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|
/*
+----------------------------------------------------------------------+
| Zend Engine |
+----------------------------------------------------------------------+
| Copyright (c) 1998-2002 Zend Technologies Ltd. (http://www.zend.com) |
+----------------------------------------------------------------------+
| This source file is subject to version 2.00 of the Zend license, |
| that is bundled with this package in the file LICENSE, and is |
| available at through the world-wide-web at |
| http://www.zend.com/license/2_00.txt. |
| If you did not receive a copy of the Zend license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@zend.com so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: Andi Gutmans <andi@zend.com> |
| Zeev Suraski <zeev@zend.com> |
+----------------------------------------------------------------------+
*/
#include <stdlib.h>
#include "zend_mm.h"
#if WIN32|WINNT
# ifndef inline
# define inline __inline
# endif
#endif
#define ZEND_MM_FREE_BLOCK 0
#define ZEND_MM_USED_BLOCK 1
/* Platform alignment test */
typedef union _mm_align_test {
void *ptr;
double dbl;
long lng;
} mm_align_test;
#if (defined (__GNUC__) && __GNUC__ >= 2)
#define ZEND_MM_ALIGNMENT (__alignof__ (mm_align_test))
#else
#define ZEND_MM_ALIGNMENT (sizeof(mm_align_test))
#endif
/* Aligned header size */
#define ZEND_MM_ALIGNED_SIZE(size) (size+(((ZEND_MM_ALIGNMENT-size)%ZEND_MM_ALIGNMENT+ZEND_MM_ALIGNMENT)%ZEND_MM_ALIGNMENT))
#define ZEND_MM_ALIGNED_HEADER_SIZE ZEND_MM_ALIGNED_SIZE(sizeof(zend_mm_block))
/* Memory calculations */
#define ZEND_MM_BLOCK_AT(blk, offset) ((zend_mm_block *) (((char *) (blk))+(offset)))
#define ZEND_MM_DATA_OF(p) ((void *) (((char *) (p))+ZEND_MM_ALIGNED_HEADER_SIZE))
#define ZEND_MM_HEADER_OF(blk) ZEND_MM_BLOCK_AT(blk, -(int)ZEND_MM_ALIGNED_HEADER_SIZE)
/* Debug output */
#define ZEND_MM_DEBUG(stmt)
static inline void zend_mm_add_to_free_list(zend_mm_heap *heap, zend_mm_block *mm_block)
{
mm_block->next_free_block = heap->free_list;
mm_block->prev_free_block = NULL;
heap->free_list = mm_block;
if (mm_block->next_free_block) {
mm_block->next_free_block->prev_free_block = mm_block;
}
}
static inline void zend_mm_remove_from_free_list(zend_mm_heap *heap, zend_mm_block *mm_block)
{
if (mm_block->prev_free_block) {
mm_block->prev_free_block->next_free_block = mm_block->next_free_block;
} else {
heap->free_list = mm_block->next_free_block;
}
if (mm_block->next_free_block) {
mm_block->next_free_block->prev_free_block = mm_block->prev_free_block;
}
}
zend_bool zend_mm_add_memory_block(zend_mm_heap *heap, size_t block_size)
{
zend_mm_block *mm_block;
zend_mm_block *guard_block;
/* align block size downwards */
block_size -= block_size % ZEND_MM_ALIGNMENT;
mm_block = (zend_mm_block *) malloc(block_size);
if (!mm_block) {
return 1;
}
mm_block->size = block_size - ZEND_MM_ALIGNED_HEADER_SIZE; /* keep one guard block in the end */
mm_block->type = ZEND_MM_FREE_BLOCK;
mm_block->prev_size = 0; /* Size is always at least ZEND_MM_ALIGNED_HEADER_SIZE big (>0) so 0 is OK */
/* setup guard block */
guard_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
guard_block->type = ZEND_MM_USED_BLOCK;
guard_block->size = ZEND_MM_ALIGNED_HEADER_SIZE;
guard_block->prev_size = mm_block->size;
ZEND_MM_DEBUG(("Setup guard block at 0x%0.8X\n", guard_block));
zend_mm_add_to_free_list(heap, mm_block);
return 0;
}
/* Notes:
* - This function may alter the block_sizes values to match platform alignment
* - This function does *not* perform sanity checks on the arguments
*/
zend_bool zend_mm_startup(zend_mm_heap *heap, size_t block_size)
{
block_size -= block_size % ZEND_MM_ALIGNMENT;
heap->block_size = block_size;
heap->free_list = NULL;
if (zend_mm_add_memory_block(heap, block_size)) {
return 1;
}
return 0;
}
void zend_mm_shutdown(zend_mm_heap *heap)
{
}
void *zend_mm_alloc(zend_mm_heap *heap, size_t size)
{
size_t true_size;
zend_mm_block *p, *best_fit=NULL, *new_free_block;
size_t remaining_size;
true_size = ZEND_MM_ALIGNED_SIZE(size)+ZEND_MM_ALIGNED_HEADER_SIZE;
for (p = heap->free_list; p; p = p->next_free_block) {
if (p->size == true_size) {
best_fit = p;
break;
}
if ((p->size > true_size) && (!best_fit || (best_fit->size > p->size))) { /* better fit */
best_fit = p;
}
}
if (!best_fit) {
if (true_size > (heap->block_size - ZEND_MM_ALIGNED_HEADER_SIZE)) {
/* Make sure we add a memory block which is big enough */
zend_mm_add_memory_block(heap, true_size + ZEND_MM_ALIGNED_HEADER_SIZE);
} else {
zend_mm_add_memory_block(heap, heap->block_size);
}
return zend_mm_alloc(heap, size);
}
/* mark as used */
best_fit->type = ZEND_MM_USED_BLOCK;
/* remove from free list */
zend_mm_remove_from_free_list(heap, best_fit);
/* calculate sizes */
remaining_size = best_fit->size - true_size;
if (remaining_size < ZEND_MM_ALIGNED_HEADER_SIZE) {
/* keep best_fit->size as is, it'll include this extra space */
return ZEND_MM_DATA_OF(best_fit);
}
/* prepare new free block */
best_fit->size = true_size;
new_free_block = ZEND_MM_BLOCK_AT(best_fit, best_fit->size);
new_free_block->type = ZEND_MM_FREE_BLOCK;
new_free_block->size = remaining_size;
new_free_block->prev_size = true_size;
/* update the next block's prev_size */
ZEND_MM_BLOCK_AT(new_free_block, new_free_block->size)->prev_size = new_free_block->size;
/* add the new free block to the free list */
zend_mm_add_to_free_list(heap, new_free_block);
return ZEND_MM_DATA_OF(best_fit);
}
void zend_mm_free(zend_mm_heap *heap, void *p)
{
zend_mm_block *mm_block = ZEND_MM_HEADER_OF(p);
zend_mm_block *prev_block, *next_block;
int in_free_list=0;
if (mm_block->type!=ZEND_MM_USED_BLOCK) {
/* error */
return;
}
next_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
/* merge with previous block if empty */
if (mm_block->prev_size != 0
&& (prev_block=ZEND_MM_BLOCK_AT(mm_block, -(int)mm_block->prev_size))->type == ZEND_MM_FREE_BLOCK) {
prev_block->size += mm_block->size;
mm_block = prev_block;
next_block->prev_size = mm_block->size;
in_free_list = 1; /* linked two ways */
}
/* merge with the next block if empty */
if (next_block->type == ZEND_MM_FREE_BLOCK) {
mm_block->size += next_block->size;
zend_mm_remove_from_free_list(heap, next_block);
next_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size); /* recalculate */
next_block->prev_size = mm_block->size;
}
mm_block->type = ZEND_MM_FREE_BLOCK;
if (!in_free_list) {
zend_mm_add_to_free_list(heap, mm_block);
}
}
void *zend_mm_realloc(zend_mm_heap *heap, void *p, size_t size)
{
void *ptr;
zend_mm_block *mm_block = ZEND_MM_HEADER_OF(p);
size_t true_size = ZEND_MM_ALIGNED_SIZE(size)+ZEND_MM_ALIGNED_HEADER_SIZE;
if (true_size <= mm_block->size) {
return p;
}
ptr = zend_mm_alloc(heap, size);
memcpy(ptr, p, mm_block->size - ZEND_MM_ALIGNED_HEADER_SIZE);
zend_mm_free(heap, p);
return ptr;
}
|
