/*
 * A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined
 * in FIPS 180-1
 * Version 2.2 Copyright Paul Johnston 2000 - 2009.
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for details.
 */

/*
 * Configurable variables. You may need to tweak these to be compatible with
 * the server-side, but the defaults work in most cases.
 */

String.prototype.sha1 = (function(){
	var hexcase = 0;  /* hex output format. 0 - lowercase; 1 - uppercase        */
	var b64pad  = ""; /* base-64 pad character. "=" for strict RFC compliance   */

	  /*
	 * Calculate the SHA1 of a raw string
	 */
	function rstr_sha1(s)
	{
	  return binb2rstr(binb_sha1(rstr2binb(s), s.length * 8));
	}

	/*
	 * Calculate the HMAC-SHA1 of a key and some data (raw strings)
	 */
	function rstr_hmac_sha1(key, data)
	{
	  var bkey = rstr2binb(key);
	  if(bkey.length > 16) bkey = binb_sha1(bkey, key.length * 8);

	  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 = binb_sha1(ipad.concat(rstr2binb(data)), 512 + data.length * 8);
	  return binb2rstr(binb_sha1(opad.concat(hash), 512 + 160));
	}

	/*
	 * Convert a raw string to a hex string
	 */
	function rstr2hex(input)
	{
	  try { hexcase } catch(e) { hexcase=0; }
	  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
	  var output = "";
	  var x;
	  for(var i = 0; i < input.length; i++)
	  {
		x = input.charCodeAt(i);
		output += hex_tab.charAt((x >>> 4) & 0x0F)
			   +  hex_tab.charAt( x        & 0x0F);
	  }
	  return output;
	}

	/*
	 * Encode a string as utf-8.
	 * For efficiency, this assumes the input is valid utf-16.
	 */
	function str2rstr_utf8(input)
	{
	  var output = "";
	  var i = -1;
	  var x, y;

	  while(++i < input.length)
	  {
		/* Decode utf-16 surrogate pairs */
		x = input.charCodeAt(i);
		y = i + 1 < input.length ? input.charCodeAt(i + 1) : 0;
		if(0xD800 <= x && x <= 0xDBFF && 0xDC00 <= y && y <= 0xDFFF)
		{
		  x = 0x10000 + ((x & 0x03FF) << 10) + (y & 0x03FF);
		  i++;
		}

		/* Encode output as utf-8 */
		if(x <= 0x7F)
		  output += String.fromCharCode(x);
		else if(x <= 0x7FF)
		  output += String.fromCharCode(0xC0 | ((x >>> 6 ) & 0x1F),
										0x80 | ( x         & 0x3F));
		else if(x <= 0xFFFF)
		  output += String.fromCharCode(0xE0 | ((x >>> 12) & 0x0F),
										0x80 | ((x >>> 6 ) & 0x3F),
										0x80 | ( x         & 0x3F));
		else if(x <= 0x1FFFFF)
		  output += String.fromCharCode(0xF0 | ((x >>> 18) & 0x07),
										0x80 | ((x >>> 12) & 0x3F),
										0x80 | ((x >>> 6 ) & 0x3F),
										0x80 | ( x         & 0x3F));
	  }
	  return output;
	}

	/*
	 * Encode a string as utf-16
	 */
	function str2rstr_utf16le(input)
	{
	  var output = "";
	  for(var i = 0; i < input.length; i++)
		output += String.fromCharCode( input.charCodeAt(i)        & 0xFF,
									  (input.charCodeAt(i) >>> 8) & 0xFF);
	  return output;
	}

	function str2rstr_utf16be(input)
	{
	  var output = "";
	  for(var i = 0; i < input.length; i++)
		output += String.fromCharCode((input.charCodeAt(i) >>> 8) & 0xFF,
									   input.charCodeAt(i)        & 0xFF);
	  return output;
	}

	/*
	 * Convert a raw string to an array of big-endian words
	 * Characters >255 have their high-byte silently ignored.
	 */
	function rstr2binb(input)
	{
	  var output = Array(input.length >> 2);
	  for(var i = 0; i < output.length; i++)
		output[i] = 0;
	  for(var i = 0; i < input.length * 8; i += 8)
		output[i>>5] |= (input.charCodeAt(i / 8) & 0xFF) << (24 - i % 32);
	  return output;
	}

	/*
	 * Convert an array of big-endian words to a string
	 */
	function binb2rstr(input)
	{
	  var output = "";
	  for(var i = 0; i < input.length * 32; i += 8)
		output += String.fromCharCode((input[i>>5] >>> (24 - i % 32)) & 0xFF);
	  return output;
	}

	/*
	 * Calculate the SHA-1 of an array of big-endian words, and a bit length
	 */
	function binb_sha1(x, len)
	{
	  /* append padding */
	  x[len >> 5] |= 0x80 << (24 - len % 32);
	  x[((len + 64 >> 9) << 4) + 15] = len;

	  var w = Array(80);
	  var a =  1732584193;
	  var b = -271733879;
	  var c = -1732584194;
	  var d =  271733878;
	  var e = -1009589776;

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

		for(var j = 0; j < 80; j++)
		{
		  if(j < 16) w[j] = x[i + j];
		  else w[j] = bit_rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
		  var t = safe_add(safe_add(bit_rol(a, 5), sha1_ft(j, b, c, d)),
						   safe_add(safe_add(e, w[j]), sha1_kt(j)));
		  e = d;
		  d = c;
		  c = bit_rol(b, 30);
		  b = a;
		  a = t;
		}

		a = safe_add(a, olda);
		b = safe_add(b, oldb);
		c = safe_add(c, oldc);
		d = safe_add(d, oldd);
		e = safe_add(e, olde);
	  }
	  return Array(a, b, c, d, e);

	}

	/*
	 * Perform the appropriate triplet combination function for the current
	 * iteration
	 */
	function sha1_ft(t, b, c, d)
	{
	  if(t < 20) return (b & c) | ((~b) & d);
	  if(t < 40) return b ^ c ^ d;
	  if(t < 60) return (b & c) | (b & d) | (c & d);
	  return b ^ c ^ d;
	}

	/*
	 * Determine the appropriate additive constant for the current iteration
	 */
	function sha1_kt(t)
	{
	  return (t < 20) ?  1518500249 : (t < 40) ?  1859775393 :
			 (t < 60) ? -1894007588 : -899497514;
	}

	/*
	 * 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));
	}
	
	
	//plain ol' sha1
	return function(){ return rstr2hex(rstr_sha1(str2rstr_utf8(this))); }
})();