JS implementation of SHA-1

sha-1.js

/**
 * JS implementation of SHA-1
 *
 * http://stackoverflow.com/questions/539488/how-would-i-get-a-hash-value-of-a-users-file-with-javascript-or-flash
 **/

(function(){

	var sha1 = function (bytes) {
		return sha_hexdigest(bytes);
	};

	return register('sha1', sha1);

	function register(name, obj)
	{
		(function()
		{
			if (typeof module === 'object' && typeof module.exports === 'object')
			{
				module.exports = obj;
			}
			else if (typeof define === 'function' && define.amd)
			{
				//console.log(['define', name, obj]);

				define(name, [], function()
				{
					return obj;
				});
			}
		})();

		(function(_old)
		{
			if (obj.noConflict === undefined)
			{
				obj.noConflict = function()
				{
					window[name] = _old;
					return this;
				};
			}

			window[name] = obj;
		})(window[name]);

		return obj;
	};

function sha_hexdigest(bytes)
{
	var digest = sha_bytes(sha_calculate(sha_ints(bytes), bytes.length * 8));
	var digits = '0123456789abcdef';
	var hex = '';
	for (var i = 0; i < digest.length; i++)
	{
		var c = digest.charCodeAt(i);
		hex += digits.charAt((c >> 4) & 0xF) + digits.charAt(c & 0xF);
	}
	return hex;
}

function sha_ints(bytes)
{
	while (bytes.length % 4 != 0)
		bytes += '\x00';
	var ints = new Array();
	for (var i = 0; i < bytes.length; i += 4)
	{
		ints[ints.length] = (
			(bytes.charCodeAt(i) & 0xFF) << 24 | (bytes.charCodeAt(i + 1) & 0xFF) << 16 |
			(bytes.charCodeAt(i + 2) & 0xFF) << 8 | (bytes.charCodeAt(i + 3) & 0xFF)
		);
	}
	return ints;
}

function sha_bytes(ints)
{
	var bytes = '';
	for (var i = 0; i < ints.length; i++)
		bytes += String.fromCharCode((ints[i] >> 24) & 0xFF, (ints[i] >> 16) & 0xFF, (ints[i] >> 8) & 0xFF, ints[i] & 0xFF)
	return bytes;
}

function sha_calculate(ints, bitn)
{
	while (ints.length * 32 <= bitn) ints[ints.length] = 0;
	ints[ints.length - 1] |= 1 << (31 - bitn % 32)
	while (ints.length % 16 != 14) ints[ints.length] = 0;
	ints[ints.length] = Math.floor(bitn / 0x100000000);
	ints[ints.length] = bitn & 0xFFFFFFFF;

	var h0 = 1732584193,
		h1 = -271733879,
		h2 = -1732584194,
		h3 = 271733878,
		h4 = -1009589776;
	var a, b, c, d, e, f, k, temp, w = new Array(80);
	for (var inti = 0; inti < ints.length; inti += 16)
	{
		a = h0;
		b = h1;
		c = h2;
		d = h3;
		e = h4;
		for (var i = 0; i < 16; i++) w[i] = ints[inti + i];
		for (; i < 80; i++) w[i] = sha_rol(w[i - 3] ^ w[i - 8] ^ w[i - 14] ^ w[i - 16], 1);

		for (var i = 0; i < 80; i++)
		{
			switch (Math.floor(i / 20))
			{
				case 0:
					f = sha_add(1518500249, (b & c) | ((~b) & d));
					break;
				case 1:
					f = sha_add(1859775393, b ^ c ^ d);
					break;
				case 2:
					f = sha_add(-1894007588, (b & c) | (b & d) | (c & d));
					break;
				case 3:
					f = sha_add(-899497514, b ^ c ^ d);
					break;
			}
			temp = sha_add(sha_add(sha_rol(a, 5), w[i]), sha_add(e, f));
			e = d;
			d = c;
			c = b;
			b = a;
			a = temp;
			c = sha_rol(c, 30);
		}

		h0 = sha_add(h0, a);
		h1 = sha_add(h1, b);
		h2 = sha_add(h2, c);
		h3 = sha_add(h3, d);
		h4 = sha_add(h4, e);
	}
	return new Array(h0, h1, h2, h3, h4);
}

function sha_add(a, b)
{
	var lsw = (a & 0xFFFF) + (b & 0xFFFF);
	var msw = (a >> 16) + (b >> 16) + (lsw >> 16);
	return (msw << 16) | (lsw & 0xFFFF);
}

function sha_rol(n, bits)
{
	return (n << bits) | (n >>> (32 - bits));
}

})();