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authorHans-Christoph Steiner <hans@eds.org>2012-03-30 20:42:12 -0400
committerHans-Christoph Steiner <hans@eds.org>2012-03-30 20:42:12 -0400
commit7bb481fda9ecb134804b49c2ce77ca28f7eea583 (patch)
tree31b520b9914d3e2453968abe375f2c102772c3dc /src/mem1.c
Imported Upstream version 2.0.3
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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.
+*/
+#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 */