80 lines
2.5 KiB
C
80 lines
2.5 KiB
C
/* $NetBSD: sum2.c,v 1.13 2005/02/05 00:13:34 simonb Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c) 1991, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#if HAVE_NBTOOL_CONFIG_H
|
|
#include "nbtool_config.h"
|
|
#endif
|
|
|
|
#include <sys/cdefs.h>
|
|
#if defined(__RCSID) && !defined(lint)
|
|
#if 0
|
|
static char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93";
|
|
#else
|
|
__RCSID("$NetBSD: sum2.c,v 1.13 2005/02/05 00:13:34 simonb Exp $");
|
|
#endif
|
|
#endif /* not lint */
|
|
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
|
|
#include "extern.h"
|
|
|
|
int
|
|
csum2(int fd, u_int32_t *cval, off_t *clen)
|
|
{
|
|
u_int32_t thecrc;
|
|
off_t total;
|
|
int nr;
|
|
u_char *p;
|
|
u_char buf[8192];
|
|
|
|
/*
|
|
* Draft 8 POSIX 1003.2:
|
|
*
|
|
* s = sum of all bytes
|
|
* r = s % 2^16 + (s % 2^32) / 2^16
|
|
* thecrc = (r % 2^16) + r / 2^16
|
|
*/
|
|
thecrc = 0;
|
|
total = 0;
|
|
while ((nr = read(fd, buf, sizeof(buf))) > 0)
|
|
for (total += nr, p = buf; nr--; ++p)
|
|
thecrc += *p;
|
|
if (nr < 0)
|
|
return 1;
|
|
|
|
thecrc = (thecrc & 0xffff) + (thecrc >> 16);
|
|
thecrc = (thecrc & 0xffff) + (thecrc >> 16);
|
|
|
|
*cval = thecrc;
|
|
*clen = total;
|
|
return 0;
|
|
}
|