CodeIgniter 核心代码阅读-Utf8转码文件Utf8.php

Utf8.php--Utf8转码文件

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');class CI_Utf8 {function __construct(){log_message('debug', "Utf8 Class Initialized");global $CFG;if (preg_match('/./u', '茅') === 1// PCRE must support UTF-8AND function_exists('iconv')// iconv must be installedAND ini_get('mbstring.func_overload') != 1// Multibyte string function overloading cannot be enabledAND $CFG->item('charset') == 'UTF-8'// Application charset must be UTF-8){log_message('debug', "UTF-8 Support Enabled");define('UTF8_ENABLED', TRUE);// set internal encoding for multibyte string functions if necessary// and set a flag so we don't have to repeatedly use extension_loaded()// or function_exists()if (extension_loaded('mbstring')){define('MB_ENABLED', TRUE);mb_internal_encoding('UTF-8');}else{define('MB_ENABLED', FALSE);}}else{log_message('debug', "UTF-8 Support Disabled");define('UTF8_ENABLED', FALSE);}}function clean_string($str){if ($this->_is_ascii($str) === FALSE){$str = @iconv('UTF-8', 'UTF-8//IGNORE', $str);}return $str;}function safe_ascii_for_xml($str){return remove_invisible_characters($str, FALSE);}function convert_to_utf8($str, $encoding){if (function_exists('iconv')){$str = @iconv($encoding, 'UTF-8', $str);}elseif (function_exists('mb_convert_encoding')){$str = @mb_convert_encoding($str, 'UTF-8', $encoding);}else{return FALSE;}return $str;}function _is_ascii($str){return (preg_match('/[^\x00-\x7F]/S', $str) == 0);}}