<?php
/**********************************************************\
 |                                                          |
 | The implementation of PHPRPC Protocol 3.0                |
 |                                                          |
 | xxtea.php                                                |
 |                                                          |
 | Release 3.0.1                                            |
 | Copyright by Team-PHPRPC                                 |
 |                                                          |
 | WebSite:  http://www.phprpc.org/                         |
 |           http://www.phprpc.net/                         |
 |           http://www.phprpc.com/                         |
 |           http://sourceforge.net/projects/php-rpc/       |
 |                                                          |
 | Authors:  Ma Bingyao <andot@ujn.edu.cn>                  |
 |                                                          |
 | This file may be distributed and/or modified under the   |
 | terms of the GNU General Public License (GPL) version    |
 | 2.0 as published by the Free Software Foundation and     |
 | appearing in the included file LICENSE.                  |
 |                                                          |
 \**********************************************************/

/* XXTEA encryption arithmetic library.
 *
 * Copyright: Ma Bingyao <andot@ujn.edu.cn>
 * Version: 1.6
 * LastModified: Apr 12, 2010
 * This library is free.  You can redistribute it and/or modify it under GPL.
 */
if (!extension_loaded('xxtea')) {
	function long2str($v, $w) {
		$len = count($v);
		$n = ($len - 1) << 2;
		if ($w) {
			$m = $v[$len - 1];
			if (($m < $n - 3) || ($m > $n)) return false;
			$n = $m;
		}
		$s = array();
		for ($i = 0; $i < $len; $i++) {
			$s[$i] = pack("V", $v[$i]);
		}
		if ($w) {
			return substr(join('', $s), 0, $n);
		}
		else {
			return join('', $s);
		}
	}

	function str2long($s, $w) {
		$v = unpack("V*", $s. str_repeat("\0", (4 - strlen($s) % 4) & 3));
		$v = array_values($v);
		if ($w) {
			$v[count($v)] = strlen($s);
		}
		return $v;
	}

	function int32($n) {
		while ($n >= 2147483648) $n -= 4294967296;
		while ($n <= -2147483649) $n += 4294967296;
		return (int)$n;
	}

	function xxtea_encrypt($str, $key) {
		if ($str == "") {
			return "";
		}
		$v = str2long($str, true);
		$k = str2long($key, false);
		if (count($k) < 4) {
			for ($i = count($k); $i < 4; $i++) {
				$k[$i] = 0;
			}
		}
		$n = count($v) - 1;

		$z = $v[$n];
		$y = $v[0];
		$delta = 0x9E3779B9;
		$q = floor(6 + 52 / ($n + 1));
		$sum = 0;
		while (0 < $q--) {
			$sum = int32($sum + $delta);
			$e = $sum >> 2 & 3;
			for ($p = 0; $p < $n; $p++) {
				$y = $v[$p + 1];
				$mx = int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
				$z = $v[$p] = int32($v[$p] + $mx);
			}
			$y = $v[0];
			$mx = int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
			$z = $v[$n] = int32($v[$n] + $mx);
		}
		return long2str($v, false);
	}

	function xxtea_decrypt($str, $key) {
		if ($str == "") {
			return "";
		}
		$v = str2long($str, false);
		$k = str2long($key, false);
		if (count($k) < 4) {
			for ($i = count($k); $i < 4; $i++) {
				$k[$i] = 0;
			}
		}
		$n = count($v) - 1;

		$z = $v[$n];
		$y = $v[0];
		$delta = 0x9E3779B9;
		$q = floor(6 + 52 / ($n + 1));
		$sum = int32($q * $delta);
		while ($sum != 0) {
			$e = $sum >> 2 & 3;
			for ($p = $n; $p > 0; $p--) {
				$z = $v[$p - 1];
				$mx = int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
				$y = $v[$p] = int32($v[$p] - $mx);
			}
			$z = $v[$n];
			$mx = int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
			$y = $v[0] = int32($v[0] - $mx);
			$sum = int32($sum - $delta);
		}
		return long2str($v, true);
	}
}
?>