ObjFW  Artifact [65056dd7ed]

Artifact 65056dd7ed2d8519ddea0ad93574ebf9d2bf62c8164aa6b09d0d29cfa6a2634d:

• File src/OFMD5Hash.m — part of check-in [e1e7ffa903] at 2011-09-22 23:25:42 on branch trunk — Exceptions are now autoreleased.

  This is safe as an "exception loop" can't happen, since if allocating
  an exception fails, it throws an OFAllocFailedException which is
  preallocated and can always be thrown.

  So, the worst case would be that an autorelease of an exception fails,
  triggering an OFOutOfMemoryException for which there is no memory,
  resulting in an OFAllocFailedException to be thrown. (user: js, size: 6836) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011
 *   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"

#import "macros.h"

/* The four MD5 core functions - F1 is optimized somewhat */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
	(w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)

static void
md5_transform(uint32_t buffer[4], const uint32_t in[16])
{
	register uint32_t a, b, c, d;

	a = buffer[0];
	b = buffer[1];
	c = buffer[2];
	d = buffer[3];

	MD5STEP(F1, a, b, c, d, in[0]  + 0xD76AA478, 7);
	MD5STEP(F1, d, a, b, c, in[1]  + 0xE8C7B756, 12);
	MD5STEP(F1, c, d, a, b, in[2]  + 0x242070DB, 17);
	MD5STEP(F1, b, c, d, a, in[3]  + 0xC1BDCEEE, 22);
	MD5STEP(F1, a, b, c, d, in[4]  + 0xF57C0FAF, 7);
	MD5STEP(F1, d, a, b, c, in[5]  + 0x4787C62A, 12);
	MD5STEP(F1, c, d, a, b, in[6]  + 0xA8304613, 17);
	MD5STEP(F1, b, c, d, a, in[7]  + 0xFD469501, 22);
	MD5STEP(F1, a, b, c, d, in[8]  + 0x698098D8, 7);
	MD5STEP(F1, d, a, b, c, in[9]  + 0x8B44F7AF, 12);
	MD5STEP(F1, c, d, a, b, in[10] + 0xFFFF5BB1, 17);
	MD5STEP(F1, b, c, d, a, in[11] + 0x895CD7Be, 22);
	MD5STEP(F1, a, b, c, d, in[12] + 0x6B901122, 7);
	MD5STEP(F1, d, a, b, c, in[13] + 0xFD987193, 12);
	MD5STEP(F1, c, d, a, b, in[14] + 0xA679438e, 17);
	MD5STEP(F1, b, c, d, a, in[15] + 0x49B40821, 22);

	MD5STEP(F2, a, b, c, d, in[1]  + 0xF61E2562, 5);
	MD5STEP(F2, d, a, b, c, in[6]  + 0xC040B340, 9);
	MD5STEP(F2, c, d, a, b, in[11] + 0x265E5A51, 14);
	MD5STEP(F2, b, c, d, a, in[0]  + 0xE9B6C7AA, 20);
	MD5STEP(F2, a, b, c, d, in[5]  + 0xD62F105D, 5);
	MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
	MD5STEP(F2, c, d, a, b, in[15] + 0xD8A1E681, 14);
	MD5STEP(F2, b, c, d, a, in[4]  + 0xE7D3FBC8, 20);
	MD5STEP(F2, a, b, c, d, in[9]  + 0x21E1CDE6, 5);
	MD5STEP(F2, d, a, b, c, in[14] + 0xC33707D6, 9);
	MD5STEP(F2, c, d, a, b, in[3]  + 0xF4D50D87, 14);
	MD5STEP(F2, b, c, d, a, in[8]  + 0x455A14ED, 20);
	MD5STEP(F2, a, b, c, d, in[13] + 0xA9E3E905, 5);
	MD5STEP(F2, d, a, b, c, in[2]  + 0xFCEFA3F8, 9);
	MD5STEP(F2, c, d, a, b, in[7]  + 0x676F02D9, 14);
	MD5STEP(F2, b, c, d, a, in[12] + 0x8D2A4C8a, 20);

	MD5STEP(F3, a, b, c, d, in[5]  + 0xFFFA3942, 4);
	MD5STEP(F3, d, a, b, c, in[8]  + 0x8771F681, 11);
	MD5STEP(F3, c, d, a, b, in[11] + 0x6D9D6122, 16);
	MD5STEP(F3, b, c, d, a, in[14] + 0xFDE5380c, 23);
	MD5STEP(F3, a, b, c, d, in[1]  + 0xA4BEEA44, 4);
	MD5STEP(F3, d, a, b, c, in[4]  + 0x4BDECFA9, 11);
	MD5STEP(F3, c, d, a, b, in[7]  + 0xF6BB4B60, 16);
	MD5STEP(F3, b, c, d, a, in[10] + 0xBEBFBC70, 23);
	MD5STEP(F3, a, b, c, d, in[13] + 0x289B7EC6, 4);
	MD5STEP(F3, d, a, b, c, in[0]  + 0xEAA127FA, 11);
	MD5STEP(F3, c, d, a, b, in[3]  + 0xD4EF3085, 16);
	MD5STEP(F3, b, c, d, a, in[6]  + 0x04881D05, 23);
	MD5STEP(F3, a, b, c, d, in[9]  + 0xD9D4D039, 4);
	MD5STEP(F3, d, a, b, c, in[12] + 0xE6DB99E5, 11);
	MD5STEP(F3, c, d, a, b, in[15] + 0x1FA27CF8, 16);
	MD5STEP(F3, b, c, d, a, in[2]  + 0xC4AC5665, 23);

	MD5STEP(F4, a, b, c, d, in[0]  + 0xF4292244, 6);
	MD5STEP(F4, d, a, b, c, in[7]  + 0x432AFF97, 10);
	MD5STEP(F4, c, d, a, b, in[14] + 0xAB9423A7, 15);
	MD5STEP(F4, b, c, d, a, in[5]  + 0xFC93A039, 21);
	MD5STEP(F4, a, b, c, d, in[12] + 0x655B59C3, 6);
	MD5STEP(F4, d, a, b, c, in[3]  + 0x8F0CCC92, 10);
	MD5STEP(F4, c, d, a, b, in[10] + 0xFFEFF47d, 15);
	MD5STEP(F4, b, c, d, a, in[1]  + 0x85845DD1, 21);
	MD5STEP(F4, a, b, c, d, in[8]  + 0x6FA87E4F, 6);
	MD5STEP(F4, d, a, b, c, in[15] + 0xFE2CE6E0, 10);
	MD5STEP(F4, c, d, a, b, in[6]  + 0xA3014314, 15);
	MD5STEP(F4, b, c, d, a, in[13] + 0x4E0811A1, 21);
	MD5STEP(F4, a, b, c, d, in[4]  + 0xF7537E82, 6);
	MD5STEP(F4, d, a, b, c, in[11] + 0xBD3AF235, 10);
	MD5STEP(F4, c, d, a, b, in[2]  + 0x2AD7D2BB, 15);
	MD5STEP(F4, b, c, d, a, in[9]  + 0xEB86D391, 21);

	buffer[0] += a;
	buffer[1] += b;
	buffer[2] += c;
	buffer[3] += d;
}

@implementation OFMD5Hash
+ MD5Hash
{
	return [[[self alloc] init] autorelease];
}

+ (size_t)digestSize
{
	return 16;
}

+ (size_t)blockSize
{
	return 64;
}

- init
{
	self = [super init];

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

	return self;
}

- (void)updateWithBuffer: (const char*)buffer_
		  length: (size_t)length
{
	uint32_t t;

	if (length == 0)
		return;

	if (calculated)
		@throw [OFHashAlreadyCalculatedException
		    exceptionWithClass: isa
				  hash: self];

	/* Update bitcount */
	t = bits[0];
	if ((bits[0] = t + ((uint32_t)length << 3)) < t)
		/* Carry from low to high */
		bits[1]++;
	bits[1] += (uint32_t)length >> 29;

	/* Bytes already in shsInfo->data */
	t = (t >> 3) & 0x3F;

	/* Handle any leading odd-sized chunks */
	if (t) {
		uint8_t *p = in.u8 + t;

		t = 64 - t;

		if (length < t) {
			memcpy(p, buffer_, length);
			return;
		}

		memcpy(p, buffer_, t);
		of_bswap32_vec_if_be(in.u32, 16);
		md5_transform(buffer, in.u32);

		buffer_ += t;
		length -= t;
	}

	/* Process data in 64-byte chunks */
	while (length >= 64) {
		memcpy(in.u8, buffer_, 64);
		of_bswap32_vec_if_be(in.u32, 16);
		md5_transform(buffer, in.u32);

		buffer_ += 64;
		length -= 64;
	}

	/* Handle any remaining bytes of data. */
	memcpy(in.u8, buffer_, length);
}

- (uint8_t*)digest
{
	uint8_t	*p;
	size_t	count;

	if (calculated)
		return (uint8_t*)buffer;

	/* Compute number of bytes mod 64 */
	count = (bits[0] >> 3) & 0x3F;

	/*
	 * Set the first char of padding to 0x80. This is safe since there is
	 * always at least one byte free
	 */
	p = in.u8 + count;
	*p++ = 0x80;

	/* Bytes of padding needed to make 64 bytes */
	count = 64 - 1 - count;

	/* Pad out to 56 mod 64 */
	if (count < 8) {
		/* Two lots of padding: Pad the first block to 64 bytes */
		memset(p, 0, count);
		of_bswap32_vec_if_be(in.u32, 16);
		md5_transform(buffer, in.u32);

		/* Now fill the next block with 56 bytes */
		memset(in.u8, 0, 56);
	} else {
		/* Pad block to 56 bytes */
		memset(p, 0, count - 8);
	}
	of_bswap32_vec_if_be(in.u32, 14);

	/* Append length in bits and transform */
	in.u32[14] = bits[0];
	in.u32[15] = bits[1];

	md5_transform(buffer, in.u32);
	of_bswap32_vec_if_be(buffer, 4);

	calculated = YES;

	return (uint8_t*)buffer;
}
@end