11590Srgrimes/*- 21590Srgrimes * Copyright (c) 1991, 1993 31590Srgrimes * The Regents of the University of California. All rights reserved. 41590Srgrimes * 51590Srgrimes * Redistribution and use in source and binary forms, with or without 61590Srgrimes * modification, are permitted provided that the following conditions 71590Srgrimes * are met: 81590Srgrimes * 1. Redistributions of source code must retain the above copyright 91590Srgrimes * notice, this list of conditions and the following disclaimer. 101590Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111590Srgrimes * notice, this list of conditions and the following disclaimer in the 121590Srgrimes * documentation and/or other materials provided with the distribution. 131590Srgrimes * 4. Neither the name of the University nor the names of its contributors 141590Srgrimes * may be used to endorse or promote products derived from this software 151590Srgrimes * without specific prior written permission. 161590Srgrimes * 171590Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 181590Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 191590Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 201590Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 211590Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 221590Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 231590Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 241590Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 251590Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 261590Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 271590Srgrimes * SUCH DAMAGE. 281590Srgrimes */ 291590Srgrimes 301590Srgrimes#ifndef lint 3154162Scharnier#if 0 3254162Scharnierstatic char sccsid[] = "@(#)sum1.c 8.1 (Berkeley) 6/6/93"; 3354162Scharnier#endif 341590Srgrimes#endif /* not lint */ 35112212Srobert 3699112Sobrien#include <sys/cdefs.h> 3799112Sobrien__FBSDID("$FreeBSD$"); 381590Srgrimes 391590Srgrimes#include <sys/types.h> 40112212Srobert 411590Srgrimes#include <unistd.h> 42200462Sdelphij#include <stdint.h> 431590Srgrimes 4487212Smarkm#include "extern.h" 4587212Smarkm 461590Srgrimesint 47112212Srobertcsum1(int fd, uint32_t *cval, off_t *clen) 481590Srgrimes{ 4987212Smarkm int nr; 5087212Smarkm u_int lcrc; 51112212Srobert off_t total; 5287212Smarkm u_char *p; 531590Srgrimes u_char buf[8192]; 541590Srgrimes 551590Srgrimes /* 561590Srgrimes * 16-bit checksum, rotating right before each addition; 571590Srgrimes * overflow is discarded. 581590Srgrimes */ 5987212Smarkm lcrc = total = 0; 601590Srgrimes while ((nr = read(fd, buf, sizeof(buf))) > 0) 611590Srgrimes for (total += nr, p = buf; nr--; ++p) { 6287212Smarkm if (lcrc & 1) 6387212Smarkm lcrc |= 0x10000; 6487212Smarkm lcrc = ((lcrc >> 1) + *p) & 0xffff; 651590Srgrimes } 661590Srgrimes if (nr < 0) 67112212Srobert return (1); 681590Srgrimes 6987212Smarkm *cval = lcrc; 701590Srgrimes *clen = total; 71112212Srobert return (0); 721590Srgrimes} 73