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Overview
Comment:Modify the code generated for a DELETE to use registers instead of the vdbe stack. (CVS 4675)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 173f281334d340290e1978abea5d1ea804141910
User & Date: danielk1977 2008-01-04 13:24:29
Context
2008-01-04
13:57
Modify FifoRead and FifoWrite to work exclusively with memory cells. (CVS 4676) check-in: 2c913908 user: danielk1977 tags: trunk
13:24
Modify the code generated for a DELETE to use registers instead of the vdbe stack. (CVS 4675) check-in: 173f2813 user: danielk1977 tags: trunk
11:01
Add OP_MemSet, for setting a memory cell to a string value. (CVS 4674) check-in: 8bb9f970 user: danielk1977 tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/delete.c.

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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.144 2008/01/03 18:03:09 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
      }
    }
  } 
  /* The usual case: There is a WHERE clause so we have to scan through
  ** the table and pick which records to delete.
  */
  else{


    /* Begin the database scan
    */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
    if( pWInfo==0 ) goto delete_from_cleanup;

    /* Remember the rowid of every item to be deleted.
    */
................................................................................

    /* This is the beginning of the delete loop. If a trigger encounters
    ** an IGNORE constraint, it jumps back to here.
    */
    if( triggers_exist ){
      sqlite3VdbeResolveLabel(v, addr);
    }
    addr = sqlite3VdbeAddOp2(v, OP_FifoRead, 0, end);
    sqlite3VdbeAddOp1(v, OP_StackDepth, -1);

    if( triggers_exist ){
      int mem1 = ++pParse->nMem;
      if( !isView ){
        sqlite3VdbeAddOp1(v, OP_MemStore, mem1);
      }
      sqlite3VdbeAddOp2(v, OP_NotExists, iCur, addr);
      sqlite3VdbeAddOp1(v, OP_Rowid, iCur);
      if( old_col_mask ){
        sqlite3VdbeAddOp1(v, OP_RowData, iCur);
      }else{
        sqlite3VdbeAddOp0(v, OP_Null);
      }
      sqlite3CodeInsert(pParse, oldIdx, 0);



      /* Jump back and run the BEFORE triggers */
      sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
      sqlite3VdbeJumpHere(v, iEndBeforeTrigger);

      if( !isView ){
        sqlite3VdbeAddOp1(v, OP_MemLoad, mem1);
      }
    }

    if( !isView ){
      /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
      if( IsVirtual(pTab) ){
        int iReg = sqlite3StackToReg(pParse, 1);
        pParse->pVirtualLock = pTab;
        sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iReg,
                          (const char*)pTab->pVtab, P4_VTAB);
      }else
#endif
      {
        sqlite3GenerateRowDelete(db, v, pTab, iCur, pParse->nested==0);
      }
    }

    /* If there are row triggers, close all cursors then invoke
    ** the AFTER triggers
    */
    if( triggers_exist ){
................................................................................
**
**   1.  A read/write cursor pointing to pTab, the table containing the row
**       to be deleted, must be opened as cursor number "base".
**
**   2.  Read/write cursors for all indices of pTab must be open as
**       cursor number base+i for the i-th index.
**
**   3.  The record number of the row to be deleted must be on the top
**       of the stack.
**
** This routine pops the top of the stack to remove the record number
** and then generates code to remove both the table record and all index
** entries that point to that record.
*/
void sqlite3GenerateRowDelete(
  sqlite3 *db,       /* The database containing the index */
  Vdbe *v,           /* Generate code into this VDBE */
  Table *pTab,       /* Table containing the row to be deleted */
  int iCur,          /* Cursor number for the table */

  int count          /* Increment the row change counter */
){
  int addr;
  addr = sqlite3VdbeAddOp1(v, OP_NotExists, iCur);
  sqlite3GenerateRowIndexDelete(v, pTab, iCur, 0);
  sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0));
  if( count ){
    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
  }
  sqlite3VdbeJumpHere(v, addr);
}







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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.145 2008/01/04 13:24:29 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
      }
    }
  } 
  /* The usual case: There is a WHERE clause so we have to scan through
  ** the table and pick which records to delete.
  */
  else{
    int iRowid = ++pParse->nMem;    /* Used for storing value read from fifo */

    /* Begin the database scan
    */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
    if( pWInfo==0 ) goto delete_from_cleanup;

    /* Remember the rowid of every item to be deleted.
    */
................................................................................

    /* This is the beginning of the delete loop. If a trigger encounters
    ** an IGNORE constraint, it jumps back to here.
    */
    if( triggers_exist ){
      sqlite3VdbeResolveLabel(v, addr);
    }
    addr = sqlite3VdbeAddOp2(v, OP_FifoRead, iRowid, end);
    sqlite3VdbeAddOp1(v, OP_StackDepth, -1);

    if( triggers_exist ){
      int iData = ++pParse->nMem;   /* For storing row data of OLD table */

      /* If the record is no longer present in the table, jump to the
      ** next iteration of the loop through the contents of the fifo.
      */
      sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, iRowid);

      /* Populate the OLD.* pseudo-table */
      if( old_col_mask ){
        sqlite3VdbeAddOp3(v, OP_RowData, iCur, 0, iData);
      }else{
        sqlite3VdbeAddOp2(v, OP_MemNull, 0, iData);
      }
      sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, iData, iRowid);

      /* Jump back and run the BEFORE triggers */
      sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
      sqlite3VdbeJumpHere(v, iEndBeforeTrigger);




    }

    if( !isView ){
      /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
      if( IsVirtual(pTab) ){
        const char *pVtab = (const char *)pTab->pVtab;
        pParse->pVirtualLock = pTab;
        sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVtab, P4_VTAB);

      }else
#endif
      {
        sqlite3GenerateRowDelete(db, v, pTab, iCur, iRowid, pParse->nested==0);
      }
    }

    /* If there are row triggers, close all cursors then invoke
    ** the AFTER triggers
    */
    if( triggers_exist ){
................................................................................
**
**   1.  A read/write cursor pointing to pTab, the table containing the row
**       to be deleted, must be opened as cursor number "base".
**
**   2.  Read/write cursors for all indices of pTab must be open as
**       cursor number base+i for the i-th index.
**
**   3.  The record number of the row to be deleted must be stored in
**       memory cell iRowid.
**
** This routine pops the top of the stack to remove the record number
** and then generates code to remove both the table record and all index
** entries that point to that record.
*/
void sqlite3GenerateRowDelete(
  sqlite3 *db,       /* The database containing the index */
  Vdbe *v,           /* Generate code into this VDBE */
  Table *pTab,       /* Table containing the row to be deleted */
  int iCur,          /* Cursor number for the table */
  int iRowid,        /* Memory cell that contains the rowid to delete */
  int count          /* Increment the row change counter */
){
  int addr;
  addr = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iRowid);
  sqlite3GenerateRowIndexDelete(v, pTab, iCur, 0);
  sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0));
  if( count ){
    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
  }
  sqlite3VdbeJumpHere(v, addr);
}

Changes to src/insert.c.

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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.208 2008/01/03 23:44:53 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P4 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
      case OE_Ignore: {
        assert( seenReplace==0 );
        sqlite3VdbeAddOp2(v, OP_Pop, nCol+extra+3+hasTwoRowids, 0);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {

        sqlite3GenerateRowDelete(pParse->db, v, pTab, base, 0);
        if( isUpdate ){
          sqlite3VdbeAddOp2(v, OP_Dup, nCol+extra+1+hasTwoRowids, 1);
          sqlite3VdbeAddOp2(v, OP_MoveGe, base, 0);
        }
        seenReplace = 1;
        break;
      }







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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.209 2008/01/04 13:24:29 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Set P4 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
      case OE_Ignore: {
        assert( seenReplace==0 );
        sqlite3VdbeAddOp2(v, OP_Pop, nCol+extra+3+hasTwoRowids, 0);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        int iRowid = sqlite3StackToReg(pParse, 1);
        sqlite3GenerateRowDelete(pParse->db, v, pTab, base, iRowid, 0);
        if( isUpdate ){
          sqlite3VdbeAddOp2(v, OP_Dup, nCol+extra+1+hasTwoRowids, 1);
          sqlite3VdbeAddOp2(v, OP_MoveGe, base, 0);
        }
        seenReplace = 1;
        break;
      }

Changes to src/sqliteInt.h.

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**    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 1.636 2008/01/03 23:44:53 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds
................................................................................
void sqlite3CommitTransaction(Parse*);
void sqlite3RollbackTransaction(Parse*);
int sqlite3ExprIsConstant(Expr*);
int sqlite3ExprIsConstantNotJoin(Expr*);
int sqlite3ExprIsConstantOrFunction(Expr*);
int sqlite3ExprIsInteger(Expr*, int*);
int sqlite3IsRowid(const char*);
void sqlite3GenerateRowDelete(sqlite3*, Vdbe*, Table*, int, int);
void sqlite3GenerateRowIndexDelete(Vdbe*, Table*, int, char*);
void sqlite3GenerateIndexKey(Vdbe*, Index*, int);
void sqlite3GenerateConstraintChecks(Parse*,Table*,int,char*,int,int,int,int);
void sqlite3CompleteInsertion(Parse*, Table*, int, char*, int, int, int, int);
void sqlite3OpenTableAndIndices(Parse*, Table*, int, int);
void sqlite3BeginWriteOperation(Parse*, int, int);
Expr *sqlite3ExprDup(sqlite3*,Expr*);







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**    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 1.637 2008/01/04 13:24:29 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds
................................................................................
void sqlite3CommitTransaction(Parse*);
void sqlite3RollbackTransaction(Parse*);
int sqlite3ExprIsConstant(Expr*);
int sqlite3ExprIsConstantNotJoin(Expr*);
int sqlite3ExprIsConstantOrFunction(Expr*);
int sqlite3ExprIsInteger(Expr*, int*);
int sqlite3IsRowid(const char*);
void sqlite3GenerateRowDelete(sqlite3*, Vdbe*, Table*, int, int, int);
void sqlite3GenerateRowIndexDelete(Vdbe*, Table*, int, char*);
void sqlite3GenerateIndexKey(Vdbe*, Index*, int);
void sqlite3GenerateConstraintChecks(Parse*,Table*,int,char*,int,int,int,int);
void sqlite3CompleteInsertion(Parse*, Table*, int, char*, int, int, int, int);
void sqlite3OpenTableAndIndices(Parse*, Table*, int, int);
void sqlite3BeginWriteOperation(Parse*, int, int);
Expr *sqlite3ExprDup(sqlite3*,Expr*);

Changes to src/vdbe.c.

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**
** 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 1.674 2008/01/04 11:01:04 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................
    pTos++;
    pTos->u.i = v;
    pTos->flags = MEM_Int;
  }
  break;
}

/* Opcode: NotExists P1 P2 *
**
** Use the top of the stack as a integer key.  If a record with that key

** does not exist in table of P1, then jump to P2.  If the record
** does exist, then fall thru.  The cursor is left pointing to the
** record if it exists.  The integer key is popped from the stack.

**
** The difference between this operation and NotFound is that this
** operation assumes the key is an integer and that P1 is a table whereas
** NotFound assumes key is a blob constructed from MakeRecord and
** P1 is an index.
**
** See also: Distinct, Found, MoveTo, NotFound, IsUnique
*/
case OP_NotExists: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;






  assert( pTos>=p->aStack );

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res;
    u64 iKey;
    assert( pTos->flags & MEM_Int );
    assert( p->apCsr[i]->isTable );
    iKey = intToKey(pTos->u.i);
    rc = sqlite3BtreeMoveto(pCrsr, 0, iKey, 0,&res);
    pC->lastRowid = pTos->u.i;
    pC->rowidIsValid = res==0;
    pC->nullRow = 0;
    pC->cacheStatus = CACHE_STALE;
    /* res might be uninitialized if rc!=SQLITE_OK.  But if rc!=SQLITE_OK
    ** processing is about to abort so we really do not care whether or not
    ** the following jump is taken.  (In other words, do not stress over
    ** the error that valgrind sometimes shows on the next statement when
    ** running ioerr.test and similar failure-recovery test scripts.) */
    if( res!=0 ){
      pc = pOp->p2 - 1;
      pC->rowidIsValid = 0;
    }
  }

  Release(pTos);
  pTos--;

  break;
}

/* Opcode: Sequence P1 * *
**
** Push an integer onto the stack which is the next available
** sequence number for cursor P1.  The sequence number on the
................................................................................
  if( pOp->p1 ){
    sqlite3VdbeSetChanges(db, p->nChange);
  }
  p->nChange = 0;
  break;
}

/* Opcode: RowData P1 * *
**
** 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;
  Cursor *pC;
  u32 n;


  /* Note that RowKey and RowData are really exactly the same instruction */



  pTos++;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC->isTable || pOp->opcode==OP_RowKey );
  assert( pC->isIndex || pOp->opcode==OP_RowData );
  assert( pC!=0 );
  if( pC->nullRow ){
    pTos->flags = MEM_Null;
  }else if( pC->pCursor!=0 ){
    BtCursor *pCrsr = pC->pCursor;
    rc = sqlite3VdbeCursorMoveto(pC);
    if( rc ) goto abort_due_to_error;
    if( pC->nullRow ){
      pTos->flags = MEM_Null;
      break;
    }else if( pC->isIndex ){
      i64 n64;
      assert( !pC->isTable );
      sqlite3BtreeKeySize(pCrsr, &n64);
      if( n64>SQLITE_MAX_LENGTH ){
        goto too_big;
................................................................................
      n = n64;
    }else{
      sqlite3BtreeDataSize(pCrsr, &n);
    }
    if( n>SQLITE_MAX_LENGTH ){
      goto too_big;
    }
    pTos->n = n;
    if( n<=NBFS ){
      pTos->flags = MEM_Blob | MEM_Short;
      pTos->z = pTos->zShort;
    }else{
      char *z = sqlite3_malloc( n );
      if( z==0 ) goto no_mem;
      pTos->flags = MEM_Blob | MEM_Dyn;
      pTos->xDel = 0;
      pTos->z = z;
    }
    if( pC->isIndex ){
      rc = sqlite3BtreeKey(pCrsr, 0, n, pTos->z);
    }else{
      rc = sqlite3BtreeData(pCrsr, 0, n, pTos->z);
    }
  }else if( pC->pseudoTable ){
    pTos->n = pC->nData;
    assert( pC->nData<=SQLITE_MAX_LENGTH );
    pTos->z = pC->pData;
    pTos->flags = MEM_Blob|MEM_Ephem;
  }else{
    pTos->flags = MEM_Null;
  }
  pTos->enc = SQLITE_UTF8;  /* In case the blob is ever cast to text */
  break;
}

/* Opcode: Rowid P1 P2 * * *
**
** Store in register P2 an integer which is the key of the table entry that
** P1 is currently point to.  If p2==0 then pust the integer.
................................................................................
  sqlite3_free(aRoot);
  break;
}
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */

/* Opcode: FifoWrite * * *
**
** Write the integer on the top of the stack
** into the Fifo.
*/
case OP_FifoWrite: {        /* no-push */
  assert( pTos>=p->aStack );
  sqlite3VdbeMemIntegerify(pTos);
  if( sqlite3VdbeFifoPush(&p->sFifo, pTos->u.i)==SQLITE_NOMEM ){
    goto no_mem;
  }
  assert( (pTos->flags & MEM_Dyn)==0 );
  pTos--;
  break;
}

/* Opcode: FifoRead * P2 *
**
** Attempt to read a single integer from the Fifo
** and push it onto the stack.  If the Fifo is empty



** push nothing but instead jump to P2.
*/
case OP_FifoRead: {
  i64 v;
  CHECK_FOR_INTERRUPT;
  if( sqlite3VdbeFifoPop(&p->sFifo, &v)==SQLITE_DONE ){
    pc = pOp->p2 - 1;
  }else{
    pTos++;
    pTos->u.i = v;
    pTos->flags = MEM_Int;




  }
  break;
}

#ifndef SQLITE_OMIT_TRIGGER
/* Opcode: ContextPush * * * 
**







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39
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....
3340
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3398
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3400
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3402
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3404
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3406
3407
3408
....
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
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3749

3750
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....
3797
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3800
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3802
3803
3804
3805
3806
3807
3808
3809
3810
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3812
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3823
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3825
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3828
3829
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3831
3832
3833
3834
3835
....
4521
4522
4523
4524
4525
4526
4527
4528

4529
4530
4531
4532
4533
4534
4535
4536
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**
** 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 1.675 2008/01/04 13:24:29 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................
    pTos++;
    pTos->u.i = v;
    pTos->flags = MEM_Int;
  }
  break;
}

/* Opcode: NotExists P1 P2 P3
**
** Use the top of the stack as a integer key. Or, if P3 is non-zero,
** use the contents of memory cell P3 as an integer key. If a record 
** with that key does not exist in table of P1, then jump to P2. 
** If the record does exist, then fall thru.  The cursor is left 
** pointing to the record if it exists. The integer key is popped 
** from the stack (unless it was read from a memory cell).
**
** The difference between this operation and NotFound is that this
** operation assumes the key is an integer and that P1 is a table whereas
** NotFound assumes key is a blob constructed from MakeRecord and
** P1 is an index.
**
** See also: Distinct, Found, MoveTo, NotFound, IsUnique
*/
case OP_NotExists: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  Mem *pKey;
  if( pOp->p3 ){
    assert( pOp->p3<=p->nMem );
    pKey = &p->aMem[pOp->p3];
  }else{
    pKey = pTos;
    assert( pTos>=p->aStack );
  }
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res;
    u64 iKey;
    assert( pKey->flags & MEM_Int );
    assert( p->apCsr[i]->isTable );
    iKey = intToKey(pKey->u.i);
    rc = sqlite3BtreeMoveto(pCrsr, 0, iKey, 0,&res);
    pC->lastRowid = pKey->u.i;
    pC->rowidIsValid = res==0;
    pC->nullRow = 0;
    pC->cacheStatus = CACHE_STALE;
    /* res might be uninitialized if rc!=SQLITE_OK.  But if rc!=SQLITE_OK
    ** processing is about to abort so we really do not care whether or not
    ** the following jump is taken.  (In other words, do not stress over
    ** the error that valgrind sometimes shows on the next statement when
    ** running ioerr.test and similar failure-recovery test scripts.) */
    if( res!=0 ){
      pc = pOp->p2 - 1;
      pC->rowidIsValid = 0;
    }
  }
  if( pOp->p3==0 ){
    Release(pTos);
    pTos--;
  }
  break;
}

/* Opcode: Sequence P1 * *
**
** Push an integer onto the stack which is the next available
** sequence number for cursor P1.  The sequence number on the
................................................................................
  if( pOp->p1 ){
    sqlite3VdbeSetChanges(db, p->nChange);
  }
  p->nChange = 0;
  break;
}

/* Opcode: RowData P1 * P3
**
** Push onto the stack the complete row data for cursor P1. Or if P3 
** is a positive non-zero integer register number, then the value 
** is written into that register. There is no interpretation of the data.  
** It is just copied onto the stack or into the memory cell exactly as 
** it is found in the database file.
**
** If the cursor is not pointing to a valid row, a NULL value is

** pushed/inserted instead.
*/
/* Opcode: RowKey P1 * P3
**
** Push onto the stack the complete row key for cursor P1. Or if P3 
** is a positive non-zero integer register number, then the value 
** is written into that register. There is no interpretation of the data.  
** It is just copied onto the stack or into the memory cell 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;
  Cursor *pC;
  u32 n;
  Mem *pOut;

  /* Note that RowKey and RowData are really exactly the same instruction */
  if( pOp->p3 ){
    pOut = &p->aMem[pOp->p3];
  }else{
    pOut = ++pTos;
  }
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC->isTable || pOp->opcode==OP_RowKey );
  assert( pC->isIndex || pOp->opcode==OP_RowData );
  assert( pC!=0 );
  if( pC->nullRow ){
    pOut->flags = MEM_Null;
  }else if( pC->pCursor!=0 ){
    BtCursor *pCrsr = pC->pCursor;
    rc = sqlite3VdbeCursorMoveto(pC);
    if( rc ) goto abort_due_to_error;
    if( pC->nullRow ){
      pOut->flags = MEM_Null;
      break;
    }else if( pC->isIndex ){
      i64 n64;
      assert( !pC->isTable );
      sqlite3BtreeKeySize(pCrsr, &n64);
      if( n64>SQLITE_MAX_LENGTH ){
        goto too_big;
................................................................................
      n = n64;
    }else{
      sqlite3BtreeDataSize(pCrsr, &n);
    }
    if( n>SQLITE_MAX_LENGTH ){
      goto too_big;
    }
    pOut->n = n;
    if( n<=NBFS ){
      pOut->flags = MEM_Blob | MEM_Short;
      pOut->z = pOut->zShort;
    }else{
      char *z = sqlite3_malloc( n );
      if( z==0 ) goto no_mem;
      pOut->flags = MEM_Blob | MEM_Dyn;
      pOut->xDel = 0;
      pOut->z = z;
    }
    if( pC->isIndex ){
      rc = sqlite3BtreeKey(pCrsr, 0, n, pOut->z);
    }else{
      rc = sqlite3BtreeData(pCrsr, 0, n, pOut->z);
    }
  }else if( pC->pseudoTable ){
    pOut->n = pC->nData;
    assert( pC->nData<=SQLITE_MAX_LENGTH );
    pOut->z = pC->pData;
    pOut->flags = MEM_Blob|MEM_Ephem;
  }else{
    pOut->flags = MEM_Null;
  }
  pOut->enc = SQLITE_UTF8;  /* In case the blob is ever cast to text */
  break;
}

/* Opcode: Rowid P1 P2 * * *
**
** Store in register P2 an integer which is the key of the table entry that
** P1 is currently point to.  If p2==0 then pust the integer.
................................................................................
  sqlite3_free(aRoot);
  break;
}
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */

/* Opcode: FifoWrite * * *
**
** Write the integer on the top of the stack into the Fifo.

*/
case OP_FifoWrite: {        /* no-push */
  assert( pTos>=p->aStack );
  sqlite3VdbeMemIntegerify(pTos);
  if( sqlite3VdbeFifoPush(&p->sFifo, pTos->u.i)==SQLITE_NOMEM ){
    goto no_mem;
  }
  assert( (pTos->flags & MEM_Dyn)==0 );
  pTos--;
  break;
}

/* Opcode: FifoRead P1 P2 *
**
** Attempt to read a single integer from the Fifo. If P1 is zero,
** push the result onto the stack. Otherwise, store the read integer 
** in register P1.
** 
** If the Fifo is empty do not push an entry onto the stack or set
** a memory register but instead jump to P2.
*/
case OP_FifoRead: {
  i64 v;
  CHECK_FOR_INTERRUPT;
  if( sqlite3VdbeFifoPop(&p->sFifo, &v)==SQLITE_DONE ){
    pc = pOp->p2 - 1;
  }else{
    Mem *pOut;
    if( pOp->p1 ){
      pOut = &p->aMem[pOp->p1];
    }else{
      pOut = ++pTos;
    }
    sqlite3VdbeMemSetInt64(pOut, v);
  }
  break;
}

#ifndef SQLITE_OMIT_TRIGGER
/* Opcode: ContextPush * * * 
**