深入php内核之php in array

先给大家介绍phpinarray函数基本知识热热身。定义和用法in_array()函数在数组中搜索给定的值

先给大家介绍php in array函数基本知识热热身。

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)

参数	描述
value	必需。规定要在数组搜索的值。
array	必需。规定要搜索的数组。
type	可选。如果设置该参数为 true，则检查搜索的数据与数组的值的类型是否相同。

 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

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)<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 php_in_array