深入php内核之phpinarray_php实例

定义和用法

in_array() 函数在数组中搜索给定的值。

语法
in_array(value,array,type)

说明

如果给定的值 value 存在于数组 array 中则返回 true。如果第三个参数设置为 true，函数只有在元素存在于数组中且数据类型与给定值相同时才返回 true。

如果没有在数组中找到参数，函数返回 false。

注释：如果 value 参数是字符串，且 type 参数设置为 true，则搜索区分大小写。

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

代码如下:
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;
   }
  } 
 }  
}   
/* }}} */