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Check-in [6bda711f93]
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Overview
Comment:Follow-on to the previous check-in to prevent a division by zero if the lookahead slot size is something goofy like 6 on a 32-bit machine.
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SHA1: 6bda711f93e753dd0be8d896a007b3f7b5064787
User & Date: drh 2011-11-10 02:39:28.949
Context
2011-11-11
14:12
Pull over all the latest changes from trunk. (check-in: 1bbbf8574a user: drh tags: experimental-pcache)
2011-11-10
02:39
Follow-on to the previous check-in to prevent a division by zero if the lookahead slot size is something goofy like 6 on a 32-bit machine. (check-in: 6bda711f93 user: drh tags: experimental-pcache)
02:24
Use sqlite3MallocSize() to get the actual size of the memory allocation used for lookaside cache and increase the size of the cache to use the full allocation. (check-in: 0e53ecad94 user: drh tags: experimental-pcache)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/main.c.
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  /* 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<=(int)sizeof(LookasideSlot*) ) sz = 0;
  if( cnt<0 ) cnt = 0;
  if( sz==0 || cnt==0 ){
    sz = 0;
    pStart = 0;
  }else if( pBuf==0 ){
    sz = ROUNDDOWN8(sz); /* IMP: R-33038-09382 */
    sqlite3BeginBenignMalloc();
    pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
    sqlite3EndBenignMalloc();
    if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
  }else{
    sz = ROUNDDOWN8(sz); /* IMP: R-33038-09382 */
    pStart = pBuf;
  }
  db->lookaside.pStart = pStart;
  db->lookaside.pFree = 0;
  db->lookaside.sz = (u16)sz;
  if( pStart ){
    int i;








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  /* 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 after ROUNDDOWN8 needs to be larger
  ** than a pointer to be useful.
  */
  sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
  if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
  if( cnt<0 ) cnt = 0;
  if( sz==0 || cnt==0 ){
    sz = 0;
    pStart = 0;
  }else if( pBuf==0 ){

    sqlite3BeginBenignMalloc();
    pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
    sqlite3EndBenignMalloc();
    if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
  }else{

    pStart = pBuf;
  }
  db->lookaside.pStart = pStart;
  db->lookaside.pFree = 0;
  db->lookaside.sz = (u16)sz;
  if( pStart ){
    int i;
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