mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-24 11:29:10 +00:00
74 lines
2.5 KiB
C
74 lines
2.5 KiB
C
/*-
|
|
* 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. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. 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.
|
|
*/
|
|
|
|
#ifndef lint
|
|
#if 0
|
|
static char sccsid[] = "@(#)sum1.c 8.1 (Berkeley) 6/6/93";
|
|
#endif
|
|
#endif /* not lint */
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
|
|
#include "extern.h"
|
|
|
|
int
|
|
csum1(int fd, u_int32_t *cval, u_int32_t *clen)
|
|
{
|
|
u_int32_t total;
|
|
int nr;
|
|
u_int lcrc;
|
|
u_char *p;
|
|
u_char buf[8192];
|
|
|
|
/*
|
|
* 16-bit checksum, rotating right before each addition;
|
|
* overflow is discarded.
|
|
*/
|
|
lcrc = total = 0;
|
|
while ((nr = read(fd, buf, sizeof(buf))) > 0)
|
|
for (total += nr, p = buf; nr--; ++p) {
|
|
if (lcrc & 1)
|
|
lcrc |= 0x10000;
|
|
lcrc = ((lcrc >> 1) + *p) & 0xffff;
|
|
}
|
|
if (nr < 0)
|
|
return(1);
|
|
|
|
*cval = lcrc;
|
|
*clen = total;
|
|
return(0);
|
|
}
|