Clear Vietnamese signs by PHP

StringUtil.php

<?php

class StringUtils
{
  static $unicode = array(
        'a'=>'á|à|ả|ã|ạ|ă|ắ|ặ|ằ|ẳ|ẵ|â|ấ|ầ|ẩ|ẫ|ậ',
        'd'=>'đ',
        'e'=>'é|è|ẻ|ẽ|ẹ|ê|ế|ề|ể|ễ|ệ',
        'i'=>'í|ì|ỉ|ĩ|ị',
        'o'=>'ó|ò|ỏ|õ|ọ|ô|ố|ồ|ổ|ỗ|ộ|ơ|ớ|ờ|ở|ỡ|ợ',
        'u'=>'ú|ù|ủ|ũ|ụ|ư|ứ|ừ|ử|ữ|ự',
        'y'=>'ý|ỳ|ỷ|ỹ|ỵ',
        'A'=>'Á|À|Ả|Ã|Ạ|Ă|Ắ|Ặ|Ằ|Ẳ|Ẵ|Â|Ấ|Ầ|Ẩ|Ẫ|Ậ',
        'D'=>'Đ',
        'E'=>'É|È|Ẻ|Ẽ|Ẹ|Ê|Ế|Ề|Ể|Ễ|Ệ',
        'I'=>"Í|Ì|Ỉ|Ĩ|Ị",
        'O'=>"Ó|Ò|Ỏ|Õ|Ọ|Ô|Ố|Ồ|Ổ|Ỗ|Ộ|Ơ|Ớ|Ờ|Ở|Ỡ|Ợ",
        'U'=>'Ú|Ù|Ủ|Ũ|Ụ|Ư|Ứ|Ừ|Ử|Ữ|Ự',
        'Y'=>'Ý|Ỳ|Ỷ|Ỹ|Ỵ',
    );
    
    /**
     * Clear Vietnamese's signs from string
     * @param $str string
     * @return string The result string without Vietnamese's signs
     */
    public static function clearStrVnSigns ($str){
        //mb_internal_encoding('UTF-8');
        foreach(static::$unicode as $nonUnicode=>$uni){
            $str = preg_replace("/($uni)/u", $nonUnicode, $str);
        }
        return $str;
    }
}