Convert Russian letters to Latin

Russian.php

<?php

/**
 * Converts Russian letters to Latin
 *
 * Usage:
 * <code>
 * Russian::transliterate('Привет, как дела?');
 * Russian::transliterateUrl('Привет, как дела?');
 * </code>
 *
 * @package default
 * @author Dmitri Smirnov
 */
class Russian
{
    /**
     * Converts text
     *
     * @param string $str 
     * @return string
     */
    public static function transliterate($str) 
    {
        $tr = array(
            "А"=>"A","Б"=>"B","В"=>"V","Г"=>"G",
            "Д"=>"D","Е"=>"E", "Ё"=>'E',"Ж"=>"J","З"=>"Z","И"=>"I",
            "Й"=>"Y","К"=>"K","Л"=>"L","М"=>"M","Н"=>"N",
            "О"=>"O","П"=>"P","Р"=>"R","С"=>"S","Т"=>"T",
            "У"=>"U","Ф"=>"F","Х"=>"H","Ц"=>"TS","Ч"=>"CH",
            "Ш"=>"SH","Щ"=>"SCH","Ъ"=>"","Ы"=>"YI","Ь"=>"",
            "Э"=>"E","Ю"=>"YU","Я"=>"YA","а"=>"a","б"=>"b",
            "в"=>"v","г"=>"g","д"=>"d","е"=>"e", "ё"=>"e","ж"=>"j",
            "з"=>"z","и"=>"i","й"=>"y","к"=>"k","л"=>"l",
            "м"=>"m","н"=>"n","о"=>"o","п"=>"p","р"=>"r",
            "с"=>"s","т"=>"t","у"=>"u","ф"=>"f","х"=>"h",
            "ц"=>"ts","ч"=>"ch","ш"=>"sh","щ"=>"sch","ъ"=>"y",
            "ы"=>"yi","ь"=>"","э"=>"e","ю"=>"yu","я"=>"ya"
        );
        return strtr($str,$tr);
    }
    
    /**
     * Convert to URL slug like 'skidki-na-tovaryi'
     *
     * @param string $urlstr 
     * @return string
     */
    public static function transliterateUrl($urlstr) {
        if (preg_match('/[^A-Za-z0-9_\-]/', $urlstr)) {
            $urlstr = self::transliterate($urlstr);
            $urlstr = preg_replace('/[^A-Za-z0-9]+/', '-', $urlstr);
        }
        return $urlstr;
    }
}