<?php

/*	EPP Client class for PHP, Copyright 2005 CentralNic Ltd
	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/**
* Low-level functions useful for both EPP clients and servers
* @package Net_EPP
* @version 0.0.4
* @author Gavin Brown <gavin.brown@nospam.centralnic.com>
* @revision $Id: Protocol.php,v 1.4 2011/06/28 09:48:02 gavin Exp $
*/

require_once('PEAR.php');

/**
* Low-level functions useful for both EPP clients and servers
* @package Net_EPP
*/
class Net_EPP_Protocol {

	static function _fread_nb($socket,$length) {
		$result = '';

		// Loop reading and checking info to see if we hit timeout
		$info = stream_get_meta_data($socket);
		while (!$info['timed_out'] && !feof($socket)) {
			// Try read remaining data from socket
			$buffer = @fread($socket,$length - strlen($result));
			// If the buffer actually contains something then add it to the result
			if ($buffer !== false) {
				$result .= $buffer;
				// If we hit the length we looking for, break
				if (strlen($result) == $length) {
					break;
				}
			} else {
				// Sleep 0.25s
	       	 		usleep(2500);
			}
			// Update metadata
			$info = stream_get_meta_data($socket);
		}

		// Check for timeout
		if ($info['timed_out']) {
			return new PEAR_Error('Timeout while reading data from socket');
		}

		return $result;
	}

	/**
	* get an EPP frame from the remote peer
	* @param resource $socket a socket connected to the remote peer
	* @return PEAR_Error|string either an error or a string
	*/
	static function getFrame($socket) {
		// Read header
		if (PEAR::isError($hdr = Net_EPP_Protocol::_fread_nb($socket,4))) {
	       		return $hdr;
		}

		// Unpack first 4 bytes which is our length
		$unpacked = unpack('N', $hdr);
		$length = $unpacked[1];
		if ($length < 5) {
			return new PEAR_Error(sprintf('Got a bad frame header length of %d bytes from peer', $length));

		} else {
			$length -= 4; // discard the length of the header itself
			// Read frame
			return Net_EPP_Protocol::_fread_nb($socket,$length);
		}
	}

	/**
	* send an EPP frame to the remote peer
	* @param resource $socket a socket connected to the remote peer
	* @param string $xml the XML to send
	*/
	static function sendFrame($socket, $xml) {
		// Grab XML length & add on 4 bytes for the counter
		$length = strlen($xml) + 4;
		$res = fwrite($socket, pack('N',$length) . $xml);
		// Check our write matches
		if ($length != $res) {
			return new PEAR_Error("Short write when sending XML");
		}

		return $res;
	}
}