function char_code_to_bytes(code)
{
	var result = [];
	do
	{
		result.unshift(code & 0xff);
		code >>= 8;
	} while (code);
	return result;
}

function str_to_bytes(str)
{
	var result = [];
	for (var i = 0; i < str.length; i++)
	{
		result = result.concat( char_code_to_bytes(str.charCodeAt(i)) );
	};
	return result;
}

function num_to_big_endian_64(num)
{
	return [
		(num & 0xff00000000000000) >>> 56,
		(num & 0x00ff000000000000) >>> 48,
		(num & 0x0000ff0000000000) >>> 40,
		(num & 0x000000ff00000000) >>> 32,
		(num & 0x00000000ff000000) >>> 24,
		(num & 0x0000000000ff0000) >>> 16,
		(num & 0x000000000000ff00) >>>  8,
		(num & 0x00000000000000ff)       
	];
}

function bytes_to_big_endian_32(array)
{
	var result = [];
	for (var i = 0; i < array.length; i += 4)
	{
		result.push((array[i] << 24) | (array[i+1] << 16) | (array[i+2] <<  8) | array[i+3]);
	};
	return result;
}

function to_hex(x)
{
	var h = ["0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"];
	
	return String( 
		h[(x & 0xf0000000) >>> 28] + 
		h[(x & 0x0f000000) >>> 24] + 
		h[(x & 0x00f00000) >>> 20] + 
		h[(x & 0x000f0000) >>> 16] + 
		h[(x & 0x0000f000) >>> 12] + 
		h[(x & 0x00000f00) >>>  8] + 
		h[(x & 0x000000f0) >>>  4] + 
		h[(x & 0x0000000f) >>>  0]
		);
}

function sha1(byte_array)
{
	// copy array
	var message = byte_array.slice();

	// store message size for later use
	var message_size_in_bits = message.length * 8;

	// Initialize variables:
	var h0 = 0x67452301;
	var h1 = 0xefcdab89;
	var h2 = 0x98badcfe;
	var h3 = 0x10325476;
	var h4 = 0xc3d2e1f0;

	// Pre-processing:

	// append the bit '1' to the message
	message.push(0x80); 

	// append (0 <= k < 512) bits '0', so that the resulting message length (in bits) is congruent to 448 = -64 (mod 512)
	while ((message.length + 8) % 64) 
	{
		message.push(0);
	};

	// append length of message (before pre-processing), in bits, as 64-bit big-endian integer
	message = message.concat(num_to_big_endian_64(message_size_in_bits));

	// Process the message in successive 512-bit chunks:

	// break message into 512-bit chunks
	for (var i_chunk = 0; i_chunk < (message.length/64); i_chunk++)
	{
		// break chunk into sixteen 32-bit big-endian words w[i], 0 <= i <= 15
		var w = bytes_to_big_endian_32(message.slice(i_chunk*64,(i_chunk*64)+64));

		// Initialize hash value for this chunk:
		var a = h0, b = h1, c = h2, d = h3, e = h4, s, temp;

		// Main loop:
		for (var i = 0; i < 80; i++)
		{
			s = i & 0xf;
			if (i >= 16)
			{
				var _w = w[(s + 13) & 0xf] ^ w[(s + 8) & 0xf] ^ w[(s + 2) & 0xf] ^ w[s];
				w[s] = (_w << 1) | (_w >>> 31);
			}
			if (i < 20)
			{
				// f =                            ( d ^ (b & (c ^ d)) )
				temp = (((a << 5) | (a >>> 27)) + ( d ^ (b & (c ^ d)) ) + e + 0x5a827999 + w[s]) & 0xffffffff;
			}
			else if (i < 40)
			{
				// f =                            ( b ^ c ^ d )
				temp = (((a << 5) | (a >>> 27)) + ( b ^ c ^ d ) + e + 0x6ed9eba1 + w[s]) & 0xffffffff;
			}
			else if (i < 60)
			{
				// f =                            ( (b & c) | (b & d) | (c & d) )
				temp = (((a << 5) | (a >>> 27)) + ( (b & c) | (b & d) | (c & d) ) + e + 0x8f1bbcdc + w[s]) & 0xffffffff;
			}
			else
			{
				// f =                            ( b ^ c ^ d )
				temp = (((a << 5) | (a >>> 27)) + ( b ^ c ^ d ) + e + 0xca62c1d6 + w[s]) & 0xffffffff;
			}
			
			e = d;
			d = c;
			c = (b << 30) | (b >>> 2);
			b = a;
			a = temp;
		};

		// Add this chunk's hash to result so far:
		h0 = (h0 + a) & 0xffffffff;
		h1 = (h1 + b) & 0xffffffff;
		h2 = (h2 + c) & 0xffffffff;
		h3 = (h3 + d) & 0xffffffff;
		h4 = (h4 + e) & 0xffffffff;
	};

	// Produce the final hash value (big-endian):
	return [h0, h1, h2, h3, h4];
};

function sha1_string(str)
{
	// get text into byte array
	var message = str_to_bytes(str);

	// perform SHA-1
	h = sha1(message);

	// convert to string
	return to_hex(h[0]) + to_hex(h[1]) + to_hex(h[2]) + to_hex(h[3]) + to_hex(h[4]);
};

function sha1_verify()
{
	return Boolean(
		(sha1_string("The quick brown fox jumps over the lazy dog") == "2fd4e1c67a2d28fced849ee1bb76e7391b93eb12") &&
		(sha1_string("")                                            == "da39a3ee5e6b4b0d3255bfef95601890afd80709")
		);
};

function sha1_profile()
{
	var data = [1,2,3,4,5,6];
	for (var i = 0; i < 5000; i++) {
		sha1(data);
	};
};