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深入php內核之php in array

編輯：PHP綜合

先給大家介紹php in array函數基本知識熱熱身。

定義和用法

in_array() 函數在數組中搜索給定的值。

語法
in_array(value,array,type)

參數描述 value 必需。規定要在數組搜索的值。 array 必需。規定要搜索的數組。 type 可選。如果設置該參數為 true，則檢查搜索的數據與數組的值的類型是否相同。

說明

如果給定的值 value 存在於數組 array 中則返回 true。如果第三個參數設置為 true，函數只有在元素存在於數組中且數據類型與給定值相同時才返回 true。

如果沒有在數組中找到參數，函數返回 false。

注釋：如果 value 參數是字符串，且 type 參數設置為 true，則搜索區分大小寫。

無意中看到一段代碼

<?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;
 } 
}

測試了一下

[root@dev tmp]# time php b.php
real    0m9.517s
user    0m4.486s
sys     0m0.015s

竟然需要9s

in_array是這個樣子的

復制代碼代碼如下:
bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )

在 haystack 中搜索 needle，如果沒有設置 strict 則使用寬松的比較。

needle

待搜索的值。如果 needle 是字符串，則比較是區分大小寫的。

haystack

這個數組。

strict

如果第三個參數 strict 的值為 TRUE 則 in_array() 函數還會檢查 needle 的類型是否和 haystack 中的相同。

那麼我看一下源代碼

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); 
}                
/* }}} */

順便看到了array_search，原來和in_array的內部實現基本一致

其中函數的參數在./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 */

我們發現 strict 這個值的不同有兩種比較方式，看一下兩個函數的不同之處

is_identical_function 檢查類型是否相同

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 不檢查類型是否相同，所以需要隱式轉換

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)<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;
   }
  } 
 }  
}   
/* }}} */