<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category  Zend

 * @package   Zend_TimeSync

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license   http://framework.zend.com/license/new-bsd     New BSD License

 * @version   $Id: Protocol.php 20096 2010-01-06 02:05:09Z bkarwin $

 */

/**

 * Abstract class definition for all timeserver protocols

 *

 * @category  Zend

 * @package   Zend_TimeSync

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license   http://framework.zend.com/license/new-bsd     New BSD License

 */

abstract class Zend_TimeSync_Protocol

{

    /**

     * Holds the current socket connection

     *

     * @var array

     */

    protected $_socket;

    /**

     * Exceptions that might have occured

     *

     * @var array

     */

    protected $_exceptions;

    /**

     * Hostname for timeserver

     *

     * @var string

     */

    protected $_timeserver;

    /**

     * Holds information passed/returned from timeserver

     *

     * @var array

     */

    protected $_info = array();

    /**

     * Abstract method that prepares the data to send to the timeserver

     *

     * @return mixed

     */

    abstract protected function _prepare();

    /**

     * Abstract method that reads the data returned from the timeserver

     *

     * @return mixed

     */

    abstract protected function _read();

    /**

     * Abstract method that writes data to to the timeserver

     *

     * @param  string $data Data to write

     * @return void

     */

    abstract protected function _write($data);

    /**

     * Abstract method that extracts the binary data returned from the timeserver

     *

     * @param  string|array $data Data returned from the timeserver

     * @return integer

     */

    abstract protected function _extract($data);

    /**

     * Connect to the specified timeserver.

     *

     * @return void

     * @throws Zend_TimeSync_Exception When the connection failed

     */

    protected function _connect()

    {

        $socket = @fsockopen($this->_timeserver, $this->_port, $errno, $errstr,

                             Zend_TimeSync::$options['timeout']);

        if ($socket === false) {

            throw new Zend_TimeSync_Exception('could not connect to ' .

                "'$this->_timeserver' on port '$this->_port', reason: '$errstr'");

        }

        $this->_socket = $socket;

    }

    /**

     * Disconnects from the peer, closes the socket.

     *

     * @return void

     */

    protected function _disconnect()

    {

        @fclose($this->_socket);

        $this->_socket = null;

    }

    /**

     * Return information sent/returned from the timeserver

     *

     * @return  array

     */

    public function getInfo()

    {

        if (empty($this->_info) === true) {

            $this->_write($this->_prepare());

            $timestamp = $this->_extract($this->_read());

        }

        return $this->_info;

    }

    /**

     * Query this timeserver without using the fallback mechanism

     *

     * @param  string|Zend_Locale $locale (Optional) Locale

     * @return Zend_Date

     */

    public function getDate($locale = null)

    {

        $this->_write($this->_prepare());

        $timestamp = $this->_extract($this->_read());

        $date = new Zend_Date($this, null, $locale);

        return $date;

    }

}