1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)sum2.c 8.1 (Berkeley) 6/6/93 34 * $FreeBSD: src/usr.bin/cksum/sum2.c,v 1.4 1999/12/05 20:03:22 charnier Exp $ 35 * $DragonFly: src/usr.bin/cksum/sum2.c,v 1.4 2005/04/10 20:55:38 drhodus Exp $ 36 */ 37 38 #include <sys/types.h> 39 #include <unistd.h> 40 41 int 42 csum2(int fd, u_int32_t *cval, u_int32_t *clen) 43 { 44 u_int32_t crc, total; 45 int nr; 46 u_char *p; 47 u_char buf[8192]; 48 49 /* 50 * Draft 8 POSIX 1003.2: 51 * 52 * s = sum of all bytes 53 * r = s % 2^16 + (s % 2^32) / 2^16 54 * crc = (r % 2^16) + r / 2^16 55 */ 56 crc = total = 0; 57 while ((nr = read(fd, buf, sizeof(buf))) > 0) 58 for (total += nr, p = buf; nr--; ++p) 59 crc += *p; 60 if (nr < 0) 61 return(1); 62 63 crc = (crc & 0xffff) + (crc >> 16); 64 crc = (crc & 0xffff) + (crc >> 16); 65 66 *cval = crc; 67 *clen = total; 68 return(0); 69 } 70