PHP Decode

<?php 
/* XXTEA encryption arithmetic library. 
* 
* Copyright (C) 2006 Ma Bingyao <[email protected]> 
* Version:      1.5 
* LastModified: Dec 5, 2006 
* This library is free.  You can redistribute it and/or modify it. 
*/ 
 
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*", $s. str_repeat("", (4 - strlen($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 encrypt($str, $key) { 
    if ($str == "") { 
        return ""; 
    } 
    mb_internal_encoding("ISO-8859-1"); 
    $v = str2long($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); 
    } 
    $ret_val=long2str($v, false); 
    mb_internal_encoding("UTF-8"); 
    return $ret_val; 
} 
 
function decrypt($str, $key) { 
    if ($str == "") { 
        return ""; 
    } 
    mb_internal_encoding("ISO-8859-1"); 
    $v = str2long($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); 
    } 
    $ret_val=long2str($v, true); 
    mb_internal_encoding("UTF-8");  
    return $ret_val; 
     
} 
?>