XCache is a fast, stable PHP opcode cacher that has been proven and is now running on production servers under high load. https://xcache.lighttpd.net/
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#define _xc_allocator_t _xc_allocator_bestfit_t
#define _xc_allocator_block_t _xc_allocator_bestfit_block_t
#include "xc_allocator.h"
#undef _xc_allocator_t
#undef _xc_allocator_block_t
#ifdef TEST
# include <limits.h>
# include <stdio.h>
# define XCACHE_DEBUG
typedef int zend_bool;
# define ZEND_ATTRIBUTE_PTR_FORMAT(a, b, c)
# define zend_error(type, error) fprintf(stderr, "%s", error)
#else
# include <php.h>
#endif
#ifdef XCACHE_DEBUG
# define ALLOC_DEBUG_BLOCK_CHECK
#endif
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "xc_shm.h"
#include "util/xc_align.h"
#include "util/xc_trace.h"
#if 0
#undef ALLOC_DEBUG_BLOCK_CHECK
#endif
#define CHAR_PTR(p) ((char *) (p))
#define PADD(p, a) (CHAR_PTR(p) + a)
#define PSUB(p1, p2) (CHAR_PTR(p1) - CHAR_PTR(p2))
/* {{{ allocator */
typedef struct _xc_allocator_bestfit_block_t xc_allocator_bestfit_block_t;
struct _xc_allocator_bestfit_block_t {
#ifdef ALLOC_DEBUG_BLOCK_CHECK
unsigned int magic;
#endif
xc_memsize_t size; /* reserved even after alloc */
xc_allocator_bestfit_block_t *next; /* not used after alloc */
};
typedef struct _xc_allocator_bestfit_t {
const xc_allocator_vtable_t *vtable;
xc_shm_t *shm;
xc_memsize_t size;
xc_memsize_t avail; /* total free */
xc_allocator_bestfit_block_t headblock[1]; /* just as a pointer to first block*/
} xc_allocator_bestfit_t;
#include <stddef.h>
#define SizeOf(type, field) sizeof( ((type *) 0)->field )
#define BLOCK_HEADER_SIZE() (ALIGN( offsetof(xc_allocator_bestfit_block_t, size) + SizeOf(xc_allocator_bestfit_block_t, size) ))
#define BLOCK_MAGIC ((unsigned int) 0x87655678)
/* }}} */
static inline void xc_block_setup(xc_allocator_bestfit_block_t *b, xc_memsize_t size, xc_allocator_bestfit_block_t *next) /* {{{ */
{
#ifdef ALLOC_DEBUG_BLOCK_CHECK
b->magic = BLOCK_MAGIC;
#endif
b->size = size;
b->next = next;
}
/* }}} */
#ifdef ALLOC_DEBUG_BLOCK_CHECK
static void xc_block_check(xc_allocator_bestfit_block_t *b) /* {{{ */
{
if (b->magic != BLOCK_MAGIC) {
fprintf(stderr, "0x%X != 0x%X magic wrong \n", b->magic, BLOCK_MAGIC);
}
}
/* }}} */
#else
# define xc_block_check(b) do { } while(0)
#endif
static XC_ALLOCATOR_MALLOC(xc_allocator_bestfit_malloc) /* {{{ */
{
xc_allocator_bestfit_block_t *prev, *cur;
xc_allocator_bestfit_block_t *newb, *b;
xc_memsize_t realsize;
xc_memsize_t minsize;
void *p;
/* [xc_allocator_bestfit_block_t:size|size] */
realsize = BLOCK_HEADER_SIZE() + size;
/* realsize is ALIGNed so next block start at ALIGNed address */
realsize = ALIGN(realsize);
TRACE("avail: %lu (%luKB). Allocate size: %lu realsize: %lu (%luKB)"
, allocator->avail, allocator->avail / 1024
, size
, realsize, realsize / 1024
);
do {
p = NULL;
if (allocator->avail < realsize) {
TRACE("%s", " oom");
break;
}
b = NULL;
minsize = ULONG_MAX;
/* prev|cur */
for (prev = allocator->headblock; prev->next; prev = cur) {
/* while (prev->next != 0) { */
cur = prev->next;
xc_block_check(cur);
if (cur->size == realsize) {
/* found a perfect fit, stop searching */
b = prev;
break;
}
/* make sure we can split on the block */
else if (cur->size > (sizeof(xc_allocator_bestfit_block_t) + realsize) &&
cur->size < minsize) {
/* cur is acceptable and memller */
b = prev;
minsize = cur->size;
}
prev = cur;
}
if (b == NULL) {
TRACE("%s", " no fit chunk");
break;
}
prev = b;
cur = prev->next;
p = PADD(cur, BLOCK_HEADER_SIZE());
/* update the block header */
allocator->avail -= realsize;
/* perfect fit, just unlink */
if (cur->size == realsize) {
prev->next = cur->next;
TRACE(" perfect fit. Got: %p", p);
break;
}
/* make new free block after alloced space */
/* save, as it might be overwrited by newb (cur->size is ok) */
b = cur->next;
/* prev|cur |next=b */
newb = (xc_allocator_bestfit_block_t *)PADD(cur, realsize);
xc_block_setup(newb, cur->size - realsize, b);
cur->size = realsize;
/* prev|cur|newb|next
* `--^
*/
TRACE(" -> avail: %lu (%luKB). new next: %p offset: %lu %luKB. Got: %p"
, allocator->avail, allocator->avail / 1024
, (void *) newb
, PSUB(newb, allocator), PSUB(newb, allocator) / 1024
, p
);
prev->next = newb;
/* prev|cur|newb|next
* `-----^
*/
} while (0);
return p;
}
/* }}} */
static XC_ALLOCATOR_FREE(xc_allocator_bestfit_free) /* {{{ return block size freed */
{
xc_allocator_bestfit_block_t *cur, *b;
int size;
cur = (xc_allocator_bestfit_block_t *) (CHAR_PTR(p) - BLOCK_HEADER_SIZE());
TRACE("freeing: %p, size=%lu", p, cur->size);
xc_block_check(cur);
assert((char*)allocator < (char*)cur);
assert((char*)cur < (char*)allocator + allocator->size);
/* find free block right before the p */
b = allocator->headblock;
while (b->next != 0 && b->next < cur) {
b = b->next;
}
/* restore block */
cur->next = b->next;
b->next = cur;
size = cur->size;
TRACE(" avail %lu (%luKB)", allocator->avail, allocator->avail / 1024);
allocator->avail += size;
/* combine prev|cur */
if (PADD(b, b->size) == (char *)cur) {
b->size += cur->size;
b->next = cur->next;
cur = b;
TRACE("%s", " combine prev");
}
/* combine cur|next */
b = cur->next;
if (PADD(cur, cur->size) == (char *)b) {
cur->size += b->size;
cur->next = b->next;
TRACE("%s", " combine next");
}
TRACE(" -> avail %lu (%luKB)", allocator->avail, allocator->avail / 1024);
return size;
}
/* }}} */
static XC_ALLOCATOR_CALLOC(xc_allocator_bestfit_calloc) /* {{{ */
{
xc_memsize_t realsize = memb * size;
void *p = xc_allocator_bestfit_malloc(allocator, realsize);
if (p) {
memset(p, 0, realsize);
}
return p;
}
/* }}} */
static XC_ALLOCATOR_REALLOC(xc_allocator_bestfit_realloc) /* {{{ */
{
void *newp = xc_allocator_bestfit_malloc(allocator, size);
if (p && newp) {
memcpy(newp, p, size);
xc_allocator_bestfit_free(allocator, p);
}
return newp;
}
/* }}} */
static XC_ALLOCATOR_AVAIL(xc_allocator_bestfit_avail) /* {{{ */
{
return allocator->avail;
}
/* }}} */
static XC_ALLOCATOR_SIZE(xc_allocator_bestfit_size) /* {{{ */
{
return allocator->size;
}
/* }}} */
static XC_ALLOCATOR_FREEBLOCK_FIRST(xc_allocator_bestfit_freeblock_first) /* {{{ */
{
return allocator->headblock->next;
}
/* }}} */
static XC_ALLOCATOR_FREEBLOCK_NEXT(xc_allocator_bestfit_freeblock_next) /* {{{ */
{
return block->next;
}
/* }}} */
static XC_ALLOCATOR_BLOCK_SIZE(xc_allocator_bestfit_block_size) /* {{{ */
{
return block->size;
}
/* }}} */
static XC_ALLOCATOR_BLOCK_OFFSET(xc_allocator_bestfit_block_offset) /* {{{ */
{
return ((char *) block) - ((char *) allocator);
}
/* }}} */
static XC_ALLOCATOR_INIT(xc_allocator_bestfit_init) /* {{{ */
{
xc_allocator_bestfit_block_t *b;
#define MINSIZE (ALIGN(sizeof(xc_allocator_bestfit_t)) + sizeof(xc_allocator_bestfit_block_t))
/* requires at least the header and 1 tail block */
if (size < MINSIZE) {
fprintf(stderr, "xc_allocator_bestfit_init requires %lu bytes at least\n", (unsigned long) MINSIZE);
return NULL;
}
TRACE("size=%lu", size);
allocator->shm = shm;
allocator->size = size;
allocator->avail = size - MINSIZE;
/* pointer to first block, right after ALIGNed header */
b = allocator->headblock;
xc_block_setup(b, 0, (xc_allocator_bestfit_block_t *) PADD(allocator, ALIGN(sizeof(xc_allocator_bestfit_t))));
/* first block*/
b = b->next;
xc_block_setup(b, allocator->avail, 0);
#undef MINSIZE
return allocator;
}
/* }}} */
static XC_ALLOCATOR_DESTROY(xc_allocator_bestfit_destroy) /* {{{ */
{
}
/* }}} */
static xc_allocator_vtable_t xc_allocator_bestfit = XC_ALLOCATOR_VTABLE(allocator_bestfit);
void xc_allocator_bestfit_register() /* {{{ */
{
if (xc_allocator_register("bestfit", &xc_allocator_bestfit) == 0) {
zend_error(E_ERROR, "XCache: failed to register allocator 'bestfit'");
}
}
/* }}} */