/*
* A JavaScript implementation of the RSA Data Security, Inc. MD4 Message
* Digest Algorithm, as defined in RFC 1320.
* Copyright (C) Jerrad Pierce 2000. Distributed under the LGPL.
* Updated by Paul Johnston 2000 - 2002.
*/

/*
* Convert a 32-bit number to a hex string with ls-byte first
*/
var hex_chr = "0123456789abcdef";
function rhex(num) {
    var str = "";
    for (var j = 0; j <= 3; j++)
        str += hex_chr.charAt((num >> (j * 8 + 4)) & 0x0F) +
           hex_chr.charAt((num >> (j * 8)) & 0x0F);
    return str;
}

/*
* Convert a string to a sequence of 16-word blocks, stored as an array.
* Append padding bits and the length, as described in the MD5 standard.
* MD5 here is not a typo - this function is borrowed from the MD5 code.
*/
function str2blks_MD5(str) {
    var nblk = ((str.length + 8) >> 6) + 1;
    var blks = new Array(nblk * 16);
    for (var i = 0; i < nblk * 16; i++) blks[i] = 0;
    for (var i = 0; i < str.length; i++)
        blks[i >> 2] |= str.charCodeAt(i) << ((i % 4) * 8);
    blks[i >> 2] |= 0x80 << ((i % 4) * 8);
    blks[nblk * 16 - 2] = str.length * 8;
    return blks;
}

/*
* Add integers, wrapping at 2^32. This uses 16-bit operations internally
* to work around bugs in some JS interpreters.
*/
function safe_add(x, y) {
    var lsw = (x & 0xFFFF) + (y & 0xFFFF);
    var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
    return (msw << 16) | (lsw & 0xFFFF);
}

/*
* Bitwise rotate a 32-bit number to the left
*/
function rol(num, cnt) {
    return (num << cnt) | (num >>> (32 - cnt));
}

/*
* These functions implement the basic operation for each round of the
* algorithm.
*/
function cmn(q, a, b, x, s, t) {
    return safe_add(rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);
}
function ffMD4(a, b, c, d, x, s) {
    return cmn((b & c) | ((~b) & d), a, 0, x, s, 0);
}
function ggMD4(a, b, c, d, x, s) {
    return cmn((b & c) | (b & d) | (c & d), a, 0, x, s, 1518500249);
}
function hhMD4(a, b, c, d, x, s) {
    return cmn(b ^ c ^ d, a, 0, x, s, 1859775393);
}

/*
* Take a string and return the hex representation of its MD4.
*/
function calcMD4(str) {
    var x = str2blks_MD5(str);
    var a = 1732584193;
    var b = -271733879;
    var c = -1732584194;
    var d = 271733878;

    for (var i = 0; i < x.length; i += 16) {
        var olda = a;
        var oldb = b;
        var oldc = c;
        var oldd = d;

        a = ffMD4(a, b, c, d, x[i + 0], 3);
        d = ffMD4(d, a, b, c, x[i + 1], 7);
        c = ffMD4(c, d, a, b, x[i + 2], 11);
        b = ffMD4(b, c, d, a, x[i + 3], 19);
        a = ffMD4(a, b, c, d, x[i + 4], 3);
        d = ffMD4(d, a, b, c, x[i + 5], 7);
        c = ffMD4(c, d, a, b, x[i + 6], 11);
        b = ffMD4(b, c, d, a, x[i + 7], 19);
        a = ffMD4(a, b, c, d, x[i + 8], 3);
        d = ffMD4(d, a, b, c, x[i + 9], 7);
        c = ffMD4(c, d, a, b, x[i + 10], 11);
        b = ffMD4(b, c, d, a, x[i + 11], 19);
        a = ffMD4(a, b, c, d, x[i + 12], 3);
        d = ffMD4(d, a, b, c, x[i + 13], 7);
        c = ffMD4(c, d, a, b, x[i + 14], 11);
        b = ffMD4(b, c, d, a, x[i + 15], 19);

        a = ggMD4(a, b, c, d, x[i + 0], 3);
        d = ggMD4(d, a, b, c, x[i + 4], 5);
        c = ggMD4(c, d, a, b, x[i + 8], 9);
        b = ggMD4(b, c, d, a, x[i + 12], 13);
        a = ggMD4(a, b, c, d, x[i + 1], 3);
        d = ggMD4(d, a, b, c, x[i + 5], 5);
        c = ggMD4(c, d, a, b, x[i + 9], 9);
        b = ggMD4(b, c, d, a, x[i + 13], 13);
        a = ggMD4(a, b, c, d, x[i + 2], 3);
        d = ggMD4(d, a, b, c, x[i + 6], 5);
        c = ggMD4(c, d, a, b, x[i + 10], 9);
        b = ggMD4(b, c, d, a, x[i + 14], 13);
        a = ggMD4(a, b, c, d, x[i + 3], 3);
        d = ggMD4(d, a, b, c, x[i + 7], 5);
        c = ggMD4(c, d, a, b, x[i + 11], 9);
        b = ggMD4(b, c, d, a, x[i + 15], 13);

        a = hhMD4(a, b, c, d, x[i + 0], 3);
        d = hhMD4(d, a, b, c, x[i + 8], 9);
        c = hhMD4(c, d, a, b, x[i + 4], 11);
        b = hhMD4(b, c, d, a, x[i + 12], 15);
        a = hhMD4(a, b, c, d, x[i + 2], 3);
        d = hhMD4(d, a, b, c, x[i + 10], 9);
        c = hhMD4(c, d, a, b, x[i + 6], 11);
        b = hhMD4(b, c, d, a, x[i + 14], 15);
        a = hhMD4(a, b, c, d, x[i + 1], 3);
        d = hhMD4(d, a, b, c, x[i + 9], 9);
        c = hhMD4(c, d, a, b, x[i + 5], 11);
        b = hhMD4(b, c, d, a, x[i + 13], 15);
        a = hhMD4(a, b, c, d, x[i + 3], 3);
        d = hhMD4(d, a, b, c, x[i + 11], 9);
        c = hhMD4(c, d, a, b, x[i + 7], 11);
        b = hhMD4(b, c, d, a, x[i + 15], 15);

        a = safe_add(a, olda);
        b = safe_add(b, oldb);
        c = safe_add(c, oldc);
        d = safe_add(d, oldd);

    }
    return rhex(a) + rhex(b) + rhex(c) + rhex(d);
}