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 1.548 2008/12/16 13:46:30 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"

  apCell = sqlite3ScratchMalloc( szScratch ); 
  if( apCell==0 ){
    rc = SQLITE_NOMEM;
    goto balance_cleanup;
  }
  szCell = (u16*)&apCell[nMaxCells];
  aCopy[0] = (u8*)&szCell[nMaxCells];
  assert( ((aCopy[0] - (u8*)0) & 7)==0 ); /* 8-byte alignment required */
  for(i=1; i<NB; i++){
    aCopy[i] = &aCopy[i-1][pBt->pageSize+ROUND8(sizeof(MemPage))];
    assert( ((aCopy[i] - (u8*)0) & 7)==0 ); /* 8-byte alignment required */
  }
  aSpace1 = &aCopy[NB-1][pBt->pageSize+ROUND8(sizeof(MemPage))];
  assert( ((aSpace1 - (u8*)0) & 7)==0 ); /* 8-byte alignment required */
  if( ISAUTOVACUUM ){
    aFrom = &aSpace1[pBt->pageSize];
  }
  aSpace2 = sqlite3PageMalloc(pBt->pageSize);
  if( aSpace2==0 ){
    rc = SQLITE_NOMEM;
    goto balance_cleanup;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** Memory allocation functions used throughout sqlite.
**
** $Id: malloc.c,v 1.52 2008/12/16 13:46:30 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** This routine runs when the memory allocator sees that the

  memset(&mem0, 0, sizeof(mem0));
  if( sqlite3GlobalConfig.bCoreMutex ){
    mem0.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
  }
  if( sqlite3GlobalConfig.pScratch && sqlite3GlobalConfig.szScratch>=100
      && sqlite3GlobalConfig.nScratch>=0 ){
    int i;
    sqlite3GlobalConfig.szScratch = (sqlite3GlobalConfig.szScratch - 4) & ~7;
    mem0.aScratchFree = (u32*)&((char*)sqlite3GlobalConfig.pScratch)
                  [sqlite3GlobalConfig.szScratch*sqlite3GlobalConfig.nScratch];
    for(i=0; i<sqlite3GlobalConfig.nScratch; i++){ mem0.aScratchFree[i] = i; }
    mem0.nScratchFree = sqlite3GlobalConfig.nScratch;
  }else{
    sqlite3GlobalConfig.pScratch = 0;
    sqlite3GlobalConfig.szScratch = 0;
  }
  if( sqlite3GlobalConfig.pPage && sqlite3GlobalConfig.szPage>=512
      && sqlite3GlobalConfig.nPage>=1 ){
    int i;
    int overhead;
    int sz = sqlite3GlobalConfig.szPage & ~7;
    int n = sqlite3GlobalConfig.nPage;
    overhead = (4*n + sz - 1)/sz;
    sqlite3GlobalConfig.nPage -= overhead;
    mem0.aPageFree = (u32*)&((char*)sqlite3GlobalConfig.pPage)
                  [sqlite3GlobalConfig.szPage*sqlite3GlobalConfig.nPage];
    for(i=0; i<sqlite3GlobalConfig.nPage; i++){ mem0.aPageFree[i] = i; }
    mem0.nPageFree = sqlite3GlobalConfig.nPage;

      int i;
      i = mem0.aScratchFree[--mem0.nScratchFree];
      i *= sqlite3GlobalConfig.szScratch;
      sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, 1);
      sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);
      sqlite3_mutex_leave(mem0.mutex);
      p = (void*)&((char*)sqlite3GlobalConfig.pScratch)[i];
      assert(  ((p - (void*)0) & 7)==0 );
    }
  }
#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
  scratchAllocOut = p!=0;
#endif

  return p;

** on how SQLite interfaces are suppose to operate.
**
** The name of this file under configuration management is "sqlite.h.in".
** The makefile makes some minor changes to this file (such as inserting
** the version number) and changes its name to "sqlite3.h" as
** part of the build process.
**
** @(#) $Id: sqlite.h.in,v 1.420 2008/12/16 13:46:30 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.

**          enabled by default.
**
** {H14150} A successful call to [sqlite3_config]([SQLITE_CONFIG_SCRATCH],S,Z,N)
**          where Z and N are non-negative integers and 
**          S is a pointer to an aligned memory buffer not less than
**          Z*N bytes in size shall cause S to be used by the
**          [scratch memory allocator] for as many as N simulataneous
**          allocations each of size (Z & ~7).
**
** {H14153} A successful call to [sqlite3_config]([SQLITE_CONFIG_SCRATCH],S,Z,N)
**          where S is a NULL pointer shall disable the
**          [scratch memory allocator].
**
** {H14156} A successful call to
**          [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],S,Z,N)
**          where Z and N are non-negative integers and 
**          S is a pointer to an aligned memory buffer not less than
**          Z*N bytes in size shall cause S to be used by the
**          [pagecache memory allocator] for as many as N simulataneous
**          allocations each of size (Z & ~7).
**
** {H14159} A successful call to
**          [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],S,Z,N)
**          where S is a NULL pointer shall disable the
**          [pagecache memory allocator].
**
** {H14162} A successful call to [sqlite3_config]([SQLITE_CONFIG_HEAP],H,Z,N)