**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.522 2009/01/20 16:53:41 danielk1977 Exp $
*/
#include "sqliteInt.h"

#ifdef SQLITE_ENABLE_FTS3
# include "fts3.h"
#endif
#ifdef SQLITE_ENABLE_RTREE
................................................................................
** the lookaside memory.
*/
static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
  void *pStart;
  if( db->lookaside.nOut ){
    return SQLITE_BUSY;
  }
  if( sz<0 ) sz = 0;










  if( cnt<0 ) cnt = 0;



  if( pBuf==0 ){
    sz = (sz + 7)&~7;
    sqlite3BeginBenignMalloc();
    pStart = sqlite3Malloc( sz*cnt );
    sqlite3EndBenignMalloc();
  }else{
    sz = sz&~7;
    pStart = pBuf;
  }
  if( db->lookaside.bMalloced ){
    sqlite3_free(db->lookaside.pStart);
  }
  db->lookaside.pStart = pStart;
  db->lookaside.pFree = 0;
  db->lookaside.sz = (u16)sz;
  db->lookaside.bMalloced = pBuf==0 ?1:0;
  if( pStart ){
    int i;
    LookasideSlot *p;

    p = (LookasideSlot*)pStart;
    for(i=cnt-1; i>=0; i--){
      p->pNext = db->lookaside.pFree;
      db->lookaside.pFree = p;
      p = (LookasideSlot*)&((u8*)p)[sz];
    }
    db->lookaside.pEnd = p;
    db->lookaside.bEnabled = 1;

  }else{
    db->lookaside.pEnd = 0;
    db->lookaside.bEnabled = 0;

  }
  return SQLITE_OK;
}

/*
** Return the mutex associated with a database connection.
*/

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.523 2009/01/30 06:11:55 shane Exp $
*/
#include "sqliteInt.h"

#ifdef SQLITE_ENABLE_FTS3
# include "fts3.h"
#endif
#ifdef SQLITE_ENABLE_RTREE
................................................................................
** the lookaside memory.
*/
static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
  void *pStart;
  if( db->lookaside.nOut ){
    return SQLITE_BUSY;
  }
  /* Free any existing lookaside buffer for this handle before
  ** allocating a new one so we don't have to have space for 
  ** both at the same time.
  */
  if( db->lookaside.bMalloced ){
    sqlite3_free(db->lookaside.pStart);
  }
  /* The size of a lookaside slot needs to be larger than a pointer
  ** to be useful.
  */
  if( sz<=sizeof(LookasideSlot*) ) sz = 0;
  if( cnt<0 ) cnt = 0;
  if( sz==0 || cnt==0 ){
    sz = 0;
    pStart = 0;
  }else if( pBuf==0 ){
    sz = (sz + 7)&~7;
    sqlite3BeginBenignMalloc();
    pStart = sqlite3Malloc( sz*cnt );
    sqlite3EndBenignMalloc();
  }else{
    sz = sz&~7;
    pStart = pBuf;
  }



  db->lookaside.pStart = pStart;
  db->lookaside.pFree = 0;
  db->lookaside.sz = (u16)sz;

  if( pStart ){
    int i;
    LookasideSlot *p;
    assert( sz > sizeof(LookasideSlot*) );
    p = (LookasideSlot*)pStart;
    for(i=cnt-1; i>=0; i--){
      p->pNext = db->lookaside.pFree;
      db->lookaside.pFree = p;
      p = (LookasideSlot*)&((u8*)p)[sz];
    }
    db->lookaside.pEnd = p;
    db->lookaside.bEnabled = 1;
    db->lookaside.bMalloced = pBuf==0 ?1:0;
  }else{
    db->lookaside.pEnd = 0;
    db->lookaside.bEnabled = 0;
    db->lookaside.bMalloced = 0;
  }
  return SQLITE_OK;
}

/*
** Return the mutex associated with a database connection.
*/