SQLite

/*
** 2005 July 8
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code associated with the ANALYZE command.
**
** @(#) $Id: analyze.c,v 1.25 2008/01/02 00:34:37 drh Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

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

  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);

    /* Open a cursor to the index to be analyzed
    */
    assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "%s", pIdx->zName));
    sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum,
        (char *)pKey, P3_KEYINFO_HANDOFF);
    nCol = pIdx->nColumn;
    if( iMem+nCol*2>=pParse->nMem ){
      pParse->nMem = iMem+nCol*2+1;
    }
    sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, nCol+1);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.136 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"

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

){
  Vdbe *v;
  if( IsVirtual(pTab) ) return;
  v = sqlite3GetVdbe(p);
  assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
  sqlite3TableLock(p, iDb, pTab->tnum, (opcode==OP_OpenWrite), pTab->zName);
  sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
  VdbeComment((v, "%s", pTab->zName));
  sqlite3VdbeAddOp(v, opcode, iCur, pTab->tnum);
  sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
}


/*
** Generate code for a DELETE FROM statement.

  /*
  ** Return the number of rows that were deleted. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( db->flags & SQLITE_CountRows && pParse->nested==0 && !pParse->trigStack ){

    sqlite3VdbeAddOp(v, OP_ResultRow, memCnt, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", P3_STATIC);
  }

delete_from_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3SrcListDelete(pTabList);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.322 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**

          sqlite3VdbeUsesBtree(v, iDb);

          sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0);
          iAddr = sqlite3VdbeAddOp(v, OP_If, 0, iMem);
          sqlite3VdbeAddOp(v, OP_MemInt, 1, iMem);
  
          sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
          VdbeComment((v, "%s", pIdx->zName));
          sqlite3VdbeOp3(v,OP_OpenRead,iTab,pIdx->tnum,pKey,P3_KEYINFO_HANDOFF);
          eType = IN_INDEX_INDEX;
          sqlite3VdbeAddOp(v, OP_SetNumColumns, iTab, pIdx->nColumn);

          sqlite3VdbeJumpHere(v, iAddr);
        }
      }

      int sop;

      pExpr->iColumn = iMem = pParse->nMem++;
      pSel = pExpr->pSelect;
      if( pExpr->op==TK_SELECT ){
        sop = SRT_Mem;
        sqlite3VdbeAddOp(v, OP_MemNull, iMem, 0);
        VdbeComment((v, "Init subquery result"));
      }else{
        sop = SRT_Exists;
        sqlite3VdbeAddOp(v, OP_MemInt, 0, iMem);
        VdbeComment((v, "Init EXISTS result"));
      }
      sqlite3ExprDelete(pSel->pLimit);
      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
      if( sqlite3Select(pParse, pSel, sop, iMem, 0, 0, 0, 0) ){
        return;
      }
      break;

#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS:
    case TK_SELECT: {
      if( pExpr->iColumn==0 ){
        sqlite3CodeSubselect(pParse, pExpr);
      }
      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
      VdbeComment((v, "load subquery result"));
      break;
    }
    case TK_IN: {
      int addr;
      char affinity;
      int ckOffset = pParse->ckOffset;
      int eType;

         sqlite3DequoteExpr(pParse->db, pExpr);
         sqlite3VdbeOp3(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn,
                        (char*)pExpr->token.z, pExpr->token.n);
      } else {
         assert( pExpr->iColumn == OE_Ignore );
         sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0);
         sqlite3VdbeAddOp(v, OP_Goto, 0, pParse->trigStack->ignoreJump);
         VdbeComment((v, "raise(IGNORE)"));
      }
      stackChng = 0;
      break;
    }
#endif
  }

   || ((pOp = sqlite3VdbeGetOp(v, addr1))!=0 && pOp->opcode==OP_Function) ){
    iMem = pExpr->iTable = pParse->nMem++;
    sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);
    pExpr->op = TK_REGISTER;
  }
}
#endif

/*
** Generate code to evaluate an expression and store the result in
** a designated register.  If the target register number is negative,
** allocate a new register to store the result.  Return the target
** register number regardless.
**
** The current implementation is a rough prototype for experimental
** purposes.  There are many optimization opportunities here.
*/
int sqlite3ExprIntoReg(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;
  if( v==0 ) return -1;
  sqlite3ExprCode(pParse, pExpr);
  if( target<0 ){
    target = pParse->nMem++;
  }
  sqlite3VdbeAddOp(v, OP_MemStore, target, 1);
  return target;
}

/*
** Generate code that pushes the value of every element of the given
** expression list onto the stack.
**
** Return the number of elements pushed onto the stack.
*/

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.199 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:

          if( tnum==pIndex->tnum ){
            return 1;
          }
        }
      }
    }
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( pOp->opcode==OP_VOpen && pOp->p3.p==(const char*)pTab->pVtab ){
      assert( pOp->p3.p!=0 );
      assert( pOp->p3type==P3_VTAB );
      return 1;
    }
#endif
  }
  return 0;
}

  /*
  ** Return the number of rows inserted. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( db->flags & SQLITE_CountRows && pParse->nested==0 && !pParse->trigStack ){

    sqlite3VdbeAddOp(v, OP_ResultRow, iCntMem, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", P3_STATIC);
  }

insert_cleanup:
  sqlite3SrcListDelete(pTabList);
  sqlite3ExprListDelete(pList);

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3OpenTable(pParse, base, iDb, pTab, op);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "%s", pIdx->zName));
    sqlite3VdbeOp3(v, op, i+base, pIdx->tnum, (char*)pKey, P3_KEYINFO_HANDOFF);
  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
}

      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
    }
    assert( pSrcIdx );
    sqlite3VdbeAddOp(v, OP_Close, iSrc, 0);
    sqlite3VdbeAddOp(v, OP_Close, iDest, 0);
    sqlite3VdbeAddOp(v, OP_Integer, iDbSrc, 0);
    pKey = sqlite3IndexKeyinfo(pParse, pSrcIdx);
    VdbeComment((v, "%s", pSrcIdx->zName));
    sqlite3VdbeOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, 
                   (char*)pKey, P3_KEYINFO_HANDOFF);
    sqlite3VdbeAddOp(v, OP_Integer, iDbDest, 0);
    pKey = sqlite3IndexKeyinfo(pParse, pDestIdx);
    VdbeComment((v, "%s", pDestIdx->zName));
    sqlite3VdbeOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, 
                   (char*)pKey, P3_KEYINFO_HANDOFF);
    addr1 = sqlite3VdbeAddOp(v, OP_Rewind, iSrc, 0);
    sqlite3VdbeAddOp(v, OP_RowKey, iSrc, 0);
    sqlite3VdbeAddOp(v, OP_IdxInsert, iDest, 1);
    sqlite3VdbeAddOp(v, OP_Next, iSrc, addr1+1);
    sqlite3VdbeJumpHere(v, addr1);

/*
** 2003 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the PRAGMA command.
**
** $Id: pragma.c,v 1.154 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/* Ignore this whole file if pragmas are disabled
*/
#if !defined(SQLITE_OMIT_PRAGMA) && !defined(SQLITE_OMIT_PARSER)

#endif /* SQLITE_PAGER_PRAGMAS */

/*
** Generate code to return a single integer value.
*/
static void returnSingleInt(Parse *pParse, const char *zLabel, int value){
  Vdbe *v = sqlite3GetVdbe(pParse);
  int mem = pParse->nMem++;
  sqlite3VdbeAddOp(v, OP_MemInt, value, mem);
  if( pParse->explain==0 ){
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zLabel, P3_STATIC);
  }
  sqlite3VdbeAddOp(v, OP_ResultRow, mem, 1);
}

#ifndef SQLITE_OMIT_FLAG_PRAGMAS
/*
** Check to see if zRight and zLeft refer to a pragma that queries
** or changes one of the flags in db->flags.  Return 1 if so and 0 if not.
** Also, implement the pragma.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.374 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.

    int addr;
    sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iOffset);
    addr = sqlite3VdbeAddOp(v, OP_IfMemNeg, p->iOffset, 0);
    if( nPop>0 ){
      sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
    }
    sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
    VdbeComment((v, "skip OFFSET records"));
    sqlite3VdbeJumpHere(v, addr);
  }
}

/*
** Add code that will check to make sure the top N elements of the
** stack are distinct.  iTab is a sorting index that holds previously

  int addrRepeat,    /* Jump to here if not distinct */
  int N              /* The top N elements of the stack must be distinct */
){
  sqlite3VdbeAddOp(v, OP_MakeRecord, -N, 0);
  sqlite3VdbeAddOp(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp(v, OP_Pop, N+1, 0);
  sqlite3VdbeAddOp(v, OP_Goto, 0, addrRepeat);
  VdbeComment((v, "skip indistinct records"));
  sqlite3VdbeAddOp(v, OP_IdxInsert, iTab, 0);
}

/*
** Generate an error message when a SELECT is used within a subexpression
** (example:  "a IN (SELECT * FROM table)") but it has more than 1 result
** column.  We do this in a subroutine because the error occurs in multiple

    p->iLimit = iLimit = pParse->nMem;
    pParse->nMem += 2;
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;
    sqlite3ExprCode(pParse, p->pLimit);
    sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, iLimit, 1);
    VdbeComment((v, "LIMIT counter"));
    sqlite3VdbeAddOp(v, OP_IfMemZero, iLimit, iBreak);
    sqlite3VdbeAddOp(v, OP_MemLoad, iLimit, 0);
  }
  if( p->pOffset ){
    p->iOffset = iOffset = pParse->nMem++;
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;
    sqlite3ExprCode(pParse, p->pOffset);
    sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, iOffset, p->pLimit==0);
    VdbeComment((v, "OFFSET counter"));
    addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iOffset, 0);
    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
    sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
    if( p->pLimit ){
      sqlite3VdbeAddOp(v, OP_Add, 0, 0);
    }
  }
  if( p->pLimit ){
    addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iLimit, 0);
    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
    sqlite3VdbeAddOp(v, OP_MemInt, -1, iLimit+1);
    addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp(v, OP_MemStore, iLimit+1, 1);
    VdbeComment((v, "LIMIT+OFFSET"));
    sqlite3VdbeJumpHere(v, addr2);
  }
}

/*
** Allocate a virtual index to use for sorting.
*/

          goto multi_select_end;
        }
        p->pPrior = 0;
        p->iLimit = pPrior->iLimit;
        p->iOffset = pPrior->iOffset;
        if( p->iLimit>=0 ){
          addr = sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, 0);
          VdbeComment((v, "Jump ahead if LIMIT reached"));
        }
        rc = sqlite3Select(pParse, p, eDest, iParm, 0, 0, 0, aff);
        p->pPrior = pPrior;
        if( rc ){
          goto multi_select_end;
        }
        if( addr ){

      iUseFlag = pParse->nMem++;
      iAbortFlag = pParse->nMem++;
      iAMem = pParse->nMem;
      pParse->nMem += pGroupBy->nExpr;
      iBMem = pParse->nMem;
      pParse->nMem += pGroupBy->nExpr;
      sqlite3VdbeAddOp(v, OP_MemInt, 0, iAbortFlag);
      VdbeComment((v, "clear abort flag"));
      sqlite3VdbeAddOp(v, OP_MemInt, 0, iUseFlag);
      VdbeComment((v, "indicate accumulator empty"));
      sqlite3VdbeAddOp(v, OP_Goto, 0, addrInitializeLoop);

      /* Generate a subroutine that outputs a single row of the result
      ** set.  This subroutine first looks at the iUseFlag.  If iUseFlag
      ** is less than or equal to zero, the subroutine is a no-op.  If
      ** the processing calls for the query to abort, this subroutine
      ** increments the iAbortFlag memory location before returning in
      ** order to signal the caller to abort.
      */
      addrSetAbort = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_MemInt, 1, iAbortFlag);
      VdbeComment((v, "set abort flag"));
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);
      addrOutputRow = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_IfMemPos, iUseFlag, addrOutputRow+2);
      VdbeComment((v, "Groupby result generator entry point"));
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);
      finalizeAggFunctions(pParse, &sAggInfo);
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, 1);
      }
      rc = selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
                           distinct, eDest, iParm, 
                           addrOutputRow+1, addrSetAbort, aff);
      if( rc ){
        goto select_end;
      }
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);
      VdbeComment((v, "end groupby result generator"));

      /* Generate a subroutine that will reset the group-by accumulator
      */
      addrReset = sqlite3VdbeCurrentAddr(v);
      resetAccumulator(pParse, &sAggInfo);
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);

          sqlite3ExprCodeGetColumn(v, pCol->pTab, pCol->iColumn, pCol->iTable);
          j++;
        }
        sqlite3VdbeAddOp(v, OP_MakeRecord, j, 0);
        sqlite3VdbeAddOp(v, OP_IdxInsert, sAggInfo.sortingIdx, 0);
        sqlite3WhereEnd(pWInfo);
        sqlite3VdbeAddOp(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
        VdbeComment((v, "GROUP BY sort"));
        sAggInfo.useSortingIdx = 1;
      }

      /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
      ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
      ** Then compare the current GROUP BY terms against the GROUP BY terms
      ** from the previous row currently stored in a0, a1, a2...

      ** for the next GROUP BY batch.
      */
      sqlite3VdbeResolveLabel(v, addrGroupByChange);
      for(j=0; j<pGroupBy->nExpr; j++){
        sqlite3VdbeAddOp(v, OP_MemMove, iAMem+j, iBMem+j);
      }
      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
      VdbeComment((v, "output one row"));
      sqlite3VdbeAddOp(v, OP_IfMemPos, iAbortFlag, addrEnd);
      VdbeComment((v, "check abort flag"));
      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
      VdbeComment((v, "reset accumulator"));

      /* Update the aggregate accumulators based on the content of
      ** the current row
      */
      sqlite3VdbeResolveLabel(v, addrProcessRow);
      updateAccumulator(pParse, &sAggInfo);
      sqlite3VdbeAddOp(v, OP_MemInt, 1, iUseFlag);
      VdbeComment((v, "indicate data in accumulator"));

      /* End of the loop
      */
      if( groupBySort ){
        sqlite3VdbeAddOp(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
      }else{
        sqlite3WhereEnd(pWInfo);
        sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
      }

      /* Output the final row of result
      */
      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
      VdbeComment((v, "output final row"));
      
    } /* endif pGroupBy */
    else {
      /* This case runs if the aggregate has no GROUP BY clause.  The
      ** processing is much simpler since there is only a single row
      ** of output.
      */

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.628 2008/01/02 00:34:37 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds

void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**);
void sqlite3WhereEnd(WhereInfo*);
void sqlite3ExprCodeGetColumn(Vdbe*, Table*, int, int);
void sqlite3ExprCode(Parse*, Expr*);
void sqlite3ExprCodeAndCache(Parse*, Expr*);
int sqlite3ExprIntoReg(Parse*,Expr*,int);
int sqlite3ExprCodeExprList(Parse*, ExprList*);
void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
Table *sqlite3FindTable(sqlite3*,const char*, const char*);
Table *sqlite3LocateTable(Parse*,const char*, const char*);
Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);

  int orconf;
  Vdbe *v = pParse->pVdbe;
  sqlite3 *db = pParse->db;

  assert( pTriggerStep!=0 );
  assert( v!=0 );
  sqlite3VdbeAddOp(v, OP_ContextPush, 0, 0);
  VdbeComment((v, "begin trigger %s", pStepList->pTrig->name));
  while( pTriggerStep ){
    orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
    pParse->trigStack->orconf = orconf;
    switch( pTriggerStep->op ){
      case TK_SELECT: {
        Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
        if( ss ){

      }
      default:
        assert(0);
    } 
    pTriggerStep = pTriggerStep->pNext;
  }
  sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0);
  VdbeComment((v, "end trigger %s", pStepList->pTrig->name));

  return 0;
}

/*
** This is called to code FOR EACH ROW triggers.
**

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.146 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */

** sqlite3_value objects.
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
  if( pTab && !pTab->pSelect ){
    sqlite3_value *pValue;
    u8 enc = ENC(sqlite3VdbeDb(v));
    Column *pCol = &pTab->aCol[i];
    VdbeComment((v, "%s.%s", pTab->zName, pCol->zName));
    assert( i<pTab->nCol );
    sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc, 
                         pCol->affinity, &pValue);
    if( pValue ){
      sqlite3VdbeAddOp(v, OP_DfltValue, 0, 0);
      sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM);


    }
  }
}

/*
** Process an UPDATE statement.
**

  /*
  ** Return the number of rows that were changed. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){

    sqlite3VdbeAddOp(v, OP_ResultRow, memCnt, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P3_STATIC);
  }

update_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3_free(apIdx);

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.662 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor

  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
  p->rc = SQLITE_OK;
  assert( p->explain==0 );
  if( p->popStack ){
    popStack(&pTos, p->popStack);
    p->popStack = 0;
  }
  p->pResultSet = 0;
  db->busyHandler.nBusy = 0;
  CHECK_FOR_INTERRUPT;
  sqlite3VdbeIOTraceSql(p);
#ifdef SQLITE_DEBUG
  if( (p->db->flags & SQLITE_VdbeListing)!=0
    || sqlite3OsAccess(db->pVfs, "vdbe_explain", SQLITE_ACCESS_EXISTS)
  ){

** is the same as executing Halt.
*/
case OP_Halt: {            /* no-push */
  p->pTos = pTos;
  p->rc = pOp->p1;
  p->pc = pc;
  p->errorAction = pOp->p2;
  if( pOp->p3.p ){
    sqlite3SetString(&p->zErrMsg, pOp->p3.p, (char*)0);
  }
  rc = sqlite3VdbeHalt(p);
  assert( rc==SQLITE_BUSY || rc==SQLITE_OK );
  if( rc==SQLITE_BUSY ){
    p->rc = rc = SQLITE_BUSY;
  }else{
    rc = p->rc ? SQLITE_ERROR : SQLITE_DONE;

/* Opcode: Int64 * * P3
**
** P3 is a pointer to a 64-bit integer value.
** Push  that value onto  the stack.
*/
case OP_Int64: {
  pTos++;
  assert( pOp->p3.p!=0 );
  pTos->flags = MEM_Int;
  memcpy(&pTos->u.i, pOp->p3.p, 8);
  break;
}

/* Opcode: Real * * P3
**
** P3 is a pointer to a 64-bit floating point value.  Push that value
** onto the stack.
*/
case OP_Real: {            /* same as TK_FLOAT, */
  pTos++;
  pTos->flags = MEM_Real;
  memcpy(&pTos->r, pOp->p3.p, 8);
  break;
}

/* Opcode: String8 * * P3
**
** P3 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 */
  assert( pOp->p3.p!=0 );
  pOp->opcode = OP_String;
  pOp->p1 = strlen(pOp->p3.p);

#ifndef SQLITE_OMIT_UTF16
  if( encoding!=SQLITE_UTF8 ){
    pTos++;
    sqlite3VdbeMemSetStr(pTos, pOp->p3.p, -1, SQLITE_UTF8, SQLITE_STATIC);
    if( SQLITE_OK!=sqlite3VdbeChangeEncoding(pTos, encoding) ) goto no_mem;
    if( SQLITE_OK!=sqlite3VdbeMemDynamicify(pTos) ) goto no_mem;
    pTos->flags &= ~(MEM_Dyn);
    pTos->flags |= MEM_Static;
    if( pOp->p3type==P3_DYNAMIC ){
      sqlite3_free(pOp->p3.p);
    }
    pOp->p3type = P3_DYNAMIC;
    pOp->p3.p = pTos->z;
    pOp->p1 = pTos->n;
    if( pOp->p1>SQLITE_MAX_LENGTH ){
      goto too_big;
    }
    break;
  }
#endif
  if( pOp->p1>SQLITE_MAX_LENGTH ){
    goto too_big;
  }
  /* Fall through to the next case, OP_String */
}
  
/* Opcode: String P1 * P3
**
** The string value P3 of length P1 (bytes) is pushed onto the stack.
*/
case OP_String: {
  pTos++;
  assert( pOp->p3.p!=0 );
  pTos->flags = MEM_Str|MEM_Static|MEM_Term;
  pTos->z = pOp->p3.p;
  pTos->n = pOp->p1;
  pTos->enc = encoding;
  break;
}

/* Opcode: Null * * *
**

** vdbe stack.
**
** The first time this instruction executes, in transforms itself into a
** 'Blob' opcode with a binary blob as P3.
*/
case OP_HexBlob: {            /* same as TK_BLOB */
  pOp->opcode = OP_Blob;
  pOp->p1 = strlen(pOp->p3.p)/2;
  if( pOp->p1>SQLITE_MAX_LENGTH ){
    goto too_big;
  }
  if( pOp->p1 ){
    char *zBlob = sqlite3HexToBlob(db, pOp->p3.p);
    if( !zBlob ) goto no_mem;
    if( pOp->p3type==P3_DYNAMIC ){
      sqlite3_free(pOp->p3.p);
    }
    pOp->p3.p = zBlob;
    pOp->p3type = P3_DYNAMIC;
  }else{
    if( pOp->p3type==P3_DYNAMIC ){
      sqlite3_free(pOp->p3.p);
    }
    pOp->p3type = P3_STATIC;
    pOp->p3.p = "";
  }

  /* Fall through to the next case, OP_Blob. */
}

/* Opcode: Blob P1 * P3
**
** P3 points to a blob of data P1 bytes long. Push this
** value onto the stack. This instruction is not coded directly
** by the compiler. Instead, the compiler layer specifies
** an OP_HexBlob opcode, with the hex string representation of
** the blob as P3. This opcode is transformed to an OP_Blob
** the first time it is executed.
*/
case OP_Blob: {
  pTos++;
  assert( pOp->p1 <= SQLITE_MAX_LENGTH );
  sqlite3VdbeMemSetStr(pTos, pOp->p3.p, pOp->p1, 0, 0);
  pTos->enc = encoding;
  break;
}
#endif /* SQLITE_OMIT_BLOB_LITERAL */

/* Opcode: Variable P1 * *
**

  /* Data in the pager might be moved or changed out from under us
  ** in between the return from this sqlite3_step() call and the
  ** next call to sqlite3_step().  So deephermeralize everything on 
  ** the stack.  Note that ephemeral data is never stored in memory 
  ** cells so we do not have to worry about them.
  */
  pFirstColumn = &pTos[1-pOp->p1];
  for(pMem = p->aStack; pMem<pFirstColumn; pMem++){
    Deephemeralize(pMem);
  }

  /* Invalidate all ephemeral cursor row caches */
  p->cacheCtr = (p->cacheCtr + 2)|1;

  /* Make sure the results of the current row are \000 terminated
  ** and have an assigned type.  The results are deephemeralized as
  ** as side effect.
  */
  for(; pMem<=pTos; pMem++ ){
    sqlite3VdbeMemNulTerminate(pMem);
    storeTypeInfo(pMem, encoding);
  }

  /* Set up the statement structure so that it will pop the current
  ** results from the stack when the statement returns.
  */
  p->pResultSet = pFirstColumn;
  p->nCallback++;
  p->popStack = pOp->p1;
  p->pc = pc + 1;
  p->pTos = pTos;
  rc = SQLITE_ROW;
  goto vdbe_return;
}

/* Opcode: ResultRow P1 P2 *
**
** The registers P1 throught 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.  When the sqlite3_step() function is run again, the top P1
** values will be automatically popped from the stack before the next
** instruction executes.
*/
case OP_ResultRow: {            /* no-push */
  Mem *pMem;
  int i;
  assert( p->nResColumn==pOp->p2 );
  assert( pOp->p1>=0 );
  assert( pOp->p1+pOp->p2<p->nMem );

  /* Data in the pager might be moved or changed out from under us
  ** in between the return from this sqlite3_step() call and the
  ** next call to sqlite3_step().  So deephermeralize everything on 
  ** the stack.  Note that ephemeral data is never stored in memory 
  ** cells so we do not have to worry about them.
  */
  for(pMem = p->aStack; pMem<=pTos; pMem++){
    Deephemeralize(pMem);
  }

  /* Invalidate all ephemeral cursor row caches */
  p->cacheCtr = (p->cacheCtr + 2)|1;

  /* Make sure the results of the current row are \000 terminated
  ** and have an assigned type.  The results are deephemeralized as
  ** as side effect.
  */
  pMem = p->pResultSet = &p->aMem[pOp->p1];
  for(i=0; i<pOp->p2; i++){
    sqlite3VdbeMemNulTerminate(&pMem[i]);
    storeTypeInfo(&pMem[i], encoding);
  }

  /* Return SQLITE_ROW
  */
  p->nCallback++;
  p->popStack = 0;
  p->pc = pc + 1;
  p->pTos = pTos;
  rc = SQLITE_ROW;
  goto vdbe_return;
}

/* Opcode: Concat P1 P2 *
**

  for(i=0; i<n; i++, pArg++){
    apVal[i] = pArg;
    storeTypeInfo(pArg, encoding);
  }

  assert( pOp->p3type==P3_FUNCDEF || pOp->p3type==P3_VDBEFUNC );
  if( pOp->p3type==P3_FUNCDEF ){
    ctx.pFunc = (FuncDef*)pOp->p3.p;
    ctx.pVdbeFunc = 0;
  }else{
    ctx.pVdbeFunc = (VdbeFunc*)pOp->p3.p;
    ctx.pFunc = ctx.pVdbeFunc->pFunc;
  }

  ctx.s.flags = MEM_Null;
  ctx.s.z = 0;
  ctx.s.xDel = 0;
  ctx.s.db = db;
  ctx.isError = 0;
  if( ctx.pFunc->needCollSeq ){
    assert( pOp>p->aOp );
    assert( pOp[-1].p3type==P3_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = (CollSeq *)pOp[-1].p3.p;
  }
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  (*ctx.pFunc->xFunc)(&ctx, n, apVal);
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  if( db->mallocFailed ){
    /* Even though a malloc() has failed, the implementation of the
    ** user function may have called an sqlite3_result_XXX() function

  popStack(&pTos, n);

  /* If any auxilary data functions have been called by this user function,
  ** immediately call the destructor for any non-static values.
  */
  if( ctx.pVdbeFunc ){
    sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p1);
    pOp->p3.p = (char *)ctx.pVdbeFunc;
    pOp->p3type = P3_VDBEFUNC;
  }

  /* If the function returned an error, throw an exception */
  if( ctx.isError ){
    sqlite3SetString(&p->zErrMsg, sqlite3_value_text(&ctx.s), (char*)0);
    rc = SQLITE_ERROR;

  affinity = pOp->p1 & 0xFF;
  if( affinity ){
    applyAffinity(pNos, affinity, encoding);
    applyAffinity(pTos, affinity, encoding);
  }

  assert( pOp->p3type==P3_COLLSEQ || pOp->p3.p==0 );
  ExpandBlob(pNos);
  ExpandBlob(pTos);
  res = sqlite3MemCompare(pNos, pTos, (CollSeq*)pOp->p3.p);
  switch( pOp->opcode ){
    case OP_Eq:    res = res==0;     break;
    case OP_Ne:    res = res!=0;     break;
    case OP_Lt:    res = res<0;      break;
    case OP_Le:    res = res<=0;     break;
    case OP_Gt:    res = res>0;      break;
    default:       res = res>=0;     break;

  break;
}

/* Opcode: Column P1 P2 P3
**
** Interpret the data that cursor P1 points to as a structure built using
** the MakeRecord instruction.  (See the MakeRecord opcode for additional
** information about the format of the data.)  Extract the P2-th column
** from this record.  If there are less that (P2+1) 
** values in the record, extract a NULL.
**
** The value extracted is pushed onto the stack.  Or if P3 is an integer
** register number, then the value is written into that register.
**
** If the KeyAsData opcode has previously executed on this cursor, then the
** field might be extracted from the key rather than the data.
**
** If the column contains fewer than P2 fields, then extract a NULL.  Or
** if the next instruction is OP_DfltValue then the P3 argument to the
** OP_DfltValue instruction will be a P3_MEM.  Use the P3 argument of
** the OP_DfltValue instruction as the extracted value instead of NULL.
** The OP_DfltValue P3 value will be a default value for a column 
** that has been added using the ALTER TABLE ADD COLUMN command.



*/
case OP_Column: {
  u32 payloadSize;   /* Number of bytes in the record */
  int p1 = pOp->p1;  /* P1 value of the opcode */
  int p2 = pOp->p2;  /* column number to retrieve */
  Cursor *pC = 0;    /* The VDBE cursor */
  char *zRec;        /* Pointer to complete record-data */
  BtCursor *pCrsr;   /* The BTree cursor */
  u32 *aType;        /* aType[i] holds the numeric type of the i-th column */
  u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
  u32 nField;        /* number of fields in the record */
  int len;           /* The length of the serialized data for the column */
  int i;             /* Loop counter */
  char *zData;       /* Part of the record being decoded */
  Mem *pDest;        /* Where to write the extracted value */
  Mem sMem;          /* For storing the record being decoded */

  sMem.flags = 0;
  assert( p1<p->nCursor );
  if( pOp->p3type==P3_INT32 ){
    assert( pOp->p3.i>=0 && pOp->p3.i<p->nMem );
    pDest = &p->aMem[pOp->p3.i];
  }else{
    pDest = ++pTos;
  }
  sqlite3VdbeMemSetNull(pDest);

  /* This block sets the variable payloadSize to be the total number of
  ** bytes in the record.
  **
  ** zRec is set to be the complete text of the record if it is available.
  ** The complete record text is always available for pseudo-tables
  ** If the record is stored in a cursor, the complete record text

    payloadSize = 0;
    pCrsr = 0;
    nField = 0;
  }

  /* If payloadSize is 0, then just push a NULL onto the stack. */
  if( payloadSize==0 ){
    assert( pDest->flags==MEM_Null );

    goto op_column_out;
  }
  if( payloadSize>SQLITE_MAX_LENGTH ){
    goto too_big;
  }

  assert( p2<nField );

      len = sqlite3VdbeSerialTypeLen(aType[p2]);
      rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex, &sMem);
      if( rc!=SQLITE_OK ){
        goto op_column_out;
      }
      zData = sMem.z;
    }
    sqlite3VdbeSerialGet((u8*)zData, aType[p2], pDest);
    pDest->enc = encoding;
  }else{
    if( pOp[1].opcode==OP_DfltValue ){
      assert( pOp[1].p3type==P3_MEM );
      sqlite3VdbeMemShallowCopy(pDest, (Mem *)(pOp[1].p3.p), MEM_Static);
    }else{
      assert( pDest->flags==MEM_Null );
    }
  }

  /* If we dynamically allocated space to hold the data (in the
  ** sqlite3VdbeMemFromBtree() call above) then transfer control of that
  ** dynamically allocated space over to the pDest structure.
  ** This prevents a memory copy.
  */
  if( (sMem.flags & MEM_Dyn)!=0 ){
    assert( pDest->flags & MEM_Ephem );
    assert( pDest->flags & (MEM_Str|MEM_Blob) );
    assert( pDest->z==sMem.z );
    assert( sMem.flags & MEM_Term );
    pDest->flags &= ~MEM_Ephem;
    pDest->flags |= MEM_Dyn|MEM_Term;
  }

  /* pDest->z might be pointing to sMem.zShort[].  Fix that so that we
  ** can abandon sMem */
  rc = sqlite3VdbeMemMakeWriteable(pDest);

op_column_out:
  if( pOp[1].opcode==OP_DfltValue ){
    pc++;
  }
  break;
}

/* Opcode: DfltValue * * P3
**
** This instruction always follows an OP_Column.  This instruction
** does nothing by itself.  It is just a place holder for the default
** value for the previous OP_Column instruction.
*/
case OP_DfltValue: {       /* no-push */
  assert( 0 );
}

/* Opcode: MakeRecord P1 P2 P3
**
** Convert the top abs(P1) entries of the stack into a single entry
** suitable for use as a data record in a database table or as a key
** in an index.  The details of the format are irrelavant as long as
** the OP_Column opcode can decode the record later and as long as the

/* Opcode: MakeIdxRec P1 P2 P3
**
** This opcode works just OP_MakeRecord except that it reads an extra
** integer from the stack (thus reading a total of abs(P1+1) entries)
** and appends that extra integer to the end of the record as a varint.
** This results in an index key.
*/
/*
** Opcode: RegMakeRec P1 P2 P3
**
** Works like OP_MakeRecord except data is taken from registers
** rather than from the stack.  The P1 register is an integer which
** is the number of register to use in building the new record.
** Data is taken from P1+1, P1+2, ..., P1+mem[P1].
*/
/*
** Opcode: RegMakeIRec P1 P2 P3
**
** Works like OP_MakeIdxRec except data is taken from registers
** rather than from the stack.  The P1 register is an integer which
** is the number of register to use in building the new record.
** Data is taken from P1+1, P1+2, ..., P1+mem[P1].
*/
case OP_RegMakeRec:
case OP_RegMakeIRec:
case OP_MakeIdxRec:
case OP_MakeRecord: {
  /* Assuming the record contains N fields, the record format looks
  ** like this:
  **
  ** ------------------------------------------------------------------------
  ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 | 

  int jumpIfNull;        /* Jump here if non-zero and any entries are NULL. */
  int addRowid;          /* True to append a rowid column at the end */
  char *zAffinity;       /* The affinity string for the record */
  int file_format;       /* File format to use for encoding */
  int i;                 /* Space used in zNewRecord[] */
  char zTemp[NBFS];      /* Space to hold small records */

  if( pOp->p1<0 ){
    assert( pOp->opcode==OP_MakeRecord || pOp->opcode==OP_MakeIdxRec );
    leaveOnStack = 1;
    nField = -pOp->p1;
  }else{
    leaveOnStack = 0;
    nField = pOp->p1;
  }
  jumpIfNull = pOp->p2;
  addRowid = pOp->opcode==OP_MakeIdxRec || pOp->opcode==OP_RegMakeIRec;
  zAffinity = pOp->p3.p;

  if( pOp->opcode==OP_RegMakeRec || pOp->opcode==OP_RegMakeIRec ){
    Mem *pCount;
    assert( nField>=0 && nField<p->nMem );
    pCount = &p->aMem[nField];
    assert( pCount->flags & MEM_Int );
    assert( pCount->u.i>=0 && pCount->u.i+nField<p->nMem );
    assert( leaveOnStack==1 );
    nField = pCount->u.i;
    pData0 = &pCount[1];
  }else{
    pData0 = &pTos[1-nField];
    assert( pData0>=p->aStack );
  }
  containsNull = 0;
  file_format = p->minWriteFileFormat;

  /* Loop through the elements that will make up the record to figure
  ** out how much space is required for the new record.
  */
  for(pRec=pData0; pRec<=pTos; pRec++){

  pCur = allocateCursor(p, i, iDb);
  if( pCur==0 ) goto no_mem;
  pCur->nullRow = 1;
  if( pX==0 ) break;
  /* We always provide a key comparison function.  If the table being
  ** opened is of type INTKEY, the comparision function will be ignored. */
  rc = sqlite3BtreeCursor(pX, p2, wrFlag,
           sqlite3VdbeRecordCompare, pOp->p3.p,
           &pCur->pCursor);
  if( pOp->p3type==P3_KEYINFO ){
    pCur->pKeyInfo = (KeyInfo*)pOp->p3.p;
    pCur->pIncrKey = &pCur->pKeyInfo->incrKey;
    pCur->pKeyInfo->enc = ENC(p->db);
  }else{
    pCur->pKeyInfo = 0;
    pCur->pIncrKey = &pCur->bogusIncrKey;
  }
  switch( rc ){

  }
  if( rc==SQLITE_OK ){
    /* If a transient index is required, create it by calling
    ** sqlite3BtreeCreateTable() with the BTREE_ZERODATA flag before
    ** opening it. If a transient table is required, just use the
    ** automatically created table with root-page 1 (an INTKEY table).
    */
    if( pOp->p3.p ){
      int pgno;
      assert( pOp->p3type==P3_KEYINFO );
      rc = sqlite3BtreeCreateTable(pCx->pBt, &pgno, BTREE_ZERODATA); 
      if( rc==SQLITE_OK ){
        assert( pgno==MASTER_ROOT+1 );
        rc = sqlite3BtreeCursor(pCx->pBt, pgno, 1, sqlite3VdbeRecordCompare,
            pOp->p3.p, &pCx->pCursor);
        pCx->pKeyInfo = (KeyInfo*)pOp->p3.p;
        pCx->pKeyInfo->enc = ENC(p->db);
        pCx->pIncrKey = &pCx->pKeyInfo->incrKey;
      }
      pCx->isTable = 0;
    }else{
      rc = sqlite3BtreeCursor(pCx->pBt, MASTER_ROOT, 1, 0, 0, &pCx->pCursor);
      pCx->isTable = 1;

    }
    
    pC->rowidIsValid = 0;
    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;

    /* Invoke the update-hook if required. */
    if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p3.p ){
      const char *zDb = db->aDb[pC->iDb].zName;
      const char *zTbl = pOp->p3.p;
      int op = ((pOp->p2 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
      assert( pC->isTable );
      db->xUpdateCallback(db->pUpdateArg, op, zDb, zTbl, iKey);
      assert( pC->iDb>=0 );
    }
  }
  popStack(&pTos, 2);

  assert( pC!=0 );
  if( pC->pCursor!=0 ){
    i64 iKey;

    /* If the update-hook will be invoked, set iKey to the rowid of the
    ** row being deleted.
    */
    if( db->xUpdateCallback && pOp->p3.p ){
      assert( pC->isTable );
      if( pC->rowidIsValid ){
        iKey = pC->lastRowid;
      }else{
        rc = sqlite3BtreeKeySize(pC->pCursor, &iKey);
        if( rc ){
          goto abort_due_to_error;
        }
        iKey = keyToInt(iKey);
      }
    }

    rc = sqlite3VdbeCursorMoveto(pC);
    if( rc ) goto abort_due_to_error;
    rc = sqlite3BtreeDelete(pC->pCursor);
    pC->nextRowidValid = 0;
    pC->cacheStatus = CACHE_STALE;

    /* Invoke the update-hook if required. */
    if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p3.p ){
      const char *zDb = db->aDb[pC->iDb].zName;
      const char *zTbl = pOp->p3.p;
      db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, zTbl, iKey);
      assert( pC->iDb>=0 );
    }
  }
  if( pOp->p2 & OPFLAG_NCHANGE ) p->nChange++;
  break;
}

  assert( pTos>=p->aStack );
  if( (pC = p->apCsr[i])->pCursor!=0 ){
    int res;
 
    assert( pTos->flags & MEM_Blob );  /* Created using OP_MakeRecord */
    assert( pC->deferredMoveto==0 );
    ExpandBlob(pTos);
    *pC->pIncrKey = pOp->p3.p!=0;
    assert( pOp->p3.p==0 || pOp->opcode!=OP_IdxGT );
    rc = sqlite3VdbeIdxKeyCompare(pC, pTos->n, (u8*)pTos->z, &res);
    *pC->pIncrKey = 0;
    if( rc!=SQLITE_OK ){
      break;
    }
    if( pOp->opcode==OP_IdxLT ){
      res = -res;

case OP_Clear: {        /* no-push */

  /* For consistency with the way other features of SQLite operate
  ** with a truncate, we will also skip the update callback.
  */
#if 0
  Btree *pBt = db->aDb[pOp->p2].pBt;
  if( db->xUpdateCallback && pOp->p3.p ){
    const char *zDb = db->aDb[pOp->p2].zName;
    const char *zTbl = pOp->p3.p;
    BtCursor *pCur = 0;
    int fin = 0;

    rc = sqlite3BtreeCursor(pBt, pOp->p1, 0, 0, 0, &pCur);
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }

  }
  zMaster = SCHEMA_TABLE(iDb);
  initData.db = db;
  initData.iDb = pOp->p1;
  initData.pzErrMsg = &p->zErrMsg;
  zSql = sqlite3MPrintf(db,
     "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s",
     db->aDb[iDb].zName, zMaster, pOp->p3.p);
  if( zSql==0 ) goto no_mem;
  sqlite3SafetyOff(db);
  assert( db->init.busy==0 );
  db->init.busy = 1;
  assert( !db->mallocFailed );
  rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
  if( rc==SQLITE_ABORT ) rc = initData.rc;

**
** Remove the internal (in-memory) data structures that describe
** the table named P3 in database P1.  This is called after a table
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropTable: {        /* no-push */
  sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p3.p);
  break;
}

/* Opcode: DropIndex P1 * P3
**
** Remove the internal (in-memory) data structures that describe
** the index named P3 in database P1.  This is called after an index
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropIndex: {        /* no-push */
  sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p3.p);
  break;
}

/* Opcode: DropTrigger P1 * P3
**
** Remove the internal (in-memory) data structures that describe
** the trigger named P3 in database P1.  This is called after a trigger
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropTrigger: {        /* no-push */
  sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p3.p);
  break;
}


#ifndef SQLITE_OMIT_INTEGRITY_CHECK
/* Opcode: IntegrityCk P1 P2 *
**

  assert( pRec>=p->aStack );
  apVal = p->apArg;
  assert( apVal || n==0 );
  for(i=0; i<n; i++, pRec++){
    apVal[i] = pRec;
    storeTypeInfo(pRec, encoding);
  }
  ctx.pFunc = (FuncDef*)pOp->p3.p;
  assert( pOp->p1>=0 && pOp->p1<p->nMem );
  ctx.pMem = pMem = &p->aMem[pOp->p1];
  pMem->n++;
  ctx.s.flags = MEM_Null;
  ctx.s.z = 0;
  ctx.s.xDel = 0;
  ctx.s.db = db;
  ctx.isError = 0;
  ctx.pColl = 0;
  if( ctx.pFunc->needCollSeq ){
    assert( pOp>p->aOp );
    assert( pOp[-1].p3type==P3_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = (CollSeq *)pOp[-1].p3.p;
  }
  (ctx.pFunc->xStep)(&ctx, n, apVal);
  popStack(&pTos, n);
  if( ctx.isError ){
    sqlite3SetString(&p->zErrMsg, sqlite3_value_text(&ctx.s), (char*)0);
    rc = SQLITE_ERROR;
  }

** the step function was not previously called.
*/
case OP_AggFinal: {        /* no-push */
  Mem *pMem;
  assert( pOp->p1>=0 && pOp->p1<p->nMem );
  pMem = &p->aMem[pOp->p1];
  assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
  rc = sqlite3VdbeMemFinalize(pMem, (FuncDef*)pOp->p3.p);
  if( rc==SQLITE_ERROR ){
    sqlite3SetString(&p->zErrMsg, sqlite3_value_text(pMem), (char*)0);
  }
  if( sqlite3VdbeMemTooBig(pMem) ){
    goto too_big;
  }
  break;

  if( isWriteLock ){
    p1 = (-1*p1)-1;
  }
  assert( p1>=0 && p1<db->nDb );
  assert( (p->btreeMask & (1<<p1))!=0 );
  rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
  if( rc==SQLITE_LOCKED ){
    const char *z = (const char *)pOp->p3.p;
    sqlite3SetString(&p->zErrMsg, "database table is locked: ", z, (char*)0);
  }
  break;
}
#endif /* SQLITE_OMIT_SHARED_CACHE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VBegin * * P3
**
** P3 a pointer to an sqlite3_vtab structure. Call the xBegin method 
** for that table.
*/
case OP_VBegin: {   /* no-push */
  rc = sqlite3VtabBegin(db, (sqlite3_vtab *)pOp->p3.p);
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VCreate P1 * P3
**
** P3 is the name of a virtual table in database P1. Call the xCreate method
** for that table.
*/
case OP_VCreate: {   /* no-push */
  rc = sqlite3VtabCallCreate(db, pOp->p1, pOp->p3.p, &p->zErrMsg);
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VDestroy P1 * P3
**
** P3 is the name of a virtual table in database P1.  Call the xDestroy method
** of that table.
*/
case OP_VDestroy: {   /* no-push */
  p->inVtabMethod = 2;
  rc = sqlite3VtabCallDestroy(db, pOp->p1, pOp->p3.p);
  p->inVtabMethod = 0;
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VOpen P1 * P3
**
** P3 is a pointer to a virtual table object, an sqlite3_vtab structure.
** P1 is a cursor number.  This opcode opens a cursor to the virtual
** table and stores that cursor in P1.
*/
case OP_VOpen: {   /* no-push */
  Cursor *pCur = 0;
  sqlite3_vtab_cursor *pVtabCursor = 0;

  sqlite3_vtab *pVtab = (sqlite3_vtab *)(pOp->p3.p);
  sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;

  assert(pVtab && pModule);
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  rc = pModule->xOpen(pVtab, &pVtabCursor);
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  if( SQLITE_OK==rc ){

    for(i = 0; i<nArg; i++){
      apArg[i] = &pTos[i+1-2-nArg];
      storeTypeInfo(apArg[i], 0);
    }

    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    p->inVtabMethod = 1;
    rc = pModule->xFilter(pCur->pVtabCursor, pTos->u.i, pOp->p3.p, nArg, apArg);
    p->inVtabMethod = 0;
    if( rc==SQLITE_OK ){
      res = pModule->xEof(pCur->pVtabCursor);
    }
    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;

    if( res ){

**
** P3 is a pointer to a virtual table object, an sqlite3_vtab structure.
** This opcode invokes the corresponding xRename method. The value
** on the top of the stack is popped and passed as the zName argument
** to the xRename method.
*/
case OP_VRename: {   /* no-push */
  sqlite3_vtab *pVtab = (sqlite3_vtab *)(pOp->p3.p);
  assert( pVtab->pModule->xRename );

  Stringify(pTos, encoding);

  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  sqlite3VtabLock(pVtab);
  rc = pVtab->pModule->xRename(pVtab, pTos->z);

** 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: {   /* no-push */
  sqlite3_vtab *pVtab = (sqlite3_vtab *)(pOp->p3.p);
  sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;
  int nArg = pOp->p2;
  assert( pOp->p3type==P3_VTAB );
  if( pModule->xUpdate==0 ){
    sqlite3SetString(&p->zErrMsg, "read-only table", 0);
    rc = SQLITE_ERROR;
  }else{

*************************************************************************
** Header file for the Virtual DataBase Engine (VDBE)
**
** This header defines the interface to the virtual database engine
** or VDBE.  The VDBE implements an abstract machine that runs a
** simple program to access and modify the underlying database.
**
** $Id: vdbe.h,v 1.116 2008/01/02 00:34:37 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines
** in the source file sqliteVdbe.c are allowed to see the insides
** of this structure.
*/
typedef struct Vdbe Vdbe;

/*
** A single instruction of the virtual machine has an opcode
** and as many as three operands.  The instruction is recorded
** as an instance of the following structure:
*/
struct VdbeOp {
  u8 opcode;          /* What operation to perform */
  char p3type;        /* One of the P3_xxx constants defined below */
  int p1;             /* First operand */
  int p2;             /* Second parameter (often the jump destination) */
  union {             /* Third parameter */
    int i;              /* Integer value if p3type==P3_INT32 */
    char *p;            /* A pointer for all other value sof p3type */
  } p3;
#ifdef SQLITE_DEBUG
  char *zComment;     /* Comment to improve readability */
#endif
#ifdef VDBE_PROFILE
  int cnt;            /* Number of times this instruction was executed */
  long long cycles;   /* Total time spend executing this instruction */
#endif
};
typedef struct VdbeOp VdbeOp;

#define P3_VDBEFUNC (-7)  /* P3 is a pointer to a VdbeFunc structure */
#define P3_MEM      (-8)  /* P3 is a pointer to a Mem*    structure */
#define P3_TRANSIENT (-9) /* P3 is a pointer to a transient string */
#define P3_VTAB     (-10) /* P3 is a pointer to an sqlite3_vtab structure */
#define P3_MPRINTF  (-11) /* P3 is a string obtained from sqlite3_mprintf() */
#define P3_REAL     (-12) /* P3 is a 64-bit floating point value */
#define P3_INT64    (-13) /* P3 is a 64-bit signed integer */
#define P3_INT32    (-14) /* P3 is a 32-bit signed integer */

/* When adding a P3 argument using P3_KEYINFO, a copy of the KeyInfo structure
** is made.  That copy is freed when the Vdbe is finalized.  But if the
** argument is P3_KEYINFO_HANDOFF, the passed in pointer is used.  It still
** gets freed when the Vdbe is finalized so it still should be obtained
** from a single sqliteMalloc().  But no copy is made and the calling
** function should *not* try to free the KeyInfo.

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.
*/
Vdbe *sqlite3VdbeCreate(sqlite3*);
int sqlite3VdbeAddOp(Vdbe*,int,int,int);
int sqlite3VdbeOp3(Vdbe*,int,int,int,const char *zP3,int);
int sqlite3VdbeOp3Int(Vdbe*,int,int,int,int);
int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
void sqlite3VdbeJumpHere(Vdbe*, int addr);
void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);
void sqlite3VdbeChangeP3(Vdbe*, int addr, const char *zP1, int N);
void sqlite3VdbeUsesBtree(Vdbe*, int);

  int inTempTrans;        /* True if temp database is transactioned */
  int returnStack[25];    /* Return address stack for OP_Gosub & OP_Return */
  int returnDepth;        /* Next unused element in returnStack[] */
  int nResColumn;         /* Number of columns in one row of the result set */
  char **azResColumn;     /* Values for one row of result */ 
  int popStack;           /* Pop the stack this much on entry to VdbeExec() */
  char *zErrMsg;          /* Error message written here */
  Mem *pResultSet;        /* Pointer to an array of results */
  u8 explain;             /* True if EXPLAIN present on SQL command */
  u8 changeCntOn;         /* True to update the change-counter */
  u8 aborted;             /* True if ROLLBACK in another VM causes an abort */
  u8 expired;             /* True if the VM needs to be recompiled */
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 inVtabMethod;        /* See comments above */
  int nChange;            /* Number of db changes made since last reset */

#ifndef SQLITE_OMIT_TRACE
    /* Invoke the trace callback if there is one
    */
    if( db->xTrace && !db->init.busy ){
      assert( p->nOp>0 );
      assert( p->aOp[p->nOp-1].opcode==OP_Noop );
      assert( p->aOp[p->nOp-1].p3.p!=0 );
      assert( p->aOp[p->nOp-1].p3type==P3_DYNAMIC );
      sqlite3SafetyOff(db);
      db->xTrace(db->pTraceArg, p->aOp[p->nOp-1].p3.p);
      if( sqlite3SafetyOn(db) ){
        p->rc = SQLITE_MISUSE;
        return SQLITE_MISUSE;
      }
    }
    if( db->xProfile && !db->init.busy ){
      double rNow;
      sqlite3OsCurrentTime(db->pVfs, &rNow);
      p->startTime = (rNow - (int)rNow)*3600.0*24.0*1000000000.0;
    }
#endif

    /* Print a copy of SQL as it is executed if the SQL_TRACE pragma is turned
    ** on in debugging mode.
    */
#ifdef SQLITE_DEBUG
    if( (db->flags & SQLITE_SqlTrace)!=0 ){
      sqlite3DebugPrintf("SQL-trace: %s\n", p->aOp[p->nOp-1].p3.p);
    }
#endif /* SQLITE_DEBUG */

    db->activeVdbeCnt++;
    p->pc = 0;
  }
#ifndef SQLITE_OMIT_EXPLAIN

    double rNow;
    u64 elapseTime;

    sqlite3OsCurrentTime(db->pVfs, &rNow);
    elapseTime = (rNow - (int)rNow)*3600.0*24.0*1000000000.0 - p->startTime;
    assert( p->nOp>0 );
    assert( p->aOp[p->nOp-1].opcode==OP_Noop );
    assert( p->aOp[p->nOp-1].p3.p!=0 );
    assert( p->aOp[p->nOp-1].p3type==P3_DYNAMIC );
    db->xProfile(db->pProfileArg, p->aOp[p->nOp-1].p3.p, elapseTime);
  }
#endif

  sqlite3Error(p->db, rc, 0);
  p->rc = sqlite3ApiExit(p->db, p->rc);
end_of_step:
  assert( (rc&0xff)==rc );

/*
** Return the number of values available from the current row of the
** currently executing statement pStmt.
*/
int sqlite3_data_count(sqlite3_stmt *pStmt){
  Vdbe *pVm = (Vdbe *)pStmt;
  if( pVm==0 || pVm->pResultSet==0 ) return 0;
  return pVm->nResColumn;
}


/*
** Check to see if column iCol of the given statement is valid.  If
** it is, return a pointer to the Mem for the value of that column.
** If iCol is not valid, return a pointer to a Mem which has a value
** of NULL.
*/
static Mem *columnMem(sqlite3_stmt *pStmt, int i){
  Vdbe *pVm;
  int vals;
  Mem *pOut;

  pVm = (Vdbe *)pStmt;
  if( pVm && pVm->pResultSet!=0 && i<pVm->nResColumn && i>=0 ){
    sqlite3_mutex_enter(pVm->db->mutex);
    vals = sqlite3_data_count(pStmt);
    pOut = &pVm->pResultSet[i];
  }else{
    static const Mem nullMem = {{0}, 0.0, 0, "", 0, MEM_Null, SQLITE_NULL };
    if( pVm->db ){
      sqlite3_mutex_enter(pVm->db->mutex);
      sqlite3Error(pVm->db, SQLITE_RANGE, 0);
    }
    pOut = (Mem*)&nullMem;

    sqlite3_mutex_enter(p->db->mutex);
    if( !p->okVar ){
      int j;
      Op *pOp;
      for(j=0, pOp=p->aOp; j<p->nOp; j++, pOp++){
        if( pOp->opcode==OP_Variable ){
          assert( pOp->p1>0 && pOp->p1<=p->nVar );
          p->azVar[pOp->p1-1] = pOp->p3.p;
        }
      }
      p->okVar = 1;
    }
    sqlite3_mutex_leave(p->db->mutex);
  }
}

    }
  }
  p->nOp++;
  pOp = &p->aOp[i];
  pOp->opcode = op;
  pOp->p1 = p1;
  pOp->p2 = p2;
  pOp->p3.p = 0;
  pOp->p3type = P3_NOTUSED;
  p->expired = 0;
#ifdef SQLITE_DEBUG
  if( sqlite3_vdbe_addop_trace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);
#endif
  return i;
}

/*
** Add an opcode that includes the p3 value as a pointer.
*/
int sqlite3VdbeOp3(
  Vdbe *p,            /* Add the opcode to this VM */
  int op,             /* The new opcode */
  int p1, int p2,     /* P1 and P2 operands */
  const char *zP3,    /* The P3 operand */
  int p3type          /* P3 operand type */
){
  int addr = sqlite3VdbeAddOp(p, op, p1, p2);
  sqlite3VdbeChangeP3(p, addr, zP3, p3type);
  return addr;
}

/*
** Add an opcode that includes the p3 value as an integer.
*/
int sqlite3VdbeOp3Int(
  Vdbe *p,            /* Add the opcode to this VM */
  int op,             /* The new opcode */
  int p1, int p2,     /* P1 and P2 operands */
  int p3              /* The P3 operand */
){
  int addr = sqlite3VdbeAddOp(p, op, p1, p2);
  if( !p->db->mallocFailed ){
    Op *pOp = &p->aOp[addr];
    pOp->p3.i = p3;
    pOp->p3type = P3_INT32;
  }
  return addr;
}

/*
** Create a new symbolic label for an instruction that has yet to be
** coded.  The symbolic label is really just a negative number.  The
** label can be used as the P2 value of an operation.  Later, when
** the label is resolved to a specific address, the VDBE will scan
** through its operation list and change all values of P2 which match

    VdbeOpList const *pIn = aOp;
    for(i=0; i<nOp; i++, pIn++){
      int p2 = pIn->p2;
      VdbeOp *pOut = &p->aOp[i+addr];
      pOut->opcode = pIn->opcode;
      pOut->p1 = pIn->p1;
      pOut->p2 = p2<0 ? addr + ADDR(p2) : p2;
      pOut->p3.p = pIn->p3;
      pOut->p3type = pIn->p3 ? P3_STATIC : P3_NOTUSED;
#ifdef SQLITE_DEBUG
      if( sqlite3_vdbe_addop_trace ){
        sqlite3VdbePrintOp(0, i+addr, &p->aOp[i+addr]);
      }
#endif
    }

/*
** Change N opcodes starting at addr to No-ops.
*/
void sqlite3VdbeChangeToNoop(Vdbe *p, int addr, int N){
  if( p && p->aOp ){
    VdbeOp *pOp = &p->aOp[addr];
    while( N-- ){
      freeP3(pOp->p3type, pOp->p3.p);
      memset(pOp, 0, sizeof(pOp[0]));
      pOp->opcode = OP_Noop;
      pOp++;
    }
  }
}

    return;
  }
  if( addr<0 || addr>=p->nOp ){
    addr = p->nOp - 1;
    if( addr<0 ) return;
  }
  pOp = &p->aOp[addr];
  freeP3(pOp->p3type, pOp->p3.p);
  pOp->p3.p = 0;
  if( zP3==0 ){
    pOp->p3.p = 0;
    pOp->p3type = P3_NOTUSED;
  }else if( n==P3_KEYINFO ){
    KeyInfo *pKeyInfo;
    int nField, nByte;

    nField = ((KeyInfo*)zP3)->nField;
    nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]) + nField;
    pKeyInfo = sqlite3_malloc( nByte );
    pOp->p3.p = (char*)pKeyInfo;
    if( pKeyInfo ){
      unsigned char *aSortOrder;
      memcpy(pKeyInfo, zP3, nByte);
      aSortOrder = pKeyInfo->aSortOrder;
      if( aSortOrder ){
        pKeyInfo->aSortOrder = (unsigned char*)&pKeyInfo->aColl[nField];
        memcpy(pKeyInfo->aSortOrder, aSortOrder, nField);
      }
      pOp->p3type = P3_KEYINFO;
    }else{
      p->db->mallocFailed = 1;
      pOp->p3type = P3_NOTUSED;
    }
  }else if( n==P3_KEYINFO_HANDOFF ){
    pOp->p3.p = (char*)zP3;
    pOp->p3type = P3_KEYINFO;
  }else if( n<0 ){
    pOp->p3.p = (char*)zP3;
    pOp->p3type = n;
  }else{
    if( n==0 ) n = strlen(zP3);
    pOp->p3.p = sqlite3DbStrNDup(p->db, zP3, n);
    pOp->p3type = P3_DYNAMIC;
  }
}

#ifndef NDEBUG
/*
** Change the comment on the the most recently coded instruction.

*/
void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
  va_list ap;
  assert( p->nOp>0 || p->aOp==0 );
  assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );
  va_start(ap, zFormat);
  p->aOp[p->nOp-1].zComment = sqlite3VMPrintf(p->db, zFormat, ap);
  va_end(ap);
}
#endif

/*
** Return the opcode for a given address.
*/
VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
  assert( p->magic==VDBE_MAGIC_INIT );
  assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
  return ((addr>=0 && addr<p->nOp)?(&p->aOp[addr]):0);
}

#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
/*
** Compute a string that describes the P3 parameter for an opcode.
** Use zTemp for any required temporary buffer space.
*/
static char *displayP3(Op *pOp, char *zTemp, int nTemp){
  char *zP3 = zTemp;
  int nP3;
  assert( nTemp>=20 );
  switch( pOp->p3type ){
    case P3_KEYINFO: {
      int i, j;
      KeyInfo *pKeyInfo = (KeyInfo*)pOp->p3.p;
      sqlite3_snprintf(nTemp, zTemp, "keyinfo(%d", pKeyInfo->nField);
      i = strlen(zTemp);
      for(j=0; j<pKeyInfo->nField; j++){
        CollSeq *pColl = pKeyInfo->aColl[j];
        if( pColl ){
          int n = strlen(pColl->zName);
          if( i+n>nTemp-6 ){

          memcpy(&zTemp[i],",nil",4);
          i += 4;
        }
      }
      zTemp[i++] = ')';
      zTemp[i] = 0;
      assert( i<nTemp );

      break;
    }
    case P3_COLLSEQ: {
      CollSeq *pColl = (CollSeq*)pOp->p3.p;
      sqlite3_snprintf(nTemp, zTemp, "collseq(%.20s)", pColl->zName);

      break;
    }
    case P3_FUNCDEF: {
      FuncDef *pDef = (FuncDef*)pOp->p3.p;
      sqlite3_snprintf(nTemp, zTemp, "%s(%d)", pDef->zName, pDef->nArg);

      break;
    }
    case P3_INT64: {
      sqlite3_snprintf(nTemp, zTemp, "%lld", *(sqlite3_int64*)pOp->p3.p);
      break;
    }
    case P3_INT32: {
      sqlite3_snprintf(nTemp, zTemp, "%d", pOp->p3.i);
      break;
    }
    case P3_REAL: {
      sqlite3_snprintf(nTemp, zTemp, "%.16g", *(double*)pOp->p3.p);
      break;
    }
    case P3_MEM: {
      Mem *pMem = (Mem*)pOp->p3.p;
      if( pMem->flags & MEM_Str ){
        zP3 = pMem->z;
      }else if( pMem->flags & MEM_Int ){
        sqlite3_snprintf(nTemp, zTemp, "%lld", pMem->u.i);
      }else if( pMem->flags & MEM_Real ){
        sqlite3_snprintf(nTemp, zTemp, "%.16g", pMem->r);
      }else if( pMem->flags & MEM_Null ){
        sqlite3_snprintf(nTemp, zTemp, "NULL");
      }
      break;
    }
#ifndef SQLITE_OMIT_VIRTUALTABLE
    case P3_VTAB: {
      sqlite3_vtab *pVtab = (sqlite3_vtab*)pOp->p3.p;
      sqlite3_snprintf(nTemp, zTemp, "vtab:%p:%p", pVtab, pVtab->pModule);

      break;
    }
#endif
    default: {
      zP3 = pOp->p3.p;
      if( zP3==0 || pOp->opcode==OP_Noop ){
        zP3 = zTemp;
        zTemp[0] = 0;
      }
    }
  }
  assert( zP3!=0 );
  if( pOp->zComment && zP3==zTemp && (nP3 = strlen(zP3))<nTemp ){
    sqlite3_snprintf(nTemp-nP3, &zP3[nP3], "%s# %s",
                     nP3>0 ? " " : "", pOp->zComment);
  }
  return zP3;
}
#endif

/*
** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
**

  assert( db->magic==SQLITE_MAGIC_BUSY );
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );

  /* Even though this opcode does not put dynamic strings onto the
  ** the stack, they may become dynamic if the user calls
  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
  */
  if( p->pResultSet ){
    releaseMemArray(p->pResultSet, 5);
    p->pResultSet = 0;
  }


  do{
    i = p->pc++;
  }while( i<p->nOp && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
  if( i>=p->nOp ){
    p->rc = SQLITE_OK;
    rc = SQLITE_DONE;
  }else if( db->u1.isInterrupted ){
    p->rc = SQLITE_INTERRUPT;
    rc = SQLITE_ERROR;
    sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(p->rc), (char*)0);
  }else{
    Op *pOp = &p->aOp[i];
    Mem *pMem = p->pResultSet = p->aStack;
    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 */

    pMem++;

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

    pMem->flags = MEM_Ephem|MEM_Str|MEM_Term;     /* P3 */
    pMem->z = displayP3(pOp, pMem->zShort, sizeof(pMem->zShort));
    assert( pMem->z!=0 );
    pMem->n = strlen(pMem->z);
    pMem->type = SQLITE_TEXT;
    pMem->enc = SQLITE_UTF8;

    p->nResColumn = 5 - 2*(p->explain-1);
    p->pTos = pMem;
    p->rc = SQLITE_OK;

    rc = SQLITE_ROW;
  }
  return rc;
}
#endif /* SQLITE_OMIT_EXPLAIN */

#ifdef SQLITE_DEBUG
/*
** Print the SQL that was used to generate a VDBE program.
*/
void sqlite3VdbePrintSql(Vdbe *p){
  int nOp = p->nOp;
  VdbeOp *pOp;
  if( nOp<1 ) return;
  pOp = &p->aOp[nOp-1];
  if( pOp->opcode==OP_Noop && pOp->p3.p!=0 ){
    const char *z = pOp->p3.p;
    while( isspace(*(u8*)z) ) z++;
    printf("SQL: [%s]\n", z);
  }
}
#endif

#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
/*
** Print an IOTRACE message showing SQL content.
*/
void sqlite3VdbeIOTraceSql(Vdbe *p){
  int nOp = p->nOp;
  VdbeOp *pOp;
  if( sqlite3_io_trace==0 ) return;
  if( nOp<1 ) return;
  pOp = &p->aOp[nOp-1];
  if( pOp->opcode==OP_Noop && pOp->p3.p!=0 ){
    int i, j;
    char z[1000];
    sqlite3_snprintf(sizeof(z), z, "%s", pOp->p3.p);
    for(i=0; isspace((unsigned char)z[i]); i++){}
    for(j=0; z[i]; i++){
      if( isspace((unsigned char)z[i]) ){
        if( z[i-1]!=' ' ){
          z[j++] = ' ';
        }
      }else{

    sqlite3_free(p->contextStack);
  }
  p->contextStack = 0;
  p->contextStackDepth = 0;
  p->contextStackTop = 0;
  sqlite3_free(p->zErrMsg);
  p->zErrMsg = 0;
  p->pResultSet = 0;
}

/*
** Set the number of result columns that will be returned by this SQL
** statement. This is now set at compile time, rather than during
** execution of the vdbe program so that sqlite3_column_count() can
** be called on an SQL statement before sqlite3_step().

    assert( p->db->pVdbe==p );
    p->db->pVdbe = p->pNext;
  }
  if( p->pNext ){
    p->pNext->pPrev = p->pPrev;
  }
  if( p->aOp ){
    Op *pOp = p->aOp;
    for(i=0; i<p->nOp; i++, pOp++){

      freeP3(pOp->p3type, pOp->p3.p);
#ifdef SQLITE_DEBUG
      sqlite3_free(pOp->zComment);
#endif     
    }
    sqlite3_free(p->aOp);
  }
  releaseMemArray(p->aVar, p->nVar);
  sqlite3_free(p->aLabel);
  sqlite3_free(p->aStack);
  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.267 2008/01/02 00:34:37 drh Exp $
*/
#include "sqliteInt.h"

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

    int iTab;
    struct InLoop *pIn;

    assert( pX->op==TK_IN );
    eType = sqlite3FindInIndex(pParse, pX, 1);
    iTab = pX->iTable;
    sqlite3VdbeAddOp(v, OP_Rewind, iTab, 0);
    VdbeComment((v, "%.*s", pX->span.n, pX->span.z));
    if( pLevel->nIn==0 ){
      pLevel->nxt = sqlite3VdbeMakeLabel(v);
    }
    pLevel->nIn++;
    pLevel->aInLoop = sqlite3DbReallocOrFree(pParse->db, pLevel->aInLoop,
                                    sizeof(pLevel->aInLoop[0])*pLevel->nIn);
    pIn = pLevel->aInLoop;

      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
    }
    pLevel->iTabCur = pTabItem->iCursor;
    if( (pIx = pLevel->pIdx)!=0 ){
      KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIx);
      assert( pIx->pSchema==pTab->pSchema );
      sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
      VdbeComment((v, "%s", pIx->zName));
      sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIx->tnum,
                     (char*)pKey, P3_KEYINFO_HANDOFF);
      sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, pIx->nColumn+1);
    }
    sqlite3CodeVerifySchema(pParse, iDb);
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);

    ** initialize a memory cell that records if this table matches any
    ** row of the left table of the join.
    */
    if( pLevel->iFrom>0 && (pTabItem[0].jointype & JT_LEFT)!=0 ){
      if( !pParse->nMem ) pParse->nMem++;
      pLevel->iLeftJoin = pParse->nMem++;
      sqlite3VdbeAddOp(v, OP_MemInt, 0, pLevel->iLeftJoin);
      VdbeComment((v, "init LEFT JOIN no-match flag"));
    }

#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( pLevel->pBestIdx ){
      /* Case 0:  The table is a virtual-table.  Use the VFilter and VNext
      **          to access the data.
      */

    /* For a LEFT OUTER JOIN, generate code that will record the fact that
    ** at least one row of the right table has matched the left table.  
    */
    if( pLevel->iLeftJoin ){
      pLevel->top = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_MemInt, 1, pLevel->iLeftJoin);
      VdbeComment((v, "record LEFT JOIN hit"));
      for(pTerm=wc.a, j=0; j<wc.nTerm; j++, pTerm++){
        if( pTerm->flags & (TERM_VIRTUAL|TERM_CODED) ) continue;
        if( (pTerm->prereqAll & notReady)!=0 ) continue;
        assert( pTerm->pExpr );
        sqlite3ExprIfFalse(pParse, pTerm->pExpr, cont, 1);
        pTerm->flags |= TERM_CODED;
      }