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ock(&used_memory_mutex); \
used_memory += (__n); \
pthread_mutex_unlock(&used_memory_mutex); \
} while(0)
#define update_zmalloc_stat_sub(__n) do { \
pthread_mutex_lock(&used_memory_mutex); \
used_memory -= (__n); \
pthread_mutex_unlock(&used_memory_mutex); \
} while(0)
#endif
//__n是分配的内存字节，更新used_memory的值，注意long型对齐
#define update_zmalloc_stat_alloc(__n) do { \
size_t _n = (__n); \
if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \ //分配字节不到long型的整数倍增加至整数倍
if (zmalloc_thread_safe) { \ //线程安全模式
update_zmalloc_stat_add(_n); \
} else { \ //非线程安全模式
used_memory += _n; \
} \
} while(0)
//__n是释放的内存字节，更新used_memory的值，注意long型对齐
#define update_zmalloc_stat_free(__n) do { \
size_t _n = (__n); \
if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
if (zmalloc_thread_safe) { \
update_zmalloc_stat_sub(_n); \
} else { \
used_memory -= _n; \
} \
} while(0)
static size_t used_memory = 0; //初始时总共使用内存空间为0
static int zmalloc_thread_safe = 0; //默认不启动线程安全模式
pthread_mutex_t used_memory_mutex = PTHREAD_MUTEX_INITIALIZER; //定义并初始化一个互斥量
//内存不足默认处理函数
static void zmalloc_default_oom(size_t size) {
fprintf(stderr, "zmalloc: Out of memory trying to allocate %zu bytes\n",
size);
fflush(stderr);
abort();
}
//内存不足处理函数指针，初始为默认函数
static void (*zmalloc_oom_handler)(size_t) = zmalloc_default_oom;
//malloc实现内存申请函数
void *zmalloc(size_t size) {
void *ptr = malloc(size+PREFIX_SIZE);
if (!ptr) zmalloc_oom_handler(size); //申请失败调用内存不足处理函数，终止程序
#ifdef HAVE_MALLOC_SIZE //tc_malloc,je_malloc,Mac平台
update_zmalloc_stat_alloc(zmalloc_size(ptr));
return ptr;
#else //其他平台
*((size_t*)ptr) = size;
update_zmalloc_stat_alloc(size+PREFIX_SIZE);
return (char*)ptr+PREFIX_SIZE;
#endif
}
//calloc实现内存释放函数
void *zcalloc(size_t size) {
void *ptr = calloc(1, size+PREFIX_SIZE);
if (!ptr) zmalloc_oom_handler(size);
#ifdef HAVE_MALLOC_SIZE
update_zmalloc_stat_alloc(zmalloc_size(ptr));
return ptr;
#else
*((size_t*)ptr) = size;
update_zmalloc_stat_alloc(size+PREFIX_SIZE);
return (char*)ptr+PREFIX_SIZE;
#endif
}
void *zrealloc(void *ptr, size_t size) {
#ifndef HAVE_MALLOC_SIZE
void *realptr;
#endif
size_t oldsize;
void *newptr;
if (ptr == NULL) return zmalloc(size);
#ifdef HAVE_MALLOC_SIZE
oldsize = zmalloc_size(ptr);
newptr = realloc(ptr,size);
if (!newptr) zmalloc_oom_handler(size);
update_zmalloc_stat_free(oldsize);
update_zmalloc_stat_alloc(zmalloc_size(newptr));
return newptr;
#else
realptr = (char*)ptr-PREFIX_SIZE;
oldsize = *((size_t*)realptr);
newptr = realloc(realptr,size+PREFIX_SIZE);
if (!newptr) zmalloc_oom_handler(size);
*((size_t*)newptr) = size;
update_zmalloc_stat_free(oldsize);
update_zmalloc_stat_alloc(size);
return (char*)newptr+PREFIX_SIZE;
#endif
}
/* Provide zmalloc_size() for systems where this function is not provided by
* malloc itself, given that in that case we store a header with this
* information as the first bytes of every allocation. */
#ifndef HAVE_MALLOC_SIZE
size_t zmalloc_size(void *ptr) {
void *realptr = (char*)ptr-PREFIX_SIZE;
size_t size = *((size_t*)realptr);
/* Assume at least that all the allocations are padded at sizeof(long) by
* the underlying allocator. */
//假设所有分配器分配时均使用long型对齐
if (size&(sizeof(long)-1)) size += sizeof(long)-(size&(sizeof(lon |