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/*
+----------------------------------------------------------------------+
| Zend Engine |
+----------------------------------------------------------------------+
| Copyright (c) 1998-2006 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 through the world-wide-web at the following url: |
| 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> |
+----------------------------------------------------------------------+
*/
/* $Id$ */
#include "zend.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
#ifndef MAX
#define MAX(a, b) (((a)>(b))?(a):(b))
#endif
#ifndef ZEND_MM_ALIGNMENT
#define ZEND_MM_ALIGNMENT 8
#define ZEND_MM_ALIGNMENT_LOG2 3
#endif
#define ZEND_MM_ALIGNMENT_MASK ~(ZEND_MM_ALIGNMENT-1)
#define ZEND_MM_BUCKET_INDEX(true_size) (true_size >> ZEND_MM_ALIGNMENT_LOG2)
/* Aligned header size */
#define ZEND_MM_ALIGNED_SIZE(size) ((size + ZEND_MM_ALIGNMENT - 1) & ZEND_MM_ALIGNMENT_MASK)
#define ZEND_MM_ALIGNED_HEADER_SIZE ZEND_MM_ALIGNED_SIZE(sizeof(zend_mm_block))
#define ZEND_MM_ALIGNED_FREE_HEADER_SIZE ZEND_MM_ALIGNED_SIZE(sizeof(zend_mm_free_block))
#define ZEND_MM_ALIGNED_SEGMENT_SIZE ZEND_MM_ALIGNED_SIZE(sizeof(zend_mm_segment))
/* 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)
/* Start Heap Code */
static int left_child[ZEND_HEAP_MAX_BUCKETS];
static int left_child_of_right_brother[ZEND_HEAP_MAX_BUCKETS];
static inline void zend_heap_init(zend_heap heap)
{
int i;
for (i=0; i<ZEND_HEAP_MAX_BUCKETS; i++) {
left_child[i] = 2*i+1;
left_child_of_right_brother[i] = 2*i+3;
}
memset(heap, 0, sizeof(zend_heap));
}
static inline void zend_heap_activate_leaf(zend_heap heap, int node)
{
int i = node + ZEND_HEAP_MAX_BUCKETS-1;
heap[i] = node;
do {
i = (i-1)>>1; /* (i-1)/2 */
if (heap[i] < node) {
heap[i] = node;
} else {
break;
}
} while (i > 0);
}
static inline void zend_heap_deactivate_leaf(zend_heap heap, int node)
{
int i = node + ZEND_HEAP_MAX_BUCKETS-1;
heap[i] = 0;
do {
i = (i-1)>>1; /* (i-1)/2 */
if (heap[i] == node) {
heap[i] = MAX(heap[2*i+1], heap[2*i+2]);
} else {
break;
}
} while (i > 0);
}
static inline int zend_heap_search_leaf(zend_heap heap, int value)
{
int i = 1;
if (heap[0] < value) {
return 0;
}
while (i < ZEND_HEAP_MAX_BUCKETS) {
if (heap[i] >= value) {
/* Go to left child */
i = left_child[i];
} else {
/* Go to left child of right brother */
i = left_child_of_right_brother[i];
}
}
if (heap[i] >= value) {
return heap[i];
} else {
return heap[i+1];
}
}
/* End Heap Code */
static inline void zend_mm_add_to_free_list(zend_mm_heap *heap, zend_mm_free_block *mm_block)
{
zend_mm_free_block **free_list_bucket;
size_t index = ZEND_MM_BUCKET_INDEX(mm_block->size);
if (index < ZEND_MM_NUM_BUCKETS) {
free_list_bucket = &heap->free_buckets[index];
if (*free_list_bucket == NULL) {
zend_heap_activate_leaf(heap->heap, index);
}
} else {
free_list_bucket = &heap->free_buckets[0];
}
mm_block->next_free_block = *free_list_bucket;
if (*free_list_bucket != NULL) {
mm_block->next_free_block->prev_free_block = mm_block;
}
*free_list_bucket = mm_block;
mm_block->prev_free_block = NULL;
}
static inline void zend_mm_remove_from_free_list(zend_mm_heap *heap, zend_mm_free_block *mm_block)
{
if (mm_block->prev_free_block) {
mm_block->prev_free_block->next_free_block = mm_block->next_free_block;
} else {
zend_mm_free_block **free_list_bucket;
size_t index = ZEND_MM_BUCKET_INDEX(mm_block->size);
if (index < ZEND_MM_NUM_BUCKETS) {
free_list_bucket = &heap->free_buckets[index];
*free_list_bucket = mm_block->next_free_block;
if (*free_list_bucket == NULL) {
zend_heap_deactivate_leaf(heap->heap, index);
}
} else {
free_list_bucket = &heap->free_buckets[0];
*free_list_bucket = mm_block->next_free_block;
}
}
if (mm_block->next_free_block) {
mm_block->next_free_block->prev_free_block = mm_block->prev_free_block;
}
}
static inline void zend_mm_create_new_free_block(zend_mm_heap *heap, zend_mm_block *mm_block, size_t true_size)
{
int remaining_size;
zend_mm_free_block *new_free_block;
/* calculate sizes */
remaining_size = mm_block->size - true_size;
if (remaining_size < ZEND_MM_ALIGNED_FREE_HEADER_SIZE) {
/* keep best_fit->size as is, it'll include this extra space */
return;
}
/* prepare new free block */
mm_block->size = true_size;
new_free_block = (zend_mm_free_block *) ZEND_MM_BLOCK_AT(mm_block, mm_block->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);
}
zend_bool zend_mm_add_memory_block(zend_mm_heap *heap, size_t block_size)
{
/* We need to make sure that block_size is big enough for the minimum segment size */
zend_mm_free_block *mm_block;
zend_mm_block *guard_block;
zend_mm_segment *segment;
/* align block size downwards */
block_size = block_size & ZEND_MM_ALIGNMENT_MASK;
segment = (zend_mm_segment *) malloc(block_size);
if (!segment) {
return 1;
}
/* fprintf(stderr, "Allocating segment %X\n", segment); */
segment->next_segment = heap->segments_list;
heap->segments_list = segment;
block_size -= ZEND_MM_ALIGNED_SEGMENT_SIZE;
mm_block = (zend_mm_free_block *) ((char *) segment + ZEND_MM_ALIGNED_SEGMENT_SIZE);
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->guard_block = 1;
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)
{
heap->block_size = block_size;
heap->segments_list = NULL;
memset(heap->free_buckets, 0, sizeof(heap->free_buckets));
zend_heap_init(heap->heap);
return zend_mm_add_memory_block(heap, block_size);
}
void zend_mm_shutdown(zend_mm_heap *heap)
{
zend_mm_segment *segment = heap->segments_list;
zend_mm_segment *prev;
while (segment) {
prev = segment;
segment = segment->next_segment;
/* fprintf(stderr, "Freeing segment %X\n", prev);*/
free(prev);
}
heap->segments_list = NULL;
}
void *zend_mm_alloc(zend_mm_heap *heap, size_t size)
{
size_t true_size;
zend_mm_free_block *p, *best_fit=NULL;
zend_mm_free_block **free_list_bucket;
size_t index;
/* The max() can probably be optimized with an if () which checks more specific cases */
true_size = MAX(ZEND_MM_ALIGNED_SIZE(size)+ZEND_MM_ALIGNED_HEADER_SIZE, ZEND_MM_ALIGNED_FREE_HEADER_SIZE);
index = ZEND_MM_BUCKET_INDEX(true_size);
if (index < ZEND_MM_NUM_BUCKETS) {
free_list_bucket = &heap->free_buckets[index];
if (*free_list_bucket) {
best_fit = *free_list_bucket;
goto zend_mm_finished_searching_for_block;
} else {
int leaf;
leaf = zend_heap_search_leaf(heap->heap, index);
if (leaf != 0) {
best_fit = heap->free_buckets[leaf];
goto zend_mm_finished_searching_for_block;
}
}
}
for (p = heap->free_buckets[0]; 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;
}
}
zend_mm_finished_searching_for_block:
if (!best_fit) {
if (true_size > (heap->block_size - ZEND_MM_ALIGNED_SEGMENT_SIZE - ZEND_MM_ALIGNED_HEADER_SIZE)) {
/* Make sure we add a memory block which is big enough */
if (zend_mm_add_memory_block(heap, true_size + ZEND_MM_ALIGNED_SEGMENT_SIZE + ZEND_MM_ALIGNED_HEADER_SIZE)) {
zend_error(E_ERROR, "Out of memory: cannot allocate %zd bytes!", true_size);
return NULL;
}
} else {
if (zend_mm_add_memory_block(heap, heap->block_size)) {
zend_error(E_ERROR, "Out of memory: cannot allocate %zd bytes!", heap->block_size);
return NULL;
}
}
return zend_mm_alloc(heap, size);
}
/* mark as used */
best_fit->type = ZEND_MM_USED_BLOCK;
((zend_mm_block *) best_fit)->guard_block = 0;
/* remove from free list */
zend_mm_remove_from_free_list(heap, best_fit);
zend_mm_create_new_free_block(heap, (zend_mm_block *) best_fit, true_size);
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;
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) {
zend_mm_remove_from_free_list(heap, (zend_mm_free_block *) prev_block);
prev_block->size += mm_block->size;
mm_block = prev_block;
next_block->prev_size = mm_block->size;
}
/* 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, (zend_mm_free_block *) 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;
zend_mm_add_to_free_list(heap, (zend_mm_free_block *) mm_block);
}
void *zend_mm_realloc(zend_mm_heap *heap, void *p, size_t size)
{
zend_mm_block *mm_block = ZEND_MM_HEADER_OF(p);
zend_mm_block *next_block;
size_t true_size = MAX(ZEND_MM_ALIGNED_SIZE(size)+ZEND_MM_ALIGNED_HEADER_SIZE, ZEND_MM_ALIGNED_FREE_HEADER_SIZE);
next_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
if (true_size <= mm_block->size) {
zend_mm_create_new_free_block(heap, mm_block, true_size);
if (next_block->type == ZEND_MM_FREE_BLOCK) {
zend_mm_block *new_next_block;
new_next_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
if (new_next_block != next_block) { /* A new free block was created */
zend_mm_remove_from_free_list(heap, (zend_mm_free_block *) new_next_block);
zend_mm_remove_from_free_list(heap, (zend_mm_free_block *) next_block);
new_next_block->size += next_block->size;
/* update the next block's prev_size */
ZEND_MM_BLOCK_AT(new_next_block, new_next_block->size)->prev_size = new_next_block->size;
zend_mm_add_to_free_list(heap, (zend_mm_free_block *) new_next_block);
}
}
return p;
}
if ((mm_block->prev_size == 0) && (next_block->type == ZEND_MM_USED_BLOCK) &&
(next_block->guard_block)) {
zend_mm_segment *segment = (zend_mm_segment *) ((char *)mm_block - ZEND_MM_ALIGNED_SEGMENT_SIZE);
zend_mm_segment *segment_copy = segment;
zend_mm_block *guard_block;
size_t realloc_to_size;
/* segment size, size of block and size of guard block */
realloc_to_size = ZEND_MM_ALIGNED_SEGMENT_SIZE+true_size+ZEND_MM_ALIGNED_HEADER_SIZE;
segment = realloc(segment, realloc_to_size);
if (!segment) {
return NULL;
}
if (segment != segment_copy) {
if (heap->segments_list == segment_copy) {
heap->segments_list = segment;
} else {
zend_mm_segment *seg = heap->segments_list;
while (seg) {
if (seg->next_segment == segment_copy) {
seg->next_segment = segment;
break;
}
seg = seg->next_segment;
}
}
mm_block = (zend_mm_block *) ((char *) segment + ZEND_MM_ALIGNED_SEGMENT_SIZE);
}
mm_block->size = true_size;
/* 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->guard_block = 1;
guard_block->prev_size = mm_block->size;
return ZEND_MM_DATA_OF(mm_block);
}
if (next_block->type != ZEND_MM_FREE_BLOCK || (mm_block->size + next_block->size < true_size)) {
void *ptr;
ptr = zend_mm_alloc(heap, size);
memcpy(ptr, p, mm_block->size - ZEND_MM_ALIGNED_HEADER_SIZE);
zend_mm_free(heap, p);
return ptr;
}
zend_mm_remove_from_free_list(heap, (zend_mm_free_block *) next_block);
mm_block->size += next_block->size;
/* update the next block's prev_size */
ZEND_MM_BLOCK_AT(mm_block, mm_block->size)->prev_size = mm_block->size;
zend_mm_create_new_free_block(heap, mm_block, true_size);
return p;
}
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* indent-tabs-mode: t
* End:
*/
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