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/*
** Copyright (C) 1997 The University of Melbourne.
** This file may only be copied under the terms of the GNU Library General
** Public License - see the file COPYING.LIB in the Mercury distribution.
**
** $Id: mem.c,v 1.6 1997/07/27 14:59:28 fjh Exp $
*/
/* Imports */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "util.h"
#include "mem.h"
/* Exported definitions */
/* Local declarations */
static char
rcs_id[] = "$Id: mem.c,v 1.6 1997/07/27 14:59:28 fjh Exp $";
/*
* Make sure the size of guard_bytes is a multiple of 8 to ensure we
* don't get unaligned accesses, even on 64-bit architectures.
*/
static const unsigned char
guard_bytes[] = {0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5,0xa5};
/* Implementation */
void*
MB_malloc(size_t size)
{
size_t real_size;
size_t guard_size;
unsigned char *real_mem, *mem;
guard_size = sizeof(guard_bytes) / sizeof(*guard_bytes);
real_size = size + 2 * guard_size;
real_mem = malloc(real_size);
if (real_mem == NULL) {
MB_fatal("mem.MB_alloc: malloc failed");
}
/*
* Now check all allocated memory for corruption.
* XXX: Fill this in later...
*/
mem = real_mem + guard_size;
return mem;
}
void
MB_free(void *mem)
{
size_t guard_size;
unsigned char *real_mem;
/*
* Check that the memory to be freed was actually allocated.
* We can't check for still-remaining references to the
* memory without some sort of memory-marking as done in
* Hans Boehm's conservative garbage collector.
*/
/*
* Check all allocated memory for corruption.
* XXX: Do this later...
*/
guard_size = sizeof(guard_bytes) / sizeof(*guard_bytes);
real_mem = (unsigned char *) mem - guard_size;
free(real_mem);
return;
}
void*
MB_realloc(void *mem, size_t size)
{
void *new_mem;
/*
* Check all allocated memory for corruption.
* XXX: Do this later...
*/
new_mem = MB_malloc(size);
memcpy(new_mem, mem, size);
/*
* Check mem was actually allocated.
* XXX: Do later...
*/
MB_free(mem);
return new_mem;
}
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