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深入PHP内核之in_array

时间：2015-11-10 12:17:38      阅读：190      评论：0      收藏：0      [点我收藏+]

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无意中看到一段代码

<?php                                                                                                                                                                                        
$y="1800";
$x = array();
for($j=0;$j<50000;$j++){
    $x[]= "{$j}";
}
 
for($i=0;$i<30000;$i++){
    if(in_array($y,$x)){
        continue;
    }   
}

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

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;
}        
/* }}} */

看一下is_equal_function

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;
}        
/* }}} */

继续跟踪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)<Z_LVAL_P(op2)?-1:0)); 
            return SUCCESS;
              
         case TYPE_PAIR(IS_DOUBLE, IS_LONG):
            Z_DVAL_P(result) = Z_DVAL_P(op1) - (double)Z_LVAL_P(op2);
            ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_DVAL_P(result)));
            return SUCCESS;
             
         case TYPE_PAIR(IS_LONG, IS_DOUBLE):
            Z_DVAL_P(result) = (double)Z_LVAL_P(op1) - Z_DVAL_P(op2);
            ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_DVAL_P(result)));
            return SUCCESS;
             
         case TYPE_PAIR(IS_DOUBLE, IS_DOUBLE):
            if (Z_DVAL_P(op1) == Z_DVAL_P(op2)) {
               ZVAL_LONG(result, 0);
            } else {
               Z_DVAL_P(result) = Z_DVAL_P(op1) - Z_DVAL_P(op2);
               ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_DVAL_P(result)));
            }
            return SUCCESS;
            
         case TYPE_PAIR(IS_ARRAY, IS_ARRAY):
            zend_compare_arrays(result, op1, op2 TSRMLS_CC);
            return SUCCESS;
            
         case TYPE_PAIR(IS_NULL, IS_NULL):
            ZVAL_LONG(result, 0);
            return SUCCESS;
            
         case TYPE_PAIR(IS_NULL, IS_BOOL):
            ZVAL_LONG(result, Z_LVAL_P(op2) ? -1 : 0);
            return SUCCESS;
             
         case TYPE_PAIR(IS_BOOL, IS_NULL):
            ZVAL_LONG(result, Z_LVAL_P(op1) ? 1 : 0);
            return SUCCESS;
             
         case TYPE_PAIR(IS_BOOL, IS_BOOL):
            ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_LVAL_P(op1) - Z_LVAL_P(op2)));
            return SUCCESS;
             
         case TYPE_PAIR(IS_STRING, IS_STRING):
            zendi_smart_strcmp(result, op1, op2);
            return SUCCESS;
             
         case TYPE_PAIR(IS_NULL, IS_STRING):
            ZVAL_LONG(result, zend_binary_strcmp("", 0, Z_STRVAL_P(op2), Z_STRLEN_P(op2)));
            return SUCCESS;
             
         case TYPE_PAIR(IS_STRING, IS_NULL):
            ZVAL_LONG(result, zend_binary_strcmp(Z_STRVAL_P(op1), Z_STRLEN_P(op1), "", 0));
            return SUCCESS;
             
         case TYPE_PAIR(IS_OBJECT, IS_NULL):
            ZVAL_LONG(result, 1);
            return SUCCESS;
             
         case TYPE_PAIR(IS_NULL, IS_OBJECT):
            ZVAL_LONG(result, -1);
            return SUCCESS;
             
         case TYPE_PAIR(IS_OBJECT, IS_OBJECT):
            /* If both are objects sharing the same comparision handler then use is */
            if (Z_OBJ_HANDLER_P(op1,compare_objects) == Z_OBJ_HANDLER_P(op2,compare_objects)) {
               if (Z_OBJ_HANDLE_P(op1) == Z_OBJ_HANDLE_P(op2)) {
                  /* object handles are identical, apparently this is the same object */
                  ZVAL_LONG(result, 0);
                  return SUCCESS;
               }
               ZVAL_LONG(result, Z_OBJ_HT_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;
            }
      }     
   }         
}             
/* }}} */

 

深入PHP内核之in_array

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原文地址：http://www.cnblogs.com/chenpingzhao/p/4935798.html
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