深入php内核之php in array
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; } } } } /* }}} */
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