/system/utf8/rtrim.php

<?php
/**
 * This file is part of the Yet Another PHP Framework package.
 * (c) 2010 Adrian Videnie <{@link mailto:avidenie@gmail.com avidenie@gmail.com}>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * @package    Framework
 * @subpackage I18n
 * @author     Adrian Videnie <avidenie@gmail.com>
 * @copyright  2010 Adrian Videnie
 * @license    http://www.opensource.org/licenses/mit-license.php The MIT license
 */

/**
 * Multi-byte aware version of rtrim native PHP function.
 *
 * @see    http://php.net/rtrim
 * @author Andreas Gohr <andi@splitbrain.org>
 *
 * @param  string The input string.
 * @param  string The list of characters you want to strip.
 * @return string
 */
function _rtrim($str, $charlist = null)
{
    if (null === $charlist) {
        return rtrim($str);
    }

    if (Utf8::isAscii($charlist)) {
        return rtrim($str, $charlist);
    }

    $charlist = preg_replace('#[-\[\]:\\\\^/]#', '\\\\$0', $charlist);
    return preg_replace('/['.$charlist.']++$/uD', '', $str);
}