protected function convertEncoding(&$string, $toEncoding, $fromEncoding) {
		if($string && is_string($string) && $toEncoding != $fromEncoding) {
			static $isMbString;
			if($isMbString === null) {
				$isMbString = extension_loaded('mbstring');
			}
			if($isMbString) {
				$string = @mb_convert_encoding($string, $toEncoding, $fromEncoding) ? : $string;
			}
			else {
				$string = @iconv($fromEncoding, $toEncoding . '//IGNORE', $string) ? : $string;
			}
			if(!$string && $toEncoding == 'UTF-8') {
				$string = utf8_encode($string);
			}
		}
	}