<?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) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id$
*/

/**
* Abstract class definition for all timeserver protocols
*
* @category Zend
* @package Zend_TimeSync
* @copyright Copyright (c) 2005-2015 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;
}
}