sum2.c revision 200462
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 * 3. All advertising materials mentioning features or use of this software 141590Srgrimes * must display the following acknowledgement: 151590Srgrimes * This product includes software developed by the University of 161590Srgrimes * California, Berkeley and its contributors. 171590Srgrimes * 4. Neither the name of the University nor the names of its contributors 181590Srgrimes * may be used to endorse or promote products derived from this software 191590Srgrimes * without specific prior written permission. 201590Srgrimes * 211590Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221590Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231590Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241590Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251590Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261590Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271590Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281590Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291590Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 301590Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311590Srgrimes * SUCH DAMAGE. 321590Srgrimes */ 331590Srgrimes 341590Srgrimes#ifndef lint 3554162Scharnier#if 0 3654162Scharnierstatic char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93"; 3754162Scharnier#endif 381590Srgrimes#endif /* not lint */ 3999112Sobrien#include <sys/cdefs.h> 4099112Sobrien__FBSDID("$FreeBSD: head/usr.bin/cksum/sum2.c 200462 2009-12-13 03:14:06Z delphij $"); 411590Srgrimes 421590Srgrimes#include <sys/types.h> 43112212Srobert 441590Srgrimes#include <unistd.h> 45200462Sdelphij#include <stdint.h> 461590Srgrimes 4787212Smarkm#include "extern.h" 4887212Smarkm 491590Srgrimesint 50112212Srobertcsum2(int fd, uint32_t *cval, off_t *clen) 511590Srgrimes{ 52112212Srobert uint32_t lcrc; 5387212Smarkm int nr; 54112212Srobert off_t total; 5587212Smarkm u_char *p; 561590Srgrimes u_char buf[8192]; 571590Srgrimes 581590Srgrimes /* 591590Srgrimes * Draft 8 POSIX 1003.2: 601590Srgrimes * 611590Srgrimes * s = sum of all bytes 621590Srgrimes * r = s % 2^16 + (s % 2^32) / 2^16 6387212Smarkm * lcrc = (r % 2^16) + r / 2^16 641590Srgrimes */ 6587212Smarkm lcrc = total = 0; 661590Srgrimes while ((nr = read(fd, buf, sizeof(buf))) > 0) 671590Srgrimes for (total += nr, p = buf; nr--; ++p) 6887212Smarkm lcrc += *p; 691590Srgrimes if (nr < 0) 70112212Srobert return (1); 711590Srgrimes 7287212Smarkm lcrc = (lcrc & 0xffff) + (lcrc >> 16); 7387212Smarkm lcrc = (lcrc & 0xffff) + (lcrc >> 16); 741590Srgrimes 7587212Smarkm *cval = lcrc; 761590Srgrimes *clen = total; 77112212Srobert return (0); 781590Srgrimes} 79