public static function ConvertEncoding($value, $to, $from)
	{
		if (self::getIsMbstringEnabled()) {
			$value = mb_convert_encoding($value, $to, $from);
			return $value;
		}

		if (self::getIsIconvEnabled()) {
			$value = iconv($from, $to, $value);
			return $value;
		}

		// else, no conversion
		return $value;
	}