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/*
* Copyright (c) 2012, 2013 ARM Ltd
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the company may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "local-malloc.h"
/*
* Implement either by merging adjacent free memory
* or by calling malloc/memcpy
*/
void *
realloc(void *ptr, size_t size)
{
void *mem;
if (ptr == NULL)
return malloc(size);
if (size == 0) {
free(ptr);
return NULL;
}
if (size > MALLOC_MAXSIZE) {
errno = ENOMEM;
return NULL;
}
size_t new_size = chunk_size(size);
chunk_t *p_to_realloc = ptr_to_chunk(ptr);
#if MALLOC_DEBUG
__malloc_validate_block(p_to_realloc);
#endif
size_t old_size = _size(p_to_realloc);
/* See if we can avoid allocating new memory
* when increasing the size
*/
if (new_size > old_size) {
void *chunk_e = chunk_end(p_to_realloc);
MALLOC_LOCK;
if (__malloc_grow_chunk(p_to_realloc, new_size)) {
/* clear new memory */
memset(chunk_e, '\0', new_size - old_size);
/* adjust chunk_t size */
old_size = new_size;
} else {
chunk_t **p, *r;
/* Check to see if there's a chunk_t of free space just past
* the current block, merge it in in case that's useful
*/
for (p = &__malloc_free_list; (r = *p) != NULL; p = &r->next) {
if (r == chunk_e) {
size_t r_size = _size(r);
/* remove R from the free list */
*p = r->next;
/* clear the memory from r */
memset(r, '\0', r_size);
/* add it's size to our block */
old_size += r_size;
_set_size(p_to_realloc, old_size);
break;
}
if (p_to_realloc < r)
break;
}
}
MALLOC_UNLOCK;
}
if (new_size <= old_size) {
size_t extra = old_size - new_size;
#ifdef __MALLOC_CLEAR_FREED
if (extra > MALLOC_HEAD)
memset((char *)ptr + new_size, 0, extra - MALLOC_HEAD);
#endif
/* If there's enough space left over, split it out
* and free it
*/
if (extra >= MALLOC_MINSIZE) {
_set_size(p_to_realloc, new_size);
make_free_chunk(chunk_after(p_to_realloc), extra);
}
return ptr;
}
/* No short cuts, allocate new memory and copy */
mem = malloc(size);
if (!mem)
return NULL;
memcpy(mem, ptr, old_size - MALLOC_HEAD);
free(ptr);
return mem;
}