/*
** 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
/*
** 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);
p = 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;
}
/*
** 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 );
p--;
free(p);
}
/*
** Report the allocated size of a prior return from xMalloc()
** or xRealloc().
*/
static int sqlite3MemSize(void *pPrior){
sqlite3_int64 *p;
if( pPrior==0 ) return 0;
p = (sqlite3_int64*)pPrior;
p--;
return (int)p[0];
}
/*
** 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 */
p--;
p = 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;
}
/*
** 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){
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 */