``` <?php /** * This file is part of workerman. * * Licensed under The MIT License * For full copyright and license information, please see the MIT-LICENSE.txt * Redistributions of files must retain the above copyright notice. * * @author walkor<walkor@workerman.net> * @copyright walkor<walkor@workerman.net> * @link http://www.workerman.net/ * @license http://www.opensource.org/licenses/mit-license.php MIT License */ namespace Workerman\Protocols; use Workerman\Connection\TcpConnection; /** * Frame Protocol. */ class Frame { /** * Check the integrity of the package. * * @param string $buffer * @param TcpConnection $connection * @return int */ public static function input($buffer, TcpConnection $connection) { if (\strlen($buffer) < 4) { return 0; } $unpack_data = \unpack('Ntotal_length', $buffer); return $unpack_data['total_length']; } /** * Decode. * * @param string $buffer * @return string */ public static function decode($buffer) { return \substr($buffer, 4); } /** * Encode. * * @param string $buffer * @return string */ public static function encode($buffer) { $total_length = 4 + \strlen($buffer); return \pack('N', $total_length) . $buffer; } } ```