/*

 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message

 * Digest Algorithm, as defined in RFC 1321.

 * Copyright (C) Paul Johnston 1999 - 2000.

 * Updated by Greg Holt 2000 - 2001.

 * See http://pajhome.org.uk/site/legal.html for details.

 */



/*

 * Convert a 32-bit number to a hex string with ls-byte first

 */

var hex_chr = "0123456789abcdef";

function rhex(num)

{

  str = "";

  for(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.

 */

function str2blks_MD5(str)

{

  nblk = ((str.length + 8) >> 6) + 1;

  blks = new Array(nblk * 16);

  for(i = 0; i < nblk * 16; i++) blks[i] = 0;

  for(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 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 add(rol(add(add(a, q), add(x, t)), s), b);

}

function ff(a, b, c, d, x, s, t)

{

  return cmn((b & c) | ((~b) & d), a, b, x, s, t);

}

function gg(a, b, c, d, x, s, t)

{

  return cmn((b & d) | (c & (~d)), a, b, x, s, t);

}

function hh(a, b, c, d, x, s, t)

{

  return cmn(b ^ c ^ d, a, b, x, s, t);

}

function ii(a, b, c, d, x, s, t)

{

  return cmn(c ^ (b | (~d)), a, b, x, s, t);

}



/*

 * Take a string and return the hex representation of its MD5.

 */

function calcMD5(str)

{

  x = str2blks_MD5(str);

  a =  1732584193;

  b = -271733879;

  c = -1732584194;

  d =  271733878;



  for(i = 0; i < x.length; i += 16)

  {

    olda = a;

    oldb = b;

    oldc = c;

    oldd = d;



    a = ff(a, b, c, d, x[i+ 0], 7 , -680876936);

    d = ff(d, a, b, c, x[i+ 1], 12, -389564586);

    c = ff(c, d, a, b, x[i+ 2], 17,  606105819);

    b = ff(b, c, d, a, x[i+ 3], 22, -1044525330);

    a = ff(a, b, c, d, x[i+ 4], 7 , -176418897);

    d = ff(d, a, b, c, x[i+ 5], 12,  1200080426);

    c = ff(c, d, a, b, x[i+ 6], 17, -1473231341);

    b = ff(b, c, d, a, x[i+ 7], 22, -45705983);

    a = ff(a, b, c, d, x[i+ 8], 7 ,  1770035416);

    d = ff(d, a, b, c, x[i+ 9], 12, -1958414417);

    c = ff(c, d, a, b, x[i+10], 17, -42063);

    b = ff(b, c, d, a, x[i+11], 22, -1990404162);

    a = ff(a, b, c, d, x[i+12], 7 ,  1804603682);

    d = ff(d, a, b, c, x[i+13], 12, -40341101);

    c = ff(c, d, a, b, x[i+14], 17, -1502002290);

    b = ff(b, c, d, a, x[i+15], 22,  1236535329);    



    a = gg(a, b, c, d, x[i+ 1], 5 , -165796510);

    d = gg(d, a, b, c, x[i+ 6], 9 , -1069501632);

    c = gg(c, d, a, b, x[i+11], 14,  643717713);

    b = gg(b, c, d, a, x[i+ 0], 20, -373897302);

    a = gg(a, b, c, d, x[i+ 5], 5 , -701558691);

    d = gg(d, a, b, c, x[i+10], 9 ,  38016083);

    c = gg(c, d, a, b, x[i+15], 14, -660478335);

    b = gg(b, c, d, a, x[i+ 4], 20, -405537848);

    a = gg(a, b, c, d, x[i+ 9], 5 ,  568446438);

    d = gg(d, a, b, c, x[i+14], 9 , -1019803690);

    c = gg(c, d, a, b, x[i+ 3], 14, -187363961);

    b = gg(b, c, d, a, x[i+ 8], 20,  1163531501);

    a = gg(a, b, c, d, x[i+13], 5 , -1444681467);

    d = gg(d, a, b, c, x[i+ 2], 9 , -51403784);

    c = gg(c, d, a, b, x[i+ 7], 14,  1735328473);

    b = gg(b, c, d, a, x[i+12], 20, -1926607734);

    

    a = hh(a, b, c, d, x[i+ 5], 4 , -378558);

    d = hh(d, a, b, c, x[i+ 8], 11, -2022574463);

    c = hh(c, d, a, b, x[i+11], 16,  1839030562);

    b = hh(b, c, d, a, x[i+14], 23, -35309556);

    a = hh(a, b, c, d, x[i+ 1], 4 , -1530992060);

    d = hh(d, a, b, c, x[i+ 4], 11,  1272893353);

    c = hh(c, d, a, b, x[i+ 7], 16, -155497632);

    b = hh(b, c, d, a, x[i+10], 23, -1094730640);

    a = hh(a, b, c, d, x[i+13], 4 ,  681279174);

    d = hh(d, a, b, c, x[i+ 0], 11, -358537222);

    c = hh(c, d, a, b, x[i+ 3], 16, -722521979);

    b = hh(b, c, d, a, x[i+ 6], 23,  76029189);

    a = hh(a, b, c, d, x[i+ 9], 4 , -640364487);

    d = hh(d, a, b, c, x[i+12], 11, -421815835);

    c = hh(c, d, a, b, x[i+15], 16,  530742520);

    b = hh(b, c, d, a, x[i+ 2], 23, -995338651);



    a = ii(a, b, c, d, x[i+ 0], 6 , -198630844);

    d = ii(d, a, b, c, x[i+ 7], 10,  1126891415);

    c = ii(c, d, a, b, x[i+14], 15, -1416354905);

    b = ii(b, c, d, a, x[i+ 5], 21, -57434055);

    a = ii(a, b, c, d, x[i+12], 6 ,  1700485571);

    d = ii(d, a, b, c, x[i+ 3], 10, -1894986606);

    c = ii(c, d, a, b, x[i+10], 15, -1051523);

    b = ii(b, c, d, a, x[i+ 1], 21, -2054922799);

    a = ii(a, b, c, d, x[i+ 8], 6 ,  1873313359);

    d = ii(d, a, b, c, x[i+15], 10, -30611744);

    c = ii(c, d, a, b, x[i+ 6], 15, -1560198380);

    b = ii(b, c, d, a, x[i+13], 21,  1309151649);

    a = ii(a, b, c, d, x[i+ 4], 6 , -145523070);

    d = ii(d, a, b, c, x[i+11], 10, -1120210379);

    c = ii(c, d, a, b, x[i+ 2], 15,  718787259);

    b = ii(b, c, d, a, x[i+ 9], 21, -343485551);



    a = add(a, olda);

    b = add(b, oldb);

    c = add(c, oldc);

    d = add(d, oldd);

  }

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

}