/**
+----------------------------------------------------------
* 解密字符串
*
+----------------------------------------------------------
* @access static
+----------------------------------------------------------
* @param string $str 字符串
* @param string $key 加密key
+----------------------------------------------------------
* @return string
+----------------------------------------------------------
* @throws ThinkExecption
+----------------------------------------------------------
*/
function decrypt($str, $key)
{
if ($str == "") {
return "";
}
$v = Xxtea::str2long($str, false);
$k = Xxtea::str2long($key, false);
$n = count($v) - 1;
$z = $v[$n];
$y = $v[0];
$delta = 0x9e3779b9;
$q = floor(6 + 52 / ($n + 1));
$sum = Xxtea::int32($q * $delta);
while ($sum != 0) {
$e = $sum >> 2 & 3;
for ($p = $n; $p > 0; $p--) {
$z = $v[$p - 1];
$mx = Xxtea::int32(($z >> 5 & 0x7ffffff ^ $y << 2) + ($y >> 3 & 0x1fffffff ^ $z << 4)) ^ Xxtea::int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
$y = $v[$p] = Xxtea::int32($v[$p] - $mx);
}
$z = $v[$n];
$mx = Xxtea::int32(($z >> 5 & 0x7ffffff ^ $y << 2) + ($y >> 3 & 0x1fffffff ^ $z << 4)) ^ Xxtea::int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
$y = $v[0] = Xxtea::int32($v[0] - $mx);
$sum = Xxtea::int32($sum - $delta);
}
return Xxtea::long2str($v, true);
}
