php内核之数组

1、zend_hash_num_elements 获取数组元素个数。宏定义如下：

 #define zend_hash_num_elements(ht) \
     (ht)->nNumOfElements

2、ZEND_HASH_FOREACH_KEY_VAL 遍历数组键值。使用方法：

 ZEND_HASH_FOREACH_KEY_VAL(Z_ARRVAL_P(array), num_key, string_key, entry) {
             // code
 } ZEND_HASH_FOREACH_END();

　ZEND_HASH_FOREACH_KEY_VAL是个宏函数：

 #define ZEND_HASH_FOREACH_KEY_VAL(ht, _h, _key, _val) \
     ZEND_HASH_FOREACH(ht, ); \
     _h = _p->h; \
     _key = _p->key; \
     _val = _z;

　  继续展开 ZEND_HASH_FOREACH：

 #define ZEND_HASH_FOREACH(_ht, indirect) do { \
         Bucket *_p = (_ht)->arData; \
         Bucket *_end = _p + (_ht)->nNumUsed; \
         for (; _p != _end; _p++) { \
             zval *_z = &_p->val; \
             if (indirect && Z_TYPE_P(_z) == IS_INDIRECT) { \
                 _z = Z_INDIRECT_P(_z); \
             } \
             if (UNEXPECTED(Z_TYPE_P(_z) == IS_UNDEF)) continue;

ZEND_HASH_FOREACH_END展开：

 #define ZEND_HASH_FOREACH_END() \
         } \
     } while ()

ZEND_HASH_FOREACH_KEY_VAL(Z_ARRVAL_P(array), num_key, string_key, entry) {
             // code
} ZEND_HASH_FOREACH_END();
完全展开：

 do {
     Bucket *_p = (_ht)->arData;  // Z_ARRVAL_P(array) ---> ht ---> _ht
     Bucket *_end = _p + (_ht)->nNumUsed;  // 起始地址+偏移地址
     for (; _p != _end; _p++) {
         zval *_z = &_p->val;
         if (indirect && Z_TYPE_P(_z) == IS_INDIRECT) {
             _z = Z_INDIRECT_P(_z);
         }
         if (UNEXPECTED(Z_TYPE_P(_z) == IS_UNDEF)) continue;
         _h = _p->h;  // zend_ulong num_key ---> _h
         _key = _p->key; // zend_string *string_key ---> _key
         _val = _z; // zval *entry ---> _val
         {
            //code
         }
     }
 } while ()