SQLite

} ScratchFreeslot;

/*
** State information local to the memory allocation subsystem.
*/
static SQLITE_WSD struct Mem0Global {
  sqlite3_mutex *mutex;         /* Mutex to serialize access */
  sqlite3_int64 alarmThreshold;  /* The soft heap limit */

  /*
  ** Pointers to the end of sqlite3GlobalConfig.pScratch memory
  ** (so that a range test can be used to determine if an allocation
  ** being freed came from pScratch) and a pointer to the list of
  ** unused scratch allocations.
  */

/*
** Return the memory allocator mutex. sqlite3_status() needs it.
*/
sqlite3_mutex *sqlite3MallocMutex(void){
  return mem0.mutex;
}

/*
** Return the amount of memory currently in use.
*/
static sqlite3_int64 memInUse(void){
  assert( sqlite3_mutex_held(mem0.mutex) );
  return sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
}

/*
** Called when the soft heap limit is exceeded for an allocation
** of nBytes.
*/
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
static void sqlite3HeapLimitExceeded(int nByte){
  sqlite3_int64 excess = memInUse() + nByte - mem0.alarmThreshold;
  sqlite3_mutex_leave(mem0.mutex);
  sqlite3_release_memory((int)(excess & 0x7fffffff));
  sqlite3_mutex_enter(mem0.mutex);
}
#else
# define sqlite3HeapLimitExceeded(X)  /* no-op */
#endif

/*
** Check to see if increasing the total memory usage by nNew bytes
** will exceed the soft heap limit.  
**
** If the soft heap limit is exceeded, set the mem0.nearlyFull flag
** and invoke sqlite3HeapLimitExceeded() to try to free up some
** memory.
*/
static void sqlite3CheckSoftHeapLimit(int nNew){
  assert( sqlite3_mutex_held(mem0.mutex) );
  if( mem0.alarmThreshold>0 ){
    if( mem0.alarmThreshold-nNew >= memInUse() ){
      mem0.nearlyFull = 1;
      sqlite3HeapLimitExceeded(nNew);
    }else{
      mem0.nearlyFull = 0;
    }
  }
}

#ifndef SQLITE_OMIT_DEPRECATED
/*
** Deprecated external interface.  First deprecated 2007-11-05.  Changed

** into a no-op on 2015-09-02.
*/
int sqlite3_memory_alarm(
  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
  void *pArg,
  sqlite3_int64 iThreshold
){



  return SQLITE_OK;
}
#endif

/*
** Set the soft heap-size limit for the library. Passing a zero or 
** negative value indicates no limit.
*/
sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){
  sqlite3_int64 priorLimit;


#ifndef SQLITE_OMIT_AUTOINIT
  int rc = sqlite3_initialize();
  if( rc ) return -1;
#endif
  sqlite3_mutex_enter(mem0.mutex);
  priorLimit = mem0.alarmThreshold;
  if( n>0 ){
    mem0.alarmThreshold = n;
    sqlite3CheckSoftHeapLimit(0);
  }else if( n==0 ){

    mem0.alarmThreshold = 0;

    mem0.nearlyFull = 0;
  }
  sqlite3_mutex_leave(mem0.mutex);


  return priorLimit;
}
void sqlite3_soft_heap_limit(int n){
  if( n<0 ) n = 0;
  sqlite3_soft_heap_limit64(n);
}

** or since the most recent reset.
*/
sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
  sqlite3_int64 res, mx;
  sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, resetFlag);
  return mx;
}











/*
** Do a memory allocation with statistics and alarms.  Assume the
** lock is already held.
*/
static int mallocWithAlarm(int n, void **pp){
  int nFull;
  void *p;
  assert( sqlite3_mutex_held(mem0.mutex) );
  nFull = sqlite3GlobalConfig.m.xRoundup(n);
  sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, n);




  sqlite3CheckSoftHeapLimit(nFull);




  p = sqlite3GlobalConfig.m.xMalloc(nFull);
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  if( p==0 && mem0.alarmThreshold ){
    sqlite3HeapLimitExceeded(nFull);
    p = sqlite3GlobalConfig.m.xMalloc(nFull);
  }
#endif
  if( p ){
    nFull = sqlite3MallocSize(p);
    sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nFull);
    sqlite3StatusUp(SQLITE_STATUS_MALLOC_COUNT, 1);

  nNew = sqlite3GlobalConfig.m.xRoundup((int)nBytes);
  if( nOld==nNew ){
    pNew = pOld;
  }else if( sqlite3GlobalConfig.bMemstat ){
    sqlite3_mutex_enter(mem0.mutex);
    sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, (int)nBytes);
    nDiff = nNew - nOld;


    sqlite3CheckSoftHeapLimit(nDiff);

    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
    if( pNew==0 && mem0.alarmThreshold ){
      sqlite3HeapLimitExceeded((int)nBytes);
      pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
    }
#endif
    if( pNew ){
      nNew = sqlite3MallocSize(pNew);
      sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
    }
    sqlite3_mutex_leave(mem0.mutex);
  }else{
    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);