/* XXTEA encryption arithmetic library.
*
* Copyright (C) 2006 Ma Bingyao <andot@ujn.edu.cn>
* Version:      1.5
* LastModified: Dec 9, 2006
* This library is free.  You can redistribute it and/or modify it.
*/
var TEA = { 
long2str : function (v, w) {
		   var vl = v.length;
		   var n = (vl - 1) << 2;
		   if (w) {
			   var m = v[vl - 1];
			   if ((m < n - 3) || (m > n)) return null;
			   n = m;
		   }
		   for (var i = 0; i < vl; i++) {
			   v[i] = String.fromCharCode(v[i] & 0xff,
					   v[i] >>> 8 & 0xff,
					   v[i] >>> 16 & 0xff,
					   v[i] >>> 24 & 0xff);
		   }
		   if (w) {
			   return v.join('').substring(0, n);
		   }
		   else {
			   return v.join('');
		   }
	   },

str2long : function (s, w) {
		   var len = s.length;
		   var v = [];
		   for (var i = 0; i < len; i += 4) {
			   v[i >> 2] = s.charCodeAt(i)
				   | s.charCodeAt(i + 1) << 8
				   | s.charCodeAt(i + 2) << 16
				   | s.charCodeAt(i + 3) << 24;
		   }
		   if (w) {
			   v[v.length] = len;
		   }
		   return v;
	   },

encrypt : function(str, key) {
		  if (str == "") {
			  return "";
		  }
		  var v = TEA.str2long(str, true);
		  var k = TEA.str2long(key, false);
		  if (k.length < 4) {
			  k.length = 4;
		  }
		  var n = v.length - 1;

		  var z = v[n], y = v[0], delta = 0x9E3779B9;
		  var mx, e, p, q = Math.floor(6 + 52 / (n + 1)), sum = 0;
		  while (0 < q--) {
			  sum = sum + delta & 0xffffffff;
			  e = sum >>> 2 & 3;
			  for (p = 0; p < n; p++) {
				  y = v[p + 1];
				  mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
				  z = v[p] = v[p] + mx & 0xffffffff;
			  }
			  y = v[0];
			  mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
			  z = v[n] = v[n] + mx & 0xffffffff;
		  }

		  return TEA.long2str(v, false);
	  },

decrypt : function (str, key) {
		  if (str == "") {
			  return "";
		  }
		  var v = TEA.str2long(str, false);
		  var k = TEA.str2long(key, false);
		  if (k.length < 4) {
			  k.length = 4;
		  }
		  var n = v.length - 1;

		  var z = v[n - 1], y = v[0], delta = 0x9E3779B9;
		  var mx, e, p, q = Math.floor(6 + 52 / (n + 1)), sum = q * delta & 0xffffffff;
		  while (sum != 0) {
			  e = sum >>> 2 & 3;
			  for (p = n; p > 0; p--) {
				  z = v[p - 1];
				  mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
				  y = v[p] = v[p] - mx & 0xffffffff;
			  }
			  z = v[n];
			  mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
			  y = v[0] = v[0] - mx & 0xffffffff;
			  sum = sum - delta & 0xffffffff;
		  }

		  return TEA.long2str(v, true);
	  }
}
// EOF