深入PHP内核之in_array

无意中看到一段代码

测试了一下
[root@dev tmp]# time php b.php 

real    0m9.517s
user    0m4.486s
sys     0m0.015s
竟然需要9s
in_array是这个样子的
bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )
在 haystack 中搜索 needle，如果没有设置 strict 则使用宽松的比较。
needle
待搜索的值。如果 needle 是字符串，则比较是区分大小写的。
haystack
这个数组。
strict
如果第三个参数 strict 的值为 TRUE 则 in_array() 函数还会检查 needle 的类型是否和 haystack 中的相同。
那么我看一下源代码
第一步 在ext/standard/array.c 文件中
/* }}} */                                                      
                                                               
/* {{{ proto bool in_array(mixed needle, array haystack [, bool strict])
   Checks if the given value exists in the array */            
PHP_FUNCTION(in_array)                                         
{                                                              
    php_search_array(INTERNAL_FUNCTION_PARAM_PASSTHRU, 0);     
}                                                              
/* }}} */                                                      
                                                               
/* {{{ proto mixed array_search(mixed needle, array haystack [, bool strict])
   Searches the array for a given value and returns the corresponding key if successful */
PHP_FUNCTION(array_search)                                     
{                                                              
    php_search_array(INTERNAL_FUNCTION_PARAM_PASSTHRU, 1);     
}                                                              
/* }}} */  
顺便看到了array_search，原来和in_array的内部实现基本一致
其中函数的参数 在./zend.h中
#define INTERNAL_FUNCTION_PARAM_PASSTHRU ht, return_value, return_value_ptr, this_ptr, return_value_used TSRMLS_CC
第二步 在ext/standard/array.c 文件中 查看php_search_array原型
/* void php_search_array(INTERNAL_FUNCTION_PARAMETERS, int behavior)
 * 0 = return boolean
 * 1 = return key
 */      
static void php_search_array(INTERNAL_FUNCTION_PARAMETERS, int behavior) /* {{{ */
{        
    zval *value,            /* value to check for */
         *array,            /* array to check in */
         **entry,           /* pointer to array entry */
         res;              /* comparison result */
    HashPosition pos;        /* hash iterator */
    zend_bool strict = 0;     /* strict comparison or not */
    ulong num_key;
    uint str_key_len;
    char *string_key;
    int (*is_equal_func)(zval *, zval *, zval * TSRMLS_DC) = is_equal_function;
         
    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "za|b", &value, &array, &strict) == FAILURE) {
        return;
    }    
         
    if (strict) {
        is_equal_func = is_identical_function;
    }    
         
    zend_hash_internal_pointer_reset_ex(Z_ARRVAL_P(array), &pos);
    while (zend_hash_get_current_data_ex(Z_ARRVAL_P(array), (void **)&entry, &pos) == SUCCESS) {
        is_equal_func(&res, value, *entry TSRMLS_CC);
        if (Z_LVAL(res)) {
            if (behavior == 0) {
                RETURN_TRUE;
            } else {
                /* Return current key */
                switch (zend_hash_get_current_key_ex(Z_ARRVAL_P(array), &string_key, &str_key_len, &num_key, 0, &pos)) {
                    case HASH_KEY_IS_STRING:
                        RETURN_STRINGL(string_key, str_key_len - 1, 1);
                        break;
                    case HASH_KEY_IS_LONG:
                        RETURN_LONG(num_key);
                        break;
                }
            }
        }
        zend_hash_move_forward_ex(Z_ARRVAL_P(array), &pos);
    }    
         
    RETURN_FALSE;
}        
/* }}} */
         
/* {{{ proto bool in_array(mixed needle, array haystack [, bool strict])
   Checks if the given value exists in the array */
我们发现 strict  这个值的不同有两种比较方式，看一下两个函数的不同之处
is_identical_function 检查类型是否相同
ZEND_API int is_identical_function(zval *result, zval *op1, zval *op2 TSRMLS_DC) /* {{{ */
{        
   Z_TYPE_P(result) = IS_BOOL;
   if (Z_TYPE_P(op1) != Z_TYPE_P(op2)) {
      Z_LVAL_P(result) = 0;
      return SUCCESS;
   }    
   switch (Z_TYPE_P(op1)) {
      case IS_NULL:
         Z_LVAL_P(result) = 1;
         break;
      case IS_BOOL:
      case IS_LONG:
      case IS_RESOURCE:
         Z_LVAL_P(result) = (Z_LVAL_P(op1) == Z_LVAL_P(op2));
         break;
      case IS_DOUBLE:
         Z_LVAL_P(result) = (Z_DVAL_P(op1) == Z_DVAL_P(op2));
         break;
      case IS_STRING:
         Z_LVAL_P(result) = ((Z_STRLEN_P(op1) == Z_STRLEN_P(op2))
            && (!memcmp(Z_STRVAL_P(op1), Z_STRVAL_P(op2), Z_STRLEN_P(op1))));
         break;
      case IS_ARRAY:
         Z_LVAL_P(result) = (Z_ARRVAL_P(op1) == Z_ARRVAL_P(op2) 
            zend_hash_compare(Z_ARRVAL_P(op1), Z_ARRVAL_P(op2), (compare_func_t) hash_zval_identical_function, 1 TSRMLS_CC)==0);
         break;
      case IS_OBJECT:
         if (Z_OBJ_HT_P(op1) == Z_OBJ_HT_P(op2)) {
            Z_LVAL_P(result) = (Z_OBJ_HANDLE_P(op1) == Z_OBJ_HANDLE_P(op2));
         } else {
            Z_LVAL_P(result) = 0;
         }
         break;
      default:
         Z_LVAL_P(result) = 0;
         return FAILURE;
   }    
   return SUCCESS;
}        
/* }}} */
is_equal_function 不检查类型是否相同，所以需要隐式转换
ZEND_API int is_equal_function(zval *result, zval *op1, zval *op2 TSRMLS_DC) /* {{{ */
{        
   if (compare_function(result, op1, op2 TSRMLS_CC) == FAILURE) {
      return FAILURE;
   }    
   ZVAL_BOOL(result, (Z_LVAL_P(result) == 0));
   return SUCCESS;
}        
/* }}} */
==》compare_function
ZEND_API int compare_function(zval *result, zval *op1, zval *op2 TSRMLS_DC) /* {{{ */
{            
   int ret; 
   int converted = 0;
   zval op1_copy, op2_copy;
   zval *op_free;
             
   while (1) {
      switch (TYPE_PAIR(Z_TYPE_P(op1), Z_TYPE_P(op2))) {
         case TYPE_PAIR(IS_LONG, IS_LONG):
            ZVAL_LONG(result, Z_LVAL_P(op1)>Z_LVAL_P(op2)?1:(Z_LVAL_P(op1)compare_objects(op1, op2 TSRMLS_CC));
               return SUCCESS;
            }
            /* break missing intentionally */
             
         default:
            if (Z_TYPE_P(op1) == IS_OBJECT) {
               if (Z_OBJ_HT_P(op1)->get) {
                  op_free = Z_OBJ_HT_P(op1)->get(op1 TSRMLS_CC);
                  ret = compare_function(result, op_free, op2 TSRMLS_CC);
                  zend_free_obj_get_result(op_free TSRMLS_CC);
                  return ret;
               } else if (Z_TYPE_P(op2) != IS_OBJECT && Z_OBJ_HT_P(op1)->cast_object) {
                  ALLOC_INIT_ZVAL(op_free);
                  if (Z_OBJ_HT_P(op1)->cast_object(op1, op_free, Z_TYPE_P(op2) TSRMLS_CC) == FAILURE) {
                     ZVAL_LONG(result, 1);
                     zend_free_obj_get_result(op_free TSRMLS_CC);
                     return SUCCESS;
                  }
                  ret = compare_function(result, op_free, op2 TSRMLS_CC);
                  zend_free_obj_get_result(op_free TSRMLS_CC);
                  return ret;
               }
            }
            if (Z_TYPE_P(op2) == IS_OBJECT) {
               if (Z_OBJ_HT_P(op2)->get) {
                  op_free = Z_OBJ_HT_P(op2)->get(op2 TSRMLS_CC);
                  ret = compare_function(result, op1, op_free TSRMLS_CC);
                  zend_free_obj_get_result(op_free TSRMLS_CC);
                  return ret;
               } else if (Z_TYPE_P(op1) != IS_OBJECT && Z_OBJ_HT_P(op2)->cast_object) {
                  ALLOC_INIT_ZVAL(op_free);
                  if (Z_OBJ_HT_P(op2)->cast_object(op2, op_free, Z_TYPE_P(op1) TSRMLS_CC) == FAILURE) {
                     ZVAL_LONG(result, -1);
                     zend_free_obj_get_result(op_free TSRMLS_CC);
                     return SUCCESS;
                  }
                  ret = compare_function(result, op1, op_free TSRMLS_CC);
                  zend_free_obj_get_result(op_free TSRMLS_CC);
                  return ret;
               } else if (Z_TYPE_P(op1) == IS_OBJECT) {
                  ZVAL_LONG(result, 1);
                  return SUCCESS;
               }
            }
            if (!converted) {
               if (Z_TYPE_P(op1) == IS_NULL) {
                  zendi_convert_to_boolean(op2, op2_copy, result);
                  ZVAL_LONG(result, Z_LVAL_P(op2) ? -1 : 0);
                  return SUCCESS;
               } else if (Z_TYPE_P(op2) == IS_NULL) {
                  zendi_convert_to_boolean(op1, op1_copy, result);
                  ZVAL_LONG(result, Z_LVAL_P(op1) ? 1 : 0);
                  return SUCCESS;
               } else if (Z_TYPE_P(op1) == IS_BOOL) {
                  zendi_convert_to_boolean(op2, op2_copy, result);
                  ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_LVAL_P(op1) - Z_LVAL_P(op2)));
                  return SUCCESS;
               } else if (Z_TYPE_P(op2) == IS_BOOL) {
                  zendi_convert_to_boolean(op1, op1_copy, result);
                  ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_LVAL_P(op1) - Z_LVAL_P(op2)));
                  return SUCCESS;
               } else {
                  zendi_convert_scalar_to_number(op1, op1_copy, result);
                  zendi_convert_scalar_to_number(op2, op2_copy, result);
                  converted = 1;
               }
            } else if (Z_TYPE_P(op1)==IS_ARRAY) {
               ZVAL_LONG(result, 1);
               return SUCCESS;
            } else if (Z_TYPE_P(op2)==IS_ARRAY) {
               ZVAL_LONG(result, -1);
               return SUCCESS;
            } else if (Z_TYPE_P(op1)==IS_OBJECT) {
               ZVAL_LONG(result, 1);
               return SUCCESS;
            } else if (Z_TYPE_P(op2)==IS_OBJECT) {
               ZVAL_LONG(result, -1);
               return SUCCESS;
            } else {
               ZVAL_LONG(result, 0);
               return FAILURE;
            }
      }     
   }         
}             
/* }}} */ 

                
                
                

                    以上就介绍了深入PHP内核之in_array，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。