB;
  p->iOffset = 0;  
  explainSetInteger(iSub2, pParse->iNextSelectId);
  sqlite3Select(pParse, p, &destB);
  p->iLimit = savedLimit;
  p->iOffset = savedOffset;

  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regAddrB);


  /* Generate a subroutine that outputs the current row of the A
  ** select as the next output row of the compound select.
  */
  VdbeNoopComment((v, "Output routine for A"));
  addrOutA = generateOutputSubroutine(pParse,
                 p, &destA, pDest, regOutA,
................................................................................
                 regPrev, pKeyDup, labelEnd);
  }
  sqlite3KeyInfoUnref(pKeyDup);

  /* Generate a subroutine to run when the results from select A
  ** are exhausted and only data in select B remains.
  */
  if( op==TK_EXCEPT || op==TK_INTERSECT ){
    addrEofA_noB = addrEofA = labelEnd;
  }else{  
    VdbeNoopComment((v, "eof-A subroutine"));
    addrEofA = sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
    addrEofA_noB = sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, labelEnd);

    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
    p->nSelectRow += pPrior->nSelectRow;
  }

  /* Generate a subroutine to run when the results from select B
  ** are exhausted and only data in select A remains.
  */
  if( op==TK_INTERSECT ){
    addrEofB = addrEofA;
    if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
  }else{  
    VdbeNoopComment((v, "eof-B subroutine"));

    addrEofB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
    sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, labelEnd);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
  }

  /* Generate code to handle the case of A<B
  */
  VdbeNoopComment((v, "A-lt-B subroutine"));
  addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);

  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);

  /* Generate code to handle the case of A==B
  */
  if( op==TK_ALL ){
    addrAeqB = addrAltB;
  }else if( op==TK_INTERSECT ){
    addrAeqB = addrAltB;
    addrAltB++;
  }else{
    VdbeNoopComment((v, "A-eq-B subroutine"));
    addrAeqB =

    sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
  }

  /* Generate code to handle the case of A>B
  */
  VdbeNoopComment((v, "A-gt-B subroutine"));
  addrAgtB = sqlite3VdbeCurrentAddr(v);
  if( op==TK_ALL || op==TK_UNION ){
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
  }

  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);

  /* This code runs once to initialize everything.
  */
  sqlite3VdbeJumpHere(v, j1);
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA_noB);
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB);





  /* Implement the main merge loop
  */
  sqlite3VdbeResolveLabel(v, labelCmpr);
  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
  sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy,
                         (char*)pKeyMerge, P4_KEYINFO);
................................................................................

  /* Reassembly the compound query so that it will be freed correctly
  ** by the calling function */
  if( p->pPrior ){
    sqlite3SelectDelete(db, p->pPrior);
  }
  p->pPrior = pPrior;
  pPrior->pNext = p;

  /*** TBD:  Insert subroutine calls to close cursors on incomplete
  **** subqueries ****/
  explainComposite(pParse, p->op, iSub1, iSub2, 0);
  return SQLITE_OK;
}
#endif
................................................................................
  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
  ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
  ** because they could be computed at compile-time.  But when LIMIT and OFFSET
  ** became arbitrary expressions, we were forced to add restrictions (13)
  ** and (14). */
  if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
  if( pSub->pOffset ) return 0;                          /* Restriction (14) */
  if( (p->selFlags & SF_Compound)!=0 && pSub->pLimit ){
    return 0;                                            /* Restriction (15) */
  }
  if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
  if( pSub->selFlags & SF_Distinct ) return 0;           /* Restriction (5)  */
  if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
     return 0;         /* Restrictions (8)(9) */
  }
................................................................................
    p->pOffset = 0;
    pNew = sqlite3SelectDup(db, p, 0);
    p->pOffset = pOffset;
    p->pLimit = pLimit;
    p->pOrderBy = pOrderBy;
    p->pSrc = pSrc;
    p->op = TK_ALL;

    if( pNew==0 ){
      p->pPrior = pPrior;
    }else{
      pNew->pPrior = pPrior;
      if( pPrior ) pPrior->pNext = pNew;
      pNew->pNext = p;

      p->pPrior = pNew;
    }
    if( db->mallocFailed ) return 1;
  }

  /* Begin flattening the iFrom-th entry of the FROM clause 
  ** in the outer query.
  */
  pSub = pSub1 = pSubitem->pSelect;
................................................................................
  p->pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ALL, 0));
  p->op = TK_SELECT;
  p->pWhere = 0;
  pNew->pGroupBy = 0;
  pNew->pHaving = 0;
  pNew->pOrderBy = 0;
  p->pPrior = 0;
  p->pNext = 0;
  p->selFlags &= ~SF_Compound;
  assert( pNew->pPrior!=0 );
  pNew->pPrior->pNext = pNew;
  pNew->pLimit = 0;
  pNew->pOffset = 0;
  return WRC_Continue;
}

#ifndef SQLITE_OMIT_CTE
/*
................................................................................
**
** This function is used as the xSelectCallback2() callback by
** sqlite3SelectExpand() when walking a SELECT tree to resolve table
** names and other FROM clause elements. 
*/
static void selectPopWith(Walker *pWalker, Select *p){
  Parse *pParse = pWalker->pParse;
  With *pWith = findRightmost(p)->pWith;
  if( pWith!=0 ){
    assert( pParse->pWith==pWith );
    pParse->pWith = pWith->pOuter;
  }
}
#else
#define selectPopWith 0
#endif

/*
................................................................................
    return WRC_Abort;
  }
  if( NEVER(p->pSrc==0) || (selFlags & SF_Expanded)!=0 ){
    return WRC_Prune;
  }
  pTabList = p->pSrc;
  pEList = p->pEList;
  sqlite3WithPush(pParse, findRightmost(p)->pWith, 0);

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, pTabList);

  /* Look up every table named in the FROM clause of the select.  If
................................................................................
    if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
      /* This subquery can be absorbed into its parent. */
      if( isAggSub ){
        isAgg = 1;
        p->selFlags |= SF_Aggregate;
      }
      i = -1;
    }else if( pTabList->nSrc==1
           && OptimizationEnabled(db, SQLITE_SubqCoroutine)
    ){
      /* Implement a co-routine that will return a single row of the result
      ** set on each invocation.
      */
      int addrTop = sqlite3VdbeCurrentAddr(v)+1;

      pItem->regReturn = ++pParse->nMem;













      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->regReturn, 0, addrTop);
      VdbeComment((v, "%s", pItem->pTab->zName));
      pItem->addrFillSub = addrTop;


      sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn);
      explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
      sqlite3Select(pParse, pSub, &dest);
      pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
      pItem->viaCoroutine = 1;
      pItem->regResult = dest.iSdst;


      sqlite3VdbeAddOp1(v, OP_EndCoroutine, pItem->regReturn);

      sqlite3VdbeJumpHere(v, addrTop-1);
      sqlite3ClearTempRegCache(pParse);
    }else{
      /* Generate a subroutine that will fill an ephemeral table with
      ** the content of this subquery.  pItem->addrFillSub will point
      ** to the address of the generated subroutine.  pItem->regReturn
      ** is a register allocated to hold the subroutine return address
................................................................................
      int topAddr;
      int onceAddr = 0;
      int retAddr;
      assert( pItem->addrFillSub==0 );
      pItem->regReturn = ++pParse->nMem;
      topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn);
      pItem->addrFillSub = topAddr+1;

      if( pItem->isCorrelated==0 ){
        /* If the subquery is not correlated and if we are not inside of
        ** a trigger, then we only need to compute the value of the subquery
        ** once. */
        onceAddr = sqlite3CodeOnce(pParse);
        VdbeComment((v, "materialize \"%s\"", pItem->pTab->zName));
      }else{
        VdbeNoopComment((v, "materialize \"%s\"", pItem->pTab->zName));
      }
      sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
      explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
      sqlite3Select(pParse, pSub, &dest);
      pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
      if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
      retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
................................................................................
  pHaving = p->pHaving;
  sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0;

#ifndef SQLITE_OMIT_COMPOUND_SELECT
  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){















    rc = multiSelect(pParse, p, pDest);
    explainSetInteger(pParse->iSelectId, iRestoreSelectId);
    return rc;
  }
#endif

  /* If there is both a GROUP BY and an ORDER BY clause and they are
................................................................................
  }
}
void sqlite3ExplainSelect(Vdbe *pVdbe, Select *p){
  if( p==0 ){
    sqlite3ExplainPrintf(pVdbe, "(null-select)");
    return;
  }




  sqlite3ExplainPush(pVdbe);
  while( p ){
    explainOneSelect(pVdbe, p);
    p = p->pNext;
    if( p==0 ) break;
    sqlite3ExplainNL(pVdbe);
    sqlite3ExplainPrintf(pVdbe, "%s\n", selectOpName(p->op));

/*
** Text of a help message
*/
static char zHelp[] =
  ".backup ?DB? FILE      Backup DB (default \"main\") to FILE\n"
  ".bail ON|OFF           Stop after hitting an error.  Default OFF\n"

  ".databases             List names and files of attached databases\n"
  ".dump ?TABLE? ...      Dump the database in an SQL text format\n"
  "                         If TABLE specified, only dump tables matching\n"
  "                         LIKE pattern TABLE.\n"
  ".echo ON|OFF           Turn command echo on or off\n"
  ".exit                  Exit this program\n"
  ".explain ?ON|OFF?      Turn output mode suitable for EXPLAIN on or off.\n"
................................................................................
      if( p->n>1 && p->z[p->n-1]=='\r' ) p->n--;
    }
    p->cTerm = c;
  }
  if( p->z ) p->z[p->n] = 0;
  return p->z;
}






















































































































































































































/*
** If an input line begins with "." then invoke this routine to
** process that line.
**
** Return 1 on error, 2 to exit, and 0 otherwise.
*/
................................................................................

  /* The undocumented ".breakpoint" command causes a call to the no-op
  ** routine named test_breakpoint().
  */
  if( c=='b' && n>=3 && strncmp(azArg[0], "breakpoint", n)==0 ){
    test_breakpoint();
  }else





  if( c=='d' && n>1 && strncmp(azArg[0], "databases", n)==0 && nArg==1 ){
    struct callback_data data;
    char *zErrMsg = 0;
    open_db(p, 0);
    memcpy(&data, p, sizeof(data));
    data.showHeader = 1;

/*
** Text of a help message
*/
static char zHelp[] =
  ".backup ?DB? FILE      Backup DB (default \"main\") to FILE\n"
  ".bail ON|OFF           Stop after hitting an error.  Default OFF\n"
  ".clone NEWDB           Clone data into NEWDB from the existing database\n"
  ".databases             List names and files of attached databases\n"
  ".dump ?TABLE? ...      Dump the database in an SQL text format\n"
  "                         If TABLE specified, only dump tables matching\n"
  "                         LIKE pattern TABLE.\n"
  ".echo ON|OFF           Turn command echo on or off\n"
  ".exit                  Exit this program\n"
  ".explain ?ON|OFF?      Turn output mode suitable for EXPLAIN on or off.\n"
................................................................................
      if( p->n>1 && p->z[p->n-1]=='\r' ) p->n--;
    }
    p->cTerm = c;
  }
  if( p->z ) p->z[p->n] = 0;
  return p->z;
}

/*
** Try to transfer data for table zTable.  If an error is seen while
** moving forward, try to go backwards.  The backwards movement won't
** work for WITHOUT ROWID tables.
*/
static void tryToCloneData(
  struct callback_data *p,
  sqlite3 *newDb,
  const char *zTable
){
  sqlite3_stmt *pQuery = 0; 
  sqlite3_stmt *pInsert = 0;
  char *zQuery = 0;
  char *zInsert = 0;
  int rc;
  int i, j, n;
  int nTable = (int)strlen(zTable);
  int k = 0;
  int cnt = 0;
  const int spinRate = 10000;

  zQuery = sqlite3_mprintf("SELECT * FROM \"%w\"", zTable);
  rc = sqlite3_prepare_v2(p->db, zQuery, -1, &pQuery, 0);
  if( rc ){
    fprintf(stderr, "Error %d: %s on [%s]\n",
            sqlite3_extended_errcode(p->db), sqlite3_errmsg(p->db),
            zQuery);
    goto end_data_xfer;
  }
  n = sqlite3_column_count(pQuery);
  zInsert = sqlite3_malloc(200 + nTable + n*3);
  if( zInsert==0 ){
    fprintf(stderr, "out of memory\n");
    goto end_data_xfer;
  }
  sqlite3_snprintf(200+nTable,zInsert,
                   "INSERT OR IGNORE INTO \"%s\" VALUES(?", zTable);
  i = (int)strlen(zInsert);
  for(j=1; j<n; j++){
    memcpy(zInsert+i, ",?", 2);
    i += 2;
  }
  memcpy(zInsert+i, ");", 3);
  rc = sqlite3_prepare_v2(newDb, zInsert, -1, &pInsert, 0);
  if( rc ){
    fprintf(stderr, "Error %d: %s on [%s]\n",
            sqlite3_extended_errcode(newDb), sqlite3_errmsg(newDb),
            zQuery);
    goto end_data_xfer;
  }
  for(k=0; k<2; k++){
    while( (rc = sqlite3_step(pQuery))==SQLITE_ROW ){
      for(i=0; i<n; i++){
        switch( sqlite3_column_type(pQuery, i) ){
          case SQLITE_NULL: {
            sqlite3_bind_null(pInsert, i+1);
            break;
          }
          case SQLITE_INTEGER: {
            sqlite3_bind_int64(pInsert, i+1, sqlite3_column_int64(pQuery,i));
            break;
          }
          case SQLITE_FLOAT: {
            sqlite3_bind_double(pInsert, i+1, sqlite3_column_double(pQuery,i));
            break;
          }
          case SQLITE_TEXT: {
            sqlite3_bind_text(pInsert, i+1,
                             (const char*)sqlite3_column_text(pQuery,i),
                             -1, SQLITE_STATIC);
            break;
          }
          case SQLITE_BLOB: {
            sqlite3_bind_blob(pInsert, i+1, sqlite3_column_blob(pQuery,i),
                                            sqlite3_column_bytes(pQuery,i),
                                            SQLITE_STATIC);
            break;
          }
        }
      } /* End for */
      rc = sqlite3_step(pInsert);
      if( rc!=SQLITE_OK && rc!=SQLITE_ROW && rc!=SQLITE_DONE ){
        fprintf(stderr, "Error %d: %s\n", sqlite3_extended_errcode(newDb),
                        sqlite3_errmsg(newDb));
      }
      sqlite3_reset(pInsert);
      cnt++;
      if( (cnt%spinRate)==0 ){
        printf("%c\b", "|/-\\"[(cnt/spinRate)%4]);
        fflush(stdout);
      }
    } /* End while */
    if( rc==SQLITE_DONE ) break;
    sqlite3_finalize(pQuery);
    sqlite3_free(zQuery);
    zQuery = sqlite3_mprintf("SELECT * FROM \"%w\" ORDER BY rowid DESC;",
                             zTable);
    rc = sqlite3_prepare_v2(p->db, zQuery, -1, &pQuery, 0);
    if( rc ){
      fprintf(stderr, "Warning: cannot step \"%s\" backwards", zTable);
      break;
    }
  } /* End for(k=0...) */

end_data_xfer:
  sqlite3_finalize(pQuery);
  sqlite3_finalize(pInsert);
  sqlite3_free(zQuery);
  sqlite3_free(zInsert);
}


/*
** Try to transfer all rows of the schema that match zWhere.  For
** each row, invoke xForEach() on the object defined by that row.
** If an error is encountered while moving forward through the
** sqlite_master table, try again moving backwards.
*/
static void tryToCloneSchema(
  struct callback_data *p,
  sqlite3 *newDb,
  const char *zWhere,
  void (*xForEach)(struct callback_data*,sqlite3*,const char*)
){
  sqlite3_stmt *pQuery = 0;
  char *zQuery = 0;
  int rc;
  const unsigned char *zName;
  const unsigned char *zSql;
  char *zErrMsg = 0;

  zQuery = sqlite3_mprintf("SELECT name, sql FROM sqlite_master"
                           " WHERE %s", zWhere);
  rc = sqlite3_prepare_v2(p->db, zQuery, -1, &pQuery, 0);
  if( rc ){
    fprintf(stderr, "Error: (%d) %s on [%s]\n",
                    sqlite3_extended_errcode(p->db), sqlite3_errmsg(p->db),
                    zQuery);
    goto end_schema_xfer;
  }
  while( (rc = sqlite3_step(pQuery))==SQLITE_ROW ){
    zName = sqlite3_column_text(pQuery, 0);
    zSql = sqlite3_column_text(pQuery, 1);
    printf("%s... ", zName); fflush(stdout);
    sqlite3_exec(newDb, (const char*)zSql, 0, 0, &zErrMsg);
    if( zErrMsg ){
      fprintf(stderr, "Error: %s\nSQL: [%s]\n", zErrMsg, zSql);
      sqlite3_free(zErrMsg);
      zErrMsg = 0;
    }
    if( xForEach ){
      xForEach(p, newDb, (const char*)zName);
    }
    printf("done\n");
  }
  if( rc!=SQLITE_DONE ){
    sqlite3_finalize(pQuery);
    sqlite3_free(zQuery);
    zQuery = sqlite3_mprintf("SELECT name, sql FROM sqlite_master"
                             " WHERE %s ORDER BY rowid DESC", zWhere);
    rc = sqlite3_prepare_v2(p->db, zQuery, -1, &pQuery, 0);
    if( rc ){
      fprintf(stderr, "Error: (%d) %s on [%s]\n",
                      sqlite3_extended_errcode(p->db), sqlite3_errmsg(p->db),
                      zQuery);
      goto end_schema_xfer;
    }
    while( (rc = sqlite3_step(pQuery))==SQLITE_ROW ){
      zName = sqlite3_column_text(pQuery, 0);
      zSql = sqlite3_column_text(pQuery, 1);
      printf("%s... ", zName); fflush(stdout);
      sqlite3_exec(newDb, (const char*)zSql, 0, 0, &zErrMsg);
      if( zErrMsg ){
        fprintf(stderr, "Error: %s\nSQL: [%s]\n", zErrMsg, zSql);
        sqlite3_free(zErrMsg);
        zErrMsg = 0;
      }
      if( xForEach ){
        xForEach(p, newDb, (const char*)zName);
      }
      printf("done\n");
    }
  }
end_schema_xfer:
  sqlite3_finalize(pQuery);
  sqlite3_free(zQuery);
}

/*
** Open a new database file named "zNewDb".  Try to recover as much information
** as possible out of the main database (which might be corrupt) and write it
** into zNewDb.
*/
static void tryToClone(struct callback_data *p, const char *zNewDb){
  int rc;
  sqlite3 *newDb = 0;
  if( access(zNewDb,0)==0 ){
    fprintf(stderr, "File \"%s\" already exists.\n", zNewDb);
    return;
  }
  rc = sqlite3_open(zNewDb, &newDb);
  if( rc ){
    fprintf(stderr, "Cannot create output database: %s\n",
            sqlite3_errmsg(newDb));
  }else{
    sqlite3_exec(newDb, "BEGIN EXCLUSIVE;", 0, 0, 0);
    tryToCloneSchema(p, newDb, "type='table'", tryToCloneData);
    tryToCloneSchema(p, newDb, "type!='table'", 0);
    sqlite3_exec(newDb, "COMMIT;", 0, 0, 0);
  }
  sqlite3_close(newDb);
}

/*
** If an input line begins with "." then invoke this routine to
** process that line.
**
** Return 1 on error, 2 to exit, and 0 otherwise.
*/
................................................................................

  /* The undocumented ".breakpoint" command causes a call to the no-op
  ** routine named test_breakpoint().
  */
  if( c=='b' && n>=3 && strncmp(azArg[0], "breakpoint", n)==0 ){
    test_breakpoint();
  }else

  if( c=='c' && strncmp(azArg[0], "clone", n)==0 && nArg>1 && nArg<3 ){
    tryToClone(p, azArg[1]);
  }else

  if( c=='d' && n>1 && strncmp(azArg[0], "databases", n)==0 && nArg==1 ){
    struct callback_data data;
    char *zErrMsg = 0;
    open_db(p, 0);
    memcpy(&data, p, sizeof(data));
    data.showHeader = 1;

** on the compiler command line.  This is necessary if you are compiling
** on a recent machine (ex: Red Hat 7.2) but you want your code to work
** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
** without this option, LFS is enable.  But LFS does not exist in the kernel
** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
** portability you should omit LFS.
**





** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
*/
#ifndef SQLITE_DISABLE_LFS
# define _LARGE_FILE       1
# ifndef _FILE_OFFSET_BITS
#   define _FILE_OFFSET_BITS 64
# endif
................................................................................
#define OptimizationEnabled(db, mask)   1
#endif

/*
** Return true if it OK to factor constant expressions into the initialization
** code. The argument is a Parse object for the code generator.
*/
#define ConstFactorOk(P) \
  ((P)->cookieGoto>0 && OptimizationEnabled((P)->db,SQLITE_FactorOutConst))

/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
................................................................................
    char *zDatabase;  /* Name of database holding this table */
    char *zName;      /* Name of the table */
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    Select *pSelect;  /* A SELECT statement used in place of a table name */
    int addrFillSub;  /* Address of subroutine to manifest a subquery */
    int regReturn;    /* Register holding return address of addrFillSub */

    u8 jointype;      /* Type of join between this able and the previous */
    unsigned notIndexed :1;    /* True if there is a NOT INDEXED clause */
    unsigned isCorrelated :1;  /* True if sub-query is correlated */
    unsigned viaCoroutine :1;  /* Implemented as a co-routine */
    unsigned isRecursive :1;   /* True for recursive reference in WITH */
#ifndef SQLITE_OMIT_EXPLAIN
    u8 iSelectId;     /* If pSelect!=0, the id of the sub-select in EQP */
................................................................................
  SrcList *pSrc;         /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
  Select *pNext;         /* Next select to the left in a compound */
  Select *pRightmost;    /* Right-most select in a compound select statement */
  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
  Expr *pOffset;         /* OFFSET expression. NULL means not used. */
  With *pWith;           /* WITH clause attached to this select. Or NULL. */
};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for
................................................................................
#define SF_Resolved        0x0002  /* Identifiers have been resolved */
#define SF_Aggregate       0x0004  /* Contains aggregate functions */
#define SF_UsesEphemeral   0x0008  /* Uses the OpenEphemeral opcode */
#define SF_Expanded        0x0010  /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo     0x0020  /* FROM subqueries have Table metadata */
#define SF_UseSorter       0x0040  /* Sort using a sorter */
#define SF_Values          0x0080  /* Synthesized from VALUES clause */
#define SF_Materialize     0x0100  /* Force materialization of views */
#define SF_NestedFrom      0x0200  /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert    0x0400  /* Need convertCompoundSelectToSubquery() */
#define SF_Recursive       0x0800  /* The recursive part of a recursive CTE */



/*
** The results of a SELECT can be distributed in several ways, as defined
** by one of the following macros.  The "SRT" prefix means "SELECT Result
** Type".
**
................................................................................
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 nTempInUse;       /* Number of aTempReg[] currently checked out */
  u8 nColCache;        /* Number of entries in aColCache[] */
  u8 iColCache;        /* Next entry in aColCache[] to replace */
  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */

  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nOnce;           /* Number of OP_Once instructions so far */
  int nOpAlloc;        /* Number of slots allocated for Vdbe.aOp[] */
  int nLabel;          /* Number of labels used */
  int *aLabel;         /* Space to hold the labels */
  int iFixedOp;        /* Never back out opcodes iFixedOp-1 or earlier */
  int ckBase;          /* Base register of data during check constraints */
  int iPartIdxTab;     /* Table corresponding to a partial index */
  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */


  struct yColCache {
    int iTable;           /* Table cursor number */
    int iColumn;          /* Table column number */
    u8 tempReg;           /* iReg is a temp register that needs to be freed */
    int iLevel;           /* Nesting level */
    int iReg;             /* Reg with value of this column. 0 means none. */
    int lru;              /* Least recently used entry has the smallest value */
  } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
  ExprList *pConstExpr;/* Constant expressions */

  yDbMask writeMask;   /* Start a write transaction on these databases */
  yDbMask cookieMask;  /* Bitmask of schema verified databases */
  int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
  int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */
  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
  int regRoot;         /* Register holding root page number for new objects */
  int nMaxArg;         /* Max args passed to user function by sub-program */
  Token constraintName;/* Name of the constraint currently being parsed */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif
  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */

  /* Information used while coding trigger programs. */
................................................................................
  u32 nQueryLoop;      /* Est number of iterations of a query (10*log2(N)) */
  u32 oldmask;         /* Mask of old.* columns referenced */
  u32 newmask;         /* Mask of new.* columns referenced */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
  u8 disableTriggers;  /* True to disable triggers */


  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */




  int nVar;                 /* Number of '?' variables seen in the SQL so far */
  int nzVar;                /* Number of available slots in azVar[] */
  u8 iPkSortOrder;          /* ASC or DESC for INTEGER PRIMARY KEY */

  u8 explain;               /* True if the EXPLAIN flag is found on the query */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  u8 declareVtab;           /* True if inside sqlite3_declare_vtab() */
  int nVtabLock;            /* Number of virtual tables to lock */
#endif
  int nAlias;               /* Number of aliased result set columns */
  int nHeight;              /* Expression tree height of current sub-select */
................................................................................
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Token sArg;               /* Complete text of a module argument */
  Table **apVtabLock;       /* Pointer to virtual tables needing locking */
#endif
  Table *pZombieTab;        /* List of Table objects to delete after code gen */
  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
  With *pWith;              /* Current WITH clause, or NULL */
  u8 bFreeWith;             /* True if pWith should be freed with parser */
};

/*
** Return true if currently inside an sqlite3_declare_vtab() call.
*/
#ifdef SQLITE_OMIT_VIRTUALTABLE
  #define IN_DECLARE_VTAB 0

** on the compiler command line.  This is necessary if you are compiling
** on a recent machine (ex: Red Hat 7.2) but you want your code to work
** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
** without this option, LFS is enable.  But LFS does not exist in the kernel
** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
** portability you should omit LFS.
**
** The previous paragraph was written in 2005.  (This paragraph is written
** on 2008-11-28.) These days, all Linux kernels support large files, so
** you should probably leave LFS enabled.  But some embedded platforms might
** lack LFS in which case the SQLITE_DISABLE_LFS macro might still be useful.
**
** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
*/
#ifndef SQLITE_DISABLE_LFS
# define _LARGE_FILE       1
# ifndef _FILE_OFFSET_BITS
#   define _FILE_OFFSET_BITS 64
# endif
................................................................................
#define OptimizationEnabled(db, mask)   1
#endif

/*
** Return true if it OK to factor constant expressions into the initialization
** code. The argument is a Parse object for the code generator.
*/
#define ConstFactorOk(P) ((P)->okConstFactor)


/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
................................................................................
    char *zDatabase;  /* Name of database holding this table */
    char *zName;      /* Name of the table */
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    Select *pSelect;  /* A SELECT statement used in place of a table name */
    int addrFillSub;  /* Address of subroutine to manifest a subquery */
    int regReturn;    /* Register holding return address of addrFillSub */
    int regResult;    /* Registers holding results of a co-routine */
    u8 jointype;      /* Type of join between this able and the previous */
    unsigned notIndexed :1;    /* True if there is a NOT INDEXED clause */
    unsigned isCorrelated :1;  /* True if sub-query is correlated */
    unsigned viaCoroutine :1;  /* Implemented as a co-routine */
    unsigned isRecursive :1;   /* True for recursive reference in WITH */
#ifndef SQLITE_OMIT_EXPLAIN
    u8 iSelectId;     /* If pSelect!=0, the id of the sub-select in EQP */
................................................................................
  SrcList *pSrc;         /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
  Select *pNext;         /* Next select to the left in a compound */

  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
  Expr *pOffset;         /* OFFSET expression. NULL means not used. */
  With *pWith;           /* WITH clause attached to this select. Or NULL. */
};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for
................................................................................
#define SF_Resolved        0x0002  /* Identifiers have been resolved */
#define SF_Aggregate       0x0004  /* Contains aggregate functions */
#define SF_UsesEphemeral   0x0008  /* Uses the OpenEphemeral opcode */
#define SF_Expanded        0x0010  /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo     0x0020  /* FROM subqueries have Table metadata */
#define SF_UseSorter       0x0040  /* Sort using a sorter */
#define SF_Values          0x0080  /* Synthesized from VALUES clause */
#define SF_Materialize     0x0100  /* NOT USED */
#define SF_NestedFrom      0x0200  /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert    0x0400  /* Need convertCompoundSelectToSubquery() */
#define SF_Recursive       0x0800  /* The recursive part of a recursive CTE */
#define SF_Compound        0x1000  /* Part of a compound query */


/*
** The results of a SELECT can be distributed in several ways, as defined
** by one of the following macros.  The "SRT" prefix means "SELECT Result
** Type".
**
................................................................................
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 nTempInUse;       /* Number of aTempReg[] currently checked out */
  u8 nColCache;        /* Number of entries in aColCache[] */
  u8 iColCache;        /* Next entry in aColCache[] to replace */
  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */
  u8 okConstFactor;    /* OK to factor out constants */
  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nOnce;           /* Number of OP_Once instructions so far */
  int nOpAlloc;        /* Number of slots allocated for Vdbe.aOp[] */


  int iFixedOp;        /* Never back out opcodes iFixedOp-1 or earlier */
  int ckBase;          /* Base register of data during check constraints */
  int iPartIdxTab;     /* Table corresponding to a partial index */
  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */
  int nLabel;          /* Number of labels used */
  int *aLabel;         /* Space to hold the labels */
  struct yColCache {
    int iTable;           /* Table cursor number */
    i16 iColumn;          /* Table column number */
    u8 tempReg;           /* iReg is a temp register that needs to be freed */
    int iLevel;           /* Nesting level */
    int iReg;             /* Reg with value of this column. 0 means none. */
    int lru;              /* Least recently used entry has the smallest value */
  } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
  ExprList *pConstExpr;/* Constant expressions */
  Token constraintName;/* Name of the constraint currently being parsed */
  yDbMask writeMask;   /* Start a write transaction on these databases */
  yDbMask cookieMask;  /* Bitmask of schema verified databases */

  int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */
  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
  int regRoot;         /* Register holding root page number for new objects */
  int nMaxArg;         /* Max args passed to user function by sub-program */

#ifndef SQLITE_OMIT_SHARED_CACHE
  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif
  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */

  /* Information used while coding trigger programs. */
................................................................................
  u32 nQueryLoop;      /* Est number of iterations of a query (10*log2(N)) */
  u32 oldmask;         /* Mask of old.* columns referenced */
  u32 newmask;         /* Mask of new.* columns referenced */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
  u8 disableTriggers;  /* True to disable triggers */

  /************************************************************************
  ** Above is constant between recursions.  Below is reset before and after
  ** each recursion.  The boundary between these two regions is determined
  ** using offsetof(Parse,nVar) so the nVar field must be the first field
  ** in the recursive region.
  ************************************************************************/

  int nVar;                 /* Number of '?' variables seen in the SQL so far */
  int nzVar;                /* Number of available slots in azVar[] */
  u8 iPkSortOrder;          /* ASC or DESC for INTEGER PRIMARY KEY */
  u8 bFreeWith;             /* True if pWith should be freed with parser */
  u8 explain;               /* True if the EXPLAIN flag is found on the query */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  u8 declareVtab;           /* True if inside sqlite3_declare_vtab() */
  int nVtabLock;            /* Number of virtual tables to lock */
#endif
  int nAlias;               /* Number of aliased result set columns */
  int nHeight;              /* Expression tree height of current sub-select */
................................................................................
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Token sArg;               /* Complete text of a module argument */
  Table **apVtabLock;       /* Pointer to virtual tables needing locking */
#endif
  Table *pZombieTab;        /* List of Table objects to delete after code gen */
  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
  With *pWith;              /* Current WITH clause, or NULL */

};

/*
** Return true if currently inside an sqlite3_declare_vtab() call.
*/
#ifdef SQLITE_OMIT_VIRTUALTABLE
  #define IN_DECLARE_VTAB 0

      ** and try to rollback the transaction.
      **
      ** But it could also be that the user executed one or more BEGIN, 
      ** COMMIT, SAVEPOINT, RELEASE or ROLLBACK commands that are confusing
      ** this method's logic. Not clear how this would be best handled.
      */
    if( rc!=TCL_ERROR ){
      Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), 0);
      rc = TCL_ERROR;
    }
    sqlite3_exec(pDb->db, "ROLLBACK", 0, 0, 0);
  }
  pDb->disableAuth--;

  return rc;
................................................................................
  ** SQLITE_IGNORE, or SQLITE_DENY.  Any other return value is an error.
  **
  ** If this method is invoked with no arguments, the current authorization
  ** callback string is returned.
  */
  case DB_AUTHORIZER: {
#ifdef SQLITE_OMIT_AUTHORIZATION
    Tcl_AppendResult(interp, "authorization not available in this build", 0);

    return TCL_ERROR;
#else
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zAuth ){
        Tcl_AppendResult(interp, pDb->zAuth, 0);
      }
    }else{
      char *zAuth;
      int len;
      if( pDb->zAuth ){
        Tcl_Free(pDb->zAuth);
      }
................................................................................
  */
  case DB_BUSY: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "CALLBACK");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zBusy ){
        Tcl_AppendResult(interp, pDb->zBusy, 0);
      }
    }else{
      char *zBusy;
      int len;
      if( pDb->zBusy ){
        Tcl_Free(pDb->zBusy);
      }
................................................................................
    }else if( *subCmd=='s' && strcmp(subCmd,"size")==0 ){
      if( objc!=4 ){
        Tcl_WrongNumArgs(interp, 2, objv, "size n");
        return TCL_ERROR;
      }else{
        if( TCL_ERROR==Tcl_GetIntFromObj(interp, objv[3], &n) ){
          Tcl_AppendResult( interp, "cannot convert \"", 
               Tcl_GetStringFromObj(objv[3],0), "\" to integer", 0);
          return TCL_ERROR;
        }else{
          if( n<0 ){
            flushStmtCache( pDb );
            n = 0;
          }else if( n>MAX_PREPARED_STMTS ){
            n = MAX_PREPARED_STMTS;
          }
          pDb->maxStmt = n;
        }
      }
    }else{
      Tcl_AppendResult( interp, "bad option \"", 
          Tcl_GetStringFromObj(objv[2],0), "\": must be flush or size", 0);

      return TCL_ERROR;
    }
    break;
  }

  /*     $db changes
  **
................................................................................
  */
  case DB_COMMIT_HOOK: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zCommit ){
        Tcl_AppendResult(interp, pDb->zCommit, 0);
      }
    }else{
      const char *zCommit;
      int len;
      if( pDb->zCommit ){
        Tcl_Free(pDb->zCommit);
      }
................................................................................
    }
    zConflict = Tcl_GetStringFromObj(objv[2], 0);
    zTable = Tcl_GetStringFromObj(objv[3], 0);
    zFile = Tcl_GetStringFromObj(objv[4], 0);
    nSep = strlen30(zSep);
    nNull = strlen30(zNull);
    if( nSep==0 ){
      Tcl_AppendResult(interp,"Error: non-null separator required for copy",0);

      return TCL_ERROR;
    }
    if(strcmp(zConflict, "rollback") != 0 &&
       strcmp(zConflict, "abort"   ) != 0 &&
       strcmp(zConflict, "fail"    ) != 0 &&
       strcmp(zConflict, "ignore"  ) != 0 &&
       strcmp(zConflict, "replace" ) != 0 ) {
      Tcl_AppendResult(interp, "Error: \"", zConflict, 
            "\", conflict-algorithm must be one of: rollback, "
            "abort, fail, ignore, or replace", 0);
      return TCL_ERROR;
    }
    zSql = sqlite3_mprintf("SELECT * FROM '%q'", zTable);
    if( zSql==0 ){
      Tcl_AppendResult(interp, "Error: no such table: ", zTable, 0);
      return TCL_ERROR;
    }
    nByte = strlen30(zSql);
    rc = sqlite3_prepare(pDb->db, zSql, -1, &pStmt, 0);
    sqlite3_free(zSql);
    if( rc ){
      Tcl_AppendResult(interp, "Error: ", sqlite3_errmsg(pDb->db), 0);
      nCol = 0;
    }else{
      nCol = sqlite3_column_count(pStmt);
    }
    sqlite3_finalize(pStmt);
    if( nCol==0 ) {
      return TCL_ERROR;
    }
    zSql = malloc( nByte + 50 + nCol*2 );
    if( zSql==0 ) {
      Tcl_AppendResult(interp, "Error: can't malloc()", 0);
      return TCL_ERROR;
    }
    sqlite3_snprintf(nByte+50, zSql, "INSERT OR %q INTO '%q' VALUES(?",
         zConflict, zTable);
    j = strlen30(zSql);
    for(i=1; i<nCol; i++){
      zSql[j++] = ',';
................................................................................
      zSql[j++] = '?';
    }
    zSql[j++] = ')';
    zSql[j] = 0;
    rc = sqlite3_prepare(pDb->db, zSql, -1, &pStmt, 0);
    free(zSql);
    if( rc ){
      Tcl_AppendResult(interp, "Error: ", sqlite3_errmsg(pDb->db), 0);
      sqlite3_finalize(pStmt);
      return TCL_ERROR;
    }
    in = fopen(zFile, "rb");
    if( in==0 ){
      Tcl_AppendResult(interp, "Error: cannot open file: ", zFile, NULL);
      sqlite3_finalize(pStmt);
      return TCL_ERROR;
    }
    azCol = malloc( sizeof(azCol[0])*(nCol+1) );
    if( azCol==0 ) {
      Tcl_AppendResult(interp, "Error: can't malloc()", 0);
      fclose(in);
      return TCL_ERROR;
    }
    (void)sqlite3_exec(pDb->db, "BEGIN", 0, 0, 0);
    zCommit = "COMMIT";
    while( (zLine = local_getline(0, in))!=0 ){
      char *z;
................................................................................
        char *zErr;
        int nErr = strlen30(zFile) + 200;
        zErr = malloc(nErr);
        if( zErr ){
          sqlite3_snprintf(nErr, zErr,
             "Error: %s line %d: expected %d columns of data but found %d",
             zFile, lineno, nCol, i+1);
          Tcl_AppendResult(interp, zErr, 0);
          free(zErr);
        }
        zCommit = "ROLLBACK";
        break;
      }
      for(i=0; i<nCol; i++){
        /* check for null data, if so, bind as null */
................................................................................
          sqlite3_bind_text(pStmt, i+1, azCol[i], -1, SQLITE_STATIC);
        }
      }
      sqlite3_step(pStmt);
      rc = sqlite3_reset(pStmt);
      free(zLine);
      if( rc!=SQLITE_OK ){
        Tcl_AppendResult(interp,"Error: ", sqlite3_errmsg(pDb->db), 0);
        zCommit = "ROLLBACK";
        break;
      }
    }
    free(azCol);
    fclose(in);
    sqlite3_finalize(pStmt);
................................................................................
      /* success, set result as number of lines processed */
      pResult = Tcl_GetObjResult(interp);
      Tcl_SetIntObj(pResult, lineno);
      rc = TCL_OK;
    }else{
      /* failure, append lineno where failed */
      sqlite3_snprintf(sizeof(zLineNum), zLineNum,"%d",lineno);
      Tcl_AppendResult(interp,", failed while processing line: ",zLineNum,0);

      rc = TCL_ERROR;
    }
    break;
  }

  /*
  **    $db enable_load_extension BOOLEAN
................................................................................
    if( Tcl_GetBooleanFromObj(interp, objv[2], &onoff) ){
      return TCL_ERROR;
    }
    sqlite3_enable_load_extension(pDb->db, onoff);
    break;
#else
    Tcl_AppendResult(interp, "extension loading is turned off at compile-time",
                     0);
    return TCL_ERROR;
#endif
  }

  /*
  **    $db errorcode
  **
................................................................................
  }

  /*
  **     $db incrblob ?-readonly? ?DB? TABLE COLUMN ROWID
  */
  case DB_INCRBLOB: {
#ifdef SQLITE_OMIT_INCRBLOB
    Tcl_AppendResult(interp, "incrblob not available in this build", 0);
    return TCL_ERROR;
#else
    int isReadonly = 0;
    const char *zDb = "main";
    const char *zTable;
    const char *zColumn;
    Tcl_WideInt iRow;
................................................................................
  ** 
  ** Invoke the given callback every N virtual machine opcodes while executing
  ** queries.
  */
  case DB_PROGRESS: {
    if( objc==2 ){
      if( pDb->zProgress ){
        Tcl_AppendResult(interp, pDb->zProgress, 0);
      }
    }else if( objc==4 ){
      char *zProgress;
      int len;
      int N;
      if( TCL_OK!=Tcl_GetIntFromObj(interp, objv[2], &N) ){
        return TCL_ERROR;
................................................................................
  */
  case DB_PROFILE: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zProfile ){
        Tcl_AppendResult(interp, pDb->zProfile, 0);
      }
    }else{
      char *zProfile;
      int len;
      if( pDb->zProfile ){
        Tcl_Free(pDb->zProfile);
      }
................................................................................
      Tcl_WrongNumArgs(interp, 2, objv, "KEY");
      return TCL_ERROR;
    }
#ifdef SQLITE_HAS_CODEC
    pKey = Tcl_GetByteArrayFromObj(objv[2], &nKey);
    rc = sqlite3_rekey(pDb->db, pKey, nKey);
    if( rc ){
      Tcl_AppendResult(interp, sqlite3_errstr(rc), 0);
      rc = TCL_ERROR;
    }
#endif
    break;
  }

  /*    $db restore ?DATABASE? FILENAME
................................................................................
  */
  case DB_TRACE: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zTrace ){
        Tcl_AppendResult(interp, pDb->zTrace, 0);
      }
    }else{
      char *zTrace;
      int len;
      if( pDb->zTrace ){
        Tcl_Free(pDb->zTrace);
      }
................................................................................
    pScript = objv[objc-1];

    /* Run the SQLite BEGIN command to open a transaction or savepoint. */
    pDb->disableAuth++;
    rc = sqlite3_exec(pDb->db, zBegin, 0, 0, 0);
    pDb->disableAuth--;
    if( rc!=SQLITE_OK ){
      Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), 0);
      return TCL_ERROR;
    }
    pDb->nTransaction++;

    /* If using NRE, schedule a callback to invoke the script pScript, then
    ** a second callback to commit (or rollback) the transaction or savepoint
    ** opened above. If not using NRE, evaluate the script directly, then
................................................................................
  }

  /*
  **    $db unlock_notify ?script?
  */
  case DB_UNLOCK_NOTIFY: {
#ifndef SQLITE_ENABLE_UNLOCK_NOTIFY
    Tcl_AppendResult(interp, "unlock_notify not available in this build", 0);

    rc = TCL_ERROR;
#else
    if( objc!=2 && objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?SCRIPT?");
      rc = TCL_ERROR;
    }else{
      void (*xNotify)(void **, int) = 0;
................................................................................
        xNotify = DbUnlockNotify;
        pNotifyArg = (void *)pDb;
        pDb->pUnlockNotify = objv[2];
        Tcl_IncrRefCount(pDb->pUnlockNotify);
      }
  
      if( sqlite3_unlock_notify(pDb->db, xNotify, pNotifyArg) ){
        Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), 0);
        rc = TCL_ERROR;
      }
    }
#endif
    break;
  }

................................................................................
#else
  flags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_NOMUTEX;
#endif

  if( objc==2 ){
    zArg = Tcl_GetStringFromObj(objv[1], 0);
    if( strcmp(zArg,"-version")==0 ){
      Tcl_AppendResult(interp,sqlite3_libversion(),0);
      return TCL_OK;
    }
    if( strcmp(zArg,"-has-codec")==0 ){
#ifdef SQLITE_HAS_CODEC
      Tcl_AppendResult(interp,"1",0);
#else
      Tcl_AppendResult(interp,"0",0);
#endif
      return TCL_OK;
    }
  }
  for(i=3; i+1<objc; i+=2){
    zArg = Tcl_GetString(objv[i]);
    if( strcmp(zArg,"-key")==0 ){
................................................................................
  MD5Context ctx;
  unsigned char digest[16];
  char zBuf[50];
  void (*converter)(unsigned char*, char*);

  if( argc!=2 ){
    Tcl_AppendResult(interp,"wrong # args: should be \"", argv[0], 
        " TEXT\"", 0);
    return TCL_ERROR;
  }
  MD5Init(&ctx);
  MD5Update(&ctx, (unsigned char*)argv[1], (unsigned)strlen(argv[1]));
  MD5Final(digest, &ctx);
  converter = (void(*)(unsigned char*,char*))cd;
  converter(digest, zBuf);
................................................................................
  MD5Context ctx;
  void (*converter)(unsigned char*, char*);
  unsigned char digest[16];
  char zBuf[10240];

  if( argc!=2 ){
    Tcl_AppendResult(interp,"wrong # args: should be \"", argv[0], 
        " FILENAME\"", 0);
    return TCL_ERROR;
  }
  in = fopen(argv[1],"rb");
  if( in==0 ){
    Tcl_AppendResult(interp,"unable to open file \"", argv[1], 
         "\" for reading", 0);
    return TCL_ERROR;
  }
  MD5Init(&ctx);
  for(;;){
    int n;
    n = (int)fread(zBuf, 1, sizeof(zBuf), in);
    if( n<=0 ) break;

      ** and try to rollback the transaction.
      **
      ** But it could also be that the user executed one or more BEGIN, 
      ** COMMIT, SAVEPOINT, RELEASE or ROLLBACK commands that are confusing
      ** this method's logic. Not clear how this would be best handled.
      */
    if( rc!=TCL_ERROR ){
      Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), (char*)0);
      rc = TCL_ERROR;
    }
    sqlite3_exec(pDb->db, "ROLLBACK", 0, 0, 0);
  }
  pDb->disableAuth--;

  return rc;
................................................................................
  ** SQLITE_IGNORE, or SQLITE_DENY.  Any other return value is an error.
  **
  ** If this method is invoked with no arguments, the current authorization
  ** callback string is returned.
  */
  case DB_AUTHORIZER: {
#ifdef SQLITE_OMIT_AUTHORIZATION
    Tcl_AppendResult(interp, "authorization not available in this build",
                     (char*)0);
    return TCL_ERROR;
#else
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zAuth ){
        Tcl_AppendResult(interp, pDb->zAuth, (char*)0);
      }
    }else{
      char *zAuth;
      int len;
      if( pDb->zAuth ){
        Tcl_Free(pDb->zAuth);
      }
................................................................................
  */
  case DB_BUSY: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "CALLBACK");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zBusy ){
        Tcl_AppendResult(interp, pDb->zBusy, (char*)0);
      }
    }else{
      char *zBusy;
      int len;
      if( pDb->zBusy ){
        Tcl_Free(pDb->zBusy);
      }
................................................................................
    }else if( *subCmd=='s' && strcmp(subCmd,"size")==0 ){
      if( objc!=4 ){
        Tcl_WrongNumArgs(interp, 2, objv, "size n");
        return TCL_ERROR;
      }else{
        if( TCL_ERROR==Tcl_GetIntFromObj(interp, objv[3], &n) ){
          Tcl_AppendResult( interp, "cannot convert \"", 
               Tcl_GetStringFromObj(objv[3],0), "\" to integer", (char*)0);
          return TCL_ERROR;
        }else{
          if( n<0 ){
            flushStmtCache( pDb );
            n = 0;
          }else if( n>MAX_PREPARED_STMTS ){
            n = MAX_PREPARED_STMTS;
          }
          pDb->maxStmt = n;
        }
      }
    }else{
      Tcl_AppendResult( interp, "bad option \"", 
          Tcl_GetStringFromObj(objv[2],0), "\": must be flush or size",
          (char*)0);
      return TCL_ERROR;
    }
    break;
  }

  /*     $db changes
  **
................................................................................
  */
  case DB_COMMIT_HOOK: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zCommit ){
        Tcl_AppendResult(interp, pDb->zCommit, (char*)0);
      }
    }else{
      const char *zCommit;
      int len;
      if( pDb->zCommit ){
        Tcl_Free(pDb->zCommit);
      }
................................................................................
    }
    zConflict = Tcl_GetStringFromObj(objv[2], 0);
    zTable = Tcl_GetStringFromObj(objv[3], 0);
    zFile = Tcl_GetStringFromObj(objv[4], 0);
    nSep = strlen30(zSep);
    nNull = strlen30(zNull);
    if( nSep==0 ){
      Tcl_AppendResult(interp,"Error: non-null separator required for copy",
                       (char*)0);
      return TCL_ERROR;
    }
    if(strcmp(zConflict, "rollback") != 0 &&
       strcmp(zConflict, "abort"   ) != 0 &&
       strcmp(zConflict, "fail"    ) != 0 &&
       strcmp(zConflict, "ignore"  ) != 0 &&
       strcmp(zConflict, "replace" ) != 0 ) {
      Tcl_AppendResult(interp, "Error: \"", zConflict, 
            "\", conflict-algorithm must be one of: rollback, "
            "abort, fail, ignore, or replace", (char*)0);
      return TCL_ERROR;
    }
    zSql = sqlite3_mprintf("SELECT * FROM '%q'", zTable);
    if( zSql==0 ){
      Tcl_AppendResult(interp, "Error: no such table: ", zTable, (char*)0);
      return TCL_ERROR;
    }
    nByte = strlen30(zSql);
    rc = sqlite3_prepare(pDb->db, zSql, -1, &pStmt, 0);
    sqlite3_free(zSql);
    if( rc ){
      Tcl_AppendResult(interp, "Error: ", sqlite3_errmsg(pDb->db), (char*)0);
      nCol = 0;
    }else{
      nCol = sqlite3_column_count(pStmt);
    }
    sqlite3_finalize(pStmt);
    if( nCol==0 ) {
      return TCL_ERROR;
    }
    zSql = malloc( nByte + 50 + nCol*2 );
    if( zSql==0 ) {
      Tcl_AppendResult(interp, "Error: can't malloc()", (char*)0);
      return TCL_ERROR;
    }
    sqlite3_snprintf(nByte+50, zSql, "INSERT OR %q INTO '%q' VALUES(?",
         zConflict, zTable);
    j = strlen30(zSql);
    for(i=1; i<nCol; i++){
      zSql[j++] = ',';
................................................................................
      zSql[j++] = '?';
    }
    zSql[j++] = ')';
    zSql[j] = 0;
    rc = sqlite3_prepare(pDb->db, zSql, -1, &pStmt, 0);
    free(zSql);
    if( rc ){
      Tcl_AppendResult(interp, "Error: ", sqlite3_errmsg(pDb->db), (char*)0);
      sqlite3_finalize(pStmt);
      return TCL_ERROR;
    }
    in = fopen(zFile, "rb");
    if( in==0 ){
      Tcl_AppendResult(interp, "Error: cannot open file: ", zFile, NULL);
      sqlite3_finalize(pStmt);
      return TCL_ERROR;
    }
    azCol = malloc( sizeof(azCol[0])*(nCol+1) );
    if( azCol==0 ) {
      Tcl_AppendResult(interp, "Error: can't malloc()", (char*)0);
      fclose(in);
      return TCL_ERROR;
    }
    (void)sqlite3_exec(pDb->db, "BEGIN", 0, 0, 0);
    zCommit = "COMMIT";
    while( (zLine = local_getline(0, in))!=0 ){
      char *z;
................................................................................
        char *zErr;
        int nErr = strlen30(zFile) + 200;
        zErr = malloc(nErr);
        if( zErr ){
          sqlite3_snprintf(nErr, zErr,
             "Error: %s line %d: expected %d columns of data but found %d",
             zFile, lineno, nCol, i+1);
          Tcl_AppendResult(interp, zErr, (char*)0);
          free(zErr);
        }
        zCommit = "ROLLBACK";
        break;
      }
      for(i=0; i<nCol; i++){
        /* check for null data, if so, bind as null */
................................................................................
          sqlite3_bind_text(pStmt, i+1, azCol[i], -1, SQLITE_STATIC);
        }
      }
      sqlite3_step(pStmt);
      rc = sqlite3_reset(pStmt);
      free(zLine);
      if( rc!=SQLITE_OK ){
        Tcl_AppendResult(interp,"Error: ", sqlite3_errmsg(pDb->db), (char*)0);
        zCommit = "ROLLBACK";
        break;
      }
    }
    free(azCol);
    fclose(in);
    sqlite3_finalize(pStmt);
................................................................................
      /* success, set result as number of lines processed */
      pResult = Tcl_GetObjResult(interp);
      Tcl_SetIntObj(pResult, lineno);
      rc = TCL_OK;
    }else{
      /* failure, append lineno where failed */
      sqlite3_snprintf(sizeof(zLineNum), zLineNum,"%d",lineno);
      Tcl_AppendResult(interp,", failed while processing line: ",zLineNum,
                       (char*)0);
      rc = TCL_ERROR;
    }
    break;
  }

  /*
  **    $db enable_load_extension BOOLEAN
................................................................................
    if( Tcl_GetBooleanFromObj(interp, objv[2], &onoff) ){
      return TCL_ERROR;
    }
    sqlite3_enable_load_extension(pDb->db, onoff);
    break;
#else
    Tcl_AppendResult(interp, "extension loading is turned off at compile-time",
                     (char*)0);
    return TCL_ERROR;
#endif
  }

  /*
  **    $db errorcode
  **
................................................................................
  }

  /*
  **     $db incrblob ?-readonly? ?DB? TABLE COLUMN ROWID
  */
  case DB_INCRBLOB: {
#ifdef SQLITE_OMIT_INCRBLOB
    Tcl_AppendResult(interp, "incrblob not available in this build", (char*)0);
    return TCL_ERROR;
#else
    int isReadonly = 0;
    const char *zDb = "main";
    const char *zTable;
    const char *zColumn;
    Tcl_WideInt iRow;
................................................................................
  ** 
  ** Invoke the given callback every N virtual machine opcodes while executing
  ** queries.
  */
  case DB_PROGRESS: {
    if( objc==2 ){
      if( pDb->zProgress ){
        Tcl_AppendResult(interp, pDb->zProgress, (char*)0);
      }
    }else if( objc==4 ){
      char *zProgress;
      int len;
      int N;
      if( TCL_OK!=Tcl_GetIntFromObj(interp, objv[2], &N) ){
        return TCL_ERROR;
................................................................................
  */
  case DB_PROFILE: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zProfile ){
        Tcl_AppendResult(interp, pDb->zProfile, (char*)0);
      }
    }else{
      char *zProfile;
      int len;
      if( pDb->zProfile ){
        Tcl_Free(pDb->zProfile);
      }
................................................................................
      Tcl_WrongNumArgs(interp, 2, objv, "KEY");
      return TCL_ERROR;
    }
#ifdef SQLITE_HAS_CODEC
    pKey = Tcl_GetByteArrayFromObj(objv[2], &nKey);
    rc = sqlite3_rekey(pDb->db, pKey, nKey);
    if( rc ){
      Tcl_AppendResult(interp, sqlite3_errstr(rc), (char*)0);
      rc = TCL_ERROR;
    }
#endif
    break;
  }

  /*    $db restore ?DATABASE? FILENAME
................................................................................
  */
  case DB_TRACE: {
    if( objc>3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?CALLBACK?");
      return TCL_ERROR;
    }else if( objc==2 ){
      if( pDb->zTrace ){
        Tcl_AppendResult(interp, pDb->zTrace, (char*)0);
      }
    }else{
      char *zTrace;
      int len;
      if( pDb->zTrace ){
        Tcl_Free(pDb->zTrace);
      }
................................................................................
    pScript = objv[objc-1];

    /* Run the SQLite BEGIN command to open a transaction or savepoint. */
    pDb->disableAuth++;
    rc = sqlite3_exec(pDb->db, zBegin, 0, 0, 0);
    pDb->disableAuth--;
    if( rc!=SQLITE_OK ){
      Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), (char*)0);
      return TCL_ERROR;
    }
    pDb->nTransaction++;

    /* If using NRE, schedule a callback to invoke the script pScript, then
    ** a second callback to commit (or rollback) the transaction or savepoint
    ** opened above. If not using NRE, evaluate the script directly, then
................................................................................
  }

  /*
  **    $db unlock_notify ?script?
  */
  case DB_UNLOCK_NOTIFY: {
#ifndef SQLITE_ENABLE_UNLOCK_NOTIFY
    Tcl_AppendResult(interp, "unlock_notify not available in this build",
                     (char*)0);
    rc = TCL_ERROR;
#else
    if( objc!=2 && objc!=3 ){
      Tcl_WrongNumArgs(interp, 2, objv, "?SCRIPT?");
      rc = TCL_ERROR;
    }else{
      void (*xNotify)(void **, int) = 0;
................................................................................
        xNotify = DbUnlockNotify;
        pNotifyArg = (void *)pDb;
        pDb->pUnlockNotify = objv[2];
        Tcl_IncrRefCount(pDb->pUnlockNotify);
      }
  
      if( sqlite3_unlock_notify(pDb->db, xNotify, pNotifyArg) ){
        Tcl_AppendResult(interp, sqlite3_errmsg(pDb->db), (char*)0);
        rc = TCL_ERROR;
      }
    }
#endif
    break;
  }

................................................................................
#else
  flags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_NOMUTEX;
#endif

  if( objc==2 ){
    zArg = Tcl_GetStringFromObj(objv[1], 0);
    if( strcmp(zArg,"-version")==0 ){
      Tcl_AppendResult(interp,sqlite3_libversion(), (char*)0);
      return TCL_OK;
    }
    if( strcmp(zArg,"-has-codec")==0 ){
#ifdef SQLITE_HAS_CODEC
      Tcl_AppendResult(interp,"1",(char*)0);
#else
      Tcl_AppendResult(interp,"0",(char*)0);
#endif
      return TCL_OK;
    }
  }
  for(i=3; i+1<objc; i+=2){
    zArg = Tcl_GetString(objv[i]);
    if( strcmp(zArg,"-key")==0 ){
................................................................................
  MD5Context ctx;
  unsigned char digest[16];
  char zBuf[50];
  void (*converter)(unsigned char*, char*);

  if( argc!=2 ){
    Tcl_AppendResult(interp,"wrong # args: should be \"", argv[0], 
        " TEXT\"", (char*)0);
    return TCL_ERROR;
  }
  MD5Init(&ctx);
  MD5Update(&ctx, (unsigned char*)argv[1], (unsigned)strlen(argv[1]));
  MD5Final(digest, &ctx);
  converter = (void(*)(unsigned char*,char*))cd;
  converter(digest, zBuf);
................................................................................
  MD5Context ctx;
  void (*converter)(unsigned char*, char*);
  unsigned char digest[16];
  char zBuf[10240];

  if( argc!=2 ){
    Tcl_AppendResult(interp,"wrong # args: should be \"", argv[0], 
        " FILENAME\"", (char*)0);
    return TCL_ERROR;
  }
  in = fopen(argv[1],"rb");
  if( in==0 ){
    Tcl_AppendResult(interp,"unable to open file \"", argv[1], 
         "\" for reading", (char*)0);
    return TCL_ERROR;
  }
  MD5Init(&ctx);
  for(;;){
    int n;
    n = (int)fread(zBuf, 1, sizeof(zBuf), in);
    if( n<=0 ) break;

  }

  if( Tcl_GetIntFromObj(interp, objv[1], &repeat_count) ) return TCL_ERROR;
  if( Tcl_GetIntFromObj(interp, objv[2], &do_calls) ) return TCL_ERROR;

  val.flags = MEM_Str|MEM_Term|MEM_Static;
  val.z = "hello world";
  val.type = SQLITE_TEXT;
  val.enc = SQLITE_UTF8;

  for(i=0; i<repeat_count; i++){
    if( do_calls ){
      sqlite3_value_text(&val);
    }
  }

  }

  if( Tcl_GetIntFromObj(interp, objv[1], &repeat_count) ) return TCL_ERROR;
  if( Tcl_GetIntFromObj(interp, objv[2], &do_calls) ) return TCL_ERROR;

  val.flags = MEM_Str|MEM_Term|MEM_Static;
  val.z = "hello world";
  val.memType = MEM_Str;
  val.enc = SQLITE_UTF8;

  for(i=0; i<repeat_count; i++){
    if( do_calls ){
      sqlite3_value_text(&val);
    }
  }

    **     INSERT OR REPLACE INTO t2 VALUES(new.a, new.b);
    **   END;
    **
    **   INSERT INTO t1 ... ;            -- insert into t2 uses REPLACE policy
    **   INSERT OR IGNORE INTO t1 ... ;  -- insert into t2 uses IGNORE policy
    */
    pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf;

    /* Clear the cookieGoto flag. When coding triggers, the cookieGoto 
    ** variable is used as a flag to indicate to sqlite3ExprCodeConstants()
    ** that it is not safe to refactor constants (this happens after the
    ** start of the first loop in the SQL statement is coded - at that 
    ** point code may be conditionally executed, so it is no longer safe to 
    ** initialize constant register values).  */
    assert( pParse->cookieGoto==0 || pParse->cookieGoto==-1 );
    pParse->cookieGoto = 0;


    switch( pStep->op ){
      case TK_UPDATE: {
        sqlite3Update(pParse, 
          targetSrcList(pParse, pStep),
          sqlite3ExprListDup(db, pStep->pExprList, 0), 
          sqlite3ExprDup(db, pStep->pWhere, 0), 

    **     INSERT OR REPLACE INTO t2 VALUES(new.a, new.b);
    **   END;
    **
    **   INSERT INTO t1 ... ;            -- insert into t2 uses REPLACE policy
    **   INSERT OR IGNORE INTO t1 ... ;  -- insert into t2 uses IGNORE policy
    */
    pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf;









    assert( pParse->okConstFactor==0 );

    switch( pStep->op ){
      case TK_UPDATE: {
        sqlite3Update(pParse, 
          targetSrcList(pParse, pStep),
          sqlite3ExprListDup(db, pStep->pExprList, 0), 
          sqlite3ExprDup(db, pStep->pWhere, 0), 

  i64 iA = *pA;
  testcase( iA==0 ); testcase( iA==1 );
  testcase( iB==-1 ); testcase( iB==0 );
  if( iB>=0 ){
    testcase( iA>0 && LARGEST_INT64 - iA == iB );
    testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
    if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
    *pA += iB;
  }else{
    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
    if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
    *pA += iB;
  }

  return 0; 
}
int sqlite3SubInt64(i64 *pA, i64 iB){
  testcase( iB==SMALLEST_INT64+1 );
  if( iB==SMALLEST_INT64 ){
    testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
    if( (*pA)>=0 ) return 1;
................................................................................
  i64 iA = *pA;
  i64 iA1, iA0, iB1, iB0, r;

  iA1 = iA/TWOPOWER32;
  iA0 = iA % TWOPOWER32;
  iB1 = iB/TWOPOWER32;
  iB0 = iB % TWOPOWER32;
  if( iA1*iB1 != 0 ) return 1;
  assert( iA1*iB0==0 || iA0*iB1==0 );





  r = iA1*iB0 + iA0*iB1;




  testcase( r==(-TWOPOWER31)-1 );
  testcase( r==(-TWOPOWER31) );
  testcase( r==TWOPOWER31 );
  testcase( r==TWOPOWER31-1 );
  if( r<(-TWOPOWER31) || r>=TWOPOWER31 ) return 1;
  r *= TWOPOWER32;
  if( sqlite3AddInt64(&r, iA0*iB0) ) return 1;

  i64 iA = *pA;
  testcase( iA==0 ); testcase( iA==1 );
  testcase( iB==-1 ); testcase( iB==0 );
  if( iB>=0 ){
    testcase( iA>0 && LARGEST_INT64 - iA == iB );
    testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
    if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;

  }else{
    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
    if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;

  }
  *pA += iB;
  return 0; 
}
int sqlite3SubInt64(i64 *pA, i64 iB){
  testcase( iB==SMALLEST_INT64+1 );
  if( iB==SMALLEST_INT64 ){
    testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
    if( (*pA)>=0 ) return 1;
................................................................................
  i64 iA = *pA;
  i64 iA1, iA0, iB1, iB0, r;

  iA1 = iA/TWOPOWER32;
  iA0 = iA % TWOPOWER32;
  iB1 = iB/TWOPOWER32;
  iB0 = iB % TWOPOWER32;
  if( iA1==0 ){
    if( iB1==0 ){
      *pA *= iB;
      return 0;
    }
    r = iA0*iB1;
  }else if( iB1==0 ){
    r = iA1*iB0;
  }else{
    /* If both iA1 and iB1 are non-zero, overflow will result */
    return 1;
  }
  testcase( r==(-TWOPOWER31)-1 );
  testcase( r==(-TWOPOWER31) );
  testcase( r==TWOPOWER31 );
  testcase( r==TWOPOWER31-1 );
  if( r<(-TWOPOWER31) || r>=TWOPOWER31 ) return 1;
  r *= TWOPOWER32;
  if( sqlite3AddInt64(&r, iA0*iB0) ) return 1;

** 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.
**
*************************************************************************
** The code in this file implements execution method of the 
** Virtual Database Engine (VDBE).  A separate file ("vdbeaux.c")
** handles housekeeping details such as creating and deleting
** VDBE instances.  This file is solely interested in executing
** the VDBE program.
**
** In the external interface, an "sqlite3_stmt*" is an opaque pointer
** to a VDBE.
**
** The SQL parser generates a program which is then executed by
** the VDBE to do the work of the SQL statement.  VDBE programs are 
** similar in form to assembly language.  The program consists of
** a linear sequence of operations.  Each operation has an opcode 
** and 5 operands.  Operands P1, P2, and P3 are integers.  Operand P4 
** is a null-terminated string.  Operand P5 is an unsigned character.
** Few opcodes use all 5 operands.
**
** Computation results are stored on a set of registers numbered beginning
** with 1 and going up to Vdbe.nMem.  Each register can store
** either an integer, a null-terminated string, a floating point
** number, or the SQL "NULL" value.  An implicit conversion from one
** type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqlite3VdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** 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.
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** Invoke this macro on memory cells just prior to changing the
** value of the cell.  This macro verifies that shallow copies are
** not misused.




*/
#ifdef SQLITE_DEBUG
# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
#else
# define memAboutToChange(P,M)
#endif

................................................................................
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
# define HAS_UPDATE_HOOK(DB)   ((DB)->xPreUpdateCallback||(DB)->xUpdateCallback)
#else
# define HAS_UPDATE_HOOK(DB)  ((DB)->xUpdateCallback)
#endif

/*
** The next global variable is incremented each type the OP_Found opcode
** is executed. This is used to test whether or not the foreign key
** operation implemented using OP_FkIsZero is working. This variable
** has no function other than to help verify the correct operation of the
** library.
*/
#ifdef SQLITE_TEST
int sqlite3_found_count = 0;
................................................................................
** converts an MEM_Ephem string into an MEM_Dyn string.
*/
#define Deephemeralize(P) \
   if( ((P)->flags&MEM_Ephem)!=0 \
       && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}

/* Return true if the cursor was opened using the OP_OpenSorter opcode. */
# define isSorter(x) ((x)->pSorter!=0)

/*
** Argument pMem points at a register that will be passed to a
** user-defined function or returned to the user as the result of a query.
** This routine sets the pMem->type variable used by the sqlite3_value_*() 
** routines.
*/
void sqlite3VdbeMemStoreType(Mem *pMem){
  int flags = pMem->flags;
  if( flags & MEM_Null ){
    pMem->type = SQLITE_NULL;
  }
  else if( flags & MEM_Int ){
    pMem->type = SQLITE_INTEGER;
  }
  else if( flags & MEM_Real ){
    pMem->type = SQLITE_FLOAT;
  }
  else if( flags & MEM_Str ){
    pMem->type = SQLITE_TEXT;
  }else{
    pMem->type = SQLITE_BLOB;
  }
}

/*
** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
** if we run out of memory.
*/
static VdbeCursor *allocateCursor(
  Vdbe *p,              /* The virtual machine */
................................................................................
/*
** Try to convert the type of a function argument or a result column
** into a numeric representation.  Use either INTEGER or REAL whichever
** is appropriate.  But only do the conversion if it is possible without
** loss of information and return the revised type of the argument.
*/
int sqlite3_value_numeric_type(sqlite3_value *pVal){


  Mem *pMem = (Mem*)pVal;
  if( pMem->type==SQLITE_TEXT ){
    applyNumericAffinity(pMem);
    sqlite3VdbeMemStoreType(pMem);

  }
  return pMem->type;
}

/*
** Exported version of applyAffinity(). This one works on sqlite3_value*, 
** not the internal Mem* type.
*/
void sqlite3ValueApplyAffinity(
................................................................................
#endif

#ifdef SQLITE_DEBUG
/*
** Print the value of a register for tracing purposes:
*/
static void memTracePrint(Mem *p){
  if( p->flags & MEM_Invalid ){
    printf(" undefined");
  }else if( p->flags & MEM_Null ){
    printf(" NULL");
  }else if( (p->flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
    printf(" si:%lld", p->u.i);
  }else if( p->flags & MEM_Int ){
    printf(" i:%lld", p->u.i);
................................................................................
/* 
** hwtime.h contains inline assembler code for implementing 
** high-performance timing routines.
*/
#include "hwtime.h"

#endif

/*
** The CHECK_FOR_INTERRUPT macro defined here looks to see if the
** sqlite3_interrupt() routine has been called.  If it has been, then
** processing of the VDBE program is interrupted.
**
** This macro added to every instruction that does a jump in order to
** implement a loop.  This test used to be on every single instruction,
** but that meant we more testing than we needed.  By only testing the
** flag on jump instructions, we get a (small) speed improvement.
*/
#define CHECK_FOR_INTERRUPT \
   if( db->u1.isInterrupted ) goto abort_due_to_interrupt;


#ifndef NDEBUG
/*
** This function is only called from within an assert() expression. It
** checks that the sqlite3.nTransaction variable is correctly set to
** the number of non-transaction savepoints currently in the 
** linked list starting at sqlite3.pSavepoint.
................................................................................
  assert( n==(db->nSavepoint + db->isTransactionSavepoint) );
  return 1;
}
#endif


/*
** Execute as much of a VDBE program as we can then return.
**
** sqlite3VdbeMakeReady() must be called before this routine in order to
** close the program with a final OP_Halt and to set up the callbacks
** and the error message pointer.
**
** Whenever a row or result data is available, this routine will either
** invoke the result callback (if there is one) or return with
** SQLITE_ROW.
**
** If an attempt is made to open a locked database, then this routine
** will either invoke the busy callback (if there is one) or it will
** return SQLITE_BUSY.
**
** If an error occurs, an error message is written to memory obtained
** from sqlite3_malloc() and p->zErrMsg is made to point to that memory.
** The error code is stored in p->rc and this routine returns SQLITE_ERROR.
**
** If the callback ever returns non-zero, then the program exits
** immediately.  There will be no error message but the p->rc field is
** set to SQLITE_ABORT and this routine will return SQLITE_ERROR.
**
** A memory allocation error causes p->rc to be set to SQLITE_NOMEM and this
** routine to return SQLITE_ERROR.
**
** Other fatal errors return SQLITE_ERROR.
**
** After this routine has finished, sqlite3VdbeFinalize() should be
** used to clean up the mess that was left behind.
*/
int sqlite3VdbeExec(
  Vdbe *p                    /* The VDBE */
){
  int pc=0;                  /* The program counter */
  Op *aOp = p->aOp;          /* Copy of p->aOp */
  Op *pOp;                   /* Current operation */
................................................................................
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
  assert( p->bIsReader || p->readOnly!=0 );
  p->rc = SQLITE_OK;
  p->iCurrentTime = 0;
  assert( p->explain==0 );
  p->pResultSet = 0;
  db->busyHandler.nBusy = 0;
  CHECK_FOR_INTERRUPT;
  sqlite3VdbeIOTraceSql(p);
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  if( db->xProgress ){
    assert( 0 < db->nProgressOps );
    nProgressLimit = (unsigned)p->aCounter[SQLITE_STMTSTATUS_VM_STEP];
    if( nProgressLimit==0 ){
      nProgressLimit = db->nProgressOps;
................................................................................
  **
  ** This code uses unstructured "goto" statements and does not look clean.
  ** But that is not due to sloppy coding habits. The code is written this
  ** way for performance, to avoid having to run the interrupt and progress
  ** checks on every opcode.  This helps sqlite3_step() to run about 1.5%
  ** faster according to "valgrind --tool=cachegrind" */
check_for_interrupt:
  CHECK_FOR_INTERRUPT;
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  /* Call the progress callback if it is configured and the required number
  ** of VDBE ops have been executed (either since this invocation of
  ** sqlite3VdbeExec() or since last time the progress callback was called).
  ** If the progress callback returns non-zero, exit the virtual machine with
  ** a return code SQLITE_ABORT.
  */
................................................................................
  REGISTER_TRACE(pOp->p1, pIn1);
  pc = pOp->p2 - 1;
  break;
}

/* Opcode:  Return P1 * * * *
**
** Jump to the next instruction after the address in register P1.

*/
case OP_Return: {           /* in1 */
  pIn1 = &aMem[pOp->p1];
  assert( pIn1->flags & MEM_Int );
  pc = (int)pIn1->u.i;

  break;
}









































/* Opcode:  Yield P1 * * * *
**
** Swap the program counter with the value in register P1.




*/
case OP_Yield: {            /* in1 */
  int pcDest;
  pIn1 = &aMem[pOp->p1];
  assert( (pIn1->flags & MEM_Dyn)==0 );
  pIn1->flags = MEM_Int;
  pcDest = (int)pIn1->u.i;
  pIn1->u.i = pc;
  REGISTER_TRACE(pOp->p1, pIn1);
  pc = pcDest;
  break;
}

/* Opcode:  HaltIfNull  P1 P2 P3 P4 P5
** Synopsis:  if r[P3] null then halt
**
** Check the value in register P3.  If it is NULL then Halt using
** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
** value in register P3 is not NULL, then this routine is a no-op.
** The P5 parameter should be 1.
*/
case OP_HaltIfNull: {      /* in3 */
................................................................................
}
#endif

/* Opcode: String8 * P2 * P4 *
** Synopsis: r[P2]='P4'
**
** P4 points to a nul terminated UTF-8 string. This opcode is transformed 
** into an OP_String before it is executed for the first time.


*/
case OP_String8: {         /* same as TK_STRING, out2-prerelease */
  assert( pOp->p4.z!=0 );
  pOp->opcode = OP_String;
  pOp->p1 = sqlite3Strlen30(pOp->p4.z);

#ifndef SQLITE_OMIT_UTF16
................................................................................
    pOut->flags = nullFlag;
    cnt--;
  }
  break;
}


/* Opcode: Blob P1 P2 * P4
** Synopsis: r[P2]=P4 (len=P1)
**
** P4 points to a blob of data P1 bytes long.  Store this
** blob in register P2.
*/
case OP_Blob: {                /* out2-prerelease */
  assert( pOp->p1 <= SQLITE_MAX_LENGTH );
................................................................................
}

/* Opcode: Variable P1 P2 * P4 *
** Synopsis: r[P2]=parameter(P1,P4)
**
** Transfer the values of bound parameter P1 into register P2
**
** If the parameter is named, then its name appears in P4 and P3==1.
** The P4 value is used by sqlite3_bind_parameter_name().
*/
case OP_Variable: {            /* out2-prerelease */
  Mem *pVar;       /* Value being transferred */

  assert( pOp->p1>0 && pOp->p1<=p->nVar );
  assert( pOp->p4.z==0 || pOp->p4.z==p->azVar[pOp->p1-1] );
................................................................................

/* Opcode: ResultRow P1 P2 * * *
** Synopsis:  output=r[P1@P2]
**
** The registers P1 through P1+P2-1 contain a single row of
** results. This opcode causes the sqlite3_step() call to terminate
** with an SQLITE_ROW return code and it sets up the sqlite3_stmt
** structure to provide access to the top P1 values as the result
** row.
*/
case OP_ResultRow: {
  Mem *pMem;
  int i;
  assert( p->nResColumn==pOp->p2 );
  assert( pOp->p1>0 );
  assert( pOp->p1+pOp->p2<=(p->nMem-p->nCursor)+1 );
................................................................................
#endif

#ifndef SQLITE_OMIT_CAST
/* Opcode: ToText P1 * * * *
**
** Force the value in register P1 to be text.
** If the value is numeric, convert it to a string using the
** equivalent of printf().  Blob values are unchanged and
** are afterwards simply interpreted as text.
**
** A NULL value is not changed by this routine.  It remains NULL.
*/
case OP_ToText: {                  /* same as TK_TO_TEXT, in1 */
  pIn1 = &aMem[pOp->p1];
  memAboutToChange(p, pIn1);
................................................................................
  }
  break;
}

/* Opcode: Once P1 P2 * * *
**
** Check if OP_Once flag P1 is set. If so, jump to instruction P2. Otherwise,
** set the flag and fall through to the next instruction.


*/
case OP_Once: {             /* jump */
  assert( pOp->p1<p->nOnceFlag );
  if( p->aOnceFlag[pOp->p1] ){
    pc = pOp->p2-1;
  }else{
    p->aOnceFlag[pOp->p1] = 1;
................................................................................
  rc = sqlite3VdbeCursorMoveto(pC);
  if( rc ) goto abort_due_to_error;
  if( pC->cacheStatus!=p->cacheCtr || (pOp->p5&OPFLAG_CLEARCACHE)!=0 ){
    if( pC->nullRow ){
      if( pCrsr==0 ){
        assert( pC->pseudoTableReg>0 );
        pReg = &aMem[pC->pseudoTableReg];
        if( pC->multiPseudo ){
          sqlite3VdbeMemShallowCopy(pDest, pReg+p2, MEM_Ephem);
          Deephemeralize(pDest);
          goto op_column_out;
        }
        assert( pReg->flags & MEM_Blob );
        assert( memIsValid(pReg) );
        pC->payloadSize = pC->szRow = avail = pReg->n;
        pC->aRow = (u8*)pReg->z;
      }else{
        MemSetTypeFlag(pDest, MEM_Null);
        goto op_column_out;
................................................................................
                   "cannot commit - no transaction is active"));
         
    rc = SQLITE_ERROR;
  }
  break;
}

/* Opcode: Transaction P1 P2 * * *
**
** Begin a transaction.  The transaction ends when a Commit or Rollback
** opcode is encountered.  Depending on the ON CONFLICT setting, the
** transaction might also be rolled back if an error is encountered.
**
** P1 is the index of the database file on which the transaction is
** started.  Index 0 is the main database file and index 1 is the
................................................................................
** connection is currently not in autocommit mode, or if there are other
** active statements. A statement transaction allows the changes made by this
** VDBE to be rolled back after an error without having to roll back the
** entire transaction. If no error is encountered, the statement transaction
** will automatically commit when the VDBE halts.
**
** If P2 is zero, then a read-lock is obtained on the database file.






*/
case OP_Transaction: {
  Btree *pBt;



  assert( p->bIsReader );
  assert( p->readOnly==0 || pOp->p2==0 );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 );
  if( pOp->p2 && (db->flags & SQLITE_QueryOnly)!=0 ){
    rc = SQLITE_READONLY;
................................................................................

      /* Store the current value of the database handles deferred constraint
      ** counter. If the statement transaction needs to be rolled back,
      ** the value of this counter needs to be restored too.  */
      p->nStmtDefCons = db->nDeferredCons;
      p->nStmtDefImmCons = db->nDeferredImmCons;
    }





























  }
  break;
}

/* Opcode: ReadCookie P1 P2 P3 * *
**
** Read cookie number P3 from database P1 and write it into register P2.
................................................................................
  }
  if( pOp->p1==1 ){
    /* Invalidate all prepared statements whenever the TEMP database
    ** schema is changed.  Ticket #1644 */
    sqlite3ExpirePreparedStatements(db);
    p->expired = 0;
  }
  break;
}

/* Opcode: VerifyCookie P1 P2 P3 * *
**
** Check the value of global database parameter number 0 (the
** schema version) and make sure it is equal to P2 and that the
** generation counter on the local schema parse equals P3.
**
** P1 is the database number which is 0 for the main database file
** and 1 for the file holding temporary tables and some higher number
** for auxiliary databases.
**
** The cookie changes its value whenever the database schema changes.
** This operation is used to detect when that the cookie has changed
** and that the current process needs to reread the schema.
**
** Either a transaction needs to have been started or an OP_Open needs
** to be executed (to establish a read lock) before this opcode is
** invoked.
*/
case OP_VerifyCookie: {
  int iMeta;
  int iGen;
  Btree *pBt;

  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 );
  assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) );
  assert( p->bIsReader );
  pBt = db->aDb[pOp->p1].pBt;
  if( pBt ){
    sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&iMeta);
    iGen = db->aDb[pOp->p1].pSchema->iGeneration;
  }else{
    iGen = iMeta = 0;
  }
  if( iMeta!=pOp->p2 || iGen!=pOp->p3 ){
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
    /* If the schema-cookie from the database file matches the cookie 
    ** stored with the in-memory representation of the schema, do
    ** not reload the schema from the database file.
    **
    ** If virtual-tables are in use, this is not just an optimization.
    ** Often, v-tables store their data in other SQLite tables, which
    ** are queried from within xNext() and other v-table methods using
    ** prepared queries. If such a query is out-of-date, we do not want to
    ** discard the database schema, as the user code implementing the
    ** v-table would have to be ready for the sqlite3_vtab structure itself
    ** to be invalidated whenever sqlite3_step() is called from within 
    ** a v-table method.
    */
    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
      sqlite3ResetOneSchema(db, pOp->p1);
    }

    p->expired = 1;
    rc = SQLITE_SCHEMA;
  }
  break;
}

/* Opcode: OpenRead P1 P2 P3 P4 P5
** Synopsis: root=P2 iDb=P3
**
** Open a read-only cursor for the database table whose root page is
................................................................................
      pCx->isTable = 1;
    }
  }
  pCx->isOrdered = (pOp->p5!=BTREE_UNORDERED);
  break;
}

/* Opcode: SorterOpen P1 * * P4 *
**
** This opcode works like OP_OpenEphemeral except that it opens
** a transient index that is specifically designed to sort large
** tables using an external merge-sort algorithm.
*/
case OP_SorterOpen: {
  VdbeCursor *pCx;
................................................................................
  pCx->pKeyInfo = pOp->p4.pKeyInfo;
  assert( pCx->pKeyInfo->db==db );
  assert( pCx->pKeyInfo->enc==ENC(db) );
  rc = sqlite3VdbeSorterInit(db, pCx);
  break;
}

/* Opcode: OpenPseudo P1 P2 P3 * P5
** Synopsis: content in r[P2@P3]
**
** Open a new cursor that points to a fake table that contains a single
** row of data.  The content of that one row in the content of memory
** register P2 when P5==0.  In other words, cursor P1 becomes an alias for the 
** MEM_Blob content contained in register P2.  When P5==1, then the
** row is represented by P3 consecutive registers beginning with P2.
**
** A pseudo-table created by this opcode is used to hold a single
** row output from the sorter so that the row can be decomposed into
** individual columns using the OP_Column opcode.  The OP_Column opcode
** is the only cursor opcode that works with a pseudo-table.
**
** P3 is the number of fields in the records that will be stored by
................................................................................
  assert( pOp->p1>=0 );
  assert( pOp->p3>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p3, -1, 0);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTableReg = pOp->p2;
  pCx->isTable = 1;
  pCx->multiPseudo = pOp->p5;
  break;
}

/* Opcode: Close P1 * * * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.
................................................................................
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
#ifdef SQLITE_TEST
  sqlite3_search_count++;
#endif
  if( oc>=OP_SeekGe ){  assert( oc==OP_SeekGe || oc==OP_SeekGt );
    if( res<0 || (res==0 && oc==OP_SeekGt) ){

      rc = sqlite3BtreeNext(pC->pCursor, &res);
      if( rc!=SQLITE_OK ) goto abort_due_to_error;
      pC->rowidIsValid = 0;
    }else{
      res = 0;
    }
  }else{
    assert( oc==OP_SeekLt || oc==OP_SeekLe );
    if( res>0 || (res==0 && oc==OP_SeekLt) ){

      rc = sqlite3BtreePrevious(pC->pCursor, &res);
      if( rc!=SQLITE_OK ) goto abort_due_to_error;
      pC->rowidIsValid = 0;
    }else{
      /* res might be negative because the table is empty.  Check to
      ** see if this is the case.
      */
................................................................................
  assert( pC->pCursor!=0 );
  assert( pC->isTable==0 );
  pFree = 0;  /* Not needed.  Only used to suppress a compiler warning. */
  if( pOp->p4.i>0 ){
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = (u16)pOp->p4.i;
    r.aMem = pIn3;
#ifdef SQLITE_DEBUG
    {
      int i;
      for(i=0; i<r.nField; i++){
        assert( memIsValid(&r.aMem[i]) );
        if( i ) REGISTER_TRACE(pOp->p3+i, &r.aMem[i]);
      }
    }
#endif
    r.flags = UNPACKED_PREFIX_MATCH;
    pIdxKey = &r;
  }else{
    pIdxKey = sqlite3VdbeAllocUnpackedRecord(
        pC->pKeyInfo, aTempRec, sizeof(aTempRec), &pFree
    ); 
    if( pIdxKey==0 ) goto no_mem;
................................................................................
** of a real table, not a pseudo-table.
*/
/* Opcode: RowKey P1 P2 * * *
** Synopsis: r[P2]=key
**
** Write into register P2 the complete row key for cursor P1.
** There is no interpretation of the data.  
** The key is copied onto the P3 register exactly as 
** it is found in the database file.
**
** If the P1 cursor must be pointing to a valid row (not a NULL row)
** of a real table, not a pseudo-table.
*/
case OP_RowKey:
case OP_RowData: {
................................................................................
  assert( pOp->p2>0 && pOp->p2<p->nOp );
  if( res ){
    pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: Next P1 P2 * * P5
**
** Advance cursor P1 so that it points to the next key/data pair in its
** table or index.  If there are no more key/value pairs then fall through
** to the following instruction.  But if the cursor advance was successful,
** jump immediately to P2.
**
** The P1 cursor must be for a real table, not a pseudo-table.  P1 must have
** been opened prior to this opcode or the program will segfault.





**
** P4 is always of type P4_ADVANCE. The function pointer points to
** sqlite3BtreeNext().
**
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
**
** See also: Prev, NextIfOpen
*/
/* Opcode: NextIfOpen P1 P2 * * P5
**
** This opcode works just like OP_Next except that if cursor P1 is not
** open it behaves a no-op.
*/
/* Opcode: Prev P1 P2 * * P5
**
** Back up cursor P1 so that it points to the previous key/data pair in its
** table or index.  If there is no previous key/value pairs then fall through
** to the following instruction.  But if the cursor backup was successful,
** jump immediately to P2.
**
** The P1 cursor must be for a real table, not a pseudo-table.  If P1 is
** not open then the behavior is undefined.





**
** P4 is always of type P4_ADVANCE. The function pointer points to
** sqlite3BtreePrevious().
**
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
*/
/* Opcode: PrevIfOpen P1 P2 * * P5
**
** This opcode works just like OP_Prev except that if cursor P1 is not
** open it behaves a no-op.
*/
case OP_SorterNext: {  /* jump */
  VdbeCursor *pC;
  int res;
................................................................................
  if( p->apCsr[pOp->p1]==0 ) break;
  /* Fall through */
case OP_Prev:          /* jump */
case OP_Next:          /* jump */
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p5<ArraySize(p->aCounter) );
  pC = p->apCsr[pOp->p1];

  assert( pC!=0 );
  assert( pC->deferredMoveto==0 );
  assert( pC->pCursor );


  assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
  assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
  assert( pOp->opcode!=OP_NextIfOpen || pOp->p4.xAdvance==sqlite3BtreeNext );
  assert( pOp->opcode!=OP_PrevIfOpen || pOp->p4.xAdvance==sqlite3BtreePrevious);
  rc = pOp->p4.xAdvance(pC->pCursor, &res);
next_tail:
  pC->cacheStatus = CACHE_STALE;
................................................................................
**
** Register P2 holds an SQL index key made using the
** MakeRecord instructions.  This opcode writes that key
** into the index P1.  Data for the entry is nil.
**
** P3 is a flag that provides a hint to the b-tree layer that this
** insert is likely to be an append.








**
** This instruction only works for indices.  The equivalent instruction
** for tables is OP_Insert.
*/
case OP_SorterInsert:       /* in2 */
case OP_IdxInsert: {        /* in2 */
  VdbeCursor *pC;
................................................................................
  }
  break;
}


#ifndef SQLITE_OMIT_TRIGGER

/* Opcode: Program P1 P2 P3 P4 *
**
** Execute the trigger program passed as P4 (type P4_SUBPROGRAM). 
**
** P1 contains the address of the memory cell that contains the first memory 
** cell in an array of values used as arguments to the sub-program. P2 
** contains the address to jump to if the sub-program throws an IGNORE 
** exception using the RAISE() function. Register P3 contains the address 
** of a memory cell in this (the parent) VM that is used to allocate the 
** memory required by the sub-vdbe at runtime.
**
** P4 is a pointer to the VM containing the trigger program.


*/
case OP_Program: {        /* jump */
  int nMem;               /* Number of memory registers for sub-program */
  int nByte;              /* Bytes of runtime space required for sub-program */
  Mem *pRt;               /* Register to allocate runtime space */
  Mem *pMem;              /* Used to iterate through memory cells */
  Mem *pEnd;              /* Last memory cell in new array */
................................................................................
    pFrame->nOp = p->nOp;
    pFrame->token = pProgram->token;
    pFrame->aOnceFlag = p->aOnceFlag;
    pFrame->nOnceFlag = p->nOnceFlag;

    pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
    for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
      pMem->flags = MEM_Invalid;
      pMem->db = db;
    }
  }else{
    pFrame = pRt->u.pFrame;
    assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem );
    assert( pProgram->nCsr==pFrame->nChildCsr );
    assert( pc==pFrame->pc );
................................................................................
    sqlite3VdbeMemSetInt64(pMem, (i64)aRes[i]);
  }    
  break;
};  
#endif

#ifndef SQLITE_OMIT_PRAGMA
/* Opcode: JournalMode P1 P2 P3 * P5
**
** Change the journal mode of database P1 to P3. P3 must be one of the
** PAGER_JOURNALMODE_XXX values. If changing between the various rollback
** modes (delete, truncate, persist, off and memory), this is a simple
** operation. No IO is required.
**
** If changing into or out of WAL mode the procedure is more complicated.
................................................................................
    p->expired = 0;
  }
  break;
}
#endif

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VUpdate P1 P2 P3 P4 *
** Synopsis: data=r[P3@P2]
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** This opcode invokes the corresponding xUpdate method. P2 values
** are contiguous memory cells starting at P3 to pass to the xUpdate 
** invocation. The value in register (P3+P2-1) corresponds to the 
** p2th element of the argv array passed to xUpdate.
................................................................................
**
** If P2==1 then no insert is performed.  argv[0] is the rowid of
** a row to delete.
**
** P1 is a boolean flag. If it is set to true and the xUpdate call
** is successful, then the value returned by sqlite3_last_insert_rowid() 
** is set to the value of the rowid for the row just inserted.



*/
case OP_VUpdate: {
  sqlite3_vtab *pVtab;
  sqlite3_module *pModule;
  int nArg;
  int i;
  sqlite_int64 rowid;
................................................................................
  }
  pOut->u.i = sqlite3BtreeMaxPageCount(pBt, newMax);
  break;
}
#endif


#ifndef SQLITE_OMIT_TRACE
/* Opcode: Trace * * * P4 *




**
** If tracing is enabled (by the sqlite3_trace()) interface, then
** the UTF-8 string contained in P4 is emitted on the trace callback.



*/
case OP_Trace: {

  char *zTrace;
  char *z;





  if( db->xTrace
   && !p->doingRerun
   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
    z = sqlite3VdbeExpandSql(p, zTrace);
    db->xTrace(db->pTraceArg, z);
    sqlite3DbFree(db, z);
................................................................................
#ifdef SQLITE_DEBUG
  if( (db->flags & SQLITE_SqlTrace)!=0
   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
    sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
  }
#endif /* SQLITE_DEBUG */

  break;
}
#endif


/* Opcode: Noop * * * * *
**
** Do nothing.  This instruction is often useful as a jump
** destination.
*/

** 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.
**
*************************************************************************
** The code in this file implements the function that runs the
** bytecode of a prepared statement.

























**
** 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.
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** Invoke this macro on memory cells just prior to changing the
** value of the cell.  This macro verifies that shallow copies are
** not misused.  A shallow copy of a string or blob just copies a
** pointer to the string or blob, not the content.  If the original
** is changed while the copy is still in use, the string or blob might
** be changed out from under the copy.  This macro verifies that nothing
** like that every happens.
*/
#ifdef SQLITE_DEBUG
# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
#else
# define memAboutToChange(P,M)
#endif

................................................................................
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
# define HAS_UPDATE_HOOK(DB)   ((DB)->xPreUpdateCallback||(DB)->xUpdateCallback)
#else
# define HAS_UPDATE_HOOK(DB)  ((DB)->xUpdateCallback)
#endif

/*
** The next global variable is incremented each time the OP_Found opcode
** is executed. This is used to test whether or not the foreign key
** operation implemented using OP_FkIsZero is working. This variable
** has no function other than to help verify the correct operation of the
** library.
*/
#ifdef SQLITE_TEST
int sqlite3_found_count = 0;
................................................................................
** converts an MEM_Ephem string into an MEM_Dyn string.
*/
#define Deephemeralize(P) \
   if( ((P)->flags&MEM_Ephem)!=0 \
       && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}

/* Return true if the cursor was opened using the OP_OpenSorter opcode. */
#define isSorter(x) ((x)->pSorter!=0)

























/*
** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
** if we run out of memory.
*/
static VdbeCursor *allocateCursor(
  Vdbe *p,              /* The virtual machine */
................................................................................
/*
** Try to convert the type of a function argument or a result column
** into a numeric representation.  Use either INTEGER or REAL whichever
** is appropriate.  But only do the conversion if it is possible without
** loss of information and return the revised type of the argument.
*/
int sqlite3_value_numeric_type(sqlite3_value *pVal){
  int eType = sqlite3_value_type(pVal);
  if( eType==SQLITE_TEXT ){
    Mem *pMem = (Mem*)pVal;

    applyNumericAffinity(pMem);
    sqlite3VdbeMemStoreType(pMem);
    eType = sqlite3_value_type(pVal);
  }
  return eType;
}

/*
** Exported version of applyAffinity(). This one works on sqlite3_value*, 
** not the internal Mem* type.
*/
void sqlite3ValueApplyAffinity(
................................................................................
#endif

#ifdef SQLITE_DEBUG
/*
** Print the value of a register for tracing purposes:
*/
static void memTracePrint(Mem *p){
  if( p->flags & MEM_Undefined ){
    printf(" undefined");
  }else if( p->flags & MEM_Null ){
    printf(" NULL");
  }else if( (p->flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
    printf(" si:%lld", p->u.i);
  }else if( p->flags & MEM_Int ){
    printf(" i:%lld", p->u.i);
................................................................................
/* 
** hwtime.h contains inline assembler code for implementing 
** high-performance timing routines.
*/
#include "hwtime.h"

#endif















#ifndef NDEBUG
/*
** This function is only called from within an assert() expression. It
** checks that the sqlite3.nTransaction variable is correctly set to
** the number of non-transaction savepoints currently in the 
** linked list starting at sqlite3.pSavepoint.
................................................................................
  assert( n==(db->nSavepoint + db->isTransactionSavepoint) );
  return 1;
}
#endif


/*
** Execute as much of a VDBE program as we can.
** This is the core of sqlite3_step().  



























*/
int sqlite3VdbeExec(
  Vdbe *p                    /* The VDBE */
){
  int pc=0;                  /* The program counter */
  Op *aOp = p->aOp;          /* Copy of p->aOp */
  Op *pOp;                   /* Current operation */
................................................................................
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
  assert( p->bIsReader || p->readOnly!=0 );
  p->rc = SQLITE_OK;
  p->iCurrentTime = 0;
  assert( p->explain==0 );
  p->pResultSet = 0;
  db->busyHandler.nBusy = 0;
  if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
  sqlite3VdbeIOTraceSql(p);
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  if( db->xProgress ){
    assert( 0 < db->nProgressOps );
    nProgressLimit = (unsigned)p->aCounter[SQLITE_STMTSTATUS_VM_STEP];
    if( nProgressLimit==0 ){
      nProgressLimit = db->nProgressOps;
................................................................................
  **
  ** This code uses unstructured "goto" statements and does not look clean.
  ** But that is not due to sloppy coding habits. The code is written this
  ** way for performance, to avoid having to run the interrupt and progress
  ** checks on every opcode.  This helps sqlite3_step() to run about 1.5%
  ** faster according to "valgrind --tool=cachegrind" */
check_for_interrupt:
  if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  /* Call the progress callback if it is configured and the required number
  ** of VDBE ops have been executed (either since this invocation of
  ** sqlite3VdbeExec() or since last time the progress callback was called).
  ** If the progress callback returns non-zero, exit the virtual machine with
  ** a return code SQLITE_ABORT.
  */
................................................................................
  REGISTER_TRACE(pOp->p1, pIn1);
  pc = pOp->p2 - 1;
  break;
}

/* Opcode:  Return P1 * * * *
**
** Jump to the next instruction after the address in register P1.  After
** the jump, register P1 becomes undefined.
*/
case OP_Return: {           /* in1 */
  pIn1 = &aMem[pOp->p1];
  assert( pIn1->flags==MEM_Int );
  pc = (int)pIn1->u.i;
  pIn1->flags = MEM_Undefined;
  break;
}

/* Opcode: InitCoroutine P1 P2 P3 * *
**
** Set up register P1 so that it will OP_Yield to the co-routine
** located at address P3.
**
** If P2!=0 then the co-routine implementation immediately follows
** this opcode.  So jump over the co-routine implementation to
** address P2.
*/
case OP_InitCoroutine: {     /* jump */
  assert( pOp->p1>0 &&  pOp->p1<=(p->nMem-p->nCursor) );
  assert( pOp->p2>=0 && pOp->p2<p->nOp );
  assert( pOp->p3>=0 && pOp->p3<p->nOp );
  pOut = &aMem[pOp->p1];
  assert( !VdbeMemDynamic(pOut) );
  pOut->u.i = pOp->p3 - 1;
  pOut->flags = MEM_Int;
  if( pOp->p2 ) pc = pOp->p2 - 1;
  break;
}

/* Opcode:  EndCoroutine P1 * * * *
**
** The instruction at the address in register P1 is an OP_Yield.
** Jump to the P2 parameter of that OP_Yield.
** After the jump, register P1 becomes undefined.
*/
case OP_EndCoroutine: {           /* in1 */
  VdbeOp *pCaller;
  pIn1 = &aMem[pOp->p1];
  assert( pIn1->flags==MEM_Int );
  assert( pIn1->u.i>=0 && pIn1->u.i<p->nOp );
  pCaller = &aOp[pIn1->u.i];
  assert( pCaller->opcode==OP_Yield );
  assert( pCaller->p2>=0 && pCaller->p2<p->nOp );
  pc = pCaller->p2 - 1;
  pIn1->flags = MEM_Undefined;
  break;
}

/* Opcode:  Yield P1 P2 * * *
**
** Swap the program counter with the value in register P1.
**
** If the co-routine ends with OP_Yield or OP_Return then continue
** to the next instruction.  But if the co-routine ends with
** OP_EndCoroutine, jump immediately to P2.
*/
case OP_Yield: {            /* in1, jump */
  int pcDest;
  pIn1 = &aMem[pOp->p1];
  assert( (pIn1->flags & MEM_Dyn)==0 );
  pIn1->flags = MEM_Int;
  pcDest = (int)pIn1->u.i;
  pIn1->u.i = pc;
  REGISTER_TRACE(pOp->p1, pIn1);
  pc = pcDest;
  break;
}

/* Opcode:  HaltIfNull  P1 P2 P3 P4 P5
** Synopsis:  if r[P3]=null halt
**
** Check the value in register P3.  If it is NULL then Halt using
** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
** value in register P3 is not NULL, then this routine is a no-op.
** The P5 parameter should be 1.
*/
case OP_HaltIfNull: {      /* in3 */
................................................................................
}
#endif

/* Opcode: String8 * P2 * P4 *
** Synopsis: r[P2]='P4'
**
** P4 points to a nul terminated UTF-8 string. This opcode is transformed 
** into an OP_String before it is executed for the first time.  During
** this transformation, the length of string P4 is computed and stored
** as the P1 parameter.
*/
case OP_String8: {         /* same as TK_STRING, out2-prerelease */
  assert( pOp->p4.z!=0 );
  pOp->opcode = OP_String;
  pOp->p1 = sqlite3Strlen30(pOp->p4.z);

#ifndef SQLITE_OMIT_UTF16
................................................................................
    pOut->flags = nullFlag;
    cnt--;
  }
  break;
}


/* Opcode: Blob P1 P2 * P4 *
** Synopsis: r[P2]=P4 (len=P1)
**
** P4 points to a blob of data P1 bytes long.  Store this
** blob in register P2.
*/
case OP_Blob: {                /* out2-prerelease */
  assert( pOp->p1 <= SQLITE_MAX_LENGTH );
................................................................................
}

/* Opcode: Variable P1 P2 * P4 *
** Synopsis: r[P2]=parameter(P1,P4)
**
** Transfer the values of bound parameter P1 into register P2
**
** If the parameter is named, then its name appears in P4.
** The P4 value is used by sqlite3_bind_parameter_name().
*/
case OP_Variable: {            /* out2-prerelease */
  Mem *pVar;       /* Value being transferred */

  assert( pOp->p1>0 && pOp->p1<=p->nVar );
  assert( pOp->p4.z==0 || pOp->p4.z==p->azVar[pOp->p1-1] );
................................................................................

/* Opcode: ResultRow P1 P2 * * *
** Synopsis:  output=r[P1@P2]
**
** The registers P1 through P1+P2-1 contain a single row of
** results. This opcode causes the sqlite3_step() call to terminate
** with an SQLITE_ROW return code and it sets up the sqlite3_stmt
** structure to provide access to the r[P1]..r[P1+P2-1] values as
** the result row.
*/
case OP_ResultRow: {
  Mem *pMem;
  int i;
  assert( p->nResColumn==pOp->p2 );
  assert( pOp->p1>0 );
  assert( pOp->p1+pOp->p2<=(p->nMem-p->nCursor)+1 );
................................................................................
#endif

#ifndef SQLITE_OMIT_CAST
/* Opcode: ToText P1 * * * *
**
** Force the value in register P1 to be text.
** If the value is numeric, convert it to a string using the
** equivalent of sprintf().  Blob values are unchanged and
** are afterwards simply interpreted as text.
**
** A NULL value is not changed by this routine.  It remains NULL.
*/
case OP_ToText: {                  /* same as TK_TO_TEXT, in1 */
  pIn1 = &aMem[pOp->p1];
  memAboutToChange(p, pIn1);
................................................................................
  }
  break;
}

/* Opcode: Once P1 P2 * * *
**
** Check if OP_Once flag P1 is set. If so, jump to instruction P2. Otherwise,
** set the flag and fall through to the next instruction.  In other words,
** this opcode causes all following up codes up through P2 (but not including
** P2) to run just once and skipped on subsequent times through the loop.
*/
case OP_Once: {             /* jump */
  assert( pOp->p1<p->nOnceFlag );
  if( p->aOnceFlag[pOp->p1] ){
    pc = pOp->p2-1;
  }else{
    p->aOnceFlag[pOp->p1] = 1;
................................................................................
  rc = sqlite3VdbeCursorMoveto(pC);
  if( rc ) goto abort_due_to_error;
  if( pC->cacheStatus!=p->cacheCtr || (pOp->p5&OPFLAG_CLEARCACHE)!=0 ){
    if( pC->nullRow ){
      if( pCrsr==0 ){
        assert( pC->pseudoTableReg>0 );
        pReg = &aMem[pC->pseudoTableReg];





        assert( pReg->flags & MEM_Blob );
        assert( memIsValid(pReg) );
        pC->payloadSize = pC->szRow = avail = pReg->n;
        pC->aRow = (u8*)pReg->z;
      }else{
        MemSetTypeFlag(pDest, MEM_Null);
        goto op_column_out;
................................................................................
                   "cannot commit - no transaction is active"));
         
    rc = SQLITE_ERROR;
  }
  break;
}

/* Opcode: Transaction P1 P2 P3 P4 P5
**
** Begin a transaction.  The transaction ends when a Commit or Rollback
** opcode is encountered.  Depending on the ON CONFLICT setting, the
** transaction might also be rolled back if an error is encountered.
**
** P1 is the index of the database file on which the transaction is
** started.  Index 0 is the main database file and index 1 is the
................................................................................
** connection is currently not in autocommit mode, or if there are other
** active statements. A statement transaction allows the changes made by this
** VDBE to be rolled back after an error without having to roll back the
** entire transaction. If no error is encountered, the statement transaction
** will automatically commit when the VDBE halts.
**
** If P2 is zero, then a read-lock is obtained on the database file.
**
** If P5!=0 then this opcode also checks the schema cookie against P3
** and the schema generation counter against P4.
** The cookie changes its value whenever the database schema changes.
** This operation is used to detect when that the cookie has changed
** and that the current process needs to reread the schema.
*/
case OP_Transaction: {
  Btree *pBt;
  int iMeta;
  int iGen;

  assert( p->bIsReader );
  assert( p->readOnly==0 || pOp->p2==0 );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 );
  if( pOp->p2 && (db->flags & SQLITE_QueryOnly)!=0 ){
    rc = SQLITE_READONLY;
................................................................................

      /* Store the current value of the database handles deferred constraint
      ** counter. If the statement transaction needs to be rolled back,
      ** the value of this counter needs to be restored too.  */
      p->nStmtDefCons = db->nDeferredCons;
      p->nStmtDefImmCons = db->nDeferredImmCons;
    }

    /* Gather the schema version number for checking */
    sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&iMeta);
    iGen = db->aDb[pOp->p1].pSchema->iGeneration;
  }else{
    iGen = iMeta = 0;
  }
  assert( pOp->p5==0 || pOp->p4type==P4_INT32 );
  if( pOp->p5 && (iMeta!=pOp->p3 || iGen!=pOp->p4.i) ){
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
    /* If the schema-cookie from the database file matches the cookie 
    ** stored with the in-memory representation of the schema, do
    ** not reload the schema from the database file.
    **
    ** If virtual-tables are in use, this is not just an optimization.
    ** Often, v-tables store their data in other SQLite tables, which
    ** are queried from within xNext() and other v-table methods using
    ** prepared queries. If such a query is out-of-date, we do not want to
    ** discard the database schema, as the user code implementing the
    ** v-table would have to be ready for the sqlite3_vtab structure itself
    ** to be invalidated whenever sqlite3_step() is called from within 
    ** a v-table method.
    */
    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
      sqlite3ResetOneSchema(db, pOp->p1);
    }
    p->expired = 1;
    rc = SQLITE_SCHEMA;
  }
  break;
}

/* Opcode: ReadCookie P1 P2 P3 * *
**
** Read cookie number P3 from database P1 and write it into register P2.
................................................................................
  }
  if( pOp->p1==1 ){
    /* Invalidate all prepared statements whenever the TEMP database
    ** schema is changed.  Ticket #1644 */
    sqlite3ExpirePreparedStatements(db);
    p->expired = 0;
  }




























































  break;
}

/* Opcode: OpenRead P1 P2 P3 P4 P5
** Synopsis: root=P2 iDb=P3
**
** Open a read-only cursor for the database table whose root page is
................................................................................
      pCx->isTable = 1;
    }
  }
  pCx->isOrdered = (pOp->p5!=BTREE_UNORDERED);
  break;
}

/* Opcode: SorterOpen P1 P2 * P4 *
**
** This opcode works like OP_OpenEphemeral except that it opens
** a transient index that is specifically designed to sort large
** tables using an external merge-sort algorithm.
*/
case OP_SorterOpen: {
  VdbeCursor *pCx;
................................................................................
  pCx->pKeyInfo = pOp->p4.pKeyInfo;
  assert( pCx->pKeyInfo->db==db );
  assert( pCx->pKeyInfo->enc==ENC(db) );
  rc = sqlite3VdbeSorterInit(db, pCx);
  break;
}

/* Opcode: OpenPseudo P1 P2 P3 * *
** Synopsis: P3 columns in r[P2]
**
** Open a new cursor that points to a fake table that contains a single
** row of data.  The content of that one row is the content of memory
** register P2.  In other words, cursor P1 becomes an alias for the 
** MEM_Blob content contained in register P2.

**
** A pseudo-table created by this opcode is used to hold a single
** row output from the sorter so that the row can be decomposed into
** individual columns using the OP_Column opcode.  The OP_Column opcode
** is the only cursor opcode that works with a pseudo-table.
**
** P3 is the number of fields in the records that will be stored by
................................................................................
  assert( pOp->p1>=0 );
  assert( pOp->p3>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p3, -1, 0);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTableReg = pOp->p2;
  pCx->isTable = 1;
  assert( pOp->p5==0 );
  break;
}

/* Opcode: Close P1 * * * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.
................................................................................
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
#ifdef SQLITE_TEST
  sqlite3_search_count++;
#endif
  if( oc>=OP_SeekGe ){  assert( oc==OP_SeekGe || oc==OP_SeekGt );
    if( res<0 || (res==0 && oc==OP_SeekGt) ){
      res = 0;
      rc = sqlite3BtreeNext(pC->pCursor, &res);
      if( rc!=SQLITE_OK ) goto abort_due_to_error;
      pC->rowidIsValid = 0;
    }else{
      res = 0;
    }
  }else{
    assert( oc==OP_SeekLt || oc==OP_SeekLe );
    if( res>0 || (res==0 && oc==OP_SeekLt) ){
      res = 0;
      rc = sqlite3BtreePrevious(pC->pCursor, &res);
      if( rc!=SQLITE_OK ) goto abort_due_to_error;
      pC->rowidIsValid = 0;
    }else{
      /* res might be negative because the table is empty.  Check to
      ** see if this is the case.
      */
................................................................................
  assert( pC->pCursor!=0 );
  assert( pC->isTable==0 );
  pFree = 0;  /* Not needed.  Only used to suppress a compiler warning. */
  if( pOp->p4.i>0 ){
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = (u16)pOp->p4.i;
    r.aMem = pIn3;
    for(ii=0; ii<r.nField; ii++){
      assert( memIsValid(&r.aMem[ii]) );
      ExpandBlob(&r.aMem[ii]);
#ifdef SQLITE_DEBUG
      if( ii ) REGISTER_TRACE(pOp->p3+ii, &r.aMem[ii]);
#endif
    }


    r.flags = UNPACKED_PREFIX_MATCH;
    pIdxKey = &r;
  }else{
    pIdxKey = sqlite3VdbeAllocUnpackedRecord(
        pC->pKeyInfo, aTempRec, sizeof(aTempRec), &pFree
    ); 
    if( pIdxKey==0 ) goto no_mem;
................................................................................
** of a real table, not a pseudo-table.
*/
/* Opcode: RowKey P1 P2 * * *
** Synopsis: r[P2]=key
**
** Write into register P2 the complete row key for cursor P1.
** There is no interpretation of the data.  
** The key is copied onto the P2 register exactly as 
** it is found in the database file.
**
** If the P1 cursor must be pointing to a valid row (not a NULL row)
** of a real table, not a pseudo-table.
*/
case OP_RowKey:
case OP_RowData: {
................................................................................
  assert( pOp->p2>0 && pOp->p2<p->nOp );
  if( res ){
    pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: Next P1 P2 P3 P4 P5
**
** Advance cursor P1 so that it points to the next key/data pair in its
** table or index.  If there are no more key/value pairs then fall through
** to the following instruction.  But if the cursor advance was successful,
** jump immediately to P2.
**
** The P1 cursor must be for a real table, not a pseudo-table.  P1 must have
** been opened prior to this opcode or the program will segfault.
**
** The P3 value is a hint to the btree implementation. If P3==1, that
** means P1 is an SQL index and that this instruction could have been
** omitted if that index had been unique.  P3 is usually 0.  P3 is
** always either 0 or 1.
**
** P4 is always of type P4_ADVANCE. The function pointer points to
** sqlite3BtreeNext().
**
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
**
** See also: Prev, NextIfOpen
*/
/* Opcode: NextIfOpen P1 P2 P3 P4 P5
**
** This opcode works just like OP_Next except that if cursor P1 is not
** open it behaves a no-op.
*/
/* Opcode: Prev P1 P2 P3 P4 P5
**
** Back up cursor P1 so that it points to the previous key/data pair in its
** table or index.  If there is no previous key/value pairs then fall through
** to the following instruction.  But if the cursor backup was successful,
** jump immediately to P2.
**
** The P1 cursor must be for a real table, not a pseudo-table.  If P1 is
** not open then the behavior is undefined.
**
** The P3 value is a hint to the btree implementation. If P3==1, that
** means P1 is an SQL index and that this instruction could have been
** omitted if that index had been unique.  P3 is usually 0.  P3 is
** always either 0 or 1.
**
** P4 is always of type P4_ADVANCE. The function pointer points to
** sqlite3BtreePrevious().
**
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
*/
/* Opcode: PrevIfOpen P1 P2 P3 P4 P5
**
** This opcode works just like OP_Prev except that if cursor P1 is not
** open it behaves a no-op.
*/
case OP_SorterNext: {  /* jump */
  VdbeCursor *pC;
  int res;
................................................................................
  if( p->apCsr[pOp->p1]==0 ) break;
  /* Fall through */
case OP_Prev:          /* jump */
case OP_Next:          /* jump */
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p5<ArraySize(p->aCounter) );
  pC = p->apCsr[pOp->p1];
  res = pOp->p3;
  assert( pC!=0 );
  assert( pC->deferredMoveto==0 );
  assert( pC->pCursor );
  assert( res==0 || (res==1 && pC->isTable==0) );
  testcase( res==1 );
  assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
  assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
  assert( pOp->opcode!=OP_NextIfOpen || pOp->p4.xAdvance==sqlite3BtreeNext );
  assert( pOp->opcode!=OP_PrevIfOpen || pOp->p4.xAdvance==sqlite3BtreePrevious);
  rc = pOp->p4.xAdvance(pC->pCursor, &res);
next_tail:
  pC->cacheStatus = CACHE_STALE;
................................................................................
**
** Register P2 holds an SQL index key made using the
** MakeRecord instructions.  This opcode writes that key
** into the index P1.  Data for the entry is nil.
**
** P3 is a flag that provides a hint to the b-tree layer that this
** insert is likely to be an append.
**
** If P5 has the OPFLAG_NCHANGE bit set, then the change counter is
** incremented by this instruction.  If the OPFLAG_NCHANGE bit is clear,
** then the change counter is unchanged.
**
** If P5 has the OPFLAG_USESEEKRESULT bit set, then the cursor must have
** just done a seek to the spot where the new entry is to be inserted.
** This flag avoids doing an extra seek.
**
** This instruction only works for indices.  The equivalent instruction
** for tables is OP_Insert.
*/
case OP_SorterInsert:       /* in2 */
case OP_IdxInsert: {        /* in2 */
  VdbeCursor *pC;
................................................................................
  }
  break;
}


#ifndef SQLITE_OMIT_TRIGGER

/* Opcode: Program P1 P2 P3 P4 P5
**
** Execute the trigger program passed as P4 (type P4_SUBPROGRAM). 
**
** P1 contains the address of the memory cell that contains the first memory 
** cell in an array of values used as arguments to the sub-program. P2 
** contains the address to jump to if the sub-program throws an IGNORE 
** exception using the RAISE() function. Register P3 contains the address 
** of a memory cell in this (the parent) VM that is used to allocate the 
** memory required by the sub-vdbe at runtime.
**
** P4 is a pointer to the VM containing the trigger program.
**
** If P5 is non-zero, then recursive program invocation is enabled.
*/
case OP_Program: {        /* jump */
  int nMem;               /* Number of memory registers for sub-program */
  int nByte;              /* Bytes of runtime space required for sub-program */
  Mem *pRt;               /* Register to allocate runtime space */
  Mem *pMem;              /* Used to iterate through memory cells */
  Mem *pEnd;              /* Last memory cell in new array */
................................................................................
    pFrame->nOp = p->nOp;
    pFrame->token = pProgram->token;
    pFrame->aOnceFlag = p->aOnceFlag;
    pFrame->nOnceFlag = p->nOnceFlag;

    pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
    for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
      pMem->flags = MEM_Undefined;
      pMem->db = db;
    }
  }else{
    pFrame = pRt->u.pFrame;
    assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem );
    assert( pProgram->nCsr==pFrame->nChildCsr );
    assert( pc==pFrame->pc );
................................................................................
    sqlite3VdbeMemSetInt64(pMem, (i64)aRes[i]);
  }    
  break;
};  
#endif

#ifndef SQLITE_OMIT_PRAGMA
/* Opcode: JournalMode P1 P2 P3 * *
**
** Change the journal mode of database P1 to P3. P3 must be one of the
** PAGER_JOURNALMODE_XXX values. If changing between the various rollback
** modes (delete, truncate, persist, off and memory), this is a simple
** operation. No IO is required.
**
** If changing into or out of WAL mode the procedure is more complicated.
................................................................................
    p->expired = 0;
  }
  break;
}
#endif

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VUpdate P1 P2 P3 P4 P5
** Synopsis: data=r[P3@P2]
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** This opcode invokes the corresponding xUpdate method. P2 values
** are contiguous memory cells starting at P3 to pass to the xUpdate 
** invocation. The value in register (P3+P2-1) corresponds to the 
** p2th element of the argv array passed to xUpdate.
................................................................................
**
** If P2==1 then no insert is performed.  argv[0] is the rowid of
** a row to delete.
**
** P1 is a boolean flag. If it is set to true and the xUpdate call
** is successful, then the value returned by sqlite3_last_insert_rowid() 
** is set to the value of the rowid for the row just inserted.
**
** P5 is the error actions (OE_Replace, OE_Fail, OE_Ignore, etc) to
** apply in the case of a constraint failure on an insert or update.
*/
case OP_VUpdate: {
  sqlite3_vtab *pVtab;
  sqlite3_module *pModule;
  int nArg;
  int i;
  sqlite_int64 rowid;
................................................................................
  }
  pOut->u.i = sqlite3BtreeMaxPageCount(pBt, newMax);
  break;
}
#endif



/* Opcode: Init * P2 * P4 *
** Synopsis:  Start at P2
**
** Programs contain a single instance of this opcode as the very first
** opcode.
**
** If tracing is enabled (by the sqlite3_trace()) interface, then
** the UTF-8 string contained in P4 is emitted on the trace callback.
** Or if P4 is blank, use the string returned by sqlite3_sql().
**
** If P2 is not zero, jump to instruction P2.
*/

case OP_Init: {          /* jump */
  char *zTrace;
  char *z;

  if( pOp->p2 ){
    pc = pOp->p2 - 1;
  }
#ifndef SQLITE_OMIT_TRACE
  if( db->xTrace
   && !p->doingRerun
   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
    z = sqlite3VdbeExpandSql(p, zTrace);
    db->xTrace(db->pTraceArg, z);
    sqlite3DbFree(db, z);
................................................................................
#ifdef SQLITE_DEBUG
  if( (db->flags & SQLITE_SqlTrace)!=0
   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
    sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
  }
#endif /* SQLITE_DEBUG */
#endif /* SQLITE_OMIT_TRACE */
  break;
}



/* Opcode: Noop * * * * *
**
** Do nothing.  This instruction is often useful as a jump
** destination.
*/

  i8 iDb;               /* Index of cursor database in db->aDb[] (or -1) */
  u8 nullRow;           /* True if pointing to a row with no data */
  u8 rowidIsValid;      /* True if lastRowid is valid */
  u8 deferredMoveto;    /* A call to sqlite3BtreeMoveto() is needed */
  Bool useRandomRowid:1;/* Generate new record numbers semi-randomly */
  Bool isTable:1;       /* True if a table requiring integer keys */
  Bool isOrdered:1;     /* True if the underlying table is BTREE_UNORDERED */
  Bool multiPseudo:1;   /* Multi-register pseudo-cursor */
  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
  i64 seqCount;         /* Sequence counter */
  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
  i64 lastRowid;        /* Rowid being deleted by OP_Delete */
  VdbeSorter *pSorter;  /* Sorter object for OP_SorterOpen cursors */

  /* Cached information about the header for the data record that the
................................................................................
    int nZero;          /* Used when bit MEM_Zero is set in flags */
    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
    RowSet *pRowSet;    /* Used only when flags==MEM_RowSet */
    VdbeFrame *pFrame;  /* Used when flags==MEM_Frame */
  } u;
  int n;              /* Number of characters in string value, excluding '\0' */
  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  u8  type;           /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
  u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
#ifdef SQLITE_DEBUG
  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
  void *pFiller;      /* So that sizeof(Mem) is a multiple of 8 */
#endif
  void (*xDel)(void *);  /* If not null, call this function to delete Mem.z */
  char *zMalloc;      /* Dynamic buffer allocated by sqlite3_malloc() */
................................................................................
#define MEM_Null      0x0001   /* Value is NULL */
#define MEM_Str       0x0002   /* Value is a string */
#define MEM_Int       0x0004   /* Value is an integer */
#define MEM_Real      0x0008   /* Value is a real number */
#define MEM_Blob      0x0010   /* Value is a BLOB */
#define MEM_RowSet    0x0020   /* Value is a RowSet object */
#define MEM_Frame     0x0040   /* Value is a VdbeFrame object */
#define MEM_Invalid   0x0080   /* Value is undefined */
#define MEM_Cleared   0x0100   /* NULL set by OP_Null, not from data */
#define MEM_TypeMask  0x01ff   /* Mask of type bits */


/* Whenever Mem contains a valid string or blob representation, one of
** the following flags must be set to determine the memory management
** policy for Mem.z.  The MEM_Term flag tells us whether or not the
................................................................................
   ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f)

/*
** Return true if a memory cell is not marked as invalid.  This macro
** is for use inside assert() statements only.
*/
#ifdef SQLITE_DEBUG
#define memIsValid(M)  ((M)->flags & MEM_Invalid)==0
#endif

/*
** Each auxilliary data pointer stored by a user defined function 
** implementation calling sqlite3_set_auxdata() is stored in an instance
** of this structure. All such structures associated with a single VM
** are stored in a linked list headed at Vdbe.pAuxData. All are destroyed
................................................................................
double sqlite3VdbeRealValue(Mem*);
void sqlite3VdbeIntegerAffinity(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemReleaseExternal(Mem *p);
#define VdbeMemRelease(X)  \
  if((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame)) \

    sqlite3VdbeMemReleaseExternal(X);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);

void sqlite3VdbeMemStoreType(Mem *pMem);
void sqlite3VdbePreUpdateHook(
    Vdbe *, VdbeCursor *, int, const char*, Table *, i64, int);
int sqlite3VdbeTransferError(Vdbe *p);

int sqlite3VdbeSorterInit(sqlite3 *, VdbeCursor *);
void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
int sqlite3VdbeSorterRowkey(const VdbeCursor *, Mem *);

  i8 iDb;               /* Index of cursor database in db->aDb[] (or -1) */
  u8 nullRow;           /* True if pointing to a row with no data */
  u8 rowidIsValid;      /* True if lastRowid is valid */
  u8 deferredMoveto;    /* A call to sqlite3BtreeMoveto() is needed */
  Bool useRandomRowid:1;/* Generate new record numbers semi-randomly */
  Bool isTable:1;       /* True if a table requiring integer keys */
  Bool isOrdered:1;     /* True if the underlying table is BTREE_UNORDERED */

  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
  i64 seqCount;         /* Sequence counter */
  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
  i64 lastRowid;        /* Rowid being deleted by OP_Delete */
  VdbeSorter *pSorter;  /* Sorter object for OP_SorterOpen cursors */

  /* Cached information about the header for the data record that the
................................................................................
    int nZero;          /* Used when bit MEM_Zero is set in flags */
    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
    RowSet *pRowSet;    /* Used only when flags==MEM_RowSet */
    VdbeFrame *pFrame;  /* Used when flags==MEM_Frame */
  } u;
  int n;              /* Number of characters in string value, excluding '\0' */
  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  u8  memType;        /* Lower 5 bits of flags */
  u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
#ifdef SQLITE_DEBUG
  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
  void *pFiller;      /* So that sizeof(Mem) is a multiple of 8 */
#endif
  void (*xDel)(void *);  /* If not null, call this function to delete Mem.z */
  char *zMalloc;      /* Dynamic buffer allocated by sqlite3_malloc() */
................................................................................
#define MEM_Null      0x0001   /* Value is NULL */
#define MEM_Str       0x0002   /* Value is a string */
#define MEM_Int       0x0004   /* Value is an integer */
#define MEM_Real      0x0008   /* Value is a real number */
#define MEM_Blob      0x0010   /* Value is a BLOB */
#define MEM_RowSet    0x0020   /* Value is a RowSet object */
#define MEM_Frame     0x0040   /* Value is a VdbeFrame object */
#define MEM_Undefined 0x0080   /* Value is undefined */
#define MEM_Cleared   0x0100   /* NULL set by OP_Null, not from data */
#define MEM_TypeMask  0x01ff   /* Mask of type bits */


/* Whenever Mem contains a valid string or blob representation, one of
** the following flags must be set to determine the memory management
** policy for Mem.z.  The MEM_Term flag tells us whether or not the
................................................................................
   ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f)

/*
** Return true if a memory cell is not marked as invalid.  This macro
** is for use inside assert() statements only.
*/
#ifdef SQLITE_DEBUG
#define memIsValid(M)  ((M)->flags & MEM_Undefined)==0
#endif

/*
** Each auxilliary data pointer stored by a user defined function 
** implementation calling sqlite3_set_auxdata() is stored in an instance
** of this structure. All such structures associated with a single VM
** are stored in a linked list headed at Vdbe.pAuxData. All are destroyed
................................................................................
double sqlite3VdbeRealValue(Mem*);
void sqlite3VdbeIntegerAffinity(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemReleaseExternal(Mem *p);
#define VdbeMemDynamic(X)  \
  (((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame))!=0)
#define VdbeMemRelease(X)  \
  if( VdbeMemDynamic(X) ) sqlite3VdbeMemReleaseExternal(X);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
#define sqlite3VdbeMemStoreType(X)  (X)->memType = (u8)((X)->flags&0x1f)
/* void sqlite3VdbeMemStoreType(Mem *pMem); */
void sqlite3VdbePreUpdateHook(
    Vdbe *, VdbeCursor *, int, const char*, Table *, i64, int);
int sqlite3VdbeTransferError(Vdbe *p);

int sqlite3VdbeSorterInit(sqlite3 *, VdbeCursor *);
void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
int sqlite3VdbeSorterRowkey(const VdbeCursor *, Mem *);

  return sqlite3ValueText(pVal, SQLITE_UTF16BE);
}
const void *sqlite3_value_text16le(sqlite3_value *pVal){
  return sqlite3ValueText(pVal, SQLITE_UTF16LE);
}
#endif /* SQLITE_OMIT_UTF16 */
int sqlite3_value_type(sqlite3_value* pVal){
  return pVal->type;


































}

/**************************** sqlite3_result_  *******************************
** The following routines are used by user-defined functions to specify
** the function result.
**
** The setStrOrError() funtion calls sqlite3VdbeMemSetStr() to store the
................................................................................
  void (*xDel)(void*)
){
  return bindText(pStmt, i, zData, nData, xDel, SQLITE_UTF16NATIVE);
}
#endif /* SQLITE_OMIT_UTF16 */
int sqlite3_bind_value(sqlite3_stmt *pStmt, int i, const sqlite3_value *pValue){
  int rc;
  switch( pValue->type ){
    case SQLITE_INTEGER: {
      rc = sqlite3_bind_int64(pStmt, i, pValue->u.i);
      break;
    }
    case SQLITE_FLOAT: {
      rc = sqlite3_bind_double(pStmt, i, pValue->r);
      break;

  return sqlite3ValueText(pVal, SQLITE_UTF16BE);
}
const void *sqlite3_value_text16le(sqlite3_value *pVal){
  return sqlite3ValueText(pVal, SQLITE_UTF16LE);
}
#endif /* SQLITE_OMIT_UTF16 */
int sqlite3_value_type(sqlite3_value* pVal){
  static const u8 aType[] = {
     SQLITE_BLOB,     /* 0x00 */
     SQLITE_NULL,     /* 0x01 */
     SQLITE_TEXT,     /* 0x02 */
     SQLITE_NULL,     /* 0x03 */
     SQLITE_INTEGER,  /* 0x04 */
     SQLITE_NULL,     /* 0x05 */
     SQLITE_INTEGER,  /* 0x06 */
     SQLITE_NULL,     /* 0x07 */
     SQLITE_FLOAT,    /* 0x08 */
     SQLITE_NULL,     /* 0x09 */
     SQLITE_FLOAT,    /* 0x0a */
     SQLITE_NULL,     /* 0x0b */
     SQLITE_INTEGER,  /* 0x0c */
     SQLITE_NULL,     /* 0x0d */
     SQLITE_INTEGER,  /* 0x0e */
     SQLITE_NULL,     /* 0x0f */
     SQLITE_BLOB,     /* 0x10 */
     SQLITE_NULL,     /* 0x11 */
     SQLITE_TEXT,     /* 0x12 */
     SQLITE_NULL,     /* 0x13 */
     SQLITE_INTEGER,  /* 0x14 */
     SQLITE_NULL,     /* 0x15 */
     SQLITE_INTEGER,  /* 0x16 */
     SQLITE_NULL,     /* 0x17 */
     SQLITE_FLOAT,    /* 0x18 */
     SQLITE_NULL,     /* 0x19 */
     SQLITE_FLOAT,    /* 0x1a */
     SQLITE_NULL,     /* 0x1b */
     SQLITE_INTEGER,  /* 0x1c */
     SQLITE_NULL,     /* 0x1d */
     SQLITE_INTEGER,  /* 0x1e */
     SQLITE_NULL,     /* 0x1f */
  };
  return aType[pVal->memType&0x1f];
}

/**************************** sqlite3_result_  *******************************
** The following routines are used by user-defined functions to specify
** the function result.
**
** The setStrOrError() funtion calls sqlite3VdbeMemSetStr() to store the
................................................................................
  void (*xDel)(void*)
){
  return bindText(pStmt, i, zData, nData, xDel, SQLITE_UTF16NATIVE);
}
#endif /* SQLITE_OMIT_UTF16 */
int sqlite3_bind_value(sqlite3_stmt *pStmt, int i, const sqlite3_value *pValue){
  int rc;
  switch( sqlite3_value_type((sqlite3_value*)pValue) ){
    case SQLITE_INTEGER: {
      rc = sqlite3_bind_int64(pStmt, i, pValue->u.i);
      break;
    }
    case SQLITE_FLOAT: {
      rc = sqlite3_bind_double(pStmt, i, pValue->r);
      break;

** routine, then a pointer to a dummy VdbeOp will be returned.  That opcode
** is readable but not writable, though it is cast to a writable value.
** The return of a dummy opcode allows the call to continue functioning
** after a OOM fault without having to check to see if the return from 
** this routine is a valid pointer.  But because the dummy.opcode is 0,
** dummy will never be written to.  This is verified by code inspection and
** by running with Valgrind.
**
** About the #ifdef SQLITE_OMIT_TRACE:  Normally, this routine is never called
** unless p->nOp>0.  This is because in the absense of SQLITE_OMIT_TRACE,
** an OP_Trace instruction is always inserted by sqlite3VdbeGet() as soon as
** a new VDBE is created.  So we are free to set addr to p->nOp-1 without
** having to double-check to make sure that the result is non-negative. But
** if SQLITE_OMIT_TRACE is defined, the OP_Trace is omitted and we do need to
** check the value of p->nOp-1 before continuing.
*/
VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
  /* C89 specifies that the constant "dummy" will be initialized to all
  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
  static VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
  assert( p->magic==VDBE_MAGIC_INIT );
  if( addr<0 ){
#ifdef SQLITE_OMIT_TRACE
    if( p->nOp==0 ) return (VdbeOp*)&dummy;
#endif
    addr = p->nOp - 1;
  }
  assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
  if( p->db->mallocFailed ){
    return (VdbeOp*)&dummy;
  }else{
    return &p->aOp[addr];
................................................................................
      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_Frame|MEM_RowSet) ){
        sqlite3VdbeMemRelease(p);
      }else if( p->zMalloc ){
        sqlite3DbFree(db, p->zMalloc);
        p->zMalloc = 0;
      }

      p->flags = MEM_Invalid;
    }
    db->mallocFailed = malloc_failed;
  }
}

/*
** Delete a VdbeFrame object and its contents. VdbeFrame objects are
................................................................................
      for(j=0; i>=apSub[j]->nOp; j++){
        i -= apSub[j]->nOp;
      }
      pOp = &apSub[j]->aOp[i];
    }
    if( p->explain==1 ){
      pMem->flags = MEM_Int;
      pMem->type = SQLITE_INTEGER;
      pMem->u.i = i;                                /* Program counter */
      pMem++;
  
      pMem->flags = MEM_Static|MEM_Str|MEM_Term;
      pMem->z = (char*)sqlite3OpcodeName(pOp->opcode); /* Opcode */
      assert( pMem->z!=0 );
      pMem->n = sqlite3Strlen30(pMem->z);
      pMem->type = SQLITE_TEXT;
      pMem->enc = SQLITE_UTF8;
      pMem++;

      /* When an OP_Program opcode is encounter (the only opcode that has
      ** a P4_SUBPROGRAM argument), expand the size of the array of subprograms
      ** kept in p->aMem[9].z to hold the new program - assuming this subprogram
      ** has not already been seen.
................................................................................
          pSub->n = nSub*sizeof(SubProgram*);
        }
      }
    }

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p1;                          /* P1 */
    pMem->type = SQLITE_INTEGER;
    pMem++;

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p2;                          /* P2 */
    pMem->type = SQLITE_INTEGER;
    pMem++;

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p3;                          /* P3 */
    pMem->type = SQLITE_INTEGER;
    pMem++;

    if( sqlite3VdbeMemGrow(pMem, 32, 0) ){            /* P4 */
      assert( p->db->mallocFailed );
      return SQLITE_ERROR;
    }
    pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
................................................................................
    if( zP4!=pMem->z ){
      sqlite3VdbeMemSetStr(pMem, zP4, -1, SQLITE_UTF8, 0);
    }else{
      assert( pMem->z!=0 );
      pMem->n = sqlite3Strlen30(pMem->z);
      pMem->enc = SQLITE_UTF8;
    }
    pMem->type = SQLITE_TEXT;
    pMem++;

    if( p->explain==1 ){
      if( sqlite3VdbeMemGrow(pMem, 4, 0) ){
        assert( p->db->mallocFailed );
        return SQLITE_ERROR;
      }
      pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
      pMem->n = 2;
      sqlite3_snprintf(3, pMem->z, "%.2x", pOp->p5);   /* P5 */
      pMem->type = SQLITE_TEXT;
      pMem->enc = SQLITE_UTF8;
      pMem++;
  
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
      if( sqlite3VdbeMemGrow(pMem, 500, 0) ){
        assert( p->db->mallocFailed );
        return SQLITE_ERROR;
      }
      pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
      pMem->n = displayComment(pOp, zP4, pMem->z, 500);
      pMem->type = SQLITE_TEXT;
      pMem->enc = SQLITE_UTF8;
#else
      pMem->flags = MEM_Null;                       /* Comment */
      pMem->type = SQLITE_NULL;
#endif
    }

    p->nResColumn = 8 - 4*(p->explain-1);
    p->pResultSet = &p->aMem[1];
    p->rc = SQLITE_OK;
    rc = SQLITE_ROW;
................................................................................
*/
void sqlite3VdbePrintSql(Vdbe *p){
  const char *z = 0;
  if( p->zSql ){
    z = p->zSql;
  }else if( p->nOp>=1 ){
    const VdbeOp *pOp = &p->aOp[0];
    if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
      z = pOp->p4.z;
      while( sqlite3Isspace(*z) ) z++;
    }
  }
  if( z ) printf("SQL: [%s]\n", z);
}
#endif
................................................................................
*/
void sqlite3VdbeIOTraceSql(Vdbe *p){
  int nOp = p->nOp;
  VdbeOp *pOp;
  if( sqlite3IoTrace==0 ) return;
  if( nOp<1 ) return;
  pOp = &p->aOp[0];
  if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
    int i, j;
    char z[1000];
    sqlite3_snprintf(sizeof(z), z, "%s", pOp->p4.z);
    for(i=0; sqlite3Isspace(z[i]); i++){}
    for(j=0; z[i]; i++){
      if( sqlite3Isspace(z[i]) ){
        if( z[i-1]!=' ' ){
................................................................................
    memcpy(p->azVar, pParse->azVar, p->nzVar*sizeof(p->azVar[0]));
    memset(pParse->azVar, 0, pParse->nzVar*sizeof(pParse->azVar[0]));
  }
  if( p->aMem ){
    p->aMem--;                      /* aMem[] goes from 1..nMem */
    p->nMem = nMem;                 /*       not from 0..nMem-1 */
    for(n=1; n<=nMem; n++){
      p->aMem[n].flags = MEM_Invalid;
      p->aMem[n].db = db;
    }
  }
  p->explain = pParse->explain;
  sqlite3VdbeRewind(p);
}

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

#ifdef SQLITE_DEBUG
  /* Execute assert() statements to ensure that the Vdbe.apCsr[] and 
  ** Vdbe.aMem[] arrays have already been cleaned up.  */
  int i;
  if( p->apCsr ) for(i=0; i<p->nCursor; i++) assert( p->apCsr[i]==0 );
  if( p->aMem ){
    for(i=1; i<=p->nMem; i++) assert( p->aMem[i].flags==MEM_Invalid );
  }
#endif

  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = 0;
  p->pResultSet = 0;
}

** routine, then a pointer to a dummy VdbeOp will be returned.  That opcode
** is readable but not writable, though it is cast to a writable value.
** The return of a dummy opcode allows the call to continue functioning
** after a OOM fault without having to check to see if the return from 
** this routine is a valid pointer.  But because the dummy.opcode is 0,
** dummy will never be written to.  This is verified by code inspection and
** by running with Valgrind.








*/
VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
  /* C89 specifies that the constant "dummy" will be initialized to all
  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
  static VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
  assert( p->magic==VDBE_MAGIC_INIT );
  if( addr<0 ){



    addr = p->nOp - 1;
  }
  assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
  if( p->db->mallocFailed ){
    return (VdbeOp*)&dummy;
  }else{
    return &p->aOp[addr];
................................................................................
      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_Frame|MEM_RowSet) ){
        sqlite3VdbeMemRelease(p);
      }else if( p->zMalloc ){
        sqlite3DbFree(db, p->zMalloc);
        p->zMalloc = 0;
      }

      p->flags = MEM_Undefined;
    }
    db->mallocFailed = malloc_failed;
  }
}

/*
** Delete a VdbeFrame object and its contents. VdbeFrame objects are
................................................................................
      for(j=0; i>=apSub[j]->nOp; j++){
        i -= apSub[j]->nOp;
      }
      pOp = &apSub[j]->aOp[i];
    }
    if( p->explain==1 ){
      pMem->flags = MEM_Int;
      pMem->memType = MEM_Int;
      pMem->u.i = i;                                /* Program counter */
      pMem++;
  
      pMem->flags = MEM_Static|MEM_Str|MEM_Term;
      pMem->z = (char*)sqlite3OpcodeName(pOp->opcode); /* Opcode */
      assert( pMem->z!=0 );
      pMem->n = sqlite3Strlen30(pMem->z);
      pMem->memType = MEM_Str;
      pMem->enc = SQLITE_UTF8;
      pMem++;

      /* When an OP_Program opcode is encounter (the only opcode that has
      ** a P4_SUBPROGRAM argument), expand the size of the array of subprograms
      ** kept in p->aMem[9].z to hold the new program - assuming this subprogram
      ** has not already been seen.
................................................................................
          pSub->n = nSub*sizeof(SubProgram*);
        }
      }
    }

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p1;                          /* P1 */
    pMem->memType = MEM_Int;
    pMem++;

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p2;                          /* P2 */
    pMem->memType = MEM_Int;
    pMem++;

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p3;                          /* P3 */
    pMem->memType = MEM_Int;
    pMem++;

    if( sqlite3VdbeMemGrow(pMem, 32, 0) ){            /* P4 */
      assert( p->db->mallocFailed );
      return SQLITE_ERROR;
    }
    pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
................................................................................
    if( zP4!=pMem->z ){
      sqlite3VdbeMemSetStr(pMem, zP4, -1, SQLITE_UTF8, 0);
    }else{
      assert( pMem->z!=0 );
      pMem->n = sqlite3Strlen30(pMem->z);
      pMem->enc = SQLITE_UTF8;
    }
    pMem->memType = MEM_Str;
    pMem++;

    if( p->explain==1 ){
      if( sqlite3VdbeMemGrow(pMem, 4, 0) ){
        assert( p->db->mallocFailed );
        return SQLITE_ERROR;
      }
      pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
      pMem->n = 2;
      sqlite3_snprintf(3, pMem->z, "%.2x", pOp->p5);   /* P5 */
      pMem->memType = MEM_Str;
      pMem->enc = SQLITE_UTF8;
      pMem++;
  
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
      if( sqlite3VdbeMemGrow(pMem, 500, 0) ){
        assert( p->db->mallocFailed );
        return SQLITE_ERROR;
      }
      pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
      pMem->n = displayComment(pOp, zP4, pMem->z, 500);
      pMem->memType = MEM_Str;
      pMem->enc = SQLITE_UTF8;
#else
      pMem->flags = MEM_Null;                       /* Comment */
      pMem->memType = MEM_Null;
#endif
    }

    p->nResColumn = 8 - 4*(p->explain-1);
    p->pResultSet = &p->aMem[1];
    p->rc = SQLITE_OK;
    rc = SQLITE_ROW;
................................................................................
*/
void sqlite3VdbePrintSql(Vdbe *p){
  const char *z = 0;
  if( p->zSql ){
    z = p->zSql;
  }else if( p->nOp>=1 ){
    const VdbeOp *pOp = &p->aOp[0];
    if( pOp->opcode==OP_Init && pOp->p4.z!=0 ){
      z = pOp->p4.z;
      while( sqlite3Isspace(*z) ) z++;
    }
  }
  if( z ) printf("SQL: [%s]\n", z);
}
#endif
................................................................................
*/
void sqlite3VdbeIOTraceSql(Vdbe *p){
  int nOp = p->nOp;
  VdbeOp *pOp;
  if( sqlite3IoTrace==0 ) return;
  if( nOp<1 ) return;
  pOp = &p->aOp[0];
  if( pOp->opcode==OP_Init && pOp->p4.z!=0 ){
    int i, j;
    char z[1000];
    sqlite3_snprintf(sizeof(z), z, "%s", pOp->p4.z);
    for(i=0; sqlite3Isspace(z[i]); i++){}
    for(j=0; z[i]; i++){
      if( sqlite3Isspace(z[i]) ){
        if( z[i-1]!=' ' ){
................................................................................
    memcpy(p->azVar, pParse->azVar, p->nzVar*sizeof(p->azVar[0]));
    memset(pParse->azVar, 0, pParse->nzVar*sizeof(pParse->azVar[0]));
  }
  if( p->aMem ){
    p->aMem--;                      /* aMem[] goes from 1..nMem */
    p->nMem = nMem;                 /*       not from 0..nMem-1 */
    for(n=1; n<=nMem; n++){
      p->aMem[n].flags = MEM_Undefined;
      p->aMem[n].db = db;
    }
  }
  p->explain = pParse->explain;
  sqlite3VdbeRewind(p);
}

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

#ifdef SQLITE_DEBUG
  /* Execute assert() statements to ensure that the Vdbe.apCsr[] and 
  ** Vdbe.aMem[] arrays have already been cleaned up.  */
  int i;
  if( p->apCsr ) for(i=0; i<p->nCursor; i++) assert( p->apCsr[i]==0 );
  if( p->aMem ){
    for(i=1; i<=p->nMem; i++) assert( p->aMem[i].flags==MEM_Undefined );
  }
#endif

  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = 0;
  p->pResultSet = 0;
}

  ** blob_bytes() functions.
  **
  ** The sqlite3_blob_close() function finalizes the vdbe program,
  ** which closes the b-tree cursor and (possibly) commits the 
  ** transaction.
  */
  static const VdbeOpList openBlob[] = {
    {OP_Transaction, 0, 0, 0},     /* 0: Start a transaction */
    {OP_VerifyCookie, 0, 0, 0},    /* 1: Check the schema cookie */
    {OP_TableLock, 0, 0, 0},       /* 2: Acquire a read or write lock */

    /* One of the following two instructions is replaced by an OP_Noop. */
    {OP_OpenRead, 0, 0, 0},        /* 3: Open cursor 0 for reading */
    {OP_OpenWrite, 0, 0, 0},       /* 4: Open cursor 0 for read/write */

    {OP_Variable, 1, 1, 1},        /* 5: Push the rowid to the stack */
    {OP_NotExists, 0, 10, 1},      /* 6: Seek the cursor */
    {OP_Column, 0, 0, 1},          /* 7  */
    {OP_ResultRow, 1, 0, 0},       /* 8  */
    {OP_Goto, 0, 5, 0},            /* 9  */
    {OP_Close, 0, 0, 0},           /* 10 */
    {OP_Halt, 0, 0, 0},            /* 11 */
  };

  int rc = SQLITE_OK;
  char *zErr = 0;
  Table *pTab;
  Parse *pParse = 0;
  Incrblob *pBlob = 0;
................................................................................

    pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(pParse);
    assert( pBlob->pStmt || db->mallocFailed );
    if( pBlob->pStmt ){
      Vdbe *v = (Vdbe *)pBlob->pStmt;
      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);

      sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);


      /* Configure the OP_Transaction */
      sqlite3VdbeChangeP1(v, 0, iDb);
      sqlite3VdbeChangeP2(v, 0, flags);

      /* Configure the OP_VerifyCookie */
      sqlite3VdbeChangeP1(v, 1, iDb);

      sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);
      sqlite3VdbeChangeP3(v, 1, pTab->pSchema->iGeneration);



      /* Make sure a mutex is held on the table to be accessed */
      sqlite3VdbeUsesBtree(v, iDb); 

      /* Configure the OP_TableLock instruction */
#ifdef SQLITE_OMIT_SHARED_CACHE
      sqlite3VdbeChangeToNoop(v, 2);
#else
      sqlite3VdbeChangeP1(v, 2, iDb);
      sqlite3VdbeChangeP2(v, 2, pTab->tnum);
      sqlite3VdbeChangeP3(v, 2, flags);
      sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
#endif

      /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
      ** parameter of the other to pTab->tnum.  */
      sqlite3VdbeChangeToNoop(v, 4 - flags);
      sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
      sqlite3VdbeChangeP3(v, 3 + flags, iDb);

      /* Configure the number of columns. Configure the cursor to
      ** think that the table has one more column than it really
      ** does. An OP_Column to retrieve this imaginary column will
      ** always return an SQL NULL. This is useful because it means
      ** we can invoke OP_Column to fill in the vdbe cursors type 
      ** and offset cache without causing any IO.
      */
      sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
      sqlite3VdbeChangeP2(v, 7, pTab->nCol);
      if( !db->mallocFailed ){
        pParse->nVar = 1;
        pParse->nMem = 1;
        pParse->nTab = 1;
        sqlite3VdbeMakeReady(v, pParse);
      }
    }

  ** blob_bytes() functions.
  **
  ** The sqlite3_blob_close() function finalizes the vdbe program,
  ** which closes the b-tree cursor and (possibly) commits the 
  ** transaction.
  */
  static const VdbeOpList openBlob[] = {
    /* {OP_Transaction, 0, 0, 0},  // 0: Inserted separately */

    {OP_TableLock, 0, 0, 0},       /* 1: Acquire a read or write lock */

    /* One of the following two instructions is replaced by an OP_Noop. */
    {OP_OpenRead, 0, 0, 0},        /* 2: Open cursor 0 for reading */
    {OP_OpenWrite, 0, 0, 0},       /* 3: Open cursor 0 for read/write */

    {OP_Variable, 1, 1, 1},        /* 4: Push the rowid to the stack */
    {OP_NotExists, 0, 10, 1},      /* 5: Seek the cursor */
    {OP_Column, 0, 0, 1},          /* 6  */
    {OP_ResultRow, 1, 0, 0},       /* 7  */
    {OP_Goto, 0, 4, 0},            /* 8  */
    {OP_Close, 0, 0, 0},           /* 9  */
    {OP_Halt, 0, 0, 0},            /* 10 */
  };

  int rc = SQLITE_OK;
  char *zErr = 0;
  Table *pTab;
  Parse *pParse = 0;
  Incrblob *pBlob = 0;
................................................................................

    pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(pParse);
    assert( pBlob->pStmt || db->mallocFailed );
    if( pBlob->pStmt ){
      Vdbe *v = (Vdbe *)pBlob->pStmt;
      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);










      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, flags, 
                           pTab->pSchema->schema_cookie,
                           pTab->pSchema->iGeneration);
      sqlite3VdbeChangeP5(v, 1);     
      sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);

      /* Make sure a mutex is held on the table to be accessed */
      sqlite3VdbeUsesBtree(v, iDb); 

      /* Configure the OP_TableLock instruction */
#ifdef SQLITE_OMIT_SHARED_CACHE
      sqlite3VdbeChangeToNoop(v, 1);
#else
      sqlite3VdbeChangeP1(v, 1, iDb);
      sqlite3VdbeChangeP2(v, 1, pTab->tnum);
      sqlite3VdbeChangeP3(v, 1, flags);
      sqlite3VdbeChangeP4(v, 1, pTab->zName, P4_TRANSIENT);
#endif

      /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
      ** parameter of the other to pTab->tnum.  */
      sqlite3VdbeChangeToNoop(v, 3 - flags);
      sqlite3VdbeChangeP2(v, 2 + flags, pTab->tnum);
      sqlite3VdbeChangeP3(v, 2 + flags, iDb);

      /* Configure the number of columns. Configure the cursor to
      ** think that the table has one more column than it really
      ** does. An OP_Column to retrieve this imaginary column will
      ** always return an SQL NULL. This is useful because it means
      ** we can invoke OP_Column to fill in the vdbe cursors type 
      ** and offset cache without causing any IO.
      */
      sqlite3VdbeChangeP4(v, 2+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
      sqlite3VdbeChangeP2(v, 6, pTab->nCol);
      if( !db->mallocFailed ){
        pParse->nVar = 1;
        pParse->nMem = 1;
        pParse->nTab = 1;
        sqlite3VdbeMakeReady(v, pParse);
      }
    }

    sqlite3VdbeMemSetNull(p);
  }
}

/*
** Release any memory held by the Mem. This may leave the Mem in an
** inconsistent state, for example with (Mem.z==0) and
** (Mem.type==SQLITE_TEXT).
*/
void sqlite3VdbeMemRelease(Mem *p){
  VdbeMemRelease(p);
  if( p->zMalloc ){
    sqlite3DbFree(p->db, p->zMalloc);
    p->zMalloc = 0;
  }
................................................................................
    pFrame->pParent = pFrame->v->pDelFrame;
    pFrame->v->pDelFrame = pFrame;
  }
  if( pMem->flags & MEM_RowSet ){
    sqlite3RowSetClear(pMem->u.pRowSet);
  }
  MemSetTypeFlag(pMem, MEM_Null);
  pMem->type = SQLITE_NULL;
}
void sqlite3ValueSetNull(sqlite3_value *p){
  sqlite3VdbeMemSetNull((Mem*)p); 
}

/*
** Delete any previous value and set the value to be a BLOB of length
** n containing all zeros.
*/
void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
  sqlite3VdbeMemRelease(pMem);
  pMem->flags = MEM_Blob|MEM_Zero;
  pMem->type = SQLITE_BLOB;
  pMem->n = 0;
  if( n<0 ) n = 0;
  pMem->u.nZero = n;
  pMem->enc = SQLITE_UTF8;

#ifdef SQLITE_OMIT_INCRBLOB
  sqlite3VdbeMemGrow(pMem, n, 0);
................................................................................
** Delete any previous value and set the value stored in *pMem to val,
** manifest type INTEGER.
*/
void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
  sqlite3VdbeMemRelease(pMem);
  pMem->u.i = val;
  pMem->flags = MEM_Int;
  pMem->type = SQLITE_INTEGER;
}

#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type REAL.
*/
................................................................................
void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
  if( sqlite3IsNaN(val) ){
    sqlite3VdbeMemSetNull(pMem);
  }else{
    sqlite3VdbeMemRelease(pMem);
    pMem->r = val;
    pMem->flags = MEM_Real;
    pMem->type = SQLITE_FLOAT;
  }
}
#endif

/*
** Delete any previous value and set the value of pMem to be an
** empty boolean index.
................................................................................
** copies are not misused.
*/
void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
  int i;
  Mem *pX;
  for(i=1, pX=&pVdbe->aMem[1]; i<=pVdbe->nMem; i++, pX++){
    if( pX->pScopyFrom==pMem ){
      pX->flags |= MEM_Invalid;
      pX->pScopyFrom = 0;
    }
  }
  pMem->pScopyFrom = 0;
}
#endif /* SQLITE_DEBUG */

................................................................................
    pMem->xDel = xDel;
    flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
  }

  pMem->n = nByte;
  pMem->flags = flags;
  pMem->enc = (enc==0 ? SQLITE_UTF8 : enc);
  pMem->type = (enc==0 ? SQLITE_BLOB : SQLITE_TEXT);

#ifndef SQLITE_OMIT_UTF16
  if( pMem->enc!=SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
    return SQLITE_NOMEM;
  }
#endif

................................................................................
  if( offset+amt<=available ){
    sqlite3VdbeMemRelease(pMem);
    pMem->z = &zData[offset];
    pMem->flags = MEM_Blob|MEM_Ephem;
  }else if( SQLITE_OK==(rc = sqlite3VdbeMemGrow(pMem, amt+2, 0)) ){
    pMem->flags = MEM_Blob|MEM_Dyn|MEM_Term;
    pMem->enc = 0;
    pMem->type = SQLITE_BLOB;
    if( key ){
      rc = sqlite3BtreeKey(pCur, offset, amt, pMem->z);
    }else{
      rc = sqlite3BtreeData(pCur, offset, amt, pMem->z);
    }
    pMem->z[amt] = 0;
    pMem->z[amt+1] = 0;
................................................................................
/*
** Create a new sqlite3_value object.
*/
sqlite3_value *sqlite3ValueNew(sqlite3 *db){
  Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
  if( p ){
    p->flags = MEM_Null;
    p->type = SQLITE_NULL;
    p->db = db;
  }
  return p;
}

/*
** Context object passed by sqlite3Stat4ProbeSetValue() through to 
................................................................................
        if( pRec->pKeyInfo ){
          assert( pRec->pKeyInfo->nField+pRec->pKeyInfo->nXField==nCol );
          assert( pRec->pKeyInfo->enc==ENC(db) );
          pRec->flags = UNPACKED_PREFIX_MATCH;
          pRec->aMem = (Mem *)((u8*)pRec + ROUND8(sizeof(UnpackedRecord)));
          for(i=0; i<nCol; i++){
            pRec->aMem[i].flags = MEM_Null;
            pRec->aMem[i].type = SQLITE_NULL;
            pRec->aMem[i].db = db;
          }
        }else{
          sqlite3DbFree(db, pRec);
          pRec = 0;
        }
      }
................................................................................
    if( pVal==0 ) goto no_mem;
    if( ExprHasProperty(pExpr, EP_IntValue) ){
      sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
    }else{
      zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
      if( zVal==0 ) goto no_mem;
      sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
      if( op==TK_FLOAT ) pVal->type = SQLITE_FLOAT;
    }
    if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
      sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
    }else{
      sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
    }
    if( pVal->flags & (MEM_Int|MEM_Real) ) pVal->flags &= ~MEM_Str;

    sqlite3VdbeMemSetNull(p);
  }
}

/*
** Release any memory held by the Mem. This may leave the Mem in an
** inconsistent state, for example with (Mem.z==0) and
** (Mem.memType==MEM_Str).
*/
void sqlite3VdbeMemRelease(Mem *p){
  VdbeMemRelease(p);
  if( p->zMalloc ){
    sqlite3DbFree(p->db, p->zMalloc);
    p->zMalloc = 0;
  }
................................................................................
    pFrame->pParent = pFrame->v->pDelFrame;
    pFrame->v->pDelFrame = pFrame;
  }
  if( pMem->flags & MEM_RowSet ){
    sqlite3RowSetClear(pMem->u.pRowSet);
  }
  MemSetTypeFlag(pMem, MEM_Null);
  pMem->memType = MEM_Null;
}
void sqlite3ValueSetNull(sqlite3_value *p){
  sqlite3VdbeMemSetNull((Mem*)p); 
}

/*
** Delete any previous value and set the value to be a BLOB of length
** n containing all zeros.
*/
void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
  sqlite3VdbeMemRelease(pMem);
  pMem->flags = MEM_Blob|MEM_Zero;
  pMem->memType = MEM_Blob;
  pMem->n = 0;
  if( n<0 ) n = 0;
  pMem->u.nZero = n;
  pMem->enc = SQLITE_UTF8;

#ifdef SQLITE_OMIT_INCRBLOB
  sqlite3VdbeMemGrow(pMem, n, 0);
................................................................................
** Delete any previous value and set the value stored in *pMem to val,
** manifest type INTEGER.
*/
void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
  sqlite3VdbeMemRelease(pMem);
  pMem->u.i = val;
  pMem->flags = MEM_Int;
  pMem->memType = MEM_Int;
}

#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type REAL.
*/
................................................................................
void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
  if( sqlite3IsNaN(val) ){
    sqlite3VdbeMemSetNull(pMem);
  }else{
    sqlite3VdbeMemRelease(pMem);
    pMem->r = val;
    pMem->flags = MEM_Real;
    pMem->memType = MEM_Real;
  }
}
#endif

/*
** Delete any previous value and set the value of pMem to be an
** empty boolean index.
................................................................................
** copies are not misused.
*/
void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
  int i;
  Mem *pX;
  for(i=1, pX=&pVdbe->aMem[1]; i<=pVdbe->nMem; i++, pX++){
    if( pX->pScopyFrom==pMem ){
      pX->flags |= MEM_Undefined;
      pX->pScopyFrom = 0;
    }
  }
  pMem->pScopyFrom = 0;
}
#endif /* SQLITE_DEBUG */

................................................................................
    pMem->xDel = xDel;
    flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
  }

  pMem->n = nByte;
  pMem->flags = flags;
  pMem->enc = (enc==0 ? SQLITE_UTF8 : enc);
  pMem->memType = flags&0x1f;

#ifndef SQLITE_OMIT_UTF16
  if( pMem->enc!=SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
    return SQLITE_NOMEM;
  }
#endif

................................................................................
  if( offset+amt<=available ){
    sqlite3VdbeMemRelease(pMem);
    pMem->z = &zData[offset];
    pMem->flags = MEM_Blob|MEM_Ephem;
  }else if( SQLITE_OK==(rc = sqlite3VdbeMemGrow(pMem, amt+2, 0)) ){
    pMem->flags = MEM_Blob|MEM_Dyn|MEM_Term;
    pMem->enc = 0;
    pMem->memType = MEM_Blob;
    if( key ){
      rc = sqlite3BtreeKey(pCur, offset, amt, pMem->z);
    }else{
      rc = sqlite3BtreeData(pCur, offset, amt, pMem->z);
    }
    pMem->z[amt] = 0;
    pMem->z[amt+1] = 0;
................................................................................
/*
** Create a new sqlite3_value object.
*/
sqlite3_value *sqlite3ValueNew(sqlite3 *db){
  Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
  if( p ){
    p->flags = MEM_Null;
    p->memType = MEM_Null;
    p->db = db;
  }
  return p;
}

/*
** Context object passed by sqlite3Stat4ProbeSetValue() through to 
................................................................................
        if( pRec->pKeyInfo ){
          assert( pRec->pKeyInfo->nField+pRec->pKeyInfo->nXField==nCol );
          assert( pRec->pKeyInfo->enc==ENC(db) );
          pRec->flags = UNPACKED_PREFIX_MATCH;
          pRec->aMem = (Mem *)((u8*)pRec + ROUND8(sizeof(UnpackedRecord)));
          for(i=0; i<nCol; i++){
            pRec->aMem[i].flags = MEM_Null;
            pRec->aMem[i].memType = MEM_Null;
            pRec->aMem[i].db = db;
          }
        }else{
          sqlite3DbFree(db, pRec);
          pRec = 0;
        }
      }
................................................................................
    if( pVal==0 ) goto no_mem;
    if( ExprHasProperty(pExpr, EP_IntValue) ){
      sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
    }else{
      zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
      if( zVal==0 ) goto no_mem;
      sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
      if( op==TK_FLOAT ) pVal->memType = MEM_Real;
    }
    if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
      sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
    }else{
      sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
    }
    if( pVal->flags & (MEM_Int|MEM_Real) ) pVal->flags &= ~MEM_Str;

    sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
    VdbeComment((v, "init LEFT JOIN no-match flag"));
  }

  /* Special case of a FROM clause subquery implemented as a co-routine */
  if( pTabItem->viaCoroutine ){
    int regYield = pTabItem->regReturn;
    sqlite3VdbeAddOp2(v, OP_Integer, pTabItem->addrFillSub-1, regYield);
    pLevel->p2 =  sqlite3VdbeAddOp1(v, OP_Yield, regYield);
    VdbeComment((v, "next row of co-routine %s", pTabItem->pTab->zName));
    sqlite3VdbeAddOp2(v, OP_If, regYield+1, addrBrk);
    pLevel->op = OP_Goto;
  }else

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
    /* Case 1:  The table is a virtual-table.  Use the VFilter and VNext
    **          to access the data.
................................................................................
      pLevel->op = OP_Noop;
    }else if( bRev ){
      pLevel->op = OP_Prev;
    }else{
      pLevel->op = OP_Next;
    }
    pLevel->p1 = iIdxCur;


    if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){
      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
    }else{
      assert( pLevel->p5==0 );
    }
  }else

................................................................................
    */
    if( pWC->nTerm>1 ){
      int iTerm;
      for(iTerm=0; iTerm<pWC->nTerm; iTerm++){
        Expr *pExpr = pWC->a[iTerm].pExpr;
        if( &pWC->a[iTerm] == pTerm ) continue;
        if( ExprHasProperty(pExpr, EP_FromJoin) ) continue;


        if( pWC->a[iTerm].wtFlags & (TERM_ORINFO) ) continue;
        if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue;
        pExpr = sqlite3ExprDup(db, pExpr, 0);
        pAndExpr = sqlite3ExprAnd(db, pAndExpr, pExpr);
      }
      if( pAndExpr ){
        pAndExpr = sqlite3PExpr(pParse, TK_AND, 0, pAndExpr, 0);
      }
................................................................................
      pNew->nOut = nRowEst + nInMul + nIn;
    }else if( pTerm->eOperator & (WO_EQ) ){
      assert(
        (pNew->wsFlags & (WHERE_COLUMN_NULL|WHERE_COLUMN_IN|WHERE_SKIPSCAN))!=0
        || nInMul==0
      );
      pNew->wsFlags |= WHERE_COLUMN_EQ;
      if( iCol<0  
       || (pProbe->onError!=OE_None && nInMul==0
           && pNew->u.btree.nEq==pProbe->nKeyCol-1)
      ){
        assert( (pNew->wsFlags & WHERE_COLUMN_IN)==0 || iCol<0 );



        pNew->wsFlags |= WHERE_ONEROW;

      }
      pNew->u.btree.nEq++;
      pNew->nOut = nRowEst + nInMul;
    }else if( pTerm->eOperator & (WO_ISNULL) ){
      pNew->wsFlags |= WHERE_COLUMN_NULL;
      pNew->u.btree.nEq++;
      /* TUNING: IS NULL selects 2 rows */
................................................................................

  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  initMaskSet(pMaskSet);
  whereClauseInit(&pWInfo->sWC, pWInfo);
  whereSplit(&pWInfo->sWC, pWhere, TK_AND);
  sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
    
  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  for(ii=0; ii<sWLB.pWC->nTerm; ii++){
    if( nTabList==0 || sqlite3ExprIsConstantNotJoin(sWLB.pWC->a[ii].pExpr) ){
      sqlite3ExprIfFalse(pParse, sWLB.pWC->a[ii].pExpr, pWInfo->iBreak,
................................................................................
      pLevel->iIdxCur = iIndexCur;
      assert( pIx->pSchema==pTab->pSchema );
      assert( iIndexCur>=0 );
      sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb);
      sqlite3VdbeSetP4KeyInfo(pParse, pIx);
      VdbeComment((v, "%s", pIx->zName));
    }
    sqlite3CodeVerifySchema(pParse, iDb);
    notReady &= ~getMask(&pWInfo->sMaskSet, pTabItem->iCursor);
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
  if( db->mallocFailed ) goto whereBeginError;

  /* Generate the code to do the search.  Each iteration of the for
  ** loop below generates code for a single nested loop of the VM
................................................................................
  sqlite3ExprCacheClear(pParse);
  for(i=pWInfo->nLevel-1; i>=0; i--){
    int addr;
    pLevel = &pWInfo->a[i];
    pLoop = pLevel->pWLoop;
    sqlite3VdbeResolveLabel(v, pLevel->addrCont);
    if( pLevel->op!=OP_Noop ){
      sqlite3VdbeAddOp2(v, pLevel->op, pLevel->p1, pLevel->p2);
      sqlite3VdbeChangeP5(v, pLevel->p5);
    }
    if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
................................................................................
  /* The "break" point is here, just past the end of the outer loop.
  ** Set it.
  */
  sqlite3VdbeResolveLabel(v, pWInfo->iBreak);

  assert( pWInfo->nLevel<=pTabList->nSrc );
  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){


    Index *pIdx = 0;
    struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom];
    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );
    pLoop = pLevel->pWLoop;

























    /* Close all of the cursors that were opened by sqlite3WhereBegin.
    ** Except, do not close cursors that will be reused by the OR optimization
    ** (WHERE_OMIT_OPEN_CLOSE).  And do not close the OP_OpenWrite cursors
    ** created for the ONEPASS optimization.
    */
    if( (pTab->tabFlags & TF_Ephemeral)==0
................................................................................
    */
    if( pLoop->wsFlags & (WHERE_INDEXED|WHERE_IDX_ONLY) ){
      pIdx = pLoop->u.btree.pIndex;
    }else if( pLoop->wsFlags & WHERE_MULTI_OR ){
      pIdx = pLevel->u.pCovidx;
    }
    if( pIdx && !db->mallocFailed ){
      int k, last;
      VdbeOp *pOp;

      last = sqlite3VdbeCurrentAddr(v);
      k = pLevel->addrBody;
      pOp = sqlite3VdbeGetOp(v, k);
      for(; k<last; k++, pOp++){
        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column ){
          int x = pOp->p2;

    sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
    VdbeComment((v, "init LEFT JOIN no-match flag"));
  }

  /* Special case of a FROM clause subquery implemented as a co-routine */
  if( pTabItem->viaCoroutine ){
    int regYield = pTabItem->regReturn;
    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pTabItem->addrFillSub);
    pLevel->p2 =  sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk);
    VdbeComment((v, "next row of \"%s\"", pTabItem->pTab->zName));

    pLevel->op = OP_Goto;
  }else

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
    /* Case 1:  The table is a virtual-table.  Use the VFilter and VNext
    **          to access the data.
................................................................................
      pLevel->op = OP_Noop;
    }else if( bRev ){
      pLevel->op = OP_Prev;
    }else{
      pLevel->op = OP_Next;
    }
    pLevel->p1 = iIdxCur;
    assert( (WHERE_UNQ_WANTED>>16)==1 );
    pLevel->p3 = (pLoop->wsFlags>>16)&1;
    if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){
      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
    }else{
      assert( pLevel->p5==0 );
    }
  }else

................................................................................
    */
    if( pWC->nTerm>1 ){
      int iTerm;
      for(iTerm=0; iTerm<pWC->nTerm; iTerm++){
        Expr *pExpr = pWC->a[iTerm].pExpr;
        if( &pWC->a[iTerm] == pTerm ) continue;
        if( ExprHasProperty(pExpr, EP_FromJoin) ) continue;
        testcase( pWC->a[iTerm].wtFlags & TERM_ORINFO );
        testcase( pWC->a[iTerm].wtFlags & TERM_VIRTUAL );
        if( pWC->a[iTerm].wtFlags & (TERM_ORINFO|TERM_VIRTUAL) ) continue;
        if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue;
        pExpr = sqlite3ExprDup(db, pExpr, 0);
        pAndExpr = sqlite3ExprAnd(db, pAndExpr, pExpr);
      }
      if( pAndExpr ){
        pAndExpr = sqlite3PExpr(pParse, TK_AND, 0, pAndExpr, 0);
      }
................................................................................
      pNew->nOut = nRowEst + nInMul + nIn;
    }else if( pTerm->eOperator & (WO_EQ) ){
      assert(
        (pNew->wsFlags & (WHERE_COLUMN_NULL|WHERE_COLUMN_IN|WHERE_SKIPSCAN))!=0
        || nInMul==0
      );
      pNew->wsFlags |= WHERE_COLUMN_EQ;


      if( iCol<0 || (nInMul==0 && pNew->u.btree.nEq==pProbe->nKeyCol-1)){

        assert( (pNew->wsFlags & WHERE_COLUMN_IN)==0 || iCol<0 );
        if( iCol>=0 && pProbe->onError==OE_None ){
          pNew->wsFlags |= WHERE_UNQ_WANTED;
        }else{
          pNew->wsFlags |= WHERE_ONEROW;
        }
      }
      pNew->u.btree.nEq++;
      pNew->nOut = nRowEst + nInMul;
    }else if( pTerm->eOperator & (WO_ISNULL) ){
      pNew->wsFlags |= WHERE_COLUMN_NULL;
      pNew->u.btree.nEq++;
      /* TUNING: IS NULL selects 2 rows */
................................................................................

  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  initMaskSet(pMaskSet);
  whereClauseInit(&pWInfo->sWC, pWInfo);
  whereSplit(&pWInfo->sWC, pWhere, TK_AND);

    
  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  for(ii=0; ii<sWLB.pWC->nTerm; ii++){
    if( nTabList==0 || sqlite3ExprIsConstantNotJoin(sWLB.pWC->a[ii].pExpr) ){
      sqlite3ExprIfFalse(pParse, sWLB.pWC->a[ii].pExpr, pWInfo->iBreak,
................................................................................
      pLevel->iIdxCur = iIndexCur;
      assert( pIx->pSchema==pTab->pSchema );
      assert( iIndexCur>=0 );
      sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb);
      sqlite3VdbeSetP4KeyInfo(pParse, pIx);
      VdbeComment((v, "%s", pIx->zName));
    }
    if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);
    notReady &= ~getMask(&pWInfo->sMaskSet, pTabItem->iCursor);
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
  if( db->mallocFailed ) goto whereBeginError;

  /* Generate the code to do the search.  Each iteration of the for
  ** loop below generates code for a single nested loop of the VM
................................................................................
  sqlite3ExprCacheClear(pParse);
  for(i=pWInfo->nLevel-1; i>=0; i--){
    int addr;
    pLevel = &pWInfo->a[i];
    pLoop = pLevel->pWLoop;
    sqlite3VdbeResolveLabel(v, pLevel->addrCont);
    if( pLevel->op!=OP_Noop ){
      sqlite3VdbeAddOp3(v, pLevel->op, pLevel->p1, pLevel->p2, pLevel->p3);
      sqlite3VdbeChangeP5(v, pLevel->p5);
    }
    if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
................................................................................
  /* The "break" point is here, just past the end of the outer loop.
  ** Set it.
  */
  sqlite3VdbeResolveLabel(v, pWInfo->iBreak);

  assert( pWInfo->nLevel<=pTabList->nSrc );
  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
    int k, last;
    VdbeOp *pOp;
    Index *pIdx = 0;
    struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom];
    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );
    pLoop = pLevel->pWLoop;

    /* For a co-routine, change all OP_Column references to the table of
    ** the co-routine into OP_SCopy of result contained in a register.
    ** OP_Rowid becomes OP_Null.
    */
    if( pTabItem->viaCoroutine ){
      last = sqlite3VdbeCurrentAddr(v);
      k = pLevel->addrBody;
      pOp = sqlite3VdbeGetOp(v, k);
      for(; k<last; k++, pOp++){
        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column ){
          pOp->opcode = OP_SCopy;
          pOp->p1 = pOp->p2 + pTabItem->regResult;
          pOp->p2 = pOp->p3;
          pOp->p3 = 0;
        }else if( pOp->opcode==OP_Rowid ){
          pOp->opcode = OP_Null;
          pOp->p1 = 0;
          pOp->p3 = 0;
        }
      }
      continue;
    }

    /* Close all of the cursors that were opened by sqlite3WhereBegin.
    ** Except, do not close cursors that will be reused by the OR optimization
    ** (WHERE_OMIT_OPEN_CLOSE).  And do not close the OP_OpenWrite cursors
    ** created for the ONEPASS optimization.
    */
    if( (pTab->tabFlags & TF_Ephemeral)==0
................................................................................
    */
    if( pLoop->wsFlags & (WHERE_INDEXED|WHERE_IDX_ONLY) ){
      pIdx = pLoop->u.btree.pIndex;
    }else if( pLoop->wsFlags & WHERE_MULTI_OR ){
      pIdx = pLevel->u.pCovidx;
    }
    if( pIdx && !db->mallocFailed ){



      last = sqlite3VdbeCurrentAddr(v);
      k = pLevel->addrBody;
      pOp = sqlite3VdbeGetOp(v, k);
      for(; k<last; k++, pOp++){
        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column ){
          int x = pOp->p2;

  int addrBrk;          /* Jump here to break out of the loop */
  int addrNxt;          /* Jump here to start the next IN combination */
  int addrSkip;         /* Jump here for next iteration of skip-scan */
  int addrCont;         /* Jump here to continue with the next loop cycle */
  int addrFirst;        /* First instruction of interior of the loop */
  int addrBody;         /* Beginning of the body of this loop */
  u8 iFrom;             /* Which entry in the FROM clause */
  u8 op, p5;            /* Opcode and P5 of the opcode that ends the loop */
  int p1, p2;           /* Operands of the opcode used to ends the loop */
  union {               /* Information that depends on pWLoop->wsFlags */
    struct {
      int nIn;              /* Number of entries in aInLoop[] */
      struct InLoop {
        int iCur;              /* The VDBE cursor used by this IN operator */
        int addrInTop;         /* Top of the IN loop */
................................................................................
#define WHERE_INDEXED      0x00000200  /* WhereLoop.u.btree.pIndex is valid */
#define WHERE_VIRTUALTABLE 0x00000400  /* WhereLoop.u.vtab is valid */
#define WHERE_IN_ABLE      0x00000800  /* Able to support an IN operator */
#define WHERE_ONEROW       0x00001000  /* Selects no more than one row */
#define WHERE_MULTI_OR     0x00002000  /* OR using multiple indices */
#define WHERE_AUTO_INDEX   0x00004000  /* Uses an ephemeral index */
#define WHERE_SKIPSCAN     0x00008000  /* Uses the skip-scan algorithm */

  int addrBrk;          /* Jump here to break out of the loop */
  int addrNxt;          /* Jump here to start the next IN combination */
  int addrSkip;         /* Jump here for next iteration of skip-scan */
  int addrCont;         /* Jump here to continue with the next loop cycle */
  int addrFirst;        /* First instruction of interior of the loop */
  int addrBody;         /* Beginning of the body of this loop */
  u8 iFrom;             /* Which entry in the FROM clause */
  u8 op, p3, p5;        /* Opcode, P3 & P5 of the opcode that ends the loop */
  int p1, p2;           /* Operands of the opcode used to ends the loop */
  union {               /* Information that depends on pWLoop->wsFlags */
    struct {
      int nIn;              /* Number of entries in aInLoop[] */
      struct InLoop {
        int iCur;              /* The VDBE cursor used by this IN operator */
        int addrInTop;         /* Top of the IN loop */
................................................................................
#define WHERE_INDEXED      0x00000200  /* WhereLoop.u.btree.pIndex is valid */
#define WHERE_VIRTUALTABLE 0x00000400  /* WhereLoop.u.vtab is valid */
#define WHERE_IN_ABLE      0x00000800  /* Able to support an IN operator */
#define WHERE_ONEROW       0x00001000  /* Selects no more than one row */
#define WHERE_MULTI_OR     0x00002000  /* OR using multiple indices */
#define WHERE_AUTO_INDEX   0x00004000  /* Uses an ephemeral index */
#define WHERE_SKIPSCAN     0x00008000  /* Uses the skip-scan algorithm */
#define WHERE_UNQ_WANTED   0x00010000  /* WHERE_ONEROW would have been helpful*/

  }
} {{} {} {} 3 6 {}}
do_test 3.1 {
  regexp {OpenEphemeral} [db eval {
    EXPLAIN SELECT DISTINCT a, b FROM t3 ORDER BY +a, +b;
  }]
} {0}


























finish_test

  }
} {{} {} {} 3 6 {}}
do_test 3.1 {
  regexp {OpenEphemeral} [db eval {
    EXPLAIN SELECT DISTINCT a, b FROM t3 ORDER BY +a, +b;
  }]
} {0}

#-------------------------------------------------------------------------
# Ticket  [fccbde530a6583bf2748400919f1603d5425995c] (2014-01-08)
# The logic that computes DISTINCT sometimes thinks that a zeroblob()
# and a blob of all zeros are different when they should be the same. 
#
do_execsql_test 4.1 {
  DROP TABLE IF EXISTS t1;
  DROP TABLE IF EXISTS t2;
  CREATE TABLE t1(a INTEGER);
  INSERT INTO t1 VALUES(3);
  INSERT INTO t1 VALUES(2);
  INSERT INTO t1 VALUES(1);
  INSERT INTO t1 VALUES(2);
  INSERT INTO t1 VALUES(3);
  INSERT INTO t1 VALUES(1);
  CREATE TABLE t2(x);
  INSERT INTO t2
    SELECT DISTINCT
      CASE a WHEN 1 THEN x'0000000000'
             WHEN 2 THEN zeroblob(5)
             ELSE 'xyzzy' END
      FROM t1;
  SELECT quote(x) FROM t2 ORDER BY 1;
} {'xyzzy' X'0000000000'}

finish_test

      UNION SELECT a,b,c FROM t3
      INTERSECT SELECT a,b,c FROM t3
      EXCEPT SELECT c,b,a FROM t1
      UNION SELECT a,b,c FROM t3
      ORDER BY y COLLATE NOCASE DESC,x,z)))
  }
} {MAD}


















finish_test

      UNION SELECT a,b,c FROM t3
      INTERSECT SELECT a,b,c FROM t3
      EXCEPT SELECT c,b,a FROM t1
      UNION SELECT a,b,c FROM t3
      ORDER BY y COLLATE NOCASE DESC,x,z)))
  }
} {MAD}
do_execsql_test selectA-3.98 {
  WITH RECURSIVE
    xyz(n) AS (
      SELECT upper((SELECT x FROM (
        SELECT x,y,z FROM t2
        INTERSECT SELECT a,b,c FROM t3
        EXCEPT SELECT c,b,a FROM t1
        UNION SELECT a,b,c FROM t3
        INTERSECT SELECT a,b,c FROM t3
        EXCEPT SELECT c,b,a FROM t1
        UNION SELECT a,b,c FROM t3
        ORDER BY y COLLATE NOCASE DESC,x,z)))
      UNION ALL
      SELECT n || '+' FROM xyz WHERE length(n)<5
    )
  SELECT n FROM xyz ORDER BY +n;
} {MAD MAD+ MAD++}

finish_test

  speedtest1_end_test();


  speedtest1_begin_test(990, "ANALYZE");
  speedtest1_exec("ANALYZE");
  speedtest1_end_test();
}




























































































































































/*
** A testset used for debugging speedtest1 itself.
*/
void testset_debug1(void){
  unsigned i, n;
  unsigned x1, x2;
................................................................................
  }

  if( g.bExplain ) printf(".explain\n.echo on\n");
  if( strcmp(zTSet,"main")==0 ){
    testset_main();
  }else if( strcmp(zTSet,"debug1")==0 ){
    testset_debug1();


  }else{
    fatal_error("unknown testset: \"%s\"\n", zTSet);
  }
  speedtest1_final();

  /* Database connection statistics printed after both prepared statements
  ** have been finalized */

  speedtest1_end_test();


  speedtest1_begin_test(990, "ANALYZE");
  speedtest1_exec("ANALYZE");
  speedtest1_end_test();
}

/*
** A testset for common table expressions.  This exercises code
** for views, subqueries, co-routines, etc.
*/
void testset_cte(void){
  static const char *azPuzzle[] = {
    /* Easy */
    "534...9.."
    "67.195..."
    ".98....6."
    "8...6...3"
    "4..8.3..1"
    "....2...6"
    ".6....28."
    "...419..5"
    "...28..79",

    /* Medium */
    "53....9.."
    "6..195..."
    ".98....6."
    "8...6...3"
    "4..8.3..1"
    "....2...6"
    ".6....28."
    "...419..5"
    "....8..79",

    /* Hard */
    "53......."
    "6..195..."
    ".98....6."
    "8...6...3"
    "4..8.3..1"
    "....2...6"
    ".6....28."
    "...419..5"
    "....8..79",
  };
  const char *zPuz;
  double rSpacing;
  int nElem;

  if( g.szTest<25 ){
    zPuz = azPuzzle[0];
  }else if( g.szTest<70 ){
    zPuz = azPuzzle[1];
  }else{
    zPuz = azPuzzle[2];
  }
  speedtest1_begin_test(100, "Sudoku with recursive 'digits'");
  speedtest1_prepare(
    "WITH RECURSIVE\n"
    "  input(sud) AS (VALUES(?1)),\n"
    "  digits(z,lp) AS (\n"
    "    VALUES('1', 1)\n"
    "    UNION ALL\n"
    "    SELECT CAST(lp+1 AS TEXT), lp+1 FROM digits WHERE lp<9\n"
    "  ),\n"
    "  x(s, ind) AS (\n"
    "    SELECT sud, instr(sud, '.') FROM input\n"
    "    UNION ALL\n"
    "    SELECT\n"
    "      substr(s, 1, ind-1) || z || substr(s, ind+1),\n"
    "      instr( substr(s, 1, ind-1) || z || substr(s, ind+1), '.' )\n"
    "     FROM x, digits AS z\n"
    "    WHERE ind>0\n"
    "      AND NOT EXISTS (\n"
    "            SELECT 1\n"
    "              FROM digits AS lp\n"
    "             WHERE z.z = substr(s, ((ind-1)/9)*9 + lp, 1)\n"
    "                OR z.z = substr(s, ((ind-1)%%9) + (lp-1)*9 + 1, 1)\n"
    "                OR z.z = substr(s, (((ind-1)/3) %% 3) * 3\n"
    "                        + ((ind-1)/27) * 27 + lp\n"
    "                        + ((lp-1) / 3) * 6, 1)\n"
    "         )\n"
    "  )\n"
    "SELECT s FROM x WHERE ind=0;"
  );
  sqlite3_bind_text(g.pStmt, 1, zPuz, -1, SQLITE_STATIC);
  speedtest1_run();
  speedtest1_end_test();

  speedtest1_begin_test(200, "Sudoku with VALUES 'digits'");
  speedtest1_prepare(
    "WITH RECURSIVE\n"
    "  input(sud) AS (VALUES(?1)),\n"
    "  digits(z,lp) AS (VALUES('1',1),('2',2),('3',3),('4',4),('5',5),\n"
    "                         ('6',6),('7',7),('8',8),('9',9)),\n"
    "  x(s, ind) AS (\n"
    "    SELECT sud, instr(sud, '.') FROM input\n"
    "    UNION ALL\n"
    "    SELECT\n"
    "      substr(s, 1, ind-1) || z || substr(s, ind+1),\n"
    "      instr( substr(s, 1, ind-1) || z || substr(s, ind+1), '.' )\n"
    "     FROM x, digits AS z\n"
    "    WHERE ind>0\n"
    "      AND NOT EXISTS (\n"
    "            SELECT 1\n"
    "              FROM digits AS lp\n"
    "             WHERE z.z = substr(s, ((ind-1)/9)*9 + lp, 1)\n"
    "                OR z.z = substr(s, ((ind-1)%%9) + (lp-1)*9 + 1, 1)\n"
    "                OR z.z = substr(s, (((ind-1)/3) %% 3) * 3\n"
    "                        + ((ind-1)/27) * 27 + lp\n"
    "                        + ((lp-1) / 3) * 6, 1)\n"
    "         )\n"
    "  )\n"
    "SELECT s FROM x WHERE ind=0;"
  );
  sqlite3_bind_text(g.pStmt, 1, zPuz, -1, SQLITE_STATIC);
  speedtest1_run();
  speedtest1_end_test();

  rSpacing = 5.0/g.szTest;
  speedtest1_begin_test(300, "Mandelbrot Set with spacing=%f", rSpacing);
  speedtest1_prepare(
   "WITH RECURSIVE \n"
   "  xaxis(x) AS (VALUES(-2.0) UNION ALL SELECT x+?1 FROM xaxis WHERE x<1.2),\n"
   "  yaxis(y) AS (VALUES(-1.0) UNION ALL SELECT y+?2 FROM yaxis WHERE y<1.0),\n"
   "  m(iter, cx, cy, x, y) AS (\n"
   "    SELECT 0, x, y, 0.0, 0.0 FROM xaxis, yaxis\n"
   "    UNION ALL\n"
   "    SELECT iter+1, cx, cy, x*x-y*y + cx, 2.0*x*y + cy FROM m \n"
   "     WHERE (x*x + y*y) < 4.0 AND iter<28\n"
   "  ),\n"
   "  m2(iter, cx, cy) AS (\n"
   "    SELECT max(iter), cx, cy FROM m GROUP BY cx, cy\n"
   "  ),\n"
   "  a(t) AS (\n"
   "    SELECT group_concat( substr(' .+*#', 1+min(iter/7,4), 1), '') \n"
   "    FROM m2 GROUP BY cy\n"
   "  )\n"
   "SELECT group_concat(rtrim(t),x'0a') FROM a;"
  );
  sqlite3_bind_double(g.pStmt, 1, rSpacing*.05);
  sqlite3_bind_double(g.pStmt, 2, rSpacing);
  speedtest1_run();
  speedtest1_end_test();

  nElem = 10000*g.szTest;
  speedtest1_begin_test(400, "EXCEPT operator on %d-element tables", nElem);
  speedtest1_prepare(
    "WITH RECURSIVE \n"
    "  t1(x) AS (VALUES(2) UNION ALL SELECT x+2 FROM t1 WHERE x<%d),\n"
    "  t2(y) AS (VALUES(3) UNION ALL SELECT y+3 FROM t2 WHERE y<%d)\n"
    "SELECT count(x), avg(x) FROM (\n"
    "  SELECT x FROM t1 EXCEPT SELECT y FROM t2 ORDER BY 1\n"
    ");",
    nElem, nElem
  );
  speedtest1_run();
  speedtest1_end_test();

}

/*
** A testset used for debugging speedtest1 itself.
*/
void testset_debug1(void){
  unsigned i, n;
  unsigned x1, x2;
................................................................................
  }

  if( g.bExplain ) printf(".explain\n.echo on\n");
  if( strcmp(zTSet,"main")==0 ){
    testset_main();
  }else if( strcmp(zTSet,"debug1")==0 ){
    testset_debug1();
  }else if( strcmp(zTSet,"cte")==0 ){
    testset_cte();
  }else{
    fatal_error("unknown testset: \"%s\"\n", zTSet);
  }
  speedtest1_final();

  /* Database connection statistics printed after both prepared statements
  ** have been finalized */

# 2014-02-11
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library. Specifically,
# it tests that ticket [4c86b126f22ad548fee0125337bdc9366912d9ac].
#
# When SQLite is compiled using SQLITE_ENABLE_STAT3 or SQLITE_ENABLE_STAT4,
# it gets the wrong answer...
#
# The problem was introduced in SQLite 3.8.1.

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

do_execsql_test tkt-4c86b126f2-1.1 {
  CREATE TABLE nodes(
     local_relpath  TEXT PRIMARY KEY,
     moved_to  TEXT
  );
  INSERT INTO nodes VALUES('A',NULL);
  INSERT INTO nodes VALUES('A/B',NULL);
  INSERT INTO nodes VALUES('',NULL);
  INSERT INTO nodes VALUES('A/B/C-move',NULL);
  INSERT INTO nodes VALUES('A/B/C','A/B/C-move');
  INSERT INTO nodes VALUES('A/B-move',NULL);
  INSERT INTO nodes VALUES('A/B-move/C-move',NULL);
  INSERT INTO nodes VALUES('A/B-move/C','x');
  SELECT local_relpath, moved_to
   FROM nodes
  WHERE (local_relpath = 'A/B' OR
           ((local_relpath > 'A/B/') AND (local_relpath < 'A/B0')))
    AND moved_to IS NOT NULL;
} {A/B/C A/B/C-move}

do_execsql_test tkt-4c86b126f2-2.1 {
  CREATE TABLE t1(x TEXT UNIQUE, y TEXT UNIQUE, z);
  INSERT INTO t1 VALUES('ghi','jkl','y');
  SELECT * FROM t1 WHERE (x='ghi' OR y='jkl') AND z IS NOT NULL;
} {ghi jkl y}


finish_test

  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a = 2 OR a = 3) AND d = a
  }
} {2 2 3 3 0 0}

do_test where8-3.5 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a = 2 OR a = 3) AND (d = a OR e = 'sixteen')
     ORDER BY +a, +d;
  }
} {2 2 2 4 3 3 3 4 0 1}

do_test where8-3.6 {
  # The first part of the WHERE clause in this query, (a=2 OR a=3) is
  # transformed into "a IN (2, 3)". This is why the sort is required.
  #
  execsql_status {
    SELECT a, d 
    FROM t1, t2 
    WHERE (a = 2 OR a = 3) AND (d = a OR e = 'sixteen')
    ORDER BY t1.rowid
  }
} {2 2 2 4 3 3 3 4 0 1}
do_test where8-3.7 {
  execsql_status {
    SELECT a, d 
    FROM t1, t2 

  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a = 2 OR a = 3) AND d = a
  }
} {2 2 3 3 0 0}

do_test where8-3.5 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a = 2 OR a = 3) AND (d = +a OR e = 'sixteen')
     ORDER BY +a, +d;
  }
} {2 2 2 4 3 3 3 4 0 1}

do_test where8-3.6 {
  # The first part of the WHERE clause in this query, (a=2 OR a=3) is
  # transformed into "a IN (2, 3)". This is why the sort is required.
  #
  execsql_status {
    SELECT a, d 
    FROM t1, t2 
    WHERE (a = 2 OR a = 3) AND (d = +a OR e = 'sixteen')
    ORDER BY t1.rowid
  }
} {2 2 2 4 3 3 3 4 0 1}
do_test where8-3.7 {
  execsql_status {
    SELECT a, d 
    FROM t1, t2 

.........Jim
.........Kate
.........Lanny
.........Mary
.........Noland
.........Olivia}}

finish_test

.........Jim
.........Kate
.........Lanny
.........Mary
.........Noland
.........Olivia}}


#--------------------------------------------------------------------------
# Ticket [31a19d11b97088296ac104aaff113a9790394927] (2014-02-09)
# Name resolution issue with compound SELECTs and Common Table Expressions 
#
do_execsql_test 12.1 {
WITH RECURSIVE
  t1(x) AS (VALUES(2) UNION ALL SELECT x+2 FROM t1 WHERE x<20),
  t2(y) AS (VALUES(3) UNION ALL SELECT y+3 FROM t2 WHERE y<20)
SELECT x FROM t1 EXCEPT SELECT y FROM t2 ORDER BY 1;
} {2 4 8 10 14 16 20}


finish_test