mirror of
https://github.com/cc65/cc65.git
synced 2024-12-27 00:29:31 +00:00
118 lines
4.5 KiB
C
118 lines
4.5 KiB
C
/*****************************************************************************/
|
|
/* */
|
|
/* realloc.c */
|
|
/* */
|
|
/* Change the size of an allocated memory block */
|
|
/* */
|
|
/* */
|
|
/* */
|
|
/* (C) 1998-2004 Ullrich von Bassewitz */
|
|
/* Wacholderweg 14 */
|
|
/* D-70597 Stuttgart */
|
|
/* EMail: uz@musoftware.de */
|
|
/* */
|
|
/* */
|
|
/* This software is provided 'as-is', without any expressed or implied */
|
|
/* warranty. In no event will the authors be held liable for any damages */
|
|
/* arising from the use of this software. */
|
|
/* */
|
|
/* Permission is granted to anyone to use this software for any purpose, */
|
|
/* including commercial applications, and to alter it and redistribute it */
|
|
/* freely, subject to the following restrictions: */
|
|
/* */
|
|
/* 1. The origin of this software must not be misrepresented; you must not */
|
|
/* claim that you wrote the original software. If you use this software */
|
|
/* in a product, an acknowledgment in the product documentation would be */
|
|
/* appreciated but is not required. */
|
|
/* 2. Altered source versions must be plainly marked as such, and must not */
|
|
/* be misrepresented as being the original software. */
|
|
/* 3. This notice may not be removed or altered from any source */
|
|
/* distribution. */
|
|
/* */
|
|
/*****************************************************************************/
|
|
|
|
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <_heap.h>
|
|
|
|
|
|
|
|
void* __fastcall__ realloc (void* block, size_t size)
|
|
{
|
|
struct usedblock* b;
|
|
struct usedblock* newblock;
|
|
unsigned oldsize;
|
|
unsigned newhptr;
|
|
int diff;
|
|
|
|
/* Check the block parameter */
|
|
if (!block) {
|
|
/* Block is NULL, same as malloc */
|
|
return malloc (size);
|
|
}
|
|
|
|
/* Check the size parameter */
|
|
if (size == 0) {
|
|
/* Block is not NULL, but size is: free the block */
|
|
free (block);
|
|
return 0;
|
|
}
|
|
|
|
/* Make the internal used size from the given size */
|
|
size += HEAP_ADMIN_SPACE;
|
|
if (size < sizeof (struct freeblock)) {
|
|
size = sizeof (struct freeblock);
|
|
}
|
|
|
|
/* The word below the user block contains a pointer to the start of the
|
|
* raw memory block. The first word of this raw memory block is the full
|
|
* size of the block. Get a pointer to the real block, get the old block
|
|
* size.
|
|
*/
|
|
b = (((struct usedblock*) block) - 1)->start;
|
|
oldsize = b->size;
|
|
|
|
/* Get the size difference as a signed quantity */
|
|
diff = size - oldsize;
|
|
|
|
/* Is the block at the current heap top? */
|
|
if (((unsigned) b) + oldsize == ((unsigned) _heapptr)) {
|
|
/* Check if we've enough memory at the heap top */
|
|
newhptr = ((unsigned) _heapptr) + diff;
|
|
if (newhptr <= ((unsigned) _heapend)) {
|
|
/* Ok, there's space enough */
|
|
_heapptr = (unsigned*) newhptr;
|
|
b->size = size;
|
|
b->start = b;
|
|
return block;
|
|
}
|
|
}
|
|
|
|
/* The given block was not located on top of the heap, or there's no
|
|
* room left. Try to allocate a new block and copy the data.
|
|
*/
|
|
if (newblock = malloc (size)) {
|
|
|
|
/* Adjust the old size to the user visible portion */
|
|
oldsize -= HEAP_ADMIN_SPACE;
|
|
|
|
/* If the new block is larger than the old one, copy the old
|
|
* data only
|
|
*/
|
|
if (size > oldsize) {
|
|
size = oldsize;
|
|
}
|
|
|
|
/* Copy the block data */
|
|
memcpy (newblock, block, size);
|
|
free (block);
|
|
}
|
|
return newblock;
|
|
}
|
|
|
|
|
|
|
|
|