text: ﻿/*
   * 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);
  }