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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#ifdef TEST
#include <limits.h>
#include <stdio.h>
#else
#include <php.h>
#endif
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#define XC_MEMBLOCK_IMPL _xc_mem_block_t
#define XC_MEM_IMPL _xc_mem_mem_t
#include "xc_shm.h"
#include "align.h"
#ifdef TEST
# define ALLOC_DEBUG
#endif
#ifdef ALLOC_DEBUG
# define ALLOC_DEBUG_BLOCK_CHECK
#endif
#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))
/* {{{ mem */
struct _xc_mem_block_t {
#ifdef ALLOC_DEBUG_BLOCK_CHECK
unsigned int magic;
#endif
xc_memsize_t size; /* reserved even after alloc */
xc_block_t *next; /* not used after alloc */
};
struct _xc_mem_mem_t {
const xc_mem_handlers_t *handlers;
xc_shm_t *shm;
xc_memsize_t size;
xc_memsize_t avail; /* total free */
xc_block_t headblock[1]; /* just as a pointer to first block*/
};
#ifndef XtOffsetOf
# include <linux/stddef.h>
# define XtOffsetOf(s_type, field) offsetof(s_type, field)
#endif
#define SizeOf(type, field) sizeof( ((type *) 0)->field )
#define BLOCK_HEADER_SIZE() (ALIGN( XtOffsetOf(xc_block_t, size) + SizeOf(xc_block_t, size) ))
#define BLOCK_MAGIC ((unsigned int) 0x87655678)
/* }}} */
static inline void xc_block_setup(xc_block_t *b, xc_memsize_t size, xc_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_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_MEM_MALLOC(xc_mem_malloc) /* {{{ */
{
xc_block_t *prev, *cur;
xc_block_t *newb, *b;
xc_memsize_t realsize;
xc_memsize_t minsize;
void *p;
/* [xc_block_t:size|size] */
realsize = BLOCK_HEADER_SIZE() + size;
/* realsize is ALIGNed so next block start at ALIGNed address */
realsize = ALIGN(realsize);
#ifdef ALLOC_DEBUG
fprintf(stderr, "avail: %d (%dKB). Allocate size: %d realsize: %d (%dKB)"
, mem->avail, mem->avail / 1024
, size
, realsize, realsize / 1024
);
#endif
do {
p = NULL;
if (mem->avail < realsize) {
#ifdef ALLOC_DEBUG
fprintf(stderr, " oom\n");
#endif
break;
}
b = NULL;
minsize = INT_MAX;
/* prev|cur */
for (prev = mem->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_block_t) + realsize) &&
cur->size < minsize) {
/* cur is acceptable and memller */
b = prev;
minsize = cur->size;
}
prev = cur;
}
if (b == NULL) {
#ifdef ALLOC_DEBUG
fprintf(stderr, " no fit chunk\n");
#endif
break;
}
prev = b;
cur = prev->next;
p = PADD(cur, BLOCK_HEADER_SIZE());
/* update the block header */
mem->avail -= realsize;
/* perfect fit, just unlink */
if (cur->size == realsize) {
prev->next = cur->next;
#ifdef ALLOC_DEBUG
fprintf(stderr, " perfect fit. Got: %p\n", p);
#endif
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_block_t *)PADD(cur, realsize);
xc_block_setup(newb, cur->size - realsize, b);
cur->size = realsize;
/* prev|cur|newb|next
* `--^
*/
#ifdef ALLOC_DEBUG
fprintf(stderr, " -> avail: %d (%dKB). new next: %p offset: %d %dKB. Got: %p\n"
, mem->avail, mem->avail / 1024
, newb
, PSUB(newb, mem), PSUB(newb, mem) / 1024
, p
);
#endif
prev->next = newb;
/* prev|cur|newb|next
* `-----^
*/
} while (0);
return p;
}
/* }}} */
static XC_MEM_FREE(xc_mem_free) /* {{{ return block size freed */
{
xc_block_t *cur, *b;
int size;
cur = (xc_block_t *) (CHAR_PTR(p) - BLOCK_HEADER_SIZE());
#ifdef ALLOC_DEBUG
fprintf(stderr, "freeing: %p", p);
fprintf(stderr, ", size=%d", cur->size);
#endif
xc_block_check(cur);
assert((char*)mem < (char*)cur && (char*)cur < (char*)mem + mem->size);
/* find free block right before the p */
b = mem->headblock;
while (b->next != 0 && b->next < cur) {
b = b->next;
}
/* restore block */
cur->next = b->next;
b->next = cur;
size = cur->size;
#ifdef ALLOC_DEBUG
fprintf(stderr, ", avail %d (%dKB)", mem->avail, mem->avail / 1024);
#endif
mem->avail += size;
/* combine prev|cur */
if (PADD(b, b->size) == (char *)cur) {
b->size += cur->size;
b->next = cur->next;
cur = b;
#ifdef ALLOC_DEBUG
fprintf(stderr, ", combine prev");
#endif
}
/* combine cur|next */
b = cur->next;
if (PADD(cur, cur->size) == (char *)b) {
cur->size += b->size;
cur->next = b->next;
#ifdef ALLOC_DEBUG
fprintf(stderr, ", combine next");
#endif
}
#ifdef ALLOC_DEBUG
fprintf(stderr, " -> avail %d (%dKB)\n", mem->avail, mem->avail / 1024);
#endif
return size;
}
/* }}} */
static XC_MEM_CALLOC(xc_mem_calloc) /* {{{ */
{
xc_memsize_t realsize = memb * size;
void *p = xc_mem_malloc(mem, realsize);
if (p) {
memset(p, 0, realsize);
}
return p;
}
/* }}} */
static XC_MEM_REALLOC(xc_mem_realloc) /* {{{ */
{
void *newp = xc_mem_malloc(mem, size);
if (p && newp) {
memcpy(newp, p, size);
xc_mem_free(mem, p);
}
return newp;
}
/* }}} */
static XC_MEM_STRNDUP(xc_mem_strndup) /* {{{ */
{
void *p = xc_mem_malloc(mem, len + 1);
if (p) {
memcpy(p, str, len + 1);
}
return p;
}
/* }}} */
static XC_MEM_STRDUP(xc_mem_strdup) /* {{{ */
{
return xc_mem_strndup(mem, str, strlen(str));
}
/* }}} */
static XC_MEM_AVAIL(xc_mem_avail) /* {{{ */
{
return mem->avail;
}
/* }}} */
static XC_MEM_SIZE(xc_mem_size) /* {{{ */
{
return mem->size;
}
/* }}} */
static XC_MEM_FREEBLOCK_FIRST(xc_mem_freeblock_first) /* {{{ */
{
return mem->headblock->next;
}
/* }}} */
XC_MEM_FREEBLOCK_NEXT(xc_mem_freeblock_next) /* {{{ */
{
return block->next;
}
/* }}} */
XC_MEM_BLOCK_SIZE(xc_mem_block_size) /* {{{ */
{
return block->size;
}
/* }}} */
XC_MEM_BLOCK_OFFSET(xc_mem_block_offset) /* {{{ */
{
return ((char *) block) - ((char *) mem);
}
/* }}} */
static XC_MEM_INIT(xc_mem_init) /* {{{ */
{
xc_block_t *b;
#define MINSIZE (ALIGN(sizeof(xc_mem_t)) + sizeof(xc_block_t))
/* requires at least the header and 1 tail block */
if (size < MINSIZE) {
fprintf(stderr, "xc_mem_init requires %lu bytes at least\n", (unsigned long) MINSIZE);
return NULL;
}
mem->shm = shm;
mem->size = size;
mem->avail = size - MINSIZE;
/* pointer to first block, right after ALIGNed header */
b = mem->headblock;
xc_block_setup(b, 0, (xc_block_t *) PADD(mem, ALIGN(sizeof(xc_mem_t))));
/* first block*/
b = b->next;
xc_block_setup(b, mem->avail, 0);
#undef MINSIZE
return mem;
}
/* }}} */
static XC_MEM_DESTROY(xc_mem_destroy) /* {{{ */
{
}
/* }}} */
#ifdef TEST
/* {{{ */
#undef CHECK
#define CHECK(a, msg) do { if ((a) == NULL) { puts(msg); return -1; } } while (0)
#include <time.h>
int main()
{
int count = 0;
void *p;
void *memory;
xc_mem_t *mem;
void **ptrs;
int size, i;
#if 0
fprintf(stderr, "%s", "Input test size: ");
scanf("%d", &size);
#else
size = 100;
#endif
CHECK(memory = malloc(size), "OOM");
CHECK(ptrs = malloc(size * sizeof(void*)), "OOM");
CHECK(mem = xc_mem_init(memory, size), "Failed init memory allocator");
while ((p = xc_mem_malloc(mem, 1))) {
ptrs[count ++] = p;
}
fprintf(stderr, "count=%d, random freeing\n", count);
srandom(time(NULL));
while (count) {
i = (random() % count);
fprintf(stderr, "freeing %d: ", i);
xc_mem_free(mem, ptrs[i]);
ptrs[i] = ptrs[count - 1];
count --;
}
free(ptrs);
free(memory);
return 0;
}
/* }}} */
#endif
typedef struct {
const char *name;
const xc_mem_handlers_t *handlers;
} xc_mem_scheme_t;
static xc_mem_scheme_t xc_mem_schemes[10];
int xc_mem_scheme_register(const char *name, const xc_mem_handlers_t *handlers) /* {{{ */
{
int i;
for (i = 0; i < 10; i ++) {
if (!xc_mem_schemes[i].name) {
xc_mem_schemes[i].name = name;
xc_mem_schemes[i].handlers = handlers;
return 1;
}
}
return 0;
}
/* }}} */
const xc_mem_handlers_t *xc_mem_scheme_find(const char *name) /* {{{ */
{
int i;
for (i = 0; i < 10 && xc_mem_schemes[i].name; i ++) {
if (strcmp(xc_mem_schemes[i].name, name) == 0) {
return xc_mem_schemes[i].handlers;
}
}
return NULL;
}
/* }}} */
static xc_mem_handlers_t xc_mem_mem_handlers = XC_MEM_HANDLERS(mem);
void xc_shm_mem_init() /* {{{ */
{
memset(xc_mem_schemes, 0, sizeof(xc_mem_schemes));
if (xc_mem_scheme_register("mem", &xc_mem_mem_handlers) == 0) {
zend_error(E_ERROR, "XCache: failed to register mem mem_scheme");
}
}
/* }}} */