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 1.149 2004/05/29 21:46:49 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

** Make sure the BtCursor.info field of the given cursor is valid.
** If it is not already valid, call parseCell() to fill it in.
**
** BtCursor.info is a cache of the information in the current cell.
** Using this cache reduces the number of calls to parseCell().
*/
static void getCellInfo(BtCursor *pCur){
  MemPage *pPage = pCur->pPage;
  if( !pCur->infoValid ){
    parseCell(pPage, pCur->idx, &pCur->info);
    pCur->infoValid = 1;
  }else{
#ifndef NDEBUG
    CellInfo info;
    parseCell(pPage, pCur->idx, &info);
    assert( memcmp(&info, &pCur->info, sizeof(info))==0 );
#endif
  }
}

/*
** Set *pSize to the size of the buffer needed to hold the value of

**
** 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 1.347 2004/05/29 11:24:50 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

/*
** Argument pMem points at a memory cell that will be passed to a
** user-defined function or returned to the user as the result of a query.
** The second argument, 'db_enc' is the text encoding used by the vdbe for
** stack variables.  This routine sets the pMem->enc and pMem->type
** variables used by the sqlite3_value_*() routines.
*/

static void StoreTypeInfo(Mem *pMem, u8 db_enc){
  int flags = pMem->flags;
  if( flags & MEM_Null ){
    pMem->type = SQLITE3_NULL;
  }
  else if( flags & MEM_Int ){
    pMem->type = SQLITE3_INTEGER;
  }

** If P1 is zero and P3 is not zero, then the value is derived from P3.
*/
case OP_Integer: {
  pTos++;
  if( pOp->p3==0 ){
    pTos->flags = MEM_Int;
    pTos->i = pOp->p1;
    pTos->type = SQLITE3_INTEGER;
  }else{
    pTos->flags = MEM_Str|MEM_Static|MEM_Term;
    pTos->z = pOp->p3;
    pTos->n = strlen(pTos->z);
    pTos->enc = TEXT_Utf8;
    Integerify(pTos, 0);
  }

case OP_Callback: {
  int i;
  assert( p->nResColumn==pOp->p1 );

  for(i=0; i<pOp->p1; i++){
    Mem *pVal = &pTos[0-i];
    sqlite3VdbeMemNulTerminate(pVal);
    StoreTypeInfo(pVal, db->enc);
  }

  p->resOnStack = 1;
  p->nCallback++;
  p->popStack = pOp->p1;
  p->pc = pc + 1;
  p->pTos = pTos;

    if( pOp->p2==0 ){
      popStack(&pTos, nField);
    }
    pTos++;
    pTos->n = j;
    pTos->flags = MEM_Str|MEM_Dyn|MEM_Term;
    pTos->enc = db->enc;
    pTos->type = SQLITE3_TEXT;
    pTos->z = zNew;
  }
  break;
}

/* Opcode: Add * * *
**

  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);
  }

  ctx.pFunc = (FuncDef*)pOp->p3;
  ctx.s.flags = MEM_Null;
  ctx.s.z = 0;
  ctx.isError = 0;
  ctx.isStep = 0;

    }
    pTos->i = v;
  }else{
    goto mismatch;
  }
  Release(pTos);
  pTos->flags = MEM_Int;
  pTos->type = SQLITE3_INTEGER;
  break;

mismatch:
  if( pOp->p2==0 ){
    rc = SQLITE_MISMATCH;
    goto abort_due_to_error;
  }else{

  if( pSorter!=0 ){
    p->pSort = pSorter->pNext;
    pTos++;
    pTos->z = pSorter->pData;
    pTos->n = pSorter->nData;
    pTos->flags = MEM_Blob|MEM_Dyn|MEM_Term;
    pTos->enc = 0;
    pTos->type = SQLITE3_BLOB;
    sqliteFree(pSorter->zKey);
    sqliteFree(pSorter);
  }else{
    pc = pOp->p2 - 1;
  }
  break;
}

  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->agg.nMem );
  ctx.pFunc = (FuncDef*)pOp->p3;
  pMem = &p->agg.pCurrent->aMem[i];
  ctx.s.z = pMem->zShort;  /* Space used for small aggregate contexts */
  ctx.pAgg = pMem->z;

    }
    for(n=0; n<len; n++){
      v = (v<<8) | buf[n];
    }
    if( serial_type==5 ){
      pMem->flags = MEM_Real;
      pMem->r = *(double*)&v;
      pMem->type = SQLITE3_FLOAT;
    }else{
      pMem->flags = MEM_Int;
      pMem->i = *(i64*)&v;
      pMem->type = SQLITE3_INTEGER;
    }
  }else if( serial_type>=12 ){
    /* String or blob */
    pMem->z = (char *)buf;
    pMem->n = len;
    if( serial_type&0x01 ){
      pMem->flags = MEM_Str | MEM_Ephem;
    }else{
      pMem->flags = MEM_Blob | MEM_Ephem;
    }
  }else{
    /* NULL */
    assert( serial_type==6 );
    assert( len==0 );
    pMem->flags = MEM_Null;
    pMem->type = SQLITE3_NULL;
  }
  return len;
}

/*
** The following is the comparison function for (non-integer)
** keys in the btrees.  This function returns negative, zero, or