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 1.862 2009/06/23 14:15:04 drh Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test

  pCrsr = pC->pCursor;
  if( ALWAYS(pCrsr!=0) ){
    rc = sqlite3VdbeCursorMoveto(pC);
    if( NEVER(rc) ) goto abort_due_to_error;
    assert( pC->deferredMoveto==0 );
    assert( pC->isTable==0 );
    if( !pC->nullRow ){
      rc = sqlite3VdbeIdxRowid(db, pCrsr, &rowid);
      if( rc!=SQLITE_OK ){
        goto abort_due_to_error;
      }
      MemSetTypeFlag(pOut, MEM_Int);
      pOut->u.i = rowid;
    }
  }

  sqlite3_vtab *pVtab;
  Mem *pName;

  pVtab = pOp->p4.pVtab;
  pName = &p->aMem[pOp->p1];
  assert( pVtab->pModule->xRename );
  REGISTER_TRACE(pOp->p1, pName);
  assert( pName->flags & MEM_Str );


  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  sqlite3VtabLock(pVtab);
  rc = pVtab->pModule->xRename(pVtab, pName->z);
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = pVtab->zErrMsg;
  pVtab->zErrMsg = 0;
  sqlite3VtabUnlock(db, pVtab);

  Mem **apArg;
  Mem *pX;

  pVtab = pOp->p4.pVtab;
  pModule = (sqlite3_module *)pVtab->pModule;
  nArg = pOp->p2;
  assert( pOp->p4type==P4_VTAB );
  if( ALWAYS(pModule->xUpdate) ){



    apArg = p->apArg;
    pX = &p->aMem[pOp->p3];
    for(i=0; i<nArg; i++){
      storeTypeInfo(pX, 0);
      apArg[i] = pX;
      pX++;
    }
    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    sqlite3VtabLock(pVtab);
    rc = pModule->xUpdate(pVtab, nArg, apArg, &rowid);
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = pVtab->zErrMsg;
    pVtab->zErrMsg = 0;
    sqlite3VtabUnlock(db, pVtab);
    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
    if( rc==SQLITE_OK && pOp->p1 ){
      assert( nArg>1 && apArg[0] && (apArg[0]->flags&MEM_Null) );
      db->lastRowid = rowid;
    }
    p->nChange++;
  }
  break;
}

  int p1;
  int nPage;
  Pager *pPager;

  p1 = pOp->p1; 
  pPager = sqlite3BtreePager(db->aDb[p1].pBt);
  rc = sqlite3PagerPagecount(pPager, &nPage);
  /* OP_Pagecount is always called from within a read transaction.  The
  ** page count has already been successfully read and cached.  So the
  ** sqlite3PagerPagecount() call above cannot fail. */
  if( ALWAYS(rc==SQLITE_OK) ){
    pOut->flags = MEM_Int;
    pOut->u.i = nPage;
  }
  break;
}
#endif

*************************************************************************
** This is the header file for information that is private to the
** VDBE.  This information used to all be at the top of the single
** source code file "vdbe.c".  When that file became too big (over
** 6000 lines long) it was split up into several smaller files and
** this header information was factored out.
**
** $Id: vdbeInt.h,v 1.174 2009/06/23 14:15:04 drh Exp $
*/
#ifndef _VDBEINT_H_
#define _VDBEINT_H_

/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine.  Each instruction is an instance

u32 sqlite3VdbeSerialType(Mem*, int);
u32 sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);

int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*);
int sqlite3VdbeIdxRowid(sqlite3*, BtCursor *, i64 *);
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
int sqlite3VdbeExec(Vdbe*);
int sqlite3VdbeList(Vdbe*);
int sqlite3VdbeHalt(Vdbe*);
int sqlite3VdbeChangeEncoding(Mem *, int);
int sqlite3VdbeMemTooBig(Mem*);
int sqlite3VdbeMemCopy(Mem*, const Mem*);

**
*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
** to version 2.8.7, all this code was combined into the vdbe.c source file.
** But that file was getting too big so this subroutines were split out.
**
** $Id: vdbeaux.c,v 1.464 2009/06/23 14:15:04 drh Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"



/*

** pCur points at an index entry created using the OP_MakeRecord opcode.
** Read the rowid (the last field in the record) and store it in *rowid.
** Return SQLITE_OK if everything works, or an error code otherwise.
**
** pCur might be pointing to text obtained from a corrupt database file.
** So the content cannot be trusted.  Do appropriate checks on the content.
*/
int sqlite3VdbeIdxRowid(sqlite3 *db, BtCursor *pCur, i64 *rowid){
  i64 nCellKey = 0;
  int rc;
  u32 szHdr;        /* Size of the header */
  u32 typeRowid;    /* Serial type of the rowid */
  u32 lenRowid;     /* Size of the rowid */
  Mem m, v;

  /* Get the size of the index entry.  Only indices entries of less
  ** than 2GiB are support - anything large must be database corruption */
  sqlite3BtreeKeySize(pCur, &nCellKey);
  if( unlikely(nCellKey<=0 || nCellKey>0x7fffffff) ){
    return SQLITE_CORRUPT_BKPT;
  }

  /* Read in the complete content of the index entry */
  m.flags = 0;
  m.db = db;
  m.zMalloc = 0;
  rc = sqlite3VdbeMemFromBtree(pCur, 0, (int)nCellKey, 1, &m);
  if( rc ){
    return rc;
  }

  /* The index entry must begin with a header size */