SQLite

**
** 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 1.249 2004/01/07 20:37:52 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  if( c ) pc = pOp->p2-1;
  break;
}

/* Opcode: IsNull P1 P2 *
**
** If any of the top abs(P1) values on the stack are NULL, then jump
** to P2.  Pop the stack P1 times if P1>0.   If P1<0 leave the stack
** unchanged.
*/
case OP_IsNull: {
  int i, cnt;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  VERIFY( if( p->tos+1-cnt<0 ) goto not_enough_stack; )
  for(i=0; i<cnt; i++){
    if( aStack[p->tos-i].flags & STK_Null ){
      pc = pOp->p2-1;
      break;
    }
  }
  if( pOp->p1>0 ) sqliteVdbePopStack(p, cnt);
  break;
}

/* Opcode: NotNull P1 P2 *
**
** Jump to P2 if the top P1 values on the stack are all not NULL.  Pop the
** stack if P1 times if P1 is greater than zero.  If P1 is less than
** zero then leave the stack unchanged.
*/
case OP_NotNull: {
  int i, cnt;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  VERIFY( if( p->tos+1-cnt<0 ) goto not_enough_stack; )
  for(i=0; i<cnt && (aStack[p->tos-i].flags & STK_Null)==0; i++){}
  if( i>=cnt ) pc = pOp->p2-1;
  if( pOp->p1>0 ) sqliteVdbePopStack(p, cnt);
  break;
}

/* Opcode: MakeRecord P1 P2 *
**
** Convert the top P1 entries of the stack into a single entry
** suitable for use as a data record in a database table.  The

** Push onto the stack the complete row data for cursor P1.
** There is no interpretation of the data.  It is just copied
** onto the stack exactly as it is found in the database file.
**
** If the cursor is not pointing to a valid row, a NULL is pushed
** onto the stack.
*/
/* Opcode: RowKey P1 * *
**
** Push onto the stack the complete row key for cursor P1.
** There is no interpretation of the key.  It is just copied
** onto the stack exactly as it is found in the database file.
**
** If the cursor is not pointing to a valid row, a NULL is pushed
** onto the stack.
*/
case OP_RowKey:
case OP_RowData: {
  int i = pOp->p1;
  int tos = ++p->tos;
  Cursor *pC;
  int n;

  assert( i>=0 && i<p->nCursor );
  pC = &p->aCsr[i];
  if( pC->nullRow ){
    aStack[tos].flags = STK_Null;
  }else if( pC->pCursor!=0 ){
    BtCursor *pCrsr = pC->pCursor;
    sqliteVdbeCursorMoveto(pC);
    if( pC->nullRow ){
      aStack[tos].flags = STK_Null;
      break;
    }else if( pC->keyAsData || pOp->opcode==OP_RowKey ){
      sqliteBtreeKeySize(pCrsr, &n);
    }else{
      sqliteBtreeDataSize(pCrsr, &n);
    }
    aStack[tos].n = n;
    if( n<=NBFS ){
      aStack[tos].flags = STK_Str;
      zStack[tos] = aStack[tos].z;
    }else{
      char *z = sqliteMallocRaw( n );
      if( z==0 ) goto no_mem;
      aStack[tos].flags = STK_Str | STK_Dyn;
      zStack[tos] = z;
    }
    if( pC->keyAsData || pOp->opcode==OP_RowKey ){
      sqliteBtreeKey(pCrsr, 0, n, zStack[tos]);
    }else{
      sqliteBtreeData(pCrsr, 0, n, zStack[tos]);
    }
  }else if( pC->pseudoTable ){
    aStack[tos].n = pC->nData;
    zStack[tos] = pC->pData;

      res = -res;
    }else if( pOp->opcode==OP_IdxGE ){
      res++;
    }
    if( res>0 ){
      pc = pOp->p2 - 1 ;
    }
  }
  POPSTACK;
  break;
}

/* Opcode: IdxIsNull P1 P2 *
**
** The top of the stack contains an index entry such as might be generated
** by the MakeIdxKey opcode.  This routine looks at the first P1 fields of
** that key.  If any of the first P1 fields are NULL, then a jump is made
** to address P2.  Otherwise we fall straight through.
**
** The index entry is always popped from the stack.
*/
case OP_IdxIsNull: {
  int i = pOp->p1;
  int tos = p->tos;
  int k, n;
  const char *z;

  assert( tos>=0 );
  assert( aStack[tos].flags & STK_Str );
  z = zStack[tos];
  n = aStack[tos].n;
  for(k=0; k<n && i>0; i--){
    if( z[k]=='a' ){
      pc = pOp->p2-1;
      break;
    }
    while( k<n && z[k] ){ k++; }
    k++;
  }
  POPSTACK;
  break;
}

/* Opcode: Destroy P1 P2 *
**

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.
**
** $Id: where.c,v 1.86 2004/01/07 20:37:52 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.

          if( pX==0 ) continue;
          if( aExpr[k].idxLeft==iCur
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pX->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            if( pX->op==TK_EQ ){
              sqliteExprCode(pParse, pX->pRight);
              aExpr[k].p = 0;
              break;
            }
            if( pX->op==TK_IN && nColumn==1 ){
              if( pX->pList ){
                sqliteVdbeAddOp(v, OP_SetFirst, pX->iTable, brk);
                pLevel->inOp = OP_SetNext;
                pLevel->inP1 = pX->iTable;
                pLevel->inP2 = sqliteVdbeCurrentAddr(v);
              }else{
                assert( pX->pSelect );
                sqliteVdbeAddOp(v, OP_Rewind, pX->iTable, brk);
                sqliteVdbeAddOp(v, OP_KeyAsData, pX->iTable, 1);
                pLevel->inP2 = sqliteVdbeAddOp(v, OP_FullKey, pX->iTable, 0);
                pLevel->inOp = OP_Next;
                pLevel->inP1 = pX->iTable;
              }
              aExpr[k].p = 0;
              break;
            }
          }
          if( aExpr[k].idxRight==iCur
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, aExpr[k].p->pLeft);
            aExpr[k].p = 0;
            break;
          }
        }
      }
      pLevel->iMem = pParse->nMem++;
      cont = pLevel->cont = sqliteVdbeMakeLabel(v);
      sqliteVdbeAddOp(v, OP_NotNull, -nColumn, sqliteVdbeCurrentAddr(v)+3);
      sqliteVdbeAddOp(v, OP_Pop, nColumn, 0);
      sqliteVdbeAddOp(v, OP_Goto, 0, brk);
      sqliteVdbeAddOp(v, OP_MakeKey, nColumn, 0);
      sqliteAddIdxKeyType(v, pIdx);
      if( nColumn==pIdx->nColumn || pLevel->bRev ){
        sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 0);
        testOp = OP_IdxGT;
      }else{
        sqliteVdbeAddOp(v, OP_Dup, 0, 0);
        sqliteVdbeAddOp(v, OP_IncrKey, 0, 0);
        sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
        testOp = OP_IdxGE;
      }
      if( pLevel->bRev ){
        /* Scan in reverse order */
        sqliteVdbeAddOp(v, OP_IncrKey, 0, 0);
        sqliteVdbeAddOp(v, OP_MoveLt, pLevel->iCur, brk);
        start = sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqliteVdbeAddOp(v, OP_IdxLT, pLevel->iCur, brk);

        pLevel->op = OP_Prev;
      }else{
        /* Scan in the forward order */
        sqliteVdbeAddOp(v, OP_MoveTo, pLevel->iCur, brk);
        start = sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqliteVdbeAddOp(v, testOp, pLevel->iCur, brk);

        pLevel->op = OP_Next;
      }
      sqliteVdbeAddOp(v, OP_RowKey, pLevel->iCur, 0);
      sqliteVdbeAddOp(v, OP_IdxIsNull, nColumn, cont);
      sqliteVdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
      if( i==pTabList->nSrc-1 && pushKey ){
        haveKey = 1;
      }else{
        sqliteVdbeAddOp(v, OP_MoveTo, iCur, 0);
        haveKey = 0;
      }
      pLevel->p1 = pLevel->iCur;

          if( aExpr[k].p==0 ) continue;
          if( aExpr[k].idxLeft==iCur
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && aExpr[k].p->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, aExpr[k].p->pRight);
            aExpr[k].p = 0;
            break;
          }
          if( aExpr[k].idxRight==iCur
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, aExpr[k].p->pLeft);
            aExpr[k].p = 0;
            break;
          }
        }
      }

      /* Duplicate the equality term values because they will all be
      ** used twice: once to make the termination key and once to make the

          if( aExpr[k].idxLeft==iCur
             && (pExpr->op==TK_LT || pExpr->op==TK_LE)
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pExpr->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, pExpr->pRight);
            leFlag = pExpr->op==TK_LE;
            aExpr[k].p = 0;
            break;
          }
          if( aExpr[k].idxRight==iCur
             && (pExpr->op==TK_GT || pExpr->op==TK_GE)
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && pExpr->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, pExpr->pLeft);
            leFlag = pExpr->op==TK_GE;
            aExpr[k].p = 0;
            break;
          }
        }
        testOp = OP_IdxGE;
      }else{
        testOp = nEqColumn>0 ? OP_IdxGE : OP_Noop;
        leFlag = 1;
      }
      if( testOp!=OP_Noop ){
        int nCol = nEqColumn + (score & 1);
        pLevel->iMem = pParse->nMem++;
        sqliteVdbeAddOp(v, OP_NotNull, -nCol, sqliteVdbeCurrentAddr(v)+3);
        sqliteVdbeAddOp(v, OP_Pop, nCol, 0);
        sqliteVdbeAddOp(v, OP_Goto, 0, brk);
        sqliteVdbeAddOp(v, OP_MakeKey, nCol, 0);
        sqliteAddIdxKeyType(v, pIdx);
        if( leFlag ){
          sqliteVdbeAddOp(v, OP_IncrKey, 0, 0);
        }
        if( pLevel->bRev ){
          sqliteVdbeAddOp(v, OP_MoveLt, pLevel->iCur, brk);
        }else{

          if( aExpr[k].idxLeft==iCur
             && (pExpr->op==TK_GT || pExpr->op==TK_GE)
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pExpr->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, pExpr->pRight);
            geFlag = pExpr->op==TK_GE;
            aExpr[k].p = 0;
            break;
          }
          if( aExpr[k].idxRight==iCur
             && (pExpr->op==TK_LT || pExpr->op==TK_LE)
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && pExpr->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, pExpr->pLeft);
            geFlag = pExpr->op==TK_LE;
            aExpr[k].p = 0;
            break;
          }
        }
      }else{
        geFlag = 1;
      }
      if( nEqColumn>0 || (score&2)!=0 ){
        int nCol = nEqColumn + ((score&2)!=0);
        sqliteVdbeAddOp(v, OP_NotNull, -nCol, sqliteVdbeCurrentAddr(v)+3);
        sqliteVdbeAddOp(v, OP_Pop, nCol, 0);
        sqliteVdbeAddOp(v, OP_Goto, 0, brk);
        sqliteVdbeAddOp(v, OP_MakeKey, nCol, 0);
        sqliteAddIdxKeyType(v, pIdx);
        if( !geFlag ){
          sqliteVdbeAddOp(v, OP_IncrKey, 0, 0);
        }
        if( pLevel->bRev ){
          pLevel->iMem = pParse->nMem++;
          sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);

      ** loop.
      */
      start = sqliteVdbeCurrentAddr(v);
      if( testOp!=OP_Noop ){
        sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqliteVdbeAddOp(v, testOp, pLevel->iCur, brk);
      }
      sqliteVdbeAddOp(v, OP_RowKey, pLevel->iCur, 0);
      sqliteVdbeAddOp(v, OP_IdxIsNull, nEqColumn + (score & 1), cont);
      sqliteVdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
      if( i==pTabList->nSrc-1 && pushKey ){
        haveKey = 1;
      }else{
        sqliteVdbeAddOp(v, OP_MoveTo, iCur, 0);
        haveKey = 0;
      }