// From http://code.google.com/p/crypto-js/
// License: http://www.opensource.org/licenses/bsd-license.php
//
// Copyright (c) 2009, Jeff Mott. All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 
// Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer. Redistributions in binary
// form must reproduce the above copyright notice, this list of conditions and
// the following disclaimer in the documentation and/or other materials provided
// with the distribution. Neither the name Crypto-JS nor the names of its
// contributors may be used to endorse or promote products derived from this
// software without specific prior written permission. THIS SOFTWARE IS PROVIDED
// BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
// EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

(function(){

// Shortcuts
var C = Crypto,
    util = C.util,
    charenc = C.charenc,
    UTF8 = charenc.UTF8,
    Binary = charenc.Binary;

// Public API
var SHA1 = C.SHA1 = function (message, options) {
	var digestbytes = util.wordsToBytes(SHA1._sha1(message));
	return options && options.asBytes ? digestbytes :
	       options && options.asString ? Binary.bytesToString(digestbytes) :
	       util.bytesToHex(digestbytes);
};

// The core
SHA1._sha1 = function (message) {

	// Convert to byte array
	if (message.constructor == String) message = UTF8.stringToBytes(message);
	/* else, assume byte array already */

	var m  = util.bytesToWords(message),
	    l  = message.length * 8,
	    w  =  [],
	    H0 =  1732584193,
	    H1 = -271733879,
	    H2 = -1732584194,
	    H3 =  271733878,
	    H4 = -1009589776;

	// Padding
	m[l >> 5] |= 0x80 << (24 - l % 32);
	m[((l + 64 >>> 9) << 4) + 15] = l;

	for (var i = 0; i < m.length; i += 16) {

		var a = H0,
		    b = H1,
		    c = H2,
		    d = H3,
		    e = H4;

		for (var j = 0; j < 80; j++) {

			if (j < 16) w[j] = m[i + j];
			else {
				var n = w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16];
				w[j] = (n << 1) | (n >>> 31);
			}

			var t = ((H0 << 5) | (H0 >>> 27)) + H4 + (w[j] >>> 0) + (
			         j < 20 ? (H1 & H2 | ~H1 & H3) + 1518500249 :
			         j < 40 ? (H1 ^ H2 ^ H3) + 1859775393 :
			         j < 60 ? (H1 & H2 | H1 & H3 | H2 & H3) - 1894007588 :
			                  (H1 ^ H2 ^ H3) - 899497514);

			H4 =  H3;
			H3 =  H2;
			H2 = (H1 << 30) | (H1 >>> 2);
			H1 =  H0;
			H0 =  t;

		}

		H0 += a;
		H1 += b;
		H2 += c;
		H3 += d;
		H4 += e;

	}

	return [H0, H1, H2, H3, H4];

};

// Package private blocksize
SHA1._blocksize = 16;

})();
