xref: /openbsd-src/bin/md5/crc.c (revision bf198cc6eba0ca1f6d79f71e8e2243d386241fa8)

/*	$OpenBSD: crc.c,v 1.5 2019/01/25 00:19:25 millert Exp $	*/

/*
 * Copyright (c) 2004 Todd C. Miller <millert@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include "crc.h"

/*
 * Table-driven version of the following polynomial from POSIX 1003.2:
 *  G(x) = x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^10 + x^8 +
 *	   x^7 + x^5 + x^4 + x^2 + x + 1
 */
static const u_int32_t crc32tab[] = {
	0x00000000U,
	0x04c11db7U, 0x09823b6eU, 0x0d4326d9U, 0x130476dcU, 0x17c56b6bU,
	0x1a864db2U, 0x1e475005U, 0x2608edb8U, 0x22c9f00fU, 0x2f8ad6d6U,
	0x2b4bcb61U, 0x350c9b64U, 0x31cd86d3U, 0x3c8ea00aU, 0x384fbdbdU,
	0x4c11db70U, 0x48d0c6c7U, 0x4593e01eU, 0x4152fda9U, 0x5f15adacU,
	0x5bd4b01bU, 0x569796c2U, 0x52568b75U, 0x6a1936c8U, 0x6ed82b7fU,
	0x639b0da6U, 0x675a1011U, 0x791d4014U, 0x7ddc5da3U, 0x709f7b7aU,
	0x745e66cdU, 0x9823b6e0U, 0x9ce2ab57U, 0x91a18d8eU, 0x95609039U,
	0x8b27c03cU, 0x8fe6dd8bU, 0x82a5fb52U, 0x8664e6e5U, 0xbe2b5b58U,
	0xbaea46efU, 0xb7a96036U, 0xb3687d81U, 0xad2f2d84U, 0xa9ee3033U,
	0xa4ad16eaU, 0xa06c0b5dU, 0xd4326d90U, 0xd0f37027U, 0xddb056feU,
	0xd9714b49U, 0xc7361b4cU, 0xc3f706fbU, 0xceb42022U, 0xca753d95U,
	0xf23a8028U, 0xf6fb9d9fU, 0xfbb8bb46U, 0xff79a6f1U, 0xe13ef6f4U,
	0xe5ffeb43U, 0xe8bccd9aU, 0xec7dd02dU, 0x34867077U, 0x30476dc0U,
	0x3d044b19U, 0x39c556aeU, 0x278206abU, 0x23431b1cU, 0x2e003dc5U,
	0x2ac12072U, 0x128e9dcfU, 0x164f8078U, 0x1b0ca6a1U, 0x1fcdbb16U,
	0x018aeb13U, 0x054bf6a4U, 0x0808d07dU, 0x0cc9cdcaU, 0x7897ab07U,
	0x7c56b6b0U, 0x71159069U, 0x75d48ddeU, 0x6b93dddbU, 0x6f52c06cU,
	0x6211e6b5U, 0x66d0fb02U, 0x5e9f46bfU, 0x5a5e5b08U, 0x571d7dd1U,
	0x53dc6066U, 0x4d9b3063U, 0x495a2dd4U, 0x44190b0dU, 0x40d816baU,
	0xaca5c697U, 0xa864db20U, 0xa527fdf9U, 0xa1e6e04eU, 0xbfa1b04bU,
	0xbb60adfcU, 0xb6238b25U, 0xb2e29692U, 0x8aad2b2fU, 0x8e6c3698U,
	0x832f1041U, 0x87ee0df6U, 0x99a95df3U, 0x9d684044U, 0x902b669dU,
	0x94ea7b2aU, 0xe0b41de7U, 0xe4750050U, 0xe9362689U, 0xedf73b3eU,
	0xf3b06b3bU, 0xf771768cU, 0xfa325055U, 0xfef34de2U, 0xc6bcf05fU,
	0xc27dede8U, 0xcf3ecb31U, 0xcbffd686U, 0xd5b88683U, 0xd1799b34U,
	0xdc3abdedU, 0xd8fba05aU, 0x690ce0eeU, 0x6dcdfd59U, 0x608edb80U,
	0x644fc637U, 0x7a089632U, 0x7ec98b85U, 0x738aad5cU, 0x774bb0ebU,
	0x4f040d56U, 0x4bc510e1U, 0x46863638U, 0x42472b8fU, 0x5c007b8aU,
	0x58c1663dU, 0x558240e4U, 0x51435d53U, 0x251d3b9eU, 0x21dc2629U,
	0x2c9f00f0U, 0x285e1d47U, 0x36194d42U, 0x32d850f5U, 0x3f9b762cU,
	0x3b5a6b9bU, 0x0315d626U, 0x07d4cb91U, 0x0a97ed48U, 0x0e56f0ffU,
	0x1011a0faU, 0x14d0bd4dU, 0x19939b94U, 0x1d528623U, 0xf12f560eU,
	0xf5ee4bb9U, 0xf8ad6d60U, 0xfc6c70d7U, 0xe22b20d2U, 0xe6ea3d65U,
	0xeba91bbcU, 0xef68060bU, 0xd727bbb6U, 0xd3e6a601U, 0xdea580d8U,
	0xda649d6fU, 0xc423cd6aU, 0xc0e2d0ddU, 0xcda1f604U, 0xc960ebb3U,
	0xbd3e8d7eU, 0xb9ff90c9U, 0xb4bcb610U, 0xb07daba7U, 0xae3afba2U,
	0xaafbe615U, 0xa7b8c0ccU, 0xa379dd7bU, 0x9b3660c6U, 0x9ff77d71U,
	0x92b45ba8U, 0x9675461fU, 0x8832161aU, 0x8cf30badU, 0x81b02d74U,
	0x857130c3U, 0x5d8a9099U, 0x594b8d2eU, 0x5408abf7U, 0x50c9b640U,
	0x4e8ee645U, 0x4a4ffbf2U, 0x470cdd2bU, 0x43cdc09cU, 0x7b827d21U,
	0x7f436096U, 0x7200464fU, 0x76c15bf8U, 0x68860bfdU, 0x6c47164aU,
	0x61043093U, 0x65c52d24U, 0x119b4be9U, 0x155a565eU, 0x18197087U,
	0x1cd86d30U, 0x029f3d35U, 0x065e2082U, 0x0b1d065bU, 0x0fdc1becU,
	0x3793a651U, 0x3352bbe6U, 0x3e119d3fU, 0x3ad08088U, 0x2497d08dU,
	0x2056cd3aU, 0x2d15ebe3U, 0x29d4f654U, 0xc5a92679U, 0xc1683bceU,
	0xcc2b1d17U, 0xc8ea00a0U, 0xd6ad50a5U, 0xd26c4d12U, 0xdf2f6bcbU,
	0xdbee767cU, 0xe3a1cbc1U, 0xe760d676U, 0xea23f0afU, 0xeee2ed18U,
	0xf0a5bd1dU, 0xf464a0aaU, 0xf9278673U, 0xfde69bc4U, 0x89b8fd09U,
	0x8d79e0beU, 0x803ac667U, 0x84fbdbd0U, 0x9abc8bd5U, 0x9e7d9662U,
	0x933eb0bbU, 0x97ffad0cU, 0xafb010b1U, 0xab710d06U, 0xa6322bdfU,
	0xa2f33668U, 0xbcb4666dU, 0xb8757bdaU, 0xb5365d03U, 0xb1f740b4U
};

void
CKSUM_Init(CKSUM_CTX *ctx)
{
	ctx->crc = 0;
	ctx->len = 0;
}

#define	UPDATE(crc, byte) do						\
	(crc) = ((crc) << 8) ^ crc32tab[((crc) >> 24) ^ (byte)];	\
while(0)

void
CKSUM_Update(CKSUM_CTX *ctx, const unsigned char *buf, size_t len)
{
	size_t i;

	for (i = 0; i < len; i++)
		UPDATE(ctx->crc, buf[i]);
	ctx->len += len;
}

void
CKSUM_Final(CKSUM_CTX *ctx)
{
	off_t len = ctx->len;

	/* add in number of bytes read and finish */
	while (len != 0) {
		UPDATE(ctx->crc, len & 0xff);
		len >>= 8;
	}
	ctx->crc = ~ctx->crc;
}

char *
CKSUM_End(CKSUM_CTX *ctx, char *outstr)
{
	CKSUM_Final(ctx);

	if (outstr == NULL) {
		if (asprintf(&outstr, "%u %lld", ctx->crc, ctx->len) == -1)
			return (NULL);
	} else {
		(void)snprintf(outstr, (size_t)CKSUM_DIGEST_STRING_LENGTH,
		    "%u %lld", ctx->crc, ctx->len);
	}

	return (outstr);
}