ObjFW  Artifact [307a03b74d]

Artifact 307a03b74d4be3bb46bc01258447c0f130a02982d12cbfeb2e77ebaf7971d37d:

• File src/OFMD5Hash.m — part of check-in [c4d2f177cb] at 2014-08-31 17:59:11 on branch trunk — Rewrite OFMD5Hash

  The old one was based on a public domain implementation, which is
  optimized for old compilers and quite unreadable. The new one is written
  from scratch and designed to be readable and to exploit optimizations of
  modern compilers. (user: js, size: 4615) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014
 *   Jonathan Schleifer <js@webkeks.org>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#include <string.h>

#import "OFMD5Hash.h"

#import "OFHashAlreadyCalculatedException.h"

#define F(a, b, c) (((a) & (b)) | (~(a) & (c)))
#define G(a, b, c) (((a) & (c)) | ((b) & ~(c)))
#define H(a, b, c) ((a) ^ (b) ^ (c))
#define I(a, b, c) ((b) ^ ((a) | ~(c)))

static const uint32_t sinTable[] = {
	0xD76AA478, 0xE8C7B756, 0x242070DB, 0xC1BDCEEE,
	0xF57C0FAF, 0x4787C62A, 0xA8304613, 0xFD469501,
	0x698098D8, 0x8B44F7AF, 0xFFFF5BB1, 0x895CD7BE,
	0x6B901122, 0xFD987193, 0xA679438E, 0x49B40821,

	0xF61E2562, 0xC040B340, 0x265E5A51, 0xE9B6C7AA,
	0xD62F105D, 0x02441453, 0xD8A1E681, 0xE7D3FBC8,
	0x21E1CDE6, 0xC33707D6, 0xF4D50D87, 0x455A14ED,
	0xA9E3E905, 0xFCEFA3F8, 0x676F02D9, 0x8D2A4C8A,

	0xFFFA3942, 0x8771F681, 0x6D9D6122, 0xFDE5380C,
	0xA4BEEA44, 0x4BDECFA9, 0xF6BB4B60, 0xBEBFBC70,
	0x289B7EC6, 0xEAA127FA, 0xD4EF3085, 0x04881D05,
	0xD9D4D039, 0xE6DB99E5, 0x1FA27CF8, 0xC4AC5665,

	0xF4292244, 0x432AFF97, 0xAB9423A7, 0xFC93A039,
	0x655B59C3, 0x8F0CCC92, 0xFFEFF47D, 0x85845DD1,
	0x6FA87E4F, 0xFE2CE6E0, 0xA3014314, 0x4E0811A1,
	0xF7537E82, 0xBD3AF235, 0x2AD7D2BB, 0xEB86D391
};
static const uint8_t wordOrder[] = {
	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
	1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12,
	5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2,
	0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9
};
static const uint8_t rotateBits[] = {
	7, 12, 17, 22,
	5, 9, 14, 20,
	4, 11, 16, 23,
	6, 10, 15, 21
};

static void
byteSwapVectorIfBE(uint32_t *vector, uint_fast8_t length)
{
	uint_fast8_t i;

	for (i = 0; i < length; i++)
		vector[i] = OF_BSWAP32_IF_BE(vector[i]);
}

static void
processBlock(uint32_t *state, uint32_t *buffer)
{
	uint32_t new[4];
	uint_fast8_t i = 0;

	new[0] = state[0];
	new[1] = state[1];
	new[2] = state[2];
	new[3] = state[3];

	byteSwapVectorIfBE(buffer, 16);

#define LOOP_BODY(f)							   \
	{								   \
		const uint_fast8_t a = (4 - (i & 3)) & 3;		   \
		const uint_fast8_t b = (a + 1) & 3;			   \
		const uint_fast8_t c = (a + 2) & 3;			   \
		const uint_fast8_t d = (a + 3) & 3;			   \
		const uint_fast8_t r = rotateBits[(i % 4) + (i / 16) * 4]; \
									   \
		new[a] += f(new[b], new[c], new[d]) +			   \
		    buffer[wordOrder[i]] + sinTable[i];			   \
		new[a] = OF_ROL(new[a], r);				   \
		new[a] += new[b];					   \
	}

	for (; i < 16; i++)
		LOOP_BODY(F)
	for (; i < 32; i++)
		LOOP_BODY(G)
	for (; i < 48; i++)
		LOOP_BODY(H)
	for (; i < 64; i++)
		LOOP_BODY(I)

#undef LOOP_BODY

	state[0] += new[0];
	state[1] += new[1];
	state[2] += new[2];
	state[3] += new[3];
}

@implementation OFMD5Hash
+ (size_t)digestSize
{
	return 16;
}

+ (size_t)blockSize
{
	return 64;
}

+ (instancetype)hash
{
	return [[[self alloc] init] autorelease];
}

- init
{
	self = [super init];

	_state[0] = 0x67452301;
	_state[1] = 0xEFCDAB89;
	_state[2] = 0x98BADCFE;
	_state[3] = 0x10325476;

	return self;
}

- (void)updateWithBuffer: (const void*)buffer_
		  length: (size_t)length
{
	const uint8_t *buffer = buffer_;

	if (_calculated)
		@throw [OFHashAlreadyCalculatedException
		    exceptionWithHash: self];

	_bits += (length * 8);

	while (length > 0) {
		size_t min = 64 - _bufferLength;

		if (min > length)
			min = length;

		memcpy(_buffer.bytes + _bufferLength, buffer, min);
		_bufferLength += min;

		buffer += min;
		length -= min;

		if (_bufferLength == 64) {
			processBlock(_state, _buffer.words);
			_bufferLength = 0;
		}
	}
}

- (const uint8_t*)digest
{
	if (_calculated)
		return (const uint8_t*)_state;

	_buffer.bytes[_bufferLength] = 0x80;
	memset(_buffer.bytes + _bufferLength + 1, 0, 64 - _bufferLength - 1);

	if (_bufferLength >= 56) {
		processBlock(_state, _buffer.words);
		memset(_buffer.bytes, 0, 64);
	}

	_buffer.words[14] = OF_BSWAP32_IF_BE((uint32_t)(_bits & 0xFFFFFFFF));
	_buffer.words[15] = OF_BSWAP32_IF_BE((uint32_t)(_bits >> 32));

	processBlock(_state, _buffer.words);
	byteSwapVectorIfBE(_state, 4);
	_calculated = true;

	return (const uint8_t*)_state;
}

- (bool)isCalculated
{
	return _calculated;
}
@end