1 /* $NetBSD: sum2.c,v 1.8 2002/03/31 14:43:23 bjh21 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(__RCSID) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93"; 40 #else 41 __RCSID("$NetBSD: sum2.c,v 1.8 2002/03/31 14:43:23 bjh21 Exp $"); 42 #endif 43 #endif /* not lint */ 44 45 #include <sys/types.h> 46 #include <unistd.h> 47 48 #include "extern.h" 49 50 int 51 csum2(fd, cval, clen) 52 register int fd; 53 u_int32_t *cval, *clen; 54 { 55 register u_int32_t thecrc, total; 56 register int nr; 57 register u_char *p; 58 u_char buf[8192]; 59 60 /* 61 * Draft 8 POSIX 1003.2: 62 * 63 * s = sum of all bytes 64 * r = s % 2^16 + (s % 2^32) / 2^16 65 * thecrc = (r % 2^16) + r / 2^16 66 */ 67 thecrc = 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