SQLite

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.499 2008/08/20 22:06:48 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

  const void *pKey,   /* Packed key if the btree is an index */
  i64 nKey,           /* Integer key for tables.  Size of pKey for indices */
  int bias,           /* Bias search to the high end */
  int *pRes           /* Write search results here */
){
  int rc;                    /* Status code */
  UnpackedRecord *pIdxKey;   /* Unpacked index key */
  UnpackedRecord aSpace[16]; /* Temp space for pIdxKey - to avoid a malloc */

  if( pKey ){
    pIdxKey = sqlite3VdbeRecordUnpack(pCur->pKeyInfo, nKey, pKey,
                                      aSpace, sizeof(aSpace));
    if( pIdxKey==0 ) return SQLITE_NOMEM;
  }else{
    pIdxKey = 0;
  }
  rc = sqlite3BtreeMovetoUnpacked(pCur, pIdxKey, nKey, bias, pRes);
  if( pKey ){
    sqlite3VdbeDeleteUnpackedRecord(pIdxKey);

**
** 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 1.776 2008/08/20 22:06:48 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

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

#ifdef VDBE_PROFILE
  u64 start;                 /* CPU clock count at start of opcode */
  int origPc;                /* Program counter at start of opcode */
#endif
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  int nProgressOps = 0;      /* Opcodes executed since progress callback. */
#endif
  UnpackedRecord aTempRec[16]; /* Space to hold a transient UnpackedRecord */


  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
  assert( db->magic==SQLITE_MAGIC_BUSY );
  sqlite3BtreeMutexArrayEnter(&p->aMutex);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or

  if( (pC = p->apCsr[i])->pCursor!=0 ){
    int res;
    UnpackedRecord *pIdxKey;

    assert( pC->isTable==0 );
    assert( pIn3->flags & MEM_Blob );
    pIdxKey = sqlite3VdbeRecordUnpack(pC->pKeyInfo, pIn3->n, pIn3->z,
                                      aTempRec, sizeof(aTempRec));
    if( pIdxKey==0 ){
      goto no_mem;
    }
    if( pOp->opcode==OP_Found ){
      pIdxKey->flags |= UNPACKED_PREFIX_MATCH;
    }
    rc = sqlite3BtreeMovetoUnpacked(pC->pCursor, pIdxKey, 0, 0, &res);

    i64 v;                     /* The record number that matches K */
    UnpackedRecord *pIdxKey;   /* Unpacked version of P4 */

    /* Make sure K is a string and make zKey point to K
    */
    assert( pK->flags & MEM_Blob );
    pIdxKey = sqlite3VdbeRecordUnpack(pCx->pKeyInfo, pK->n, pK->z,
                                      aTempRec, sizeof(aTempRec));
    if( pIdxKey==0 ){
      goto no_mem;
    }
    pIdxKey->flags |= UNPACKED_IGNORE_ROWID;

    /* Search for an entry in P1 where all but the last rowid match K
    ** If there is no such entry, jump immediately to P2.

*************************************************************************
** 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 1.138 2008/08/20 22:06:48 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines

sqlite3 *sqlite3VdbeDb(Vdbe*);
void sqlite3VdbeSetSql(Vdbe*, const char *z, int n);
void sqlite3VdbeSwap(Vdbe*,Vdbe*);

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
int sqlite3VdbeReleaseMemory(int);
#endif
UnpackedRecord *sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,
                                        UnpackedRecord*,int);
void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord*);
int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);


#ifndef NDEBUG
  void sqlite3VdbeComment(Vdbe*, const char*, ...);
# define VdbeComment(X)  sqlite3VdbeComment X

**
*************************************************************************
** 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 1.409 2008/08/20 22:06:48 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

** The returned structure should be closed by a call to
** sqlite3VdbeDeleteUnpackedRecord().
*/ 
UnpackedRecord *sqlite3VdbeRecordUnpack(
  KeyInfo *pKeyInfo,     /* Information about the record format */
  int nKey,              /* Size of the binary record */
  const void *pKey,      /* The binary record */
  UnpackedRecord *pSpace,/* Space available to hold resulting object */
  int szSpace            /* Size of pSpace[] in bytes */
){
  const unsigned char *aKey = (const unsigned char *)pKey;
  UnpackedRecord *p;
  int nByte;
  int idx, d;
  u16 u;                 /* Unsigned loop counter */