1/* $NetBSD: sum2.c,v 1.12 2005/01/12 17:04:35 xtraeme Exp $ */ 2 3/*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32#if HAVE_NBTOOL_CONFIG_H 33#include "nbtool_config.h" 34#endif 35 36#include <sys/cdefs.h> 37#if defined(__RCSID) && !defined(lint) 38#if 0 39static char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93"; 40#else 41__RCSID("$NetBSD: sum2.c,v 1.12 2005/01/12 17:04:35 xtraeme Exp $"); 42#endif 43#endif /* not lint */ 44 45#include <sys/types.h> 46#include <unistd.h> 47 48#include "extern.h" 49 50int 51csum2(int fd, u_int32_t *cval, off_t *clen) 52{ 53 u_int32_t thecrc; 54 off_t total; 55 int nr; 56 u_char *p; 57 u_char buf[8192]; 58 59 /* 60 * Draft 8 POSIX 1003.2: 61 * 62 * s = sum of all bytes 63 * r = s % 2^16 + (s % 2^32) / 2^16 64 * thecrc = (r % 2^16) + r / 2^16 65 */ 66 thecrc = 0; 67 total = 0; 68 while ((nr = read(fd, buf, sizeof(buf))) > 0) 69 for (total += nr, p = buf; nr--; ++p) 70 thecrc += *p; 71 if (nr < 0) 72 return 1; 73 74 thecrc = (thecrc & 0xffff) + (thecrc >> 16); 75 thecrc = (thecrc & 0xffff) + (thecrc >> 16); 76 77 *cval = thecrc; 78 *clen = total; 79 return 0; 80} 81