**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.344 2005/08/31 13:13:31 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

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

  /* Get the VDBE program ready for execution
  */
  if( v && pParse->nErr==0 ){
    FILE *trace = (db->flags & SQLITE_VdbeTrace)!=0 ? stdout : 0;
    sqlite3VdbeTrace(v, trace);
    sqlite3VdbeMakeReady(v, pParse->nVar, pParse->nMem+3,
                         pParse->nTab+3, pParse->nMaxDepth+1, pParse->explain);
    pParse->rc = SQLITE_DONE;
    pParse->colNamesSet = 0;
  }else if( pParse->rc==SQLITE_OK ){
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;
................................................................................
    destroyRootPage(pParse, pIndex->tnum, iDb);
    sqlite3VdbeOp3(v, OP_DropIndex, iDb, 0, pIndex->zName, 0);
  }

exit_drop_index:
  sqlite3SrcListDelete(pName);
}








































/*
** Append a new element to the given IdList.  Create a new IdList if
** need be.
**
** A new IdList is returned, or NULL if malloc() fails.
*/
IdList *sqlite3IdListAppend(IdList *pList, Token *pToken){

  if( pList==0 ){
    pList = sqliteMalloc( sizeof(IdList) );
    if( pList==0 ) return 0;
    pList->nAlloc = 0;
  }
  if( pList->nId>=pList->nAlloc ){
    struct IdList_item *a;
    pList->nAlloc = pList->nAlloc*2 + 5;
    a = sqliteRealloc(pList->a, pList->nAlloc*sizeof(pList->a[0]) );
    if( a==0 ){
      sqlite3IdListDelete(pList);
      return 0;
    }
    pList->a = a;
  }
  memset(&pList->a[pList->nId], 0, sizeof(pList->a[0]));
  pList->a[pList->nId].zName = sqlite3NameFromToken(pToken);
  pList->nId++;
  return pList;
}

/*
** Delete an IdList.
*/
void sqlite3IdListDelete(IdList *pList){

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.345 2005/09/07 21:22:46 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

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

  /* Get the VDBE program ready for execution
  */
  if( v && pParse->nErr==0 ){
    FILE *trace = (db->flags & SQLITE_VdbeTrace)!=0 ? stdout : 0;
    sqlite3VdbeTrace(v, trace);
    sqlite3VdbeMakeReady(v, pParse->nVar, pParse->nMem+3,
                         pParse->nTab+3, pParse->explain);
    pParse->rc = SQLITE_DONE;
    pParse->colNamesSet = 0;
  }else if( pParse->rc==SQLITE_OK ){
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;
................................................................................
    destroyRootPage(pParse, pIndex->tnum, iDb);
    sqlite3VdbeOp3(v, OP_DropIndex, iDb, 0, pIndex->zName, 0);
  }

exit_drop_index:
  sqlite3SrcListDelete(pName);
}

/*
** ppArray points into a structure where there is an array pointer
** followed by two integers. The first integer is the
** number of elements in the structure array.  The second integer
** is the number of allocated slots in the array.
**
** In other words, the structure looks something like this:
**
**        struct Example1 {
**          struct subElem *aEntry;
**          int nEntry;
**          int nAlloc;
**        }
**
** The pnEntry parameter points to the equivalent of Example1.nEntry.
**
** This routine allocates a new slot in the array, zeros it out,
** and returns its index.  If malloc fails a negative number is returned.
**
** szEntry is the sizeof of a single array entry.  initSize is the 
** number of array entries allocated on the initial allocation.
*/
int sqlite3ArrayAllocate(void **ppArray, int szEntry, int initSize){
  char *p;
  int *an = (int*)&ppArray[1];
  if( an[0]>=an[1] ){
    void *pNew;
    an[1] = an[1]*2 + initSize;
    pNew = sqliteRealloc(*ppArray, an[1]*szEntry);
    if( pNew==0 ){
      return -1;
    }
    *ppArray = pNew;
  }
  p = *ppArray;
  memset(&p[an[0]*szEntry], 0, szEntry);
  return an[0]++;
}

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



  if( i<0 ){
    sqlite3IdListDelete(pList);
    return 0;
  }



  pList->a[i].zName = sqlite3NameFromToken(pToken);

  return pList;
}

/*
** Delete an IdList.
*/
void sqlite3IdListDelete(IdList *pList){

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.224 2005/09/05 20:06:49 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
    case TK_FUNCTION:
      if( *((int*)pArg)==2 ) return 0;
      /* Fall through */
    case TK_ID:
    case TK_COLUMN:
    case TK_DOT:
    case TK_AGG_FUNCTION:

#ifndef SQLITE_OMIT_SUBQUERY
    case TK_SELECT:
    case TK_EXISTS:
#endif
      *((int*)pArg) = 0;
      return 2;
    case TK_IN:
................................................................................
** If the expression contains aggregate functions then set the EP_Agg
** property on the expression.
*/
int sqlite3ExprResolveNames(
  NameContext *pNC,       /* Namespace to resolve expressions in. */
  Expr *pExpr             /* The expression to be analyzed. */
){

  if( pExpr==0 ) return 0;


  walkExprTree(pExpr, nameResolverStep, pNC);
  if( pNC->nErr>0 ){
    ExprSetProperty(pExpr, EP_Error);





  }
  return ExprHasProperty(pExpr, EP_Error);
}

/*
** A pointer instance of this structure is used to pass information
** through walkExprTree into codeSubqueryStep().
................................................................................
    sqlite3VdbeAddOp(v, OP_MemLoad, mem, 0);
    testAddr = sqlite3VdbeAddOp(v, OP_If, 0, 0);
    assert( testAddr>0 );
    sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, mem, 1);
  }

  if( pExpr->pSelect ){
    sqlite3VdbeAddOp(v, OP_AggContextPush, 0, 0);
  }

  switch( pExpr->op ){
    case TK_IN: {
      char affinity;
      KeyInfo keyInfo;
      int addr;        /* Address of OP_OpenVirtual instruction */

      affinity = sqlite3ExprAffinity(pExpr->pLeft);
................................................................................
                          sqlite3Expr(TK_INTEGER, 0, 0, &one), 0);
      }
      sqlite3Select(pParse, pSel, sop, pExpr->iColumn, 0, 0, 0, 0);
      break;
    }
  }

  if( pExpr->pSelect ){
    sqlite3VdbeAddOp(v, OP_AggContextPop, 0, 0);
  }
  if( testAddr ){
    sqlite3VdbeChangeP2(v, testAddr, sqlite3VdbeCurrentAddr(v));
  }
  return;
}
#endif /* SQLITE_OMIT_SUBQUERY */

................................................................................
  if( v==0 ) return;
  if( pExpr==0 ){
    sqlite3VdbeAddOp(v, OP_Null, 0, 0);
    return;
  }
  op = pExpr->op;
  switch( op ){
    case TK_COLUMN: {
      if( !pParse->fillAgg && pExpr->iAgg>=0 ){


        sqlite3VdbeAddOp(v, OP_AggGet, pExpr->iAggCtx, pExpr->iAgg);









      }else if( pExpr->iColumn>=0 ){
        sqlite3VdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
        sqlite3ColumnDefault(v, pExpr->pTab, pExpr->iColumn);
      }else{
        sqlite3VdbeAddOp(v, OP_Rowid, pExpr->iTable, 0);
      }
      break;
    }
................................................................................
      sqlite3ExprCode(pParse, pExpr->pLeft);
      dest = sqlite3VdbeCurrentAddr(v) + 2;
      sqlite3VdbeAddOp(v, op, 1, dest);
      sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);
      break;
    }
    case TK_AGG_FUNCTION: {

      sqlite3VdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
      break;
    }
    case TK_CONST_FUNC:
    case TK_FUNCTION: {
      ExprList *pList = pExpr->pList;
      int nExpr = pList ? pList->nExpr : 0;
      FuncDef *pDef;
      int nId;
      const char *zId;
      int p2 = 0;
      int i;
      u8 enc = pParse->db->enc;
      CollSeq *pColl = 0;
      zId = pExpr->token.z;
      nId = pExpr->token.n;
      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
      assert( pDef!=0 );
      nExpr = sqlite3ExprCodeExprList(pParse, pList);
      for(i=0; i<nExpr && i<32; i++){
        if( sqlite3ExprIsConstant(pList->a[i].pExpr) ){
          p2 |= (1<<i);
        }
        if( pDef->needCollSeq && !pColl ){
          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
        }
      }
      if( pDef->needCollSeq ){
        if( !pColl ) pColl = pParse->db->pDfltColl; 
        sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
      }
      sqlite3VdbeOp3(v, OP_Function, nExpr, p2, (char*)pDef, P3_FUNCDEF);
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS:
    case TK_SELECT: {
      sqlite3CodeSubselect(pParse, pExpr);
      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
................................................................................
    if( pB->token.z==0 ) return 0;
    if( pB->token.n!=pA->token.n ) return 0;
    if( sqlite3StrNICmp(pA->token.z, pB->token.z, pB->token.n)!=0 ) return 0;
  }
  return 1;
}


/*
** Add a new element to the pParse->aAgg[] array and return its index.
** The new element is initialized to zero.  The calling function is
** expected to fill it in.
*/
static int appendAggInfo(Parse *pParse){
  if( (pParse->nAgg & 0x7)==0 ){
    int amt = pParse->nAgg + 8;
    AggExpr *aAgg = sqliteRealloc(pParse->aAgg, amt*sizeof(pParse->aAgg[0]));
    if( aAgg==0 ){
      return -1;
    }
    pParse->aAgg = aAgg;

  }
  memset(&pParse->aAgg[pParse->nAgg], 0, sizeof(pParse->aAgg[0]));











  return pParse->nAgg++;
}

/*
** This is an xFunc for walkExprTree() used to implement 
** sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
** for additional information.
**
** This routine analyzes the aggregate function at pExpr.
*/
static int analyzeAggregate(void *pArg, Expr *pExpr){
  int i;
  AggExpr *pAgg;
  NameContext *pNC = (NameContext *)pArg;
  Parse *pParse = pNC->pParse;
  SrcList *pSrcList = pNC->pSrcList;



  switch( pExpr->op ){
    case TK_COLUMN: {




      for(i=0; pSrcList && i<pSrcList->nSrc; i++){

        if( pExpr->iTable==pSrcList->a[i].iCursor ){

















          pAgg = pParse->aAgg;
          for(i=0; i<pParse->nAgg; i++, pAgg++){







            Expr *pE;
            if( pAgg->isAgg ) continue;
            pE = pAgg->pExpr;

            if( pE->iTable==pExpr->iTable && pE->iColumn==pExpr->iColumn ){

              break;
            }
          }
          if( i>=pParse->nAgg ){
            i = appendAggInfo(pParse);
            if( i<0 ) return 1;
            pAgg = &pParse->aAgg[i];
            pAgg->isAgg = 0;
            pAgg->pExpr = pExpr;
          }
          pExpr->iAgg = i;
          pExpr->iAggCtx = pNC->nDepth;
          return 1;


        }












      }
      return 1;
    }
    case TK_AGG_FUNCTION: {


      if( pNC->nDepth==0 ){
        pAgg = pParse->aAgg;
        for(i=0; i<pParse->nAgg; i++, pAgg++){
          if( !pAgg->isAgg ) continue;




          if( sqlite3ExprCompare(pAgg->pExpr, pExpr) ){
            break;
          }
        }
        if( i>=pParse->nAgg ){


          u8 enc = pParse->db->enc;
          i = appendAggInfo(pParse);
          if( i<0 ) return 1;
          pAgg = &pParse->aAgg[i];
          pAgg->isAgg = 1;

          pAgg->pExpr = pExpr;

          pAgg->pFunc = sqlite3FindFunction(pParse->db,
               pExpr->token.z, pExpr->token.n,
               pExpr->pList ? pExpr->pList->nExpr : 0, enc, 0);
        }



        pExpr->iAgg = i;

        return 1;
      }
    }
  }





  if( pExpr->pSelect ){
    pNC->nDepth++;
    walkSelectExpr(pExpr->pSelect, analyzeAggregate, pNC);
    pNC->nDepth--;
  }
  return 0;
}

**    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 1.225 2005/09/07 21:22:46 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
    case TK_FUNCTION:
      if( *((int*)pArg)==2 ) return 0;
      /* Fall through */
    case TK_ID:
    case TK_COLUMN:
    case TK_DOT:
    case TK_AGG_FUNCTION:
    case TK_AGG_COLUMN:
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_SELECT:
    case TK_EXISTS:
#endif
      *((int*)pArg) = 0;
      return 2;
    case TK_IN:
................................................................................
** If the expression contains aggregate functions then set the EP_Agg
** property on the expression.
*/
int sqlite3ExprResolveNames(
  NameContext *pNC,       /* Namespace to resolve expressions in. */
  Expr *pExpr             /* The expression to be analyzed. */
){
  int savedHasAgg;
  if( pExpr==0 ) return 0;
  savedHasAgg = pNC->hasAgg;
  pNC->hasAgg = 0;
  walkExprTree(pExpr, nameResolverStep, pNC);
  if( pNC->nErr>0 ){
    ExprSetProperty(pExpr, EP_Error);
  }
  if( pNC->hasAgg ){
    ExprSetProperty(pExpr, EP_Agg);
  }else if( savedHasAgg ){
    pNC->hasAgg = 1;
  }
  return ExprHasProperty(pExpr, EP_Error);
}

/*
** A pointer instance of this structure is used to pass information
** through walkExprTree into codeSubqueryStep().
................................................................................
    sqlite3VdbeAddOp(v, OP_MemLoad, mem, 0);
    testAddr = sqlite3VdbeAddOp(v, OP_If, 0, 0);
    assert( testAddr>0 );
    sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, mem, 1);
  }





  switch( pExpr->op ){
    case TK_IN: {
      char affinity;
      KeyInfo keyInfo;
      int addr;        /* Address of OP_OpenVirtual instruction */

      affinity = sqlite3ExprAffinity(pExpr->pLeft);
................................................................................
                          sqlite3Expr(TK_INTEGER, 0, 0, &one), 0);
      }
      sqlite3Select(pParse, pSel, sop, pExpr->iColumn, 0, 0, 0, 0);
      break;
    }
  }




  if( testAddr ){
    sqlite3VdbeChangeP2(v, testAddr, sqlite3VdbeCurrentAddr(v));
  }
  return;
}
#endif /* SQLITE_OMIT_SUBQUERY */

................................................................................
  if( v==0 ) return;
  if( pExpr==0 ){
    sqlite3VdbeAddOp(v, OP_Null, 0, 0);
    return;
  }
  op = pExpr->op;
  switch( op ){
    case TK_AGG_COLUMN: {
      AggInfo *pAggInfo = pExpr->pAggInfo;
      struct AggInfo_col *pCol = &pAggInfo->aCol[pExpr->iAgg];
      if( !pAggInfo->directMode ){
        sqlite3VdbeAddOp(v, OP_MemLoad, pCol->iMem, 0);
        break;
      }else if( pAggInfo->useSortingIdx ){
        sqlite3VdbeAddOp(v, OP_Column, pAggInfo->sortingIdx,
                              pCol->iSorterColumn);
        break;
      }
      /* Otherwise, fall thru into the TK_COLUMN case */
    }
    case TK_COLUMN: {
      if( pExpr->iColumn>=0 ){
        sqlite3VdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
        sqlite3ColumnDefault(v, pExpr->pTab, pExpr->iColumn);
      }else{
        sqlite3VdbeAddOp(v, OP_Rowid, pExpr->iTable, 0);
      }
      break;
    }
................................................................................
      sqlite3ExprCode(pParse, pExpr->pLeft);
      dest = sqlite3VdbeCurrentAddr(v) + 2;
      sqlite3VdbeAddOp(v, op, 1, dest);
      sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);
      break;
    }
    case TK_AGG_FUNCTION: {
      AggInfo *pInfo = pExpr->pAggInfo;
      sqlite3VdbeAddOp(v, OP_MemLoad, pInfo->aFunc[pExpr->iAgg].iMem, 0);
      break;
    }
    case TK_CONST_FUNC:
    case TK_FUNCTION: {
      ExprList *pList = pExpr->pList;
      int nExpr = pList ? pList->nExpr : 0;
      FuncDef *pDef;
      int nId;
      const char *zId;
      int constMask = 0;
      int i;
      u8 enc = pParse->db->enc;
      CollSeq *pColl = 0;
      zId = pExpr->token.z;
      nId = pExpr->token.n;
      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
      assert( pDef!=0 );
      nExpr = sqlite3ExprCodeExprList(pParse, pList);
      for(i=0; i<nExpr && i<32; i++){
        if( sqlite3ExprIsConstant(pList->a[i].pExpr) ){
          constMask |= (1<<i);
        }
        if( pDef->needCollSeq && !pColl ){
          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
        }
      }
      if( pDef->needCollSeq ){
        if( !pColl ) pColl = pParse->db->pDfltColl; 
        sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
      }
      sqlite3VdbeOp3(v, OP_Function, constMask, nExpr, (char*)pDef, P3_FUNCDEF);
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS:
    case TK_SELECT: {
      sqlite3CodeSubselect(pParse, pExpr);
      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
................................................................................
    if( pB->token.z==0 ) return 0;
    if( pB->token.n!=pA->token.n ) return 0;
    if( sqlite3StrNICmp(pA->token.z, pB->token.z, pB->token.n)!=0 ) return 0;
  }
  return 1;
}


/*
** Add a new element to the pAggInfo->aCol[] array.  Return the index of

** the new element.  Return a negative number if malloc fails.
*/
static int addAggInfoColumn(AggInfo *pInfo){
  int i;
  i = sqlite3ArrayAllocate((void**)&pInfo->aCol, sizeof(pInfo->aCol[0]), 3);
  if( i<0 ){

    return -1;
  }

  return i;
}    


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

/*
** This is an xFunc for walkExprTree() used to implement 
** sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
** for additional information.
**
** This routine analyzes the aggregate function at pExpr.
*/
static int analyzeAggregate(void *pArg, Expr *pExpr){
  int i;

  NameContext *pNC = (NameContext *)pArg;
  Parse *pParse = pNC->pParse;
  SrcList *pSrcList = pNC->pSrcList;
  AggInfo *pAggInfo = pNC->pAggInfo;
  

  switch( pExpr->op ){
    case TK_COLUMN: {
      /* Check to see if the column is in one of the tables in the FROM
      ** clause of the aggregate query */
      if( pSrcList ){
        struct SrcList_item *pItem = pSrcList->a;
        for(i=0; i<pSrcList->nSrc; i++, pItem++){
          struct AggInfo_col *pCol;
          if( pExpr->iTable==pItem->iCursor ){
            /* If we reach this point, it means that pExpr refers to a table
            ** that is in the FROM clause of the aggregate query.  
            **
            ** Make an entry for the column in pAggInfo->aCol[] if there
            ** is not an entry there already.
            */
            pCol = pAggInfo->aCol;
            for(i=0; i<pAggInfo->nColumn; i++, pCol++){
              if( pCol->iTable==pExpr->iTable &&
                  pCol->iColumn==pExpr->iColumn ){
                break;
              }
            }
            if( i>=pAggInfo->nColumn && (i = addAggInfoColumn(pAggInfo))>=0 ){
              pCol = &pAggInfo->aCol[i];
              pCol->iTable = pExpr->iTable;
              pCol->iColumn = pExpr->iColumn;
              pCol->iMem = pParse->nMem++;

              pCol->iSorterColumn = -1;
              if( pAggInfo->pGroupBy ){
                int j, n;
                ExprList *pGB = pAggInfo->pGroupBy;
                struct ExprList_item *pTerm = pGB->a;
                n = pGB->nExpr;
                for(j=0; j<n; j++, pTerm++){
                  Expr *pE = pTerm->pExpr;


                  if( pE->op==TK_COLUMN && pE->iTable==pExpr->iTable &&
                      pE->iColumn==pExpr->iColumn ){
                    pCol->iSorterColumn = j;
                    break;
                  }
                }






              }



              if( pCol->iSorterColumn<0 ){
                pCol->iSorterColumn = pAggInfo->nSortingColumn++;
              }
            }
            /* There is now an entry for pExpr in pAggInfo->aCol[] (either
            ** because it was there before or because we just created it).
            ** Convert the pExpr to be a TK_AGG_COLUMN referring to that
            ** pAggInfo->aCol[] entry.
            */
            pExpr->pAggInfo = pAggInfo;
            pExpr->op = TK_AGG_COLUMN;
            pExpr->iAgg = i;
            break;
          } /* endif pExpr->iTable==pItem->iCursor */
        } /* end loop over pSrcList */
      }
      return 1;
    }
    case TK_AGG_FUNCTION: {
      /* The pNC->nDepth==0 test causes aggregate functions in subqueries
      ** to be ignored */
      if( pNC->nDepth==0 ){


        /* Check to see if pExpr is a duplicate of another aggregate 
        ** function that is already in the pAggInfo structure
        */
        struct AggInfo_func *pItem = pAggInfo->aFunc;
        for(i=0; i<pAggInfo->nFunc; i++, pItem++){
          if( sqlite3ExprCompare(pItem->pExpr, pExpr) ){
            break;
          }
        }
        if( i>=pAggInfo->nFunc ){
          /* pExpr is original.  Make a new entry in pAggInfo->aFunc[]
          */
          u8 enc = pParse->db->enc;


          i = addAggInfoFunc(pAggInfo);
          if( i>=0 ){
            pItem = &pAggInfo->aFunc[i];
            pItem->pExpr = pExpr;
            pItem->iMem = pParse->nMem++;
            pItem->pFunc = sqlite3FindFunction(pParse->db,
                   pExpr->token.z, pExpr->token.n,
                   pExpr->pList ? pExpr->pList->nExpr : 0, enc, 0);
          }
        }
        /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
        */
        pExpr->iAgg = i;
        pExpr->pAggInfo = pAggInfo;
        return 1;
      }
    }
  }

  /* Recursively walk subqueries looking for TK_COLUMN nodes that need
  ** to be changed to TK_AGG_COLUMN.  But increment nDepth so that
  ** TK_AGG_FUNCTION nodes in subqueries will be unchanged.
  */
  if( pExpr->pSelect ){
    pNC->nDepth++;
    walkSelectExpr(pExpr->pSelect, analyzeAggregate, pNC);
    pNC->nDepth--;
  }
  return 0;
}

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.300 2005/08/29 23:00:04 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and
................................................................................
*/
int sqlite3_reset(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    rc = sqlite3VdbeReset((Vdbe*)pStmt);
    sqlite3VdbeMakeReady((Vdbe*)pStmt, -1, 0, 0, 0, 0);
  }
  return rc;
}

/*
** Register a new collation sequence with the database handle db.
*/

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.301 2005/09/07 21:22:46 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and
................................................................................
*/
int sqlite3_reset(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    rc = sqlite3VdbeReset((Vdbe*)pStmt);
    sqlite3VdbeMakeReady((Vdbe*)pStmt, -1, 0, 0, 0);
  }
  return rc;
}

/*
** Register a new collation sequence with the database handle db.
*/

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.175 2005/07/08 12:13:05 drh Exp $
*/

// All token codes are small integers with #defines that begin with "TK_"
%token_prefix TK_

// The type of the data attached to each token is Token.  This is also the
// default type for non-terminals.
................................................................................
} // end %include

// These are extra tokens used by the lexer but never seen by the
// parser.  We put them in a rule so that the parser generator will
// add them to the parse.h output file.
//
%nonassoc END_OF_FILE ILLEGAL SPACE UNCLOSED_STRING COMMENT FUNCTION
          COLUMN AGG_FUNCTION CONST_FUNC.

// Input is a single SQL command
input ::= cmdlist.
cmdlist ::= cmdlist ecmd.
cmdlist ::= ecmd.
cmdx ::= cmd.           { sqlite3FinishCoding(pParse); }
ecmd ::= SEMI.

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.176 2005/09/07 21:22:46 drh Exp $
*/

// All token codes are small integers with #defines that begin with "TK_"
%token_prefix TK_

// The type of the data attached to each token is Token.  This is also the
// default type for non-terminals.
................................................................................
} // end %include

// These are extra tokens used by the lexer but never seen by the
// parser.  We put them in a rule so that the parser generator will
// add them to the parse.h output file.
//
%nonassoc END_OF_FILE ILLEGAL SPACE UNCLOSED_STRING COMMENT FUNCTION
          COLUMN AGG_FUNCTION AGG_COLUMN CONST_FUNC.

// Input is a single SQL command
input ::= cmdlist.
cmdlist ::= cmdlist ecmd.
cmdlist ::= ecmd.
cmdx ::= cmd.           { sqlite3FinishCoding(pParse); }
ecmd ::= SEMI.

**    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 1.260 2005/09/05 20:06:49 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
................................................................................
static void codeLimiter(
  Vdbe *v,          /* Generate code into this VM */
  Select *p,        /* The SELECT statement being coded */
  int iContinue,    /* Jump here to skip the current record */
  int iBreak,       /* Jump here to end the loop */
  int nPop          /* Number of times to pop stack when jumping */
){
  if( p->iOffset>=0 ){
    int addr = sqlite3VdbeCurrentAddr(v) + 3;
    if( nPop>0 ) addr++;
    sqlite3VdbeAddOp(v, OP_MemIncr, p->iOffset, 0);
    sqlite3VdbeAddOp(v, OP_IfMemPos, p->iOffset, addr);
    if( nPop>0 ){
      sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
    }
    sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
    VdbeComment((v, "# skip OFFSET records"));
  }
  if( p->iLimit>=0 ){
    sqlite3VdbeAddOp(v, OP_MemIncr, p->iLimit, iBreak);
    VdbeComment((v, "# exit when LIMIT reached"));
  }
}

/*
** This routine generates the code for the inside of the inner loop
................................................................................
    sqlite3VdbeAddOp(v, OP_IdxInsert, distinct, 0);
    if( pOrderBy==0 ){
      codeLimiter(v, p, iContinue, iBreak, nColumn);
    }
  }

  switch( eDest ){
#ifndef SQLITE_OMIT_COMPOUND_SELECT
    /* In this mode, write each query result to the key of the temporary
    ** table iParm.
    */

    case SRT_Union: {
      sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, NULL_ALWAYS_DISTINCT);

      sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);

      sqlite3VdbeAddOp(v, OP_IdxInsert, iParm, 0);
      break;
    }

    /* Construct a record from the query result, but instead of
    ** saving that record, use it as a key to delete elements from
    ** the temporary table iParm.
................................................................................
    pOrderBy->iTab = pParse->nTab++;
    addr = sqlite3VdbeAddOp(pParse->pVdbe, OP_OpenVirtual,
                            pOrderBy->iTab, pOrderBy->nExpr+1);
    assert( p->addrOpenVirt[2] == -1 );
    p->addrOpenVirt[2] = addr;
  }
}















#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** Return the appropriate collating sequence for the iCol-th column of
** the result set for the compound-select statement "p".  Return NULL if
** the column has no default collating sequence.
**
................................................................................
  Parse *pParse,         /* The parser context */
  Select *p,             /* The SELECT statement being coded. */
  NameContext *pOuterNC  /* The outer name context. May be NULL. */
){
  ExprList *pEList;          /* Result set. */
  int i;                     /* For-loop variable used in multiple places */
  NameContext sNC;           /* Local name-context */


  /* If this routine has run before, return immediately. */
  if( p->isResolved ){
    assert( !pOuterNC );
    return SQLITE_OK;
  }
  p->isResolved = 1;
................................................................................
  /* Set up the local name-context to pass to ExprResolveNames() to
  ** resolve the expression-list.
  */
  sNC.allowAgg = 1;
  sNC.pSrcList = p->pSrc;
  sNC.pNext = pOuterNC;

  /* NameContext.nDepth stores the depth of recursion for this query. For
  ** an outer query (e.g. SELECT * FROM sqlite_master) this is 1. For
  ** a subquery it is 2. For a subquery of a subquery, 3. And so on. 
  ** Parse.nMaxDepth is the maximum depth for any subquery resolved so
  ** far. This is used to determine the number of aggregate contexts
  ** required at runtime.
  */
  sNC.nDepth = (pOuterNC?pOuterNC->nDepth+1:1);
  if( sNC.nDepth>pParse->nMaxDepth ){
    pParse->nMaxDepth = sNC.nDepth;
  }

  /* Resolve names in the result set. */
  pEList = p->pEList;
  if( !pEList ) return SQLITE_ERROR;
  for(i=0; i<pEList->nExpr; i++){
    Expr *pX = pEList->a[i].pExpr;
    if( sqlite3ExprResolveNames(&sNC, pX) ){
      return SQLITE_ERROR;
................................................................................
    }
  }

  /* If there are no aggregate functions in the result-set, and no GROUP BY 
  ** expression, do not allow aggregates in any of the other expressions.
  */
  assert( !p->isAgg );

  if( p->pGroupBy || sNC.hasAgg ){
    p->isAgg = 1;
  }else{
    sNC.allowAgg = 0;
  }

  /* If a HAVING clause is present, then there must be a GROUP BY clause.
  */
  if( p->pHaving && !p->pGroupBy ){
    sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
    return SQLITE_ERROR;
  }

  /* Add the expression list to the name-context before parsing the
  ** other expressions in the SELECT statement. This is so that
  ** expressions in the WHERE clause (etc.) can refer to expressions by
................................................................................
  ** Minor point: If this is the case, then the expression will be
  ** re-evaluated for each reference to it.
  */
  sNC.pEList = p->pEList;
  if( sqlite3ExprResolveNames(&sNC, p->pWhere) ||
      sqlite3ExprResolveNames(&sNC, p->pHaving) ||
      processOrderGroupBy(&sNC, p->pOrderBy, "ORDER") ||
      processOrderGroupBy(&sNC, p->pGroupBy, "GROUP")
  ){
    return SQLITE_ERROR;
  }















  return SQLITE_OK;
}

/*
** An instance of the following struct is used by sqlite3Select()
** to save aggregate related information from the Parse object
** at the start of each call and to restore it at the end. See
** saveAggregateInfo() and restoreAggregateInfo().





*/ 
struct AggregateInfo {


  int nAgg;
  AggExpr *aAgg;
};
typedef struct AggregateInfo AggregateInfo;














/* 
** Copy aggregate related information from the Parse structure
** into the AggregateInfo structure. Zero the aggregate related
** values in the Parse struct.


*/
static void saveAggregateInfo(Parse *pParse, AggregateInfo *pInfo){

  pInfo->aAgg = pParse->aAgg;
  pInfo->nAgg = pParse->nAgg;
  pParse->aAgg = 0;
  pParse->nAgg = 0;





}

/*
** Copy aggregate related information from the AggregateInfo struct
** back into the Parse structure. The aggregate related information
** currently stored in the Parse structure is deleted.
*/

static void restoreAggregateInfo(Parse *pParse, AggregateInfo *pInfo){
  sqliteFree(pParse->aAgg);
  pParse->aAgg = pInfo->aAgg;
  pParse->nAgg = pInfo->nAgg;

}









  


























/*
** Generate code for the given SELECT statement.
**
** The results are distributed in various ways depending on the
** value of eDest and iParm.
**
**     eDest Value       Result
................................................................................
  int eDest,             /* How to dispose of the results */
  int iParm,             /* A parameter used by the eDest disposal method */
  Select *pParent,       /* Another SELECT for which this is a sub-query */
  int parentTab,         /* Index in pParent->pSrc of this query */
  int *pParentAgg,       /* True if pParent uses aggregate functions */
  char *aff              /* If eDest is SRT_Union, the affinity string */
){
  int i;
  WhereInfo *pWInfo;
  Vdbe *v;
  int isAgg;             /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns to extract. */
  SrcList *pTabList;     /* List of tables to select from */
  Expr *pWhere;          /* The WHERE clause.  May be NULL */
  ExprList *pOrderBy;    /* The ORDER BY clause.  May be NULL */
  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
  Expr *pHaving;         /* The HAVING clause.  May be NULL */
  int isDistinct;        /* True if the DISTINCT keyword is present */
  int distinct;          /* Table to use for the distinct set */
  int rc = 1;            /* Value to return from this function */
  AggregateInfo sAggInfo;

  if( sqlite3_malloc_failed || pParse->nErr || p==0 ) return 1;
  if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;


#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;
................................................................................
        pLoop->pRightmost = p;
      }
    }
    return multiSelect(pParse, p, eDest, iParm, aff);
  }
#endif

  saveAggregateInfo(pParse, &sAggInfo);
  pOrderBy = p->pOrderBy;
  if( eDest==SRT_Union || eDest==SRT_Except || eDest==SRT_Discard ){

    p->pOrderBy = 0;
  }
  if( sqlite3SelectResolve(pParse, p, 0) ){
    goto select_end;
  }
  p->pOrderBy = pOrderBy;

................................................................................
       "a SELECT that is part of an expression");
    goto select_end;
  }
#endif

  /* ORDER BY is ignored for some destinations.
  */
  switch( eDest ){
    case SRT_Union:
    case SRT_Except:
    case SRT_Discard:
      pOrderBy = 0;
      break;
    default:
      break;
  }

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto select_end;

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

  /* Generate code for all sub-queries in the FROM clause
  */
#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
  for(i=0; i<pTabList->nSrc; i++){
    const char *zSavedAuthContext = 0;
    int needRestoreContext;


    if( pTabList->a[i].pSelect==0 ) continue;
    if( pTabList->a[i].zName!=0 ){
      zSavedAuthContext = pParse->zAuthContext;
      pParse->zAuthContext = pTabList->a[i].zName;
      needRestoreContext = 1;
    }else{
      needRestoreContext = 0;
    }
    sqlite3Select(pParse, pTabList->a[i].pSelect, SRT_TempTable, 
                 pTabList->a[i].iCursor, p, i, &isAgg, 0);
    if( needRestoreContext ){
      pParse->zAuthContext = zSavedAuthContext;
    }
    pTabList = p->pSrc;
    pWhere = p->pWhere;
    if( eDest!=SRT_Union && eDest!=SRT_Except && eDest!=SRT_Discard ){
      pOrderBy = p->pOrderBy;
    }
    pGroupBy = p->pGroupBy;
    pHaving = p->pHaving;
    isDistinct = p->isDistinct;
  }
#endif
................................................................................

  /* If the output is destined for a temporary table, open that table.
  */
  if( eDest==SRT_TempTable ){
    sqlite3VdbeAddOp(v, OP_OpenVirtual, iParm, pEList->nExpr);
  }

  /* Do an analysis of aggregate expressions.
  */
  if( isAgg || pGroupBy ){
    NameContext sNC;
    memset(&sNC, 0, sizeof(sNC));
    sNC.pParse = pParse;
    sNC.pSrcList = pTabList;

    assert( pParse->nAgg==0 );
    isAgg = 1;
    if( sqlite3ExprAnalyzeAggList(&sNC, pEList) ){
      goto select_end;
    }
    if( sqlite3ExprAnalyzeAggList(&sNC, pGroupBy) ){
      goto select_end;
    }
    if( pHaving && sqlite3ExprAnalyzeAggregates(&sNC, pHaving) ){
      goto select_end;
    }
    if( sqlite3ExprAnalyzeAggList(&sNC, pOrderBy) ){
      goto select_end;
    }
  }

  /* Reset the aggregator
  */
  if( isAgg ){
    int addr = sqlite3VdbeAddOp(v, OP_AggReset, (pGroupBy?0:1), pParse->nAgg);
    for(i=0; i<pParse->nAgg; i++){
      FuncDef *pFunc;
      if( (pFunc = pParse->aAgg[i].pFunc)!=0 && pFunc->xFinalize!=0 ){
        int nExpr = 0;
#ifdef SQLITE_SSE
        Expr *pAggExpr = pParse->aAgg[i].pExpr;
        if( pAggExpr && pAggExpr->pList ){
          nExpr = pAggExpr->pList->nExpr;
        }
#endif
        sqlite3VdbeOp3(v, OP_AggInit, nExpr, i, (char*)pFunc, P3_FUNCDEF);
      }
    }
    if( pGroupBy ){
      KeyInfo *pKey = keyInfoFromExprList(pParse, pGroupBy);
      if( 0==pKey ){
        goto select_end;
      }
      sqlite3VdbeChangeP3(v, addr, (char *)pKey, P3_KEYINFO_HANDOFF);
    }
  }

  /* Initialize the memory cell to NULL for SRT_Mem or 0 for SRT_Exists
  */
  if( eDest==SRT_Mem || eDest==SRT_Exists ){
    sqlite3VdbeAddOp(v, eDest==SRT_Mem ? OP_Null : OP_Integer, 0, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
  }
................................................................................
    pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
    sqlite3VdbeOp3(v, OP_OpenVirtual, distinct, 0, 
                        (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
  }else{
    distinct = -1;
  }




  /* Begin the database scan
  */
  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere,
                             pGroupBy ? 0 : &pOrderBy);
  if( pWInfo==0 ) goto select_end;

  /* Use the standard inner loop if we are not dealing with
  ** aggregates
  */
  if( !isAgg ){
    if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
                    iParm, pWInfo->iContinue, pWInfo->iBreak, aff) ){
       goto select_end;
    }
  }

  /* If we are dealing with aggregates, then do the special aggregate
  ** processing.  

  */

  else{

    AggExpr *pAgg;
    int lbl1 = 0;
    pParse->fillAgg = 1;
















































    if( pGroupBy ){















      sqlite3ExprCodeExprList(pParse, pGroupBy);
      /* No affinity string is attached to the following OP_MakeRecord 
      ** because we do not need to do any coercion of datatypes. */













      sqlite3VdbeAddOp(v, OP_MakeRecord, pGroupBy->nExpr, 0);
      lbl1 = sqlite3VdbeMakeLabel(v);


      sqlite3VdbeAddOp(v, OP_AggFocus, 0, lbl1);


    }
    for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){
      if( pAgg->isAgg ) continue;
      sqlite3ExprCode(pParse, pAgg->pExpr);









      sqlite3VdbeAddOp(v, OP_AggSet, 0, i);






    }
    pParse->fillAgg = 0;



    if( lbl1<0 ){
      sqlite3VdbeResolveLabel(v, lbl1);

    }
    for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){
      Expr *pE;
      int nExpr;
      FuncDef *pDef;
      if( !pAgg->isAgg ) continue;
      assert( pAgg->pFunc!=0 );
      assert( pAgg->pFunc->xStep!=0 );
      pDef = pAgg->pFunc;
      pE = pAgg->pExpr;
      assert( pE!=0 );
      assert( pE->op==TK_AGG_FUNCTION );























      nExpr = sqlite3ExprCodeExprList(pParse, pE->pList);












      sqlite3VdbeAddOp(v, OP_Integer, i, 0);
      if( pDef->needCollSeq ){
        CollSeq *pColl = 0;
        int j;












        for(j=0; !pColl && j<nExpr; j++){
          pColl = sqlite3ExprCollSeq(pParse, pE->pList->a[j].pExpr);





        }
        if( !pColl ) pColl = pParse->db->pDfltColl;
        sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);

      }
      sqlite3VdbeOp3(v, OP_AggFunc, 0, nExpr, (char*)pDef, P3_FUNCDEF);



    }





  }


  /* End the database scan loop.









  */





















  sqlite3WhereEnd(pWInfo);


  /* If we are processing aggregates, we need to set up a second loop
  ** over all of the aggregate values and process them.


  */
  if( isAgg ){
    int endagg = sqlite3VdbeMakeLabel(v);
    int startagg;
    startagg = sqlite3VdbeAddOp(v, OP_AggNext, 0, endagg);
    if( pHaving ){
      sqlite3ExprIfFalse(pParse, pHaving, startagg, 1);
    }












    if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
                    iParm, startagg, endagg, aff) ){
      goto select_end;

    }
    sqlite3VdbeAddOp(v, OP_Goto, 0, startagg);
    sqlite3VdbeResolveLabel(v, endagg);
    sqlite3VdbeAddOp(v, OP_Noop, 0, 0);
  }


  /* If there is an ORDER BY clause, then we need to sort the results
  ** and send them to the callback one by one.
  */
  if( pOrderBy ){
    generateSortTail(pParse, p, v, pEList->nExpr, eDest, iParm);
  }
................................................................................
  */
  rc = 0;

  /* Control jumps to here if an error is encountered above, or upon
  ** successful coding of the SELECT.
  */
select_end:
  restoreAggregateInfo(pParse, &sAggInfo);

  return rc;
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.261 2005/09/07 21:22:47 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
................................................................................
static void codeLimiter(
  Vdbe *v,          /* Generate code into this VM */
  Select *p,        /* The SELECT statement being coded */
  int iContinue,    /* Jump here to skip the current record */
  int iBreak,       /* Jump here to end the loop */
  int nPop          /* Number of times to pop stack when jumping */
){
  if( p->iOffset>=0 && iContinue!=0 ){
    int addr = sqlite3VdbeCurrentAddr(v) + 3;
    if( nPop>0 ) addr++;
    sqlite3VdbeAddOp(v, OP_MemIncr, p->iOffset, 0);
    sqlite3VdbeAddOp(v, OP_IfMemPos, p->iOffset, addr);
    if( nPop>0 ){
      sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
    }
    sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
    VdbeComment((v, "# skip OFFSET records"));
  }
  if( p->iLimit>=0 && iBreak!=0 ){
    sqlite3VdbeAddOp(v, OP_MemIncr, p->iLimit, iBreak);
    VdbeComment((v, "# exit when LIMIT reached"));
  }
}

/*
** This routine generates the code for the inside of the inner loop
................................................................................
    sqlite3VdbeAddOp(v, OP_IdxInsert, distinct, 0);
    if( pOrderBy==0 ){
      codeLimiter(v, p, iContinue, iBreak, nColumn);
    }
  }

  switch( eDest ){

    /* In this mode, write each query result to the key of the temporary
    ** table iParm.
    */
#ifndef SQLITE_OMIT_COMPOUND_SELECT
    case SRT_Union: {
      sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, NULL_ALWAYS_DISTINCT);
      if( aff ){
        sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
      }
      sqlite3VdbeAddOp(v, OP_IdxInsert, iParm, 0);
      break;
    }

    /* Construct a record from the query result, but instead of
    ** saving that record, use it as a key to delete elements from
    ** the temporary table iParm.
................................................................................
    pOrderBy->iTab = pParse->nTab++;
    addr = sqlite3VdbeAddOp(pParse->pVdbe, OP_OpenVirtual,
                            pOrderBy->iTab, pOrderBy->nExpr+1);
    assert( p->addrOpenVirt[2] == -1 );
    p->addrOpenVirt[2] = addr;
  }
}

/*
** The opcode at addr is an OP_OpenVirtual that created a sorting
** index tha we ended up not needing.  This routine changes that
** opcode to OP_Noop.
*/
static void uncreateSortingIndex(Parse *pParse, int addr){
  Vdbe *v = pParse->pVdbe;
  VdbeOp *pOp = sqlite3VdbeGetOp(v, addr);
  sqlite3VdbeChangeP3(v, addr, 0, 0);
  pOp->opcode = OP_Noop;
  pOp->p1 = 0;
  pOp->p2 = 0;
}

#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** Return the appropriate collating sequence for the iCol-th column of
** the result set for the compound-select statement "p".  Return NULL if
** the column has no default collating sequence.
**
................................................................................
  Parse *pParse,         /* The parser context */
  Select *p,             /* The SELECT statement being coded. */
  NameContext *pOuterNC  /* The outer name context. May be NULL. */
){
  ExprList *pEList;          /* Result set. */
  int i;                     /* For-loop variable used in multiple places */
  NameContext sNC;           /* Local name-context */
  ExprList *pGroupBy;        /* The group by clause */

  /* If this routine has run before, return immediately. */
  if( p->isResolved ){
    assert( !pOuterNC );
    return SQLITE_OK;
  }
  p->isResolved = 1;
................................................................................
  /* Set up the local name-context to pass to ExprResolveNames() to
  ** resolve the expression-list.
  */
  sNC.allowAgg = 1;
  sNC.pSrcList = p->pSrc;
  sNC.pNext = pOuterNC;













  /* Resolve names in the result set. */
  pEList = p->pEList;
  if( !pEList ) return SQLITE_ERROR;
  for(i=0; i<pEList->nExpr; i++){
    Expr *pX = pEList->a[i].pExpr;
    if( sqlite3ExprResolveNames(&sNC, pX) ){
      return SQLITE_ERROR;
................................................................................
    }
  }

  /* If there are no aggregate functions in the result-set, and no GROUP BY 
  ** expression, do not allow aggregates in any of the other expressions.
  */
  assert( !p->isAgg );
  pGroupBy = p->pGroupBy;
  if( pGroupBy || sNC.hasAgg ){
    p->isAgg = 1;
  }else{
    sNC.allowAgg = 0;
  }

  /* If a HAVING clause is present, then there must be a GROUP BY clause.
  */
  if( p->pHaving && !pGroupBy ){
    sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
    return SQLITE_ERROR;
  }

  /* Add the expression list to the name-context before parsing the
  ** other expressions in the SELECT statement. This is so that
  ** expressions in the WHERE clause (etc.) can refer to expressions by
................................................................................
  ** Minor point: If this is the case, then the expression will be
  ** re-evaluated for each reference to it.
  */
  sNC.pEList = p->pEList;
  if( sqlite3ExprResolveNames(&sNC, p->pWhere) ||
      sqlite3ExprResolveNames(&sNC, p->pHaving) ||
      processOrderGroupBy(&sNC, p->pOrderBy, "ORDER") ||
      processOrderGroupBy(&sNC, pGroupBy, "GROUP")
  ){
    return SQLITE_ERROR;
  }

  /* Make sure the GROUP BY clause does not contain aggregate functions.
  */
  if( pGroupBy ){
    struct ExprList_item *pItem;
  
    for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
      if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
        sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
            "the GROUP BY clause");
        return SQLITE_ERROR;
      }
    }
  }

  return SQLITE_OK;
}

/*




** Reset the aggregate accumulator.
**
** The aggregate accumulator is a set of memory cells that hold
** intermediate results while calculating an aggregate.  This
** routine simply stores NULLs in all of those memory cells.
*/

static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
  Vdbe *v = pParse->pVdbe;
  int i;



  int addr;
  if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
    return;
  }
  sqlite3VdbeAddOp(v, OP_Null, 0, 0);
  for(i=0; i<pAggInfo->nColumn; i++){
    addr = sqlite3VdbeAddOp(v, OP_MemStore, pAggInfo->aCol[i].iMem, 0);
  }
  for(i=0; i<pAggInfo->nFunc; i++){
    addr = sqlite3VdbeAddOp(v, OP_MemStore, pAggInfo->aFunc[i].iMem, 0);
  }
  sqlite3VdbeChangeP2(v, addr, 1);
}

/*



** Invoke the OP_AggFinalize opcode for every aggregate function
** in the AggInfo structure.
*/

static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
  Vdbe *v = pParse->pVdbe;



  int i;
  struct AggInfo_func *pF;
  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
    sqlite3VdbeAddOp(v, OP_AggFinal, pF->iMem, 0);
  }
}

/*
** Update the accumulator memory cells for an aggregate based on
** the current cursor position.

*/
static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
  Vdbe *v = pParse->pVdbe;
  int i;
  struct AggInfo_func *pF;
  struct AggInfo_col *pC;
  Expr fauxExpr;

  pAggInfo->directMode = 1;
  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
    int nArg;
    ExprList *pList = pF->pExpr->pList;
    if( pList ){
      nArg = pList->nExpr;
      sqlite3ExprCodeExprList(pParse, pList);
    }else{
      nArg = 0;
    }
    if( pF->pFunc->needCollSeq ){
      CollSeq *pColl = 0;
      struct ExprList_item *pItem;
      int j;
      for(j=0, pItem=pList->a; !pColl && j<pList->nExpr; j++, pItem++){
        pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
      }
      if( !pColl ){
        pColl = pParse->db->pDfltColl;
      }
      sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
    }
    sqlite3VdbeOp3(v, OP_AggStep, pF->iMem, nArg, (void*)pF->pFunc, P3_FUNCDEF);
  }
  memset(&fauxExpr, 0, sizeof(fauxExpr));
  fauxExpr.op = TK_AGG_COLUMN;
  fauxExpr.pAggInfo = pAggInfo;
  for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
    fauxExpr.iAgg = i;
    sqlite3ExprCode(pParse, &fauxExpr);
    sqlite3VdbeAddOp(v, OP_MemStore, pC->iMem, 1);
  }
  pAggInfo->directMode = 0;
}


/*
** Generate code for the given SELECT statement.
**
** The results are distributed in various ways depending on the
** value of eDest and iParm.
**
**     eDest Value       Result
................................................................................
  int eDest,             /* How to dispose of the results */
  int iParm,             /* A parameter used by the eDest disposal method */
  Select *pParent,       /* Another SELECT for which this is a sub-query */
  int parentTab,         /* Index in pParent->pSrc of this query */
  int *pParentAgg,       /* True if pParent uses aggregate functions */
  char *aff              /* If eDest is SRT_Union, the affinity string */
){
  int i, j;              /* Loop counters */
  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
  Vdbe *v;               /* The virtual machine under construction */
  int isAgg;             /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns to extract. */
  SrcList *pTabList;     /* List of tables to select from */
  Expr *pWhere;          /* The WHERE clause.  May be NULL */
  ExprList *pOrderBy;    /* The ORDER BY clause.  May be NULL */
  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
  Expr *pHaving;         /* The HAVING clause.  May be NULL */
  int isDistinct;        /* True if the DISTINCT keyword is present */
  int distinct;          /* Table to use for the distinct set */
  int rc = 1;            /* Value to return from this function */
  AggInfo sAggInfo;      /* Information used by aggregate queries */

  if( sqlite3_malloc_failed || pParse->nErr || p==0 ) return 1;
  if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
  memset(&sAggInfo, 0, sizeof(sAggInfo));

#ifndef SQLITE_OMIT_COMPOUND_SELECT
  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){
    if( p->pRightmost==0 ){
      Select *pLoop;
................................................................................
        pLoop->pRightmost = p;
      }
    }
    return multiSelect(pParse, p, eDest, iParm, aff);
  }
#endif


  pOrderBy = p->pOrderBy;

  if( IgnorableOrderby(eDest) ){
    p->pOrderBy = 0;
  }
  if( sqlite3SelectResolve(pParse, p, 0) ){
    goto select_end;
  }
  p->pOrderBy = pOrderBy;

................................................................................
       "a SELECT that is part of an expression");
    goto select_end;
  }
#endif

  /* ORDER BY is ignored for some destinations.
  */
  if( IgnorableOrderby(eDest) ){



    pOrderBy = 0;



  }

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto select_end;

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

  /* Generate code for all sub-queries in the FROM clause
  */
#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
  for(i=0; i<pTabList->nSrc; i++){
    const char *zSavedAuthContext = 0;
    int needRestoreContext;
    struct SrcList_item *pItem = &pTabList->a[i];

    if( pItem->pSelect==0 ) continue;
    if( pItem->zName!=0 ){
      zSavedAuthContext = pParse->zAuthContext;
      pParse->zAuthContext = pItem->zName;
      needRestoreContext = 1;
    }else{
      needRestoreContext = 0;
    }
    sqlite3Select(pParse, pItem->pSelect, SRT_TempTable, 
                 pItem->iCursor, p, i, &isAgg, 0);
    if( needRestoreContext ){
      pParse->zAuthContext = zSavedAuthContext;
    }
    pTabList = p->pSrc;
    pWhere = p->pWhere;
    if( !IgnorableOrderby(eDest) ){
      pOrderBy = p->pOrderBy;
    }
    pGroupBy = p->pGroupBy;
    pHaving = p->pHaving;
    isDistinct = p->isDistinct;
  }
#endif
................................................................................

  /* If the output is destined for a temporary table, open that table.
  */
  if( eDest==SRT_TempTable ){
    sqlite3VdbeAddOp(v, OP_OpenVirtual, iParm, pEList->nExpr);
  }



















































  /* Initialize the memory cell to NULL for SRT_Mem or 0 for SRT_Exists
  */
  if( eDest==SRT_Mem || eDest==SRT_Exists ){
    sqlite3VdbeAddOp(v, eDest==SRT_Mem ? OP_Null : OP_Integer, 0, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
  }
................................................................................
    pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
    sqlite3VdbeOp3(v, OP_OpenVirtual, distinct, 0, 
                        (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
  }else{
    distinct = -1;
  }

  /* Aggregate and non-aggregate queries are handled differently */
  if( !isAgg && pGroupBy==0 ){
    /* This case is for non-aggregate queries
    ** Begin the database scan
    */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy);

    if( pWInfo==0 ) goto select_end;

    /* Use the standard inner loop

    */

    if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
                    iParm, pWInfo->iContinue, pWInfo->iBreak, aff) ){
       goto select_end;
    }




    /* End the database scan loop.
    */
    sqlite3WhereEnd(pWInfo);
  }else{
    /* This is the processing for aggregate queries */
    NameContext sNC;    /* Name context for processing aggregate information */
    int iAMem;          /* First Mem address for storing current GROUP BY */
    int iBMem;          /* First Mem address for previous GROUP BY */
    int iUseFlag;       /* Mem address holding flag indicating that at least
                        ** one row of the input to the aggregator has been
                        ** processed */
    int iAbortFlag;     /* Mem address which causes query abort if positive */
    int groupBySort;    /* Rows come from source in GROUP BY order */


    /* The following variables hold addresses or labels for parts of the
    ** virtual machine program we are putting together */
    int addrOutputRow;      /* Start of subroutine that outputs a result row */
    int addrSetAbort;       /* Set the abort flag and return */
    int addrInitializeLoop; /* Start of code that initializes the input loop */
    int addrTopOfLoop;      /* Top of the input loop */
    int addrGroupByChange;  /* Code that runs when any GROUP BY term changes */
    int addrProcessRow;     /* Code to process a single input row */
    int addrEnd;            /* End of all processing */
    int addrSortingIdx;     /* The OP_OpenVirtual for the sorting index */

    addrEnd = sqlite3VdbeMakeLabel(v);

    /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
    ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
    ** SELECT statement.
    */
    memset(&sNC, 0, sizeof(sNC));
    sNC.pParse = pParse;
    sNC.pSrcList = pTabList;
    sNC.pAggInfo = &sAggInfo;
    sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
    if( sqlite3ExprAnalyzeAggList(&sNC, pEList) ){
      goto select_end;
    }
    if( sqlite3ExprAnalyzeAggList(&sNC, pOrderBy) ){
      goto select_end;
    }
    if( pHaving && sqlite3ExprAnalyzeAggregates(&sNC, pHaving) ){
      goto select_end;
    }
    sAggInfo.nAccumulator = sAggInfo.nColumn;
    for(i=0; i<sAggInfo.nFunc; i++){
      if( sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList) ){
        goto select_end;
      }
    }

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

      /* Create labels that we will be needing
      */
     
      addrInitializeLoop = sqlite3VdbeMakeLabel(v);
      addrGroupByChange = sqlite3VdbeMakeLabel(v);
      addrProcessRow = sqlite3VdbeMakeLabel(v);

      /* If there is a GROUP BY clause we might need a sorting index to
      ** implement it.  Allocate that sorting index now.  If it turns out
      ** that we do not need it after all, the OpenVirtual instruction
      ** will be converted into a Noop.  
      */
      sAggInfo.sortingIdx = pParse->nTab++;
      pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);


      addrSortingIdx =
          sqlite3VdbeOp3(v, OP_OpenVirtual, sAggInfo.sortingIdx,
                         sAggInfo.nSortingColumn,
                         (char*)pKeyInfo, P3_KEYINFO_HANDOFF);

      /* Initialize memory locations used by GROUP BY aggregate processing
      */
      iUseFlag = pParse->nMem++;
      iAbortFlag = pParse->nMem++;
      iAMem = pParse->nMem;
      pParse->nMem += pGroupBy->nExpr;
      iBMem = pParse->nMem;
      pParse->nMem += pGroupBy->nExpr;
      sqlite3VdbeAddOp(v, OP_Integer, 0, 0);

      sqlite3VdbeAddOp(v, OP_MemStore, iAbortFlag, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, iUseFlag, 1);
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, iAMem, 1);
      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_MemIncr, iAbortFlag, 0);
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);
      addrOutputRow = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_IfMemPos, iUseFlag, addrOutputRow+2);
      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);

      /* Begin a loop that will extract all source rows in GROUP BY order.
      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite3VdbeResolveLabel(v, addrInitializeLoop);
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy);
      if( pGroupBy==0 ){
        /* The optimizer is able to deliver rows in group by order so
        ** we do not have to sort.  The OP_OpenVirtual table will be
        ** cancelled later because we still need to use the pKeyInfo
        */
        pGroupBy = p->pGroupBy;
        groupBySort = 0;
      }else{
        /* Rows are coming out in undetermined order.  We have to push
        ** each row into a sorting index, terminate the first loop,
        ** then loop over the sorting index in order to get the output
        ** in sorted order
        */
        groupBySort = 1;
        sqlite3ExprCodeExprList(pParse, pGroupBy);
        sqlite3VdbeAddOp(v, OP_Sequence, sAggInfo.sortingIdx, 0);
        j = pGroupBy->nExpr+1;
        for(i=0; i<sAggInfo.nColumn; i++){
          struct AggInfo_col *pCol = &sAggInfo.aCol[i];
          if( pCol->iSorterColumn<j ) continue;
          if( pCol->iColumn<0 ){
            sqlite3VdbeAddOp(v, OP_Rowid, pCol->iTable, 0);
          }else{
            sqlite3VdbeAddOp(v, OP_Column, pCol->iTable, pCol->iColumn);
          }
          j++;
        }
        sqlite3VdbeAddOp(v, OP_MakeRecord, j, 0);



        sqlite3VdbeAddOp(v, OP_IdxInsert, sAggInfo.sortingIdx, 0);
        sqlite3WhereEnd(pWInfo);
        sqlite3VdbeAddOp(v, OP_Sort, sAggInfo.sortingIdx, 0);
        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...
      */
      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
      for(j=0; j<pGroupBy->nExpr; j++){

        if( groupBySort ){
          sqlite3VdbeAddOp(v, OP_Column, sAggInfo.sortingIdx, j);
        }else{
          sAggInfo.directMode = 1;
          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr);
        }


        sqlite3VdbeAddOp(v, OP_MemStore, iBMem+j, j<pGroupBy->nExpr-1);
      }

      for(j=pGroupBy->nExpr-1; j>=0; j--){
        if( j<pGroupBy->nExpr-1 ){
          sqlite3VdbeAddOp(v, OP_MemLoad, iBMem+j, 0);
        }
        sqlite3VdbeAddOp(v, OP_MemLoad, iAMem+j, 0);
        if( j==0 ){
          sqlite3VdbeAddOp(v, OP_Eq, 0, addrProcessRow);
        }else{
          sqlite3VdbeAddOp(v, OP_Ne, 0x100, addrGroupByChange);
        }
        sqlite3VdbeChangeP3(v, -1, (void*)pKeyInfo->aColl[j], P3_COLLSEQ);
      }


      /* Generate code that runs whenever the GROUP BY changes.
      ** Change in the GROUP BY are detected by the previous code
      ** block.  If there were no changes, this block is skipped.
      **
      ** This code copies current group by terms in b0,b1,b2,...
      ** over to a0,a1,a2.  It then calls the output subroutine
      ** and resets the aggregate accumulator registers in preparation
      ** for the next GROUP BY batch.
      */
      sqlite3VdbeResolveLabel(v, addrGroupByChange);
      for(j=0; j<pGroupBy->nExpr; j++){
        sqlite3VdbeAddOp(v, OP_MemLoad, iBMem+j, 0);
        sqlite3VdbeAddOp(v, OP_MemStore, iAMem+j, 1);
      }
      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
      sqlite3VdbeAddOp(v, OP_IfMemPos, iAbortFlag, addrEnd);
      resetAccumulator(pParse, &sAggInfo);

      /* Update the aggregate accumulators based on the content of
      ** the current row
      */
      sqlite3VdbeResolveLabel(v, addrProcessRow);
      updateAccumulator(pParse, &sAggInfo);
      sqlite3VdbeAddOp(v, OP_MemIncr, iUseFlag, 0);

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



      /* Output the final row of result
      */



      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);


      
    } /* 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.
      */
      resetAccumulator(pParse, &sAggInfo);
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
      updateAccumulator(pParse, &sAggInfo);
      sqlite3WhereEnd(pWInfo);
      finalizeAggFunctions(pParse, &sAggInfo);
      pOrderBy = 0;
      selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1, 


                      eDest, iParm, addrEnd, addrEnd, aff);
    }

    sqlite3VdbeResolveLabel(v, addrEnd);

    
  } /* endif aggregate query */

  /* If there is an ORDER BY clause, then we need to sort the results
  ** and send them to the callback one by one.
  */
  if( pOrderBy ){
    generateSortTail(pParse, p, v, pEList->nExpr, eDest, iParm);
  }
................................................................................
  */
  rc = 0;

  /* Control jumps to here if an error is encountered above, or upon
  ** successful coding of the SELECT.
  */
select_end:
  sqliteFree(sAggInfo.aCol);
  sqliteFree(sAggInfo.aFunc);
  return rc;
}

**    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 1.407 2005/09/01 03:07:44 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks
................................................................................
** an array.
*/
#define ArraySize(X)    (sizeof(X)/sizeof(X[0]))

/*
** Forward references to structures
*/
typedef struct AggExpr AggExpr;
typedef struct AuthContext AuthContext;
typedef struct CollSeq CollSeq;
typedef struct Column Column;
typedef struct Db Db;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct FKey FKey;
................................................................................
*/
struct Token {
  const unsigned char *z; /* Text of the token.  Not NULL-terminated! */
  unsigned dyn  : 1;      /* True for malloced memory, false for static */
  unsigned n    : 31;     /* Number of characters in this token */
};










































/*
** Each node of an expression in the parse tree is an instance
** of this structure.
**
** Expr.op is the opcode.  The integer parser token codes are reused
** as opcodes here.  For example, the parser defines TK_GE to be an integer
** code representing the ">=" operator.  This same integer code is reused
................................................................................
  Expr *pLeft, *pRight;  /* Left and right subnodes */
  ExprList *pList;       /* A list of expressions used as function arguments
                         ** or in "<expr> IN (<expr-list)" */
  Token token;           /* An operand token */
  Token span;            /* Complete text of the expression */
  int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
                         ** iColumn-th field of the iTable-th table. */
  int iAgg;              /* When op==TK_COLUMN and pParse->fillAgg==FALSE, pull
                         ** result from the iAgg-th element of the aggregator */
  int iAggCtx;           /* The value to pass as P1 of OP_AggGet. */
  Select *pSelect;       /* When the expression is a sub-select.  Also the
                         ** right side of "<expr> IN (<select>)" */
  Table *pTab;           /* Table for OP_Column expressions. */
};

/*
** The following are the meanings of bits in the Expr.flags field.
................................................................................
** column names after a table name in an INSERT statement.  In the statement
**
**     INSERT INTO t(a,b,c) ...
**
** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
*/
struct IdList {
  int nId;         /* Number of identifiers on the list */
  int nAlloc;      /* Number of entries allocated for a[] below */
  struct IdList_item {
    char *zName;      /* Name of the identifier */
    int idx;          /* Index in some Table.aCol[] of a column named zName */
  } *a;


};

/*
** The bitmask datatype defined below is used for various optimizations.
*/
typedef unsigned int Bitmask;

................................................................................
struct NameContext {
  Parse *pParse;       /* The parser */
  SrcList *pSrcList;   /* One or more tables used to resolve names */
  ExprList *pEList;    /* Optional list of named expressions */
  int nRef;            /* Number of names resolved by this context */
  int nErr;            /* Number of errors encountered while resolving names */
  u8 allowAgg;         /* Aggregate functions allowed here */
  u8 hasAgg;
  int nDepth;          /* Depth of subquery recursion. 1 for no recursion */

  NameContext *pNext;  /* Next outer name context.  NULL for outermost */
};

/*
** An instance of the following structure contains all information
** needed to generate code for a single SELECT statement.
**
................................................................................
  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
  int addrOpenVirt[3];   /* OP_OpenVirtual opcodes related to this select */
};

/*
** The results of a select can be distributed in several ways.
*/







#define SRT_Callback     1  /* Invoke a callback with each row of result */
#define SRT_Mem          2  /* Store result in a memory cell */
#define SRT_Set          3  /* Store result as unique keys in a table */
#define SRT_Union        5  /* Store result as keys in a table */
#define SRT_Except       6  /* Remove result from a UNION table */

#define SRT_Table        7  /* Store result as data with a unique key */
#define SRT_TempTable    8  /* Store result in a trasient table */
#define SRT_Discard      9  /* Do not save the results anywhere */
#define SRT_Sorter      10  /* Store results in the sorter */
#define SRT_Subroutine  11  /* Call a subroutine to handle results */
#define SRT_Exists      12  /* Put 0 or 1 in a memory cell */

/*
** When a SELECT uses aggregate functions (like "count(*)" or "avg(f1)")
** we have to do some additional analysis of expressions.  An instance
** of the following structure holds information about a single subexpression
** somewhere in the SELECT statement.  An array of these structures holds
** all the information we need to generate code for aggregate
** expressions.
**
** Note that when analyzing a SELECT containing aggregates, both
** non-aggregate field variables and aggregate functions are stored
** in the AggExpr array of the Parser structure.
**
** The pExpr field points to an expression that is part of either the
** field list, the GROUP BY clause, the HAVING clause or the ORDER BY
** clause.  The expression will be freed when those clauses are cleaned
** up.  Do not try to delete the expression attached to AggExpr.pExpr.
**
** If AggExpr.pExpr==0, that means the expression is "count(*)".
*/
struct AggExpr {
  int isAgg;        /* if TRUE contains an aggregate function */
  Expr *pExpr;      /* The expression */
  FuncDef *pFunc;   /* Information about the aggregate function */
};

/*
** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
**
** The structure is divided into two parts.  When the parser and code
................................................................................
  int rc;              /* Return code from execution */
  char *zErrMsg;       /* An error message */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
  u8 nameClash;        /* A permanent table name clashes with temp table name */
  u8 checkSchema;      /* Causes schema cookie check after an error */
  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 fillAgg;          /* If true, ignore the Expr.iAgg field. Normally false */
  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 */
  u32 writeMask;       /* Start a write transaction on these databases */
  u32 cookieMask;      /* Bitmask of schema verified databases */
  int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
................................................................................
  Token sLastToken;    /* The last token parsed */
  const char *zSql;    /* All SQL text */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
  TriggerStack *trigStack;  /* Trigger actions being coded */
  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
  int nAgg;            /* Number of aggregate expressions */
  AggExpr *aAgg;       /* An array of aggregate expressions */
  int nMaxDepth;       /* Maximum depth of subquery recursion */
};

/*
** An instance of the following structure can be declared on a stack and used
** to save the Parse.zAuthContext value so that it can be restored later.
*/
struct AuthContext {
................................................................................
#else
# define sqlite3ViewGetColumnNames(A,B) 0
#endif

void sqlite3DropTable(Parse*, SrcList*, int);
void sqlite3DeleteTable(sqlite3*, Table*);
void sqlite3Insert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);

IdList *sqlite3IdListAppend(IdList*, Token*);
int sqlite3IdListIndex(IdList*,const char*);
SrcList *sqlite3SrcListAppend(SrcList*, Token*, Token*);
void sqlite3SrcListAddAlias(SrcList*, Token*);
void sqlite3SrcListAssignCursors(Parse*, SrcList*);
void sqlite3IdListDelete(IdList*);
void sqlite3SrcListDelete(SrcList*);

**    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 1.408 2005/09/07 21:22:47 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks
................................................................................
** an array.
*/
#define ArraySize(X)    (sizeof(X)/sizeof(X[0]))

/*
** Forward references to structures
*/
typedef struct AggInfo AggInfo;
typedef struct AuthContext AuthContext;
typedef struct CollSeq CollSeq;
typedef struct Column Column;
typedef struct Db Db;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct FKey FKey;
................................................................................
*/
struct Token {
  const unsigned char *z; /* Text of the token.  Not NULL-terminated! */
  unsigned dyn  : 1;      /* True for malloced memory, false for static */
  unsigned n    : 31;     /* Number of characters in this token */
};

/*
** An instance of this structure contains information needed to generate
** code for a SELECT that contains aggregate functions.
**
** If Expr.op==TK_AGG_COLUMN or TK_AGG_FUNCTION then Expr.pAggInfo is a
** pointer to this structure.  The Expr.iColumn field is the index in
** AggInfo.aCol[] or AggInfo.aFunc[] of information needed to generate
** code for that node.
**
** AggInfo.pGroupBy and AggInfo.aFunc.pExpr point to fields within the
** original Select structure that describes the SELECT statement.  These
** fields do not need to be freed when deallocating the AggInfo structure.
*/
struct AggInfo {
  u8 directMode;          /* Direct rendering mode means take data directly
                          ** from source tables rather than from accumulators */
  u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
                          ** than the source table */
  int sortingIdx;         /* Cursor number of the sorting index */
  ExprList *pGroupBy;     /* The group by clause */
  int nSortingColumn;     /* Number of columns in the sorting index */
  struct AggInfo_col {    /* For each column used in source tables */
    int iTable;              /* Cursor number of the source table */
    int iColumn;             /* Column number within the source table */
    int iSorterColumn;       /* Column number in the sorting index */
    int iMem;                /* Memory location that acts as accumulator */
  } *aCol;
  int nColumn;            /* Number of used entries in aCol[] */
  int nColumnAlloc;       /* Number of slots allocated for aCol[] */
  int nAccumulator;       /* Number of columns that show through to the output.
                          ** Additional columns are used only as parameters to
                          ** aggregate functions */
  struct AggInfo_func {   /* For each aggregate function */
    Expr *pExpr;             /* Expression encoding the function */
    FuncDef *pFunc;          /* The aggregate function implementation */
    int iMem;                /* Memory location that acts as accumulator */
  } *aFunc;
  int nFunc;              /* Number of entries in aFunc[] */
  int nFuncAlloc;         /* Number of slots allocated for aFunc[] */
};

/*
** Each node of an expression in the parse tree is an instance
** of this structure.
**
** Expr.op is the opcode.  The integer parser token codes are reused
** as opcodes here.  For example, the parser defines TK_GE to be an integer
** code representing the ">=" operator.  This same integer code is reused
................................................................................
  Expr *pLeft, *pRight;  /* Left and right subnodes */
  ExprList *pList;       /* A list of expressions used as function arguments
                         ** or in "<expr> IN (<expr-list)" */
  Token token;           /* An operand token */
  Token span;            /* Complete text of the expression */
  int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
                         ** iColumn-th field of the iTable-th table. */
  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
  int iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */

  Select *pSelect;       /* When the expression is a sub-select.  Also the
                         ** right side of "<expr> IN (<select>)" */
  Table *pTab;           /* Table for OP_Column expressions. */
};

/*
** The following are the meanings of bits in the Expr.flags field.
................................................................................
** column names after a table name in an INSERT statement.  In the statement
**
**     INSERT INTO t(a,b,c) ...
**
** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
*/
struct IdList {


  struct IdList_item {
    char *zName;      /* Name of the identifier */
    int idx;          /* Index in some Table.aCol[] of a column named zName */
  } *a;
  int nId;         /* Number of identifiers on the list */
  int nAlloc;      /* Number of entries allocated for a[] below */
};

/*
** The bitmask datatype defined below is used for various optimizations.
*/
typedef unsigned int Bitmask;

................................................................................
struct NameContext {
  Parse *pParse;       /* The parser */
  SrcList *pSrcList;   /* One or more tables used to resolve names */
  ExprList *pEList;    /* Optional list of named expressions */
  int nRef;            /* Number of names resolved by this context */
  int nErr;            /* Number of errors encountered while resolving names */
  u8 allowAgg;         /* Aggregate functions allowed here */
  u8 hasAgg;           /* True if aggregates are seen */
  int nDepth;          /* Depth of subquery recursion. 1 for no recursion */
  AggInfo *pAggInfo;   /* Information about aggregates at this level */
  NameContext *pNext;  /* Next outer name context.  NULL for outermost */
};

/*
** An instance of the following structure contains all information
** needed to generate code for a single SELECT statement.
**
................................................................................
  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
  int addrOpenVirt[3];   /* OP_OpenVirtual opcodes related to this select */
};

/*
** The results of a select can be distributed in several ways.
*/
#define SRT_Union        1  /* Store result as keys in an index */
#define SRT_Except       2  /* Remove result from a UNION index */
#define SRT_Discard      3  /* Do not save the results anywhere */

/* The ORDER BY clause is ignored for all of the above */
#define IgnorableOrderby(X) (X<=SRT_Discard)

#define SRT_Callback     4  /* Invoke a callback with each row of result */
#define SRT_Mem          5  /* Store result in a memory cell */



#define SRT_Set          6  /* Store non-null results as keys in an index */
#define SRT_Table        7  /* Store result as data and add automatic rowid */
#define SRT_TempTable    8  /* Store result in a trasient table */

#define SRT_Sorter       9  /* Store results in the sorter NOT USED */
#define SRT_Subroutine  10  /* Call a subroutine to handle results */
#define SRT_Exists      11  /* Put 0 or 1 in a memory cell */


























/*
** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
**
** The structure is divided into two parts.  When the parser and code
................................................................................
  int rc;              /* Return code from execution */
  char *zErrMsg;       /* An error message */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
  u8 nameClash;        /* A permanent table name clashes with temp table name */
  u8 checkSchema;      /* Causes schema cookie check after an error */
  u8 nested;           /* Number of nested calls to the parser/code generator */

  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 */
  u32 writeMask;       /* Start a write transaction on these databases */
  u32 cookieMask;      /* Bitmask of schema verified databases */
  int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
................................................................................
  Token sLastToken;    /* The last token parsed */
  const char *zSql;    /* All SQL text */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
  TriggerStack *trigStack;  /* Trigger actions being coded */
  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */



};

/*
** An instance of the following structure can be declared on a stack and used
** to save the Parse.zAuthContext value so that it can be restored later.
*/
struct AuthContext {
................................................................................
#else
# define sqlite3ViewGetColumnNames(A,B) 0
#endif

void sqlite3DropTable(Parse*, SrcList*, int);
void sqlite3DeleteTable(sqlite3*, Table*);
void sqlite3Insert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
int sqlite3ArrayAllocate(void**,int,int);
IdList *sqlite3IdListAppend(IdList*, Token*);
int sqlite3IdListIndex(IdList*,const char*);
SrcList *sqlite3SrcListAppend(SrcList*, Token*, Token*);
void sqlite3SrcListAddAlias(SrcList*, Token*);
void sqlite3SrcListAssignCursors(Parse*, SrcList*);
void sqlite3IdListDelete(IdList*);
void sqlite3SrcListDelete(SrcList*);

**
** 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 1.481 2005/09/06 20:36:49 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  else if( flags & MEM_Str ){
    pMem->type = SQLITE_TEXT;
  }else{
    pMem->type = SQLITE_BLOB;
  }
}

/*
** Insert a new aggregate element and make it the element that
** has focus.
**
** Return 0 on success and 1 if memory is exhausted.
*/
static int AggInsert(Agg *p, char *zKey, int nKey){
  AggElem *pElem;
  int i;
  int rc;
  pElem = sqliteMalloc( sizeof(AggElem) + nKey +
                        (p->nMem-1)*sizeof(pElem->aMem[0]) );
  if( pElem==0 ) return SQLITE_NOMEM;
  pElem->zKey = (char*)&pElem->aMem[p->nMem];
  memcpy(pElem->zKey, zKey, nKey);
  pElem->nKey = nKey;

  if( p->pCsr ){
    rc = sqlite3BtreeInsert(p->pCsr, zKey, nKey, &pElem, sizeof(AggElem*));
    if( rc!=SQLITE_OK ){
      sqliteFree(pElem);
      return rc;
    }
  }

  for(i=0; i<p->nMem; i++){
    pElem->aMem[i].flags = MEM_Null;
  }
  p->pCurrent = pElem;
  return 0;
}

/*
** Pop the stack N times.
*/
static void popStack(Mem **ppTos, int N){
  Mem *pTos = *ppTos;
  while( N>0 ){
    N--;
................................................................................
  assert( pOp->p3type==P3_COLLSEQ );
  break;
}

/* Opcode: Function P1 P2 P3
**
** Invoke a user function (P3 is a pointer to a Function structure that
** defines the function) with P1 arguments taken from the stack.  Pop all
** arguments from the stack and push back the result.
**
** P2 is a 32-bit bitmask indicating whether or not each argument to the 
** function was determined to be constant at compile time. If the first
** argument was constant then bit 0 of P2 is set. This is used to determine
** whether meta data associated with a user function argument using the
** sqlite3_set_auxdata() API may be safely retained until the next
** invocation of this opcode.
**
** See also: AggFunc
*/
case OP_Function: {
  int i;
  Mem *pArg;
  sqlite3_context ctx;
  sqlite3_value **apVal;
  int n = pOp->p1;

  n = pOp->p1;
  apVal = p->apArg;
  assert( apVal || n==0 );

  pArg = &pTos[1-n];
  for(i=0; i<n; i++, pArg++){
    apVal[i] = pArg;
    storeTypeInfo(pArg, db->enc);
................................................................................
  if( sqlite3_malloc_failed ) goto no_mem;
  popStack(&pTos, n);

  /* If any auxilary data functions have been called by this user function,
  ** immediately call the destructor for any non-static values.
  */
  if( ctx.pVdbeFunc ){
    sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p2);
    pOp->p3 = (char *)ctx.pVdbeFunc;
    pOp->p3type = P3_VDBEFUNC;
  }

  /* Copy the result of the function to the top of the stack */
  sqlite3VdbeChangeEncoding(&ctx.s, db->enc);
  pTos++;
................................................................................
    pTos++;
    pTos->i = v;
    pTos->flags = MEM_Int;
  }
  break;
}

#ifndef SQLITE_OMIT_SUBQUERY
/* Opcode: AggContextPush * * * 
**
** Save the state of the current aggregator. It is restored an 
** AggContextPop opcode.
** 
*/
case OP_AggContextPush: {        /* no-push */
  p->pAgg++;
  assert( p->pAgg<&p->apAgg[p->nAgg] );
  break;
}

/* Opcode: AggContextPop * * *
**
** Restore the aggregator to the state it was in when AggContextPush
** was last called. Any data in the current aggregator is deleted.
*/
case OP_AggContextPop: {        /* no-push */
  p->pAgg--;
  assert( p->pAgg>=p->apAgg );
  break;
}
#endif

#ifndef SQLITE_OMIT_TRIGGER
/* Opcode: ContextPush * * * 
**
** Save the current Vdbe context such that it can be restored by a ContextPop
** opcode. The context stores the last insert row id, the last statement change
** count, and the current statement change count.
*/
................................................................................
  assert( pMem->flags==MEM_Int );
  if( pMem->i>0 ){
     pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: AggReset P1 P2 P3
**
** Reset the current aggregator context so that it no longer contains any 
** data. Future aggregator elements will contain P2 values each and be sorted
** using the KeyInfo structure pointed to by P3.
**
** If P1 is non-zero, then only a single aggregator row is available (i.e.
** there is no GROUP BY expression). In this case it is illegal to invoke
** OP_AggFocus.
*/
case OP_AggReset: {        /* no-push */
  assert( !pOp->p3 || pOp->p3type==P3_KEYINFO );
  if( pOp->p1 ){
    rc = sqlite3VdbeAggReset(0, p->pAgg, (KeyInfo *)pOp->p3);
    p->pAgg->nMem = pOp->p2;    /* Agg.nMem is used by AggInsert() */
    rc = AggInsert(p->pAgg, 0, 0);
  }else{
    rc = sqlite3VdbeAggReset(db, p->pAgg, (KeyInfo *)pOp->p3);
    p->pAgg->nMem = pOp->p2;
  }
  if( rc!=SQLITE_OK ){
    goto abort_due_to_error;
  }
  p->pAgg->apFunc = sqliteMalloc( p->pAgg->nMem*sizeof(p->pAgg->apFunc[0]) );
  if( p->pAgg->apFunc==0 ) goto no_mem;
  break;
}

/* Opcode: AggInit P1 P2 P3
**
** Initialize the function parameters for an aggregate function.
** The aggregate will operate out of aggregate column P2.
** P3 is a pointer to the FuncDef structure for the function.
**
** The P1 argument is not used by this opcode. However if the SSE
** extension is compiled in, P1 is set to the number of arguments that
** will be passed to the aggregate function, if any. This is used
** by SSE to select the correct function when (de)serializing statements.
*/
case OP_AggInit: {        /* no-push */
  int i = pOp->p2;
  assert( i>=0 && i<p->pAgg->nMem );
  p->pAgg->apFunc[i] = (FuncDef*)pOp->p3;
  break;
}

/* Opcode: AggFunc * P2 P3
**
** Execute the step function for an aggregate.  The
** function has P2 arguments.  P3 is a pointer to the FuncDef
** structure that specifies the function.

**
** The top of the stack must be an integer which is the index of
** the aggregate column that corresponds to this aggregate function.
** Ideally, this index would be another parameter, but there are
** no free parameters left.  The integer is popped from the stack.
*/
case OP_AggFunc: {        /* no-push */
  int n = pOp->p2;
  int i;
  Mem *pMem, *pRec;
  sqlite3_context ctx;
  sqlite3_value **apVal;

  assert( n>=0 );
  assert( pTos->flags==MEM_Int );
  pRec = &pTos[-n];
  assert( pRec>=p->aStack );

  apVal = p->apArg;
  assert( apVal || n==0 );

  for(i=0; i<n; i++, pRec++){
    apVal[i] = pRec;
    storeTypeInfo(pRec, db->enc);
  }
  i = pTos->i;
  assert( i>=0 && i<p->pAgg->nMem );
  ctx.pFunc = (FuncDef*)pOp->p3;

  ctx.pMem = pMem = &p->pAgg->pCurrent->aMem[i];
  pMem->n++;
  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;
  }
  (ctx.pFunc->xStep)(&ctx, n, apVal);
  popStack(&pTos, n+1);
  if( ctx.isError ){
    rc = SQLITE_ERROR;
  }
  break;
}

/* Opcode: AggFocus * P2 *
**
** Pop the top of the stack and use that as an aggregator key.  If
** an aggregator with that same key already exists, then make the
** aggregator the current aggregator and jump to P2.  If no aggregator
** with the given key exists, create one and make it current but
** do not jump.
**
** The order of aggregator opcodes is important.  The order is:
** AggReset AggFocus AggNext.  In other words, you must execute
** AggReset first, then zero or more AggFocus operations, then
** zero or more AggNext operations.  You must not execute an AggFocus
** in between an AggNext and an AggReset.
*/
case OP_AggFocus: {        /* no-push */
  char *zKey;
  int nKey;
  int res;
  assert( pTos>=p->aStack );
  Stringify(pTos, db->enc);
  zKey = pTos->z;
  nKey = pTos->n;
  assert( p->pAgg->pBtree );
  assert( p->pAgg->pCsr );
  rc = sqlite3BtreeMoveto(p->pAgg->pCsr, zKey, nKey, &res);
  if( rc!=SQLITE_OK ){
    goto abort_due_to_error;
  }
  if( res==0 ){
    rc = sqlite3BtreeData(p->pAgg->pCsr, 0, sizeof(AggElem*),
        (char *)&p->pAgg->pCurrent);
    pc = pOp->p2 - 1;
  }else{
    rc = AggInsert(p->pAgg, zKey, nKey);
  }
  if( rc!=SQLITE_OK ){
    goto abort_due_to_error;
  }
  Release(pTos);
  pTos--;
  break; 
}

/* Opcode: AggSet * P2 *
**
** Move the top of the stack into the P2-th field of the current
** aggregate.  String values are duplicated into new memory.
*/
case OP_AggSet: {        /* no-push */
  AggElem *pFocus;
  int i = pOp->p2;
  pFocus = p->pAgg->pCurrent;
  assert( pTos>=p->aStack );
  if( pFocus==0 ) goto no_mem;
  assert( i>=0 && i<p->pAgg->nMem );


  rc = sqlite3VdbeMemMove(&pFocus->aMem[i], pTos);
  pTos--;
  break;
}

/* Opcode: AggGet P1 P2 *
**
** Push a new entry onto the stack which is a copy of the P2-th field
** of the current aggregate.  Strings are not duplicated so
** string values will be ephemeral.
**
** If P1 is zero, then the value is pulled out of the current aggregate
** in the current aggregate context. If P1 is greater than zero, then
** the value is taken from the P1th outer aggregate context. (i.e. if
** P1==1 then read from the aggregate context that will be restored
** by the next OP_AggContextPop opcode).
*/
case OP_AggGet: {
  AggElem *pFocus;
  int i = pOp->p2;
  Agg *pAgg = &p->pAgg[-pOp->p1];
  assert( pAgg>=p->apAgg );
  pFocus = pAgg->pCurrent;
  if( pFocus==0 ){
    int res;
    if( sqlite3_malloc_failed ) goto no_mem;
    rc = sqlite3BtreeFirst(pAgg->pCsr, &res);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    if( res!=0 ){
      rc = AggInsert(pAgg, "", 1);
      pFocus = pAgg->pCurrent;
    }else{
      rc = sqlite3BtreeData(pAgg->pCsr, 0, 4, (char *)&pFocus);
    }
  }
  assert( i>=0 && i<pAgg->nMem );
  pTos++;
  sqlite3VdbeMemShallowCopy(pTos, &pFocus->aMem[i], MEM_Ephem);
  if( pTos->flags&MEM_Str ){
    sqlite3VdbeChangeEncoding(pTos, db->enc);
  }
  break;
}

/* Opcode: AggNext * P2 *
**
** Make the next aggregate value the current aggregate.  The prior
** aggregate is deleted.  If all aggregate values have been consumed,
** jump to P2.
**
** The order of aggregator opcodes is important.  The order is:
** AggReset AggFocus AggNext.  In other words, you must execute
** AggReset first, then zero or more AggFocus operations, then
** zero or more AggNext operations.  You must not execute an AggFocus
** in between an AggNext and an AggReset.
*/
case OP_AggNext: {        /* no-push */
  int res;
  assert( rc==SQLITE_OK );
  CHECK_FOR_INTERRUPT;
  if( p->pAgg->searching==0 ){
    p->pAgg->searching = 1;
    if( p->pAgg->pCsr ){
      rc = sqlite3BtreeFirst(p->pAgg->pCsr, &res);
    }else{
      res = 0;
    }
  }else{
    if( p->pAgg->pCsr ){
      rc = sqlite3BtreeNext(p->pAgg->pCsr, &res);
    }else{
      res = 1;
    }
  }
  if( rc!=SQLITE_OK ) goto abort_due_to_error;
  if( res!=0 ){
    pc = pOp->p2 - 1;
  }else{
    int i;
    Mem *aMem;

    if( p->pAgg->pCsr ){
      rc = sqlite3BtreeData(p->pAgg->pCsr, 0, sizeof(AggElem*),
          (char *)&p->pAgg->pCurrent);
      if( rc!=SQLITE_OK ) goto abort_due_to_error;
    }
    aMem = p->pAgg->pCurrent->aMem;
    for(i=0; i<p->pAgg->nMem; i++){
      FuncDef *pFunc = p->pAgg->apFunc[i];
      Mem *pMem = &aMem[i];
      sqlite3VdbeMemFinalize(pMem, pFunc);
    }
  }
  break;
}

/* Opcode: Vacuum * * *
**
** Vacuum the entire database.  This opcode will cause other virtual
** machines to be created and run.  It may not be called from within
** a transaction.
*/

**
** 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 1.482 2005/09/07 21:22:47 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  else if( flags & MEM_Str ){
    pMem->type = SQLITE_TEXT;
  }else{
    pMem->type = SQLITE_BLOB;
  }
}

































/*
** Pop the stack N times.
*/
static void popStack(Mem **ppTos, int N){
  Mem *pTos = *ppTos;
  while( N>0 ){
    N--;
................................................................................
  assert( pOp->p3type==P3_COLLSEQ );
  break;
}

/* Opcode: Function P1 P2 P3
**
** Invoke a user function (P3 is a pointer to a Function structure that
** defines the function) with P2 arguments taken from the stack.  Pop all
** arguments from the stack and push back the result.
**
** P1 is a 32-bit bitmask indicating whether or not each argument to the 
** function was determined to be constant at compile time. If the first
** argument was constant then bit 0 of P1 is set. This is used to determine
** whether meta data associated with a user function argument using the
** sqlite3_set_auxdata() API may be safely retained until the next
** invocation of this opcode.
**
** See also: AggStep and AggFinal
*/
case OP_Function: {
  int i;
  Mem *pArg;
  sqlite3_context ctx;
  sqlite3_value **apVal;
  int n = pOp->p2;


  apVal = p->apArg;
  assert( apVal || n==0 );

  pArg = &pTos[1-n];
  for(i=0; i<n; i++, pArg++){
    apVal[i] = pArg;
    storeTypeInfo(pArg, db->enc);
................................................................................
  if( sqlite3_malloc_failed ) goto no_mem;
  popStack(&pTos, n);

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

  /* Copy the result of the function to the top of the stack */
  sqlite3VdbeChangeEncoding(&ctx.s, db->enc);
  pTos++;
................................................................................
    pTos++;
    pTos->i = v;
    pTos->flags = MEM_Int;
  }
  break;
}


























#ifndef SQLITE_OMIT_TRIGGER
/* Opcode: ContextPush * * * 
**
** Save the current Vdbe context such that it can be restored by a ContextPop
** opcode. The context stores the last insert row id, the last statement change
** count, and the current statement change count.
*/
................................................................................
  assert( pMem->flags==MEM_Int );
  if( pMem->i>0 ){
     pc = pOp->p2 - 1;
  }
  break;
}















































/* Opcode: AggStep P1 P2 P3
**
** Execute the step function for an aggregate.  The
** function has P2 arguments.  P3 is a pointer to the FuncDef
** structure that specifies the function.  Use memory location
** P1 as the accumulator.
**



** The P2 arguments are popped from the stack.
*/
case OP_AggStep: {        /* no-push */
  int n = pOp->p2;
  int i;
  Mem *pMem, *pRec;
  sqlite3_context ctx;
  sqlite3_value **apVal;

  assert( n>=0 );

  pRec = &pTos[1-n];
  assert( pRec>=p->aStack );

  apVal = p->apArg;
  assert( apVal || n==0 );

  for(i=0; i<n; i++, pRec++){
    apVal[i] = pRec;
    storeTypeInfo(pRec, db->enc);
  }


  ctx.pFunc = (FuncDef*)pOp->p3;
  assert( pOp->p1>=0 && pOp->p1<p->nMem );
  ctx.pMem = pMem = &p->aMem[pOp->p1];
  pMem->n++;
  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;
  }
  (ctx.pFunc->xStep)(&ctx, n, apVal);
  popStack(&pTos, n);
  if( ctx.isError ){
    rc = SQLITE_ERROR;
  }
  break;
}

/* Opcode: AggFinal P1 * *
**
** Execute the finalizer function for an aggregate.  P1 is
** the memory location that is the accumulator for the aggregate.









*/


































case OP_AggFinal: {        /* no-push */
  Mem *pMem;





  assert( pOp->p1>=0 && pOp->p1<p->nMem );
  pMem = &p->aMem[pOp->p1];
  sqlite3VdbeMemFinalize(pMem);

  break;
}






























































































/* Opcode: Vacuum * * *
**
** Vacuum the entire database.  This opcode will cause other virtual
** machines to be created and run.  It may not be called from within
** a transaction.
*/

*************************************************************************
** 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 1.97 2005/08/19 01:07:16 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines
................................................................................
int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
void sqlite3VdbeChangeP3(Vdbe*, int addr, const char *zP1, int N);
VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
int sqlite3VdbeMakeLabel(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int,int);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
int sqlite3VdbeCurrentAddr(Vdbe*);
void sqlite3VdbeTrace(Vdbe*,FILE*);
int sqlite3VdbeReset(Vdbe*);
int sqliteVdbeSetVariables(Vdbe*,int,const char**);
void sqlite3VdbeSetNumCols(Vdbe*,int);

*************************************************************************
** 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 1.98 2005/09/07 21:22:47 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines
................................................................................
int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
void sqlite3VdbeChangeP3(Vdbe*, int addr, const char *zP1, int N);
VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
int sqlite3VdbeMakeLabel(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
int sqlite3VdbeCurrentAddr(Vdbe*);
void sqlite3VdbeTrace(Vdbe*,FILE*);
int sqlite3VdbeReset(Vdbe*);
int sqliteVdbeSetVariables(Vdbe*,int,const char**);
void sqlite3VdbeSetNumCols(Vdbe*,int);

  VdbeFunc *pVdbeFunc;  /* Auxilary data, if created. */
  Mem s;                /* The return value is stored here */
  Mem *pMem;            /* Memory cell used to store aggregate context */
  u8 isError;           /* Set to true for an error */
  CollSeq *pColl;       /* Collating sequence */
};

/*
** An Agg structure describes an Aggregator.  Each Agg consists of
** zero or more Aggregator elements (AggElem).  Each AggElem contains
** a key and one or more values.  The values are used in processing
** aggregate functions in a SELECT.  The key is used to implement
** the GROUP BY clause of a select.
*/
typedef struct Agg Agg;
typedef struct AggElem AggElem;
struct Agg {
  int nMem;            /* Number of values stored in each AggElem */
  AggElem *pCurrent;   /* The AggElem currently in focus */
  FuncDef **apFunc;    /* Information about aggregate functions */
  Btree *pBtree;       /* The tmp. btree used to group elements, if required. */
  BtCursor *pCsr;      /* Read/write cursor to the table in pBtree */
  int nTab;            /* Root page of the table in pBtree */
  u8 searching;        /* True between the first AggNext and AggReset */
};
struct AggElem {
  char *zKey;          /* The key to this AggElem */
  int nKey;            /* Number of bytes in the key, including '\0' at end */
  Mem aMem[1];         /* The values for this AggElem */
};

/*
** A Set structure is used for quick testing to see if a value
** is part of a small set.  Sets are used to implement code like
** this:
**            x.y IN ('hi','hoo','hum')
*/
typedef struct Set Set;
................................................................................
  int nVar;           /* Number of entries in aVar[] */
  Mem *aVar;          /* Values for the OP_Variable opcode. */
  char **azVar;       /* Name of variables */
  int okVar;          /* True if azVar[] has been initialized */
  int magic;              /* Magic number for sanity checking */
  int nMem;               /* Number of memory locations currently allocated */
  Mem *aMem;              /* The memory locations */
  int nAgg;               /* Number of elements in apAgg */
  Agg *apAgg;             /* Array of aggregate contexts */
  Agg *pAgg;              /* Current aggregate context */
  int nCallback;          /* Number of callbacks invoked so far */
  Fifo sFifo;             /* A list of ROWIDs */
  int contextStackTop;    /* Index of top element in the context stack */
  int contextStackDepth;  /* The size of the "context" stack */
  Context *contextStack;  /* Stack used by opcodes ContextPush & ContextPop*/
  int pc;                 /* The program counter */
  int rc;                 /* Value to return */
................................................................................
#define VDBE_MAGIC_HALT     0x519c2973    /* VDBE has completed execution */
#define VDBE_MAGIC_DEAD     0xb606c3c8    /* The VDBE has been deallocated */

/*
** Function prototypes
*/
void sqlite3VdbeFreeCursor(Cursor*);
int sqlite3VdbeAggReset(sqlite3*, Agg *, KeyInfo *);
void sqliteVdbePopStack(Vdbe*,int);
int sqlite3VdbeCursorMoveto(Cursor*);
#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
void sqlite3VdbePrintOp(FILE*, int, Op*);
#endif
#ifdef SQLITE_DEBUG
void sqlite3VdbePrintSql(Vdbe*);
................................................................................
int sqlite3VdbeMemStringify(Mem*, int);
i64 sqlite3VdbeIntValue(Mem*);
int sqlite3VdbeMemIntegerify(Mem*);
double sqlite3VdbeRealValue(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemFinalize(Mem*, FuncDef*);
#ifndef NDEBUG
void sqlite3VdbeMemSanity(Mem*, u8);
int sqlite3VdbeOpcodeNoPush(u8);
#endif
int sqlite3VdbeMemTranslate(Mem*, u8);
void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf, int nBuf);
int sqlite3VdbeMemHandleBom(Mem *pMem);
void sqlite3VdbeFifoInit(Fifo*);
int sqlite3VdbeFifoPush(Fifo*, i64);
int sqlite3VdbeFifoPop(Fifo*, i64*);
void sqlite3VdbeFifoClear(Fifo*);

  VdbeFunc *pVdbeFunc;  /* Auxilary data, if created. */
  Mem s;                /* The return value is stored here */
  Mem *pMem;            /* Memory cell used to store aggregate context */
  u8 isError;           /* Set to true for an error */
  CollSeq *pColl;       /* Collating sequence */
};

























/*
** A Set structure is used for quick testing to see if a value
** is part of a small set.  Sets are used to implement code like
** this:
**            x.y IN ('hi','hoo','hum')
*/
typedef struct Set Set;
................................................................................
  int nVar;           /* Number of entries in aVar[] */
  Mem *aVar;          /* Values for the OP_Variable opcode. */
  char **azVar;       /* Name of variables */
  int okVar;          /* True if azVar[] has been initialized */
  int magic;              /* Magic number for sanity checking */
  int nMem;               /* Number of memory locations currently allocated */
  Mem *aMem;              /* The memory locations */



  int nCallback;          /* Number of callbacks invoked so far */
  Fifo sFifo;             /* A list of ROWIDs */
  int contextStackTop;    /* Index of top element in the context stack */
  int contextStackDepth;  /* The size of the "context" stack */
  Context *contextStack;  /* Stack used by opcodes ContextPush & ContextPop*/
  int pc;                 /* The program counter */
  int rc;                 /* Value to return */
................................................................................
#define VDBE_MAGIC_HALT     0x519c2973    /* VDBE has completed execution */
#define VDBE_MAGIC_DEAD     0xb606c3c8    /* The VDBE has been deallocated */

/*
** Function prototypes
*/
void sqlite3VdbeFreeCursor(Cursor*);

void sqliteVdbePopStack(Vdbe*,int);
int sqlite3VdbeCursorMoveto(Cursor*);
#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
void sqlite3VdbePrintOp(FILE*, int, Op*);
#endif
#ifdef SQLITE_DEBUG
void sqlite3VdbePrintSql(Vdbe*);
................................................................................
int sqlite3VdbeMemStringify(Mem*, int);
i64 sqlite3VdbeIntValue(Mem*);
int sqlite3VdbeMemIntegerify(Mem*);
double sqlite3VdbeRealValue(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemFinalize(Mem*);
#ifndef NDEBUG
void sqlite3VdbeMemSanity(Mem*, u8);
int sqlite3VdbeOpcodeNoPush(u8);
#endif
int sqlite3VdbeMemTranslate(Mem*, u8);
void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf, int nBuf);
int sqlite3VdbeMemHandleBom(Mem *pMem);
void sqlite3VdbeFifoInit(Fifo*);
int sqlite3VdbeFifoPush(Fifo*, i64);
int sqlite3VdbeFifoPop(Fifo*, i64*);
void sqlite3VdbeFifoClear(Fifo*);

/*
** Loop through the program looking for P2 values that are negative.
** Each such value is a label.  Resolve the label by setting the P2
** value to its correct non-zero value.
**
** This routine is called once after all opcodes have been inserted.
**
** Variable *pMaxFuncArgs is set to the maximum value of any P1 argument 
** to an OP_Function or P2 to an OP_AggFunc opcode. This is used by 
** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
**
** The integer *pMaxStack is set to the maximum number of vdbe stack
** entries that static analysis reveals this program might need.
**
** This routine also does the following optimization:  It scans for
** Halt instructions where P1==SQLITE_CONSTRAINT or P2==OE_Abort or for
................................................................................
  Op *pOp;
  int *aLabel = p->aLabel;
  int doesStatementRollback = 0;
  int hasStatementBegin = 0;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;

    /* Todo: Maybe OP_AggFunc should change to use P1 in the same
     * way as OP_Function. 
     */
    if( opcode==OP_Function ){
      if( pOp->p1>nMaxArgs ) nMaxArgs = pOp->p1;
    }else if( opcode==OP_AggFunc ){
      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
    }else if( opcode==OP_Halt ){
      if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){
        doesStatementRollback = 1;
      }
    }else if( opcode==OP_IdxInsert ){
      if( pOp->p2 ){
................................................................................
** VDBE_MAGIC_RUN.
*/
void sqlite3VdbeMakeReady(
  Vdbe *p,                       /* The VDBE */
  int nVar,                      /* Number of '?' see in the SQL statement */
  int nMem,                      /* Number of memory cells to allocate */
  int nCursor,                   /* Number of cursors to allocate */
  int nAgg,                      /* Number of aggregate contexts required */
  int isExplain                  /* True if the EXPLAIN keywords is present */
){
  int n;

  assert( p!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );

................................................................................
    p->aStack = sqliteMalloc(
        nStack*sizeof(p->aStack[0])    /* aStack */
      + nArg*sizeof(Mem*)              /* apArg */
      + nVar*sizeof(Mem)               /* aVar */
      + nVar*sizeof(char*)             /* azVar */
      + nMem*sizeof(Mem)               /* aMem */
      + nCursor*sizeof(Cursor*)        /* apCsr */
      + nAgg*sizeof(Agg)               /* Aggregate contexts */
    );
    if( !sqlite3_malloc_failed ){
      p->aMem = &p->aStack[nStack];
      p->nMem = nMem;
      p->aVar = &p->aMem[nMem];
      p->nVar = nVar;
      p->okVar = 0;
      p->apArg = (Mem**)&p->aVar[nVar];
      p->azVar = (char**)&p->apArg[nArg];
      p->apCsr = (Cursor**)&p->azVar[nVar];
      if( nAgg>0 ){
        p->nAgg = nAgg;
        p->apAgg = (Agg*)&p->apCsr[nCursor];
      }
      p->nCursor = nCursor;
      for(n=0; n<nVar; n++){
        p->aVar[n].flags = MEM_Null;
      }
    }
  }
  p->pAgg = p->apAgg;
  for(n=0; n<p->nMem; n++){
    p->aMem[n].flags = MEM_Null;
  }

#ifdef SQLITE_DEBUG
  if( (p->db->flags & SQLITE_VdbeListing)!=0
    || sqlite3OsFileExists("vdbe_explain")
................................................................................
      p->aOp[i].cnt = 0;
      p->aOp[i].cycles = 0;
    }
  }
#endif
}

/*
** Free all resources allociated with AggElem pElem, an element of
** aggregate pAgg.
*/
static void freeAggElem(AggElem *pElem, Agg *pAgg){
  int i;
  for(i=0; i<pAgg->nMem; i++){
    Mem *pMem = &pElem->aMem[i];
    if( pAgg->apFunc && pAgg->apFunc[i] && (pMem->flags & MEM_Agg)!=0 ){
      sqlite3VdbeMemFinalize(pMem, pAgg->apFunc[i]);
    }
    sqlite3VdbeMemRelease(pMem);

  }
  sqliteFree(pElem);
}

/*
** Reset an Agg structure.  Delete all its contents.
**
** For installable aggregate functions, if the step function has been
** called, make sure the finalizer function has also been called.  The
** finalizer might need to free memory that was allocated as part of its
** private context.  If the finalizer has not been called yet, call it
** now.
**
** If db is NULL, then this is being called from sqliteVdbeReset(). In
** this case clean up all references to the temp-table used for
** aggregates (if it was ever opened).
**
** If db is not NULL, then this is being called from with an OP_AggReset
** opcode. Open the temp-table, if it has not already been opened and
** delete the contents of the table used for aggregate information, ready
** for the next round of aggregate processing.
*/
int sqlite3VdbeAggReset(sqlite3 *db, Agg *pAgg, KeyInfo *pKeyInfo){
  int rc = 0;
  BtCursor *pCsr;

  if( !pAgg ) return SQLITE_OK;
  pCsr = pAgg->pCsr;
  assert( (pCsr && pAgg->nTab>0) || (!pCsr && pAgg->nTab==0)
         || sqlite3_malloc_failed );

  /* If pCsr is not NULL, then the table used for aggregate information
  ** is open. Loop through it and free the AggElem* structure pointed at
  ** by each entry. If the finalizer has not been called for an AggElem,
  ** do that too. Finally, clear the btree table itself.
  */
  if( pCsr ){
    int res;
    assert( pAgg->pBtree );
    assert( pAgg->nTab>0 );

    rc=sqlite3BtreeFirst(pCsr, &res);
    while( res==0 && rc==SQLITE_OK ){
      AggElem *pElem;
      rc = sqlite3BtreeData(pCsr, 0, sizeof(AggElem*), (char *)&pElem);
      if( rc!=SQLITE_OK ){
        return rc;
      }
      assert( pAgg->apFunc!=0 );
      freeAggElem(pElem, pAgg);
      rc=sqlite3BtreeNext(pCsr, &res);
    }
    if( rc!=SQLITE_OK ){
      return rc;
    }

    sqlite3BtreeCloseCursor(pCsr);
    sqlite3BtreeClearTable(pAgg->pBtree, pAgg->nTab);
  }else{ 
    /* The cursor may not be open because the aggregator was never used,
    ** or it could be that it was used but there was no GROUP BY clause.
    */
    if( pAgg->pCurrent ){
      freeAggElem(pAgg->pCurrent, pAgg);
    }
  }

  /* If db is not NULL and we have not yet and we have not yet opened
  ** the temporary btree then do so and create the table to store aggregate
  ** information.
  **
  ** If db is NULL, then close the temporary btree if it is open.
  */
  if( db ){
    if( !pAgg->pBtree ){
      assert( pAgg->nTab==0 );
#ifndef SQLITE_OMIT_MEMORYDB
      rc = sqlite3BtreeFactory(db, ":memory:", 0, TEMP_PAGES, &pAgg->pBtree);
#else
      rc = sqlite3BtreeFactory(db, 0, 0, TEMP_PAGES, &pAgg->pBtree);
#endif
      if( rc!=SQLITE_OK ) return rc;
      sqlite3BtreeBeginTrans(pAgg->pBtree, 1);
      rc = sqlite3BtreeCreateTable(pAgg->pBtree, &pAgg->nTab, 0);
      if( rc!=SQLITE_OK ) return rc;
    }
    assert( pAgg->nTab!=0 );

    rc = sqlite3BtreeCursor(pAgg->pBtree, pAgg->nTab, 1,
        sqlite3VdbeRecordCompare, pKeyInfo, &pAgg->pCsr);
    if( rc!=SQLITE_OK ) return rc;
  }else{
    if( pAgg->pBtree ){
      sqlite3BtreeClose(pAgg->pBtree);
      pAgg->pBtree = 0;
      pAgg->nTab = 0;
    }
    pAgg->pCsr = 0;
  }

  if( pAgg->apFunc ){ 
    sqliteFree(pAgg->apFunc);
    pAgg->apFunc = 0;
  }
  pAgg->pCurrent = 0;
  pAgg->nMem = 0;
  pAgg->searching = 0;
  return SQLITE_OK;
}

/*
** Close a cursor and release all the resources that cursor happens
** to hold.
*/
void sqlite3VdbeFreeCursor(Cursor *pCx){
  if( pCx==0 ){
    return;
................................................................................
  sqlite3VdbeFifoClear(&p->sFifo);
  if( p->contextStack ){
    for(i=0; i<p->contextStackTop; i++){
      sqlite3VdbeFifoClear(&p->contextStack[i].sFifo);
    }
    sqliteFree(p->contextStack);
  }
  for(i=0; i<p->nAgg; i++){
    sqlite3VdbeAggReset(0, &p->apAgg[i], 0);
  }
  p->contextStack = 0;
  p->contextStackDepth = 0;
  p->contextStackTop = 0;
  sqliteFree(p->zErrMsg);
  p->zErrMsg = 0;
}

/*
** Loop through the program looking for P2 values that are negative.
** Each such value is a label.  Resolve the label by setting the P2
** value to its correct non-zero value.
**
** This routine is called once after all opcodes have been inserted.
**
** Variable *pMaxFuncArgs is set to the maximum value of any P2 argument 
** to an OP_Function or OP_AggStep opcode. This is used by 
** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
**
** The integer *pMaxStack is set to the maximum number of vdbe stack
** entries that static analysis reveals this program might need.
**
** This routine also does the following optimization:  It scans for
** Halt instructions where P1==SQLITE_CONSTRAINT or P2==OE_Abort or for
................................................................................
  Op *pOp;
  int *aLabel = p->aLabel;
  int doesStatementRollback = 0;
  int hasStatementBegin = 0;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;




    if( opcode==OP_Function || opcode==OP_AggStep ){


      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
    }else if( opcode==OP_Halt ){
      if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){
        doesStatementRollback = 1;
      }
    }else if( opcode==OP_IdxInsert ){
      if( pOp->p2 ){
................................................................................
** VDBE_MAGIC_RUN.
*/
void sqlite3VdbeMakeReady(
  Vdbe *p,                       /* The VDBE */
  int nVar,                      /* Number of '?' see in the SQL statement */
  int nMem,                      /* Number of memory cells to allocate */
  int nCursor,                   /* Number of cursors to allocate */

  int isExplain                  /* True if the EXPLAIN keywords is present */
){
  int n;

  assert( p!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );

................................................................................
    p->aStack = sqliteMalloc(
        nStack*sizeof(p->aStack[0])    /* aStack */
      + nArg*sizeof(Mem*)              /* apArg */
      + nVar*sizeof(Mem)               /* aVar */
      + nVar*sizeof(char*)             /* azVar */
      + nMem*sizeof(Mem)               /* aMem */
      + nCursor*sizeof(Cursor*)        /* apCsr */

    );
    if( !sqlite3_malloc_failed ){
      p->aMem = &p->aStack[nStack];
      p->nMem = nMem;
      p->aVar = &p->aMem[nMem];
      p->nVar = nVar;
      p->okVar = 0;
      p->apArg = (Mem**)&p->aVar[nVar];
      p->azVar = (char**)&p->apArg[nArg];
      p->apCsr = (Cursor**)&p->azVar[nVar];




      p->nCursor = nCursor;
      for(n=0; n<nVar; n++){
        p->aVar[n].flags = MEM_Null;
      }
    }
  }

  for(n=0; n<p->nMem; n++){
    p->aMem[n].flags = MEM_Null;
  }

#ifdef SQLITE_DEBUG
  if( (p->db->flags & SQLITE_VdbeListing)!=0
    || sqlite3OsFileExists("vdbe_explain")
................................................................................
      p->aOp[i].cnt = 0;
      p->aOp[i].cycles = 0;
    }
  }
#endif
}




























































































































/*
** Close a cursor and release all the resources that cursor happens
** to hold.
*/
void sqlite3VdbeFreeCursor(Cursor *pCx){
  if( pCx==0 ){
    return;
................................................................................
  sqlite3VdbeFifoClear(&p->sFifo);
  if( p->contextStack ){
    for(i=0; i<p->contextStackTop; i++){
      sqlite3VdbeFifoClear(&p->contextStack[i].sFifo);
    }
    sqliteFree(p->contextStack);
  }



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

}

/*
** Memory cell pMem contains the context of an aggregate function.
** This routine calls the finalize method for that function.  The
** result of the aggregate is stored back into pMem.
*/
void sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){


  if( pFunc && pFunc->xFinalize ){
    sqlite3_context ctx;
    ctx.s.flags = MEM_Null;
    ctx.s.z = pMem->zShort;
    ctx.pMem = pMem;
    ctx.pFunc = pFunc;
    pFunc->xFinalize(&ctx);
    if( pMem->z && pMem->z!=pMem->zShort ){
      sqliteFree( pMem->z );
    }
    *pMem = ctx.s;
    if( pMem->flags & MEM_Short ){
      pMem->z = pMem->zShort;

    }
  }
}

/*
** 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){
  if( p->flags & (MEM_Dyn|MEM_Agg) ){
    if( p->xDel ){
      if( p->flags & MEM_Agg ){
        sqlite3VdbeMemFinalize(p, (FuncDef*)&p->i);
        assert( (p->flags & MEM_Agg)==0 );
        sqlite3VdbeMemRelease(p);
      }else{
        p->xDel((void *)p->z);
      }
    }else{
      sqliteFree(p->z);

}

/*
** Memory cell pMem contains the context of an aggregate function.
** This routine calls the finalize method for that function.  The
** result of the aggregate is stored back into pMem.
*/
void sqlite3VdbeMemFinalize(Mem *pMem){
  if( pMem->flags & MEM_Agg ){
    FuncDef *pFunc = *(FuncDef**)&pMem->i;
    if( pFunc && pFunc->xFinalize ){
      sqlite3_context ctx;
      ctx.s.flags = MEM_Null;
      ctx.s.z = pMem->zShort;
      ctx.pMem = pMem;
      ctx.pFunc = pFunc;
      pFunc->xFinalize(&ctx);
      if( pMem->z && pMem->z!=pMem->zShort ){
        sqliteFree( pMem->z );
      }
      *pMem = ctx.s;
      if( pMem->flags & MEM_Short ){
        pMem->z = pMem->zShort;
      }
    }
  }
}

/*
** 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){
  if( p->flags & (MEM_Dyn|MEM_Agg) ){
    if( p->xDel ){
      if( p->flags & MEM_Agg ){
        sqlite3VdbeMemFinalize(p);
        assert( (p->flags & MEM_Agg)==0 );
        sqlite3VdbeMemRelease(p);
      }else{
        p->xDel((void *)p->z);
      }
    }else{
      sqliteFree(p->z);

#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for miscellanous features that were
# left out of other test files.
#
# $Id: misc4.test,v 1.16 2005/03/29 03:11:00 danielk1977 Exp $

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

# Prepare a statement that will create a temporary table.  Then do
# a rollback.  Then try to execute the prepared statement.
#
................................................................................
  execsql { 
    CREATE TABLE Table1(ID integer primary key, Value TEXT);
    INSERT INTO Table1 VALUES(1, 'x');
    CREATE TABLE Table2(ID integer NOT NULL, Value TEXT);
    INSERT INTO Table2 VALUES(1, 'z');
    INSERT INTO Table2 VALUES (1, 'a');
    SELECT ID, Value FROM Table1
       UNION SELECT ID, max(Value) FROM Table2 GROUP BY 1,2
    ORDER BY 1, 2;
  }
} {{} {} 1 x 1 z}
} ;# ifcapable compound

# Ticket #1047.  Make sure column types are preserved in subqueries.
#
................................................................................
do_test misc4-6.2 {
  execsql {
    SELECT a FROM abc LEFT JOIN def ON (abc.a=def.d);
  }
} {1}

finish_test

#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for miscellanous features that were
# left out of other test files.
#
# $Id: misc4.test,v 1.17 2005/09/07 21:22:47 drh Exp $

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

# Prepare a statement that will create a temporary table.  Then do
# a rollback.  Then try to execute the prepared statement.
#
................................................................................
  execsql { 
    CREATE TABLE Table1(ID integer primary key, Value TEXT);
    INSERT INTO Table1 VALUES(1, 'x');
    CREATE TABLE Table2(ID integer NOT NULL, Value TEXT);
    INSERT INTO Table2 VALUES(1, 'z');
    INSERT INTO Table2 VALUES (1, 'a');
    SELECT ID, Value FROM Table1
       UNION SELECT ID, max(Value) FROM Table2 GROUP BY 1
    ORDER BY 1, 2;
  }
} {{} {} 1 x 1 z}
} ;# ifcapable compound

# Ticket #1047.  Make sure column types are preserved in subqueries.
#
................................................................................
do_test misc4-6.2 {
  execsql {
    SELECT a FROM abc LEFT JOIN def ON (abc.a=def.d);
  }
} {1}

finish_test