var Xxtea = {

	xxtea_encrypt : function(str, key) {
        if (str == "") {
            return "";
        }
        var v = this.str2long(str, true);
        var k = this.str2long(key, false);

        if (str === undefined || str === null || str.length === 0) {
            return str;
        }
        var n = v.length - 1;
     
        var z = v[n], y = v[0], delta = 0x9E3779B9;
        var mx, e, q = Math.floor(6 + 52 / (n + 1)), sum = 0;
        while (q-- > 0) {
            sum = (sum + delta) & 0xffffffff;
            e = sum >> 2 & 3;
            for (var p = 0; p < n; p++) {
                y = v[p + 1];
                mx = ((z >> 5 & 0x07ffffff) ^ y << 2) + ((y >> 3 & 0x1fffffff) ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
                z = v[p] = (v[p] + mx) & 0xffffffff;
            }
            y = v[0];
            mx = ((z >> 5 & 0x07ffffff) ^ y << 2) + ((y >>> 3 & 0x1fffffff) ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
            z = v[n] = (v[n] + mx) & 0xffffffff;
        }
        return this.long2str(v, false);
    },

	xxtea_decrypt : function (str, key) {
        if (str == "") {
            return "";
        }
        var v = this.str2long(str, false);
        var k = this.str2long(key, false);

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

	long2str : function(v, w) {
        var vl = v.length;
        var sl = vl << 2;
        if (w) {
            m = v[vl - 1];
            sl -= 4;
            if ((m < sl - 3) || (m > sl)) return false;
            sl = 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, sl);
        } 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;
    }
};