/*
   * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
   * Digest Algorithm, as defined in RFC 1321.
   * Version 2.1 Copyright (C) Paul Johnston 1999 - 2002.
   * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
   * Distributed under the BSD License
   */
  
  /*
   * Configurable variables. You may need to tweak these to be compatible with
   * the server-side, but the defaults work in most cases.
   */
  var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase        */
  var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance   */
  var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode      */
  
  /*
   * These are the functions you'll usually want to call
   * They take string arguments and return either hex or base-64 encoded strings
   */
  function hex_md5(s) {
  	return binl2hex(core_md5(str2binl(s), s.length * chrsz));
  }
  
  function b64_md5(s) {
  	return binl2b64(core_md5(str2binl(s), s.length * chrsz));
  }
  
  function str_md5(s) {
  	return binl2str(core_md5(str2binl(s), s.length * chrsz));
  }
  
  function hex_hmac_md5(key, data) {
  	return binl2hex(core_hmac_md5(key, data));
  }
  
  function b64_hmac_md5(key, data) {
  	return binl2b64(core_hmac_md5(key, data));
  }
  
  function str_hmac_md5(key, data) {
  	return binl2str(core_hmac_md5(key, data));
  }
  
  /*
   * Perform a simple self-test to see if the VM is working
   */
  function md5_vm_test() {
  	return hex_md5("abc") == "900150983cd24fb0d6963f7d28e17f72";
  }
  
  /*
   * Calculate the MD5 of an array of little-endian words, and a bit length
   */
  function core_md5(x, len) {
  	/* append padding */
  	x[len >> 5] |= 0x80 << ((len) % 32);
  	x[(((len + 64) >>> 9) << 4) + 14] = len;
  
  	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 = md5_ff(a, b, c, d, x[i + 0], 7, -680876936);
  		d = md5_ff(d, a, b, c, x[i + 1], 12, -389564586);
  		c = md5_ff(c, d, a, b, x[i + 2], 17, 606105819);
  		b = md5_ff(b, c, d, a, x[i + 3], 22, -1044525330);
  		a = md5_ff(a, b, c, d, x[i + 4], 7, -176418897);
  		d = md5_ff(d, a, b, c, x[i + 5], 12, 1200080426);
  		c = md5_ff(c, d, a, b, x[i + 6], 17, -1473231341);
  		b = md5_ff(b, c, d, a, x[i + 7], 22, -45705983);
  		a = md5_ff(a, b, c, d, x[i + 8], 7, 1770035416);
  		d = md5_ff(d, a, b, c, x[i + 9], 12, -1958414417);
  		c = md5_ff(c, d, a, b, x[i + 10], 17, -42063);
  		b = md5_ff(b, c, d, a, x[i + 11], 22, -1990404162);
  		a = md5_ff(a, b, c, d, x[i + 12], 7, 1804603682);
  		d = md5_ff(d, a, b, c, x[i + 13], 12, -40341101);
  		c = md5_ff(c, d, a, b, x[i + 14], 17, -1502002290);
  		b = md5_ff(b, c, d, a, x[i + 15], 22, 1236535329);
  
  		a = md5_gg(a, b, c, d, x[i + 1], 5, -165796510);
  		d = md5_gg(d, a, b, c, x[i + 6], 9, -1069501632);
  		c = md5_gg(c, d, a, b, x[i + 11], 14, 643717713);
  		b = md5_gg(b, c, d, a, x[i + 0], 20, -373897302);
  		a = md5_gg(a, b, c, d, x[i + 5], 5, -701558691);
  		d = md5_gg(d, a, b, c, x[i + 10], 9, 38016083);
  		c = md5_gg(c, d, a, b, x[i + 15], 14, -660478335);
  		b = md5_gg(b, c, d, a, x[i + 4], 20, -405537848);
  		a = md5_gg(a, b, c, d, x[i + 9], 5, 568446438);
  		d = md5_gg(d, a, b, c, x[i + 14], 9, -1019803690);
  		c = md5_gg(c, d, a, b, x[i + 3], 14, -187363961);
  		b = md5_gg(b, c, d, a, x[i + 8], 20, 1163531501);
  		a = md5_gg(a, b, c, d, x[i + 13], 5, -1444681467);
  		d = md5_gg(d, a, b, c, x[i + 2], 9, -51403784);
  		c = md5_gg(c, d, a, b, x[i + 7], 14, 1735328473);
  		b = md5_gg(b, c, d, a, x[i + 12], 20, -1926607734);
  
  		a = md5_hh(a, b, c, d, x[i + 5], 4, -378558);
  		d = md5_hh(d, a, b, c, x[i + 8], 11, -2022574463);
  		c = md5_hh(c, d, a, b, x[i + 11], 16, 1839030562);
  		b = md5_hh(b, c, d, a, x[i + 14], 23, -35309556);
  		a = md5_hh(a, b, c, d, x[i + 1], 4, -1530992060);
  		d = md5_hh(d, a, b, c, x[i + 4], 11, 1272893353);
  		c = md5_hh(c, d, a, b, x[i + 7], 16, -155497632);
  		b = md5_hh(b, c, d, a, x[i + 10], 23, -1094730640);
  		a = md5_hh(a, b, c, d, x[i + 13], 4, 681279174);
  		d = md5_hh(d, a, b, c, x[i + 0], 11, -358537222);
  		c = md5_hh(c, d, a, b, x[i + 3], 16, -722521979);
  		b = md5_hh(b, c, d, a, x[i + 6], 23, 76029189);
  		a = md5_hh(a, b, c, d, x[i + 9], 4, -640364487);
  		d = md5_hh(d, a, b, c, x[i + 12], 11, -421815835);
  		c = md5_hh(c, d, a, b, x[i + 15], 16, 530742520);
  		b = md5_hh(b, c, d, a, x[i + 2], 23, -995338651);
  
  		a = md5_ii(a, b, c, d, x[i + 0], 6, -198630844);
  		d = md5_ii(d, a, b, c, x[i + 7], 10, 1126891415);
  		c = md5_ii(c, d, a, b, x[i + 14], 15, -1416354905);
  		b = md5_ii(b, c, d, a, x[i + 5], 21, -57434055);
  		a = md5_ii(a, b, c, d, x[i + 12], 6, 1700485571);
  		d = md5_ii(d, a, b, c, x[i + 3], 10, -1894986606);
  		c = md5_ii(c, d, a, b, x[i + 10], 15, -1051523);
  		b = md5_ii(b, c, d, a, x[i + 1], 21, -2054922799);
  		a = md5_ii(a, b, c, d, x[i + 8], 6, 1873313359);
  		d = md5_ii(d, a, b, c, x[i + 15], 10, -30611744);
  		c = md5_ii(c, d, a, b, x[i + 6], 15, -1560198380);
  		b = md5_ii(b, c, d, a, x[i + 13], 21, 1309151649);
  		a = md5_ii(a, b, c, d, x[i + 4], 6, -145523070);
  		d = md5_ii(d, a, b, c, x[i + 11], 10, -1120210379);
  		c = md5_ii(c, d, a, b, x[i + 2], 15, 718787259);
  		b = md5_ii(b, c, d, a, x[i + 9], 21, -343485551);
  
  		a = safe_add(a, olda);
  		b = safe_add(b, oldb);
  		c = safe_add(c, oldc);
  		d = safe_add(d, oldd);
  	}
  	return Array(a, b, c, d);
  
  }
  
  /*
   * These functions implement the four basic operations the algorithm uses.
   */
  function md5_cmn(q, a, b, x, s, t) {
  	return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);
  }
  
  function md5_ff(a, b, c, d, x, s, t) {
  	return md5_cmn((b & c) | ((~b) & d), a, b, x, s, t);
  }
  
  function md5_gg(a, b, c, d, x, s, t) {
  	return md5_cmn((b & d) | (c & (~d)), a, b, x, s, t);
  }
  
  function md5_hh(a, b, c, d, x, s, t) {
  	return md5_cmn(b ^ c ^ d, a, b, x, s, t);
  }
  
  function md5_ii(a, b, c, d, x, s, t) {
  	return md5_cmn(c ^ (b | (~d)), a, b, x, s, t);
  }
  
  /*
   * Calculate the HMAC-MD5, of a key and some data
   */
  function core_hmac_md5(key, data) {
  	var bkey = str2binl(key);
  	if (bkey.length > 16) bkey = core_md5(bkey, key.length * chrsz);
  
  	var ipad = Array(16),
  		opad = Array(16);
  	for (var i = 0; i < 16; i++) {
  		ipad[i] = bkey[i] ^ 0x36363636;
  		opad[i] = bkey[i] ^ 0x5C5C5C5C;
  	}
  
  	var hash = core_md5(ipad.concat(str2binl(data)), 512 + data.length * chrsz);
  	return core_md5(opad.concat(hash), 512 + 128);
  }
  
  /*
   * 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 bit_rol(num, cnt) {
  	return (num << cnt) | (num >>> (32 - cnt));
  }
  
  /*
   * Convert a string to an array of little-endian words
   * If chrsz is ASCII, characters >255 have their hi-byte silently ignored.
   */
  function str2binl(str) {
  	var bin = Array();
  	var mask = (1 << chrsz) - 1;
  	for (var i = 0; i < str.length * chrsz; i += chrsz)
  		bin[i >> 5] |= (str.charCodeAt(i / chrsz) & mask) << (i % 32);
  	return bin;
  }
  
  /*
   * Convert an array of little-endian words to a string
   */
  function binl2str(bin) {
  	var str = "";
  	var mask = (1 << chrsz) - 1;
  	for (var i = 0; i < bin.length * 32; i += chrsz)
  		str += String.fromCharCode((bin[i >> 5] >>> (i % 32)) & mask);
  	return str;
  }
  
  /*
   * Convert an array of little-endian words to a hex string.
   */
  function binl2hex(binarray) {
  	var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  	var str = "";
  	for (var i = 0; i < binarray.length * 4; i++) {
  		str += hex_tab.charAt((binarray[i >> 2] >> ((i % 4) * 8 + 4)) & 0xF) +
  			hex_tab.charAt((binarray[i >> 2] >> ((i % 4) * 8)) & 0xF);
  	}
  	return str;
  }
  
  /*
   * Convert an array of little-endian words to a base-64 string
   */
  function binl2b64(binarray) {
  	var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  	var str = "";
  	for (var i = 0; i < binarray.length * 4; i += 3) {
  		var triplet = (((binarray[i >> 2] >> 8 * (i % 4)) & 0xFF) << 16) |
  			(((binarray[i + 1 >> 2] >> 8 * ((i + 1) % 4)) & 0xFF) << 8) |
  			((binarray[i + 2 >> 2] >> 8 * ((i + 2) % 4)) & 0xFF);
  		for (var j = 0; j < 4; j++) {
  			if (i * 8 + j * 6 > binarray.length * 32) str += b64pad;
  			else str += tab.charAt((triplet >> 6 * (3 - j)) & 0x3F);
  		}
  	}
  	return str;
  }
  module.exports = {
  	MD5: hex_md5
  }