/*
** 2007 August 14
**
** 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.
**
*************************************************************************
**
** This file contains low-level memory allocation drivers for when
** SQLite will use the standard C-library malloc/realloc/free interface
** to obtain the memory it needs.
**
** This file contains implementations of the low-level memory allocation
** routines specified in the sqlite3_mem_methods object.
*/
#include "sqliteInt.h"
/*
** This version of the memory allocator is the default. It is
** used when no other memory allocator is specified using compile-time
** macros.
*/
#ifdef SQLITE_SYSTEM_MALLOC
#if (!defined(__APPLE__))
#define SQLITE_MALLOC(x) malloc(x)
#define SQLITE_FREE(x) free(x)
#define SQLITE_REALLOC(x,y) realloc((x),(y))
#else
#include <sys/sysctl.h>
#include <malloc/malloc.h>
#include <libkern/OSAtomic.h>
static malloc_zone_t* _sqliteZone_;
#define SQLITE_MALLOC(x) malloc_zone_malloc(_sqliteZone_, (x))
#define SQLITE_FREE(x) malloc_zone_free(_sqliteZone_, (x));
#define SQLITE_REALLOC(x,y) malloc_zone_realloc(_sqliteZone_, (x), (y))
#define SQLITE_MALLOCSIZE(x) (_sqliteZone_ ? _sqliteZone_->size(_sqliteZone_,x) : malloc_size(x))
#endif
/*
** Like malloc(), but remember the size of the allocation
** so that we can find it later using sqlite3MemSize().
**
** For this low-level routine, we are guaranteed that nByte>0 because
** cases of nByte<=0 will be intercepted and dealt with by higher level
** routines.
*/
static void *sqlite3MemMalloc(int nByte){
sqlite3_int64 *p;
assert( nByte>0 );
nByte = ROUND8(nByte);
#ifndef SQLITE_MALLOCSIZE
p = SQLITE_MALLOC( nByte + 8 );
if( p ){
p[0] = nByte;
p++;
}else{
testcase( sqlite3GlobalConfig.xLog!=0 );
sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
}
#else
p = SQLITE_MALLOC( nByte );
if( !p ){
testcase( sqlite3GlobalConfig.xLog!=0 );
sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
}
#endif
return (void *)p;
}
/*
** Like free() but works for allocations obtained from sqlite3MemMalloc()
** or sqlite3MemRealloc().
**
** For this low-level routine, we already know that pPrior!=0 since
** cases where pPrior==0 will have been intecepted and dealt with
** by higher-level routines.
*/
static void sqlite3MemFree(void *pPrior){
sqlite3_int64 *p = (sqlite3_int64*)pPrior;
assert( pPrior!=0 );
#ifndef SQLITE_MALLOCSIZE
p--;
#endif
SQLITE_FREE(p);
}
/*
** Report the allocated size of a prior return from xMalloc()
** or xRealloc().
*/
static int sqlite3MemSize(void *pPrior){
#ifndef SQLITE_MALLOCSIZE
sqlite3_int64 *p;
if( pPrior==0 ) return 0;
p = (sqlite3_int64*)pPrior;
p--;
return (int)p[0];
#else
return (int)SQLITE_MALLOCSIZE(pPrior);
#endif
}
/*
** Like realloc(). Resize an allocation previously obtained from
** sqlite3MemMalloc().
**
** For this low-level interface, we know that pPrior!=0. Cases where
** pPrior==0 while have been intercepted by higher-level routine and
** redirected to xMalloc. Similarly, we know that nByte>0 becauses
** cases where nByte<=0 will have been intercepted by higher-level
** routines and redirected to xFree.
*/
static void *sqlite3MemRealloc(void *pPrior, int nByte){
sqlite3_int64 *p = (sqlite3_int64*)pPrior;
assert( pPrior!=0 && nByte>0 );
assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */
#ifndef SQLITE_MALLOCSIZE
p--;
p = SQLITE_REALLOC(p, nByte+8 );
if( p ){
p[0] = nByte;
p++;
}else{
testcase( sqlite3GlobalConfig.xLog!=0 );
sqlite3_log(SQLITE_NOMEM,
"failed memory resize %u to %u bytes",
sqlite3MemSize(pPrior), nByte);
}
#else
p = SQLITE_REALLOC(p, nByte );
if( !p ){
testcase( sqlite3GlobalConfig.xLog!=0 );
sqlite3_log(SQLITE_NOMEM,
"failed memory resize %u to %u bytes",
sqlite3MemSize(pPrior), nByte);
}
#endif
return (void*)p;
}
/*
** Round up a request size to the next valid allocation size.
*/
static int sqlite3MemRoundup(int n){
return ROUND8(n);
}
/*
** Initialize this module.
*/
static int sqlite3MemInit(void *NotUsed){
#if defined(__APPLE__)
if (_sqliteZone_) {
return SQLITE_OK;
}
int cpuCount;
size_t len;
len = sizeof(cpuCount);
sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0); // one almost always wants to use "hw.activecpu" for MT decisions, but not here.
if (cpuCount > 1) {
// defer MT decisions to system malloc
_sqliteZone_ = malloc_default_zone();
} else {
// only 1 core, use our own zone to contention over global locks,
// e.g. we have our own dedicated locks
malloc_zone_t* newzone = malloc_create_zone(4096, 0);
malloc_set_zone_name(newzone, "Sqlite_Heap");
bool success;
do {
success = OSAtomicCompareAndSwapPtrBarrier(NULL, newzone, (void * volatile *)&_sqliteZone_);
} while (!_sqliteZone_);
if (!success) {
// somebody registered a zone first
malloc_destroy_zone(newzone);
}
}
#endif
UNUSED_PARAMETER(NotUsed);
return SQLITE_OK;
}
/*
** Deinitialize this module.
*/
static void sqlite3MemShutdown(void *NotUsed){
#if (0 && defined(__APPLE__))
if (_sqliteZone_ && (_sqliteZone_ != malloc_default_zone())) {
malloc_zone_t* oldzone = _sqliteZone_;
bool success = OSAtomicCompareAndSwapPtrBarrier(oldzone, NULL, (void * volatile *)&_sqliteZone_);
if (success) {
malloc_destroy_zone(oldzone);
}
}
#endif
UNUSED_PARAMETER(NotUsed);
return;
}
/*
** This routine is the only routine in this file with external linkage.
**
** Populate the low-level memory allocation function pointers in
** sqlite3GlobalConfig.m with pointers to the routines in this file.
*/
void sqlite3MemSetDefault(void){
static const sqlite3_mem_methods defaultMethods = {
sqlite3MemMalloc,
sqlite3MemFree,
sqlite3MemRealloc,
sqlite3MemSize,
sqlite3MemRoundup,
sqlite3MemInit,
sqlite3MemShutdown,
0
};
sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
}
#undef SQLITE_MALLOC
#undef SQLITE_FREE
#undef SQLITE_REALLOC
#endif /* SQLITE_SYSTEM_MALLOC */