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279 lines (262 loc) · 8.26 KB
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/*
** 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. The content of
** this file is only used if SQLITE_SYSTEM_MALLOC is defined. The
** SQLITE_SYSTEM_MALLOC macro is defined automatically if neither the
** SQLITE_MEMDEBUG nor the SQLITE_WIN32_MALLOC macros are defined. The
** default configuration is to use memory allocation routines in this
** file.
**
** C-preprocessor macro summary:
**
** HAVE_MALLOC_USABLE_SIZE The configure script sets this symbol if
** the malloc_usable_size() interface exists
** on the target platform. Or, this symbol
** can be set manually, if desired.
** If an equivalent interface exists by
** a different name, using a separate -D
** option to rename it.
**
** SQLITE_WITHOUT_ZONEMALLOC Some older macs lack support for the zone
** memory allocator. Set this symbol to enable
** building on older macs.
**
** SQLITE_WITHOUT_MSIZE Set this symbol to disable the use of
** _msize() on windows systems. This might
** be necessary when compiling for Delphi,
** for example.
*/
#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
/*
** The MSVCRT has malloc_usable_size() but it is called _msize().
** The use of _msize() is automatic, but can be disabled by compiling
** with -DSQLITE_WITHOUT_MSIZE
*/
#if defined(_MSC_VER) && !defined(SQLITE_WITHOUT_MSIZE)
# define SQLITE_MALLOCSIZE _msize
#endif
#if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
/*
** Use the zone allocator available on apple products unless the
** SQLITE_WITHOUT_ZONEMALLOC symbol is defined.
*/
#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))
#else /* if not __APPLE__ */
/*
** Use standard C library malloc and free on non-Apple systems.
** Also used by Apple systems if SQLITE_WITHOUT_ZONEMALLOC is defined.
*/
#define SQLITE_MALLOC(x) malloc(x)
#define SQLITE_FREE(x) free(x)
#define SQLITE_REALLOC(x,y) realloc((x),(y))
#if (defined(_MSC_VER) && !defined(SQLITE_WITHOUT_MSIZE)) \
|| (defined(HAVE_MALLOC_H) && defined(HAVE_MALLOC_USABLE_SIZE))
# include <malloc.h> /* Needed for malloc_usable_size on linux */
#endif
#ifdef HAVE_MALLOC_USABLE_SIZE
# ifndef SQLITE_MALLOCSIZE
# define SQLITE_MALLOCSIZE(x) malloc_usable_size(x)
# endif
#else
# undef SQLITE_MALLOCSIZE
#endif
#endif /* __APPLE__ or not __APPLE__ */
/*
** 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){
#ifdef SQLITE_MALLOCSIZE
void *p = SQLITE_MALLOC( nByte );
if( p==0 ){
testcase( sqlite3GlobalConfig.xLog!=0 );
sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
}
return p;
#else
sqlite3_int64 *p;
assert( nByte>0 );
nByte = ROUND8(nByte);
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);
}
return (void *)p;
#endif
}
/*
** 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){
#ifdef SQLITE_MALLOCSIZE
SQLITE_FREE(pPrior);
#else
sqlite3_int64 *p = (sqlite3_int64*)pPrior;
assert( pPrior!=0 );
p--;
SQLITE_FREE(p);
#endif
}
/*
** Report the allocated size of a prior return from xMalloc()
** or xRealloc().
*/
static int sqlite3MemSize(void *pPrior){
#ifdef SQLITE_MALLOCSIZE
return pPrior ? (int)SQLITE_MALLOCSIZE(pPrior) : 0;
#else
sqlite3_int64 *p;
if( pPrior==0 ) return 0;
p = (sqlite3_int64*)pPrior;
p--;
return (int)p[0];
#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){
#ifdef SQLITE_MALLOCSIZE
void *p = SQLITE_REALLOC(pPrior, nByte);
if( p==0 ){
testcase( sqlite3GlobalConfig.xLog!=0 );
sqlite3_log(SQLITE_NOMEM,
"failed memory resize %u to %u bytes",
SQLITE_MALLOCSIZE(pPrior), nByte);
}
return p;
#else
sqlite3_int64 *p = (sqlite3_int64*)pPrior;
assert( pPrior!=0 && nByte>0 );
assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */
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);
}
return (void*)p;
#endif
}
/*
** 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__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
int cpuCount;
size_t len;
if( _sqliteZone_ ){
return SQLITE_OK;
}
len = sizeof(cpuCount);
/* One usually wants to use hw.acctivecpu for MT decisions, but not here */
sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0);
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 */
bool success;
malloc_zone_t* newzone = malloc_create_zone(4096, 0);
malloc_set_zone_name(newzone, "Sqlite_Heap");
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){
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);
}
#endif /* SQLITE_SYSTEM_MALLOC */