1 /* $NetBSD: sum2.c,v 1.4 1995/03/26 05:15:25 glass 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 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93"; 39 #else 40 static char rcsid[] = "$NetBSD: sum2.c,v 1.4 1995/03/26 05:15:25 glass Exp $"; 41 #endif 42 #endif /* not lint */ 43 44 #include <sys/types.h> 45 #include <unistd.h> 46 47 int 48 csum2(fd, cval, clen) 49 register int fd; 50 u_long *cval, *clen; 51 { 52 register u_long crc, total; 53 register int nr; 54 register u_char *p; 55 u_char buf[8192]; 56 57 /* 58 * Draft 8 POSIX 1003.2: 59 * 60 * s = sum of all bytes 61 * r = s % 2^16 + (s % 2^32) / 2^16 62 * crc = (r % 2^16) + r / 2^16 63 */ 64 crc = total = 0; 65 while ((nr = read(fd, buf, sizeof(buf))) > 0) 66 for (total += nr, p = buf; nr--; ++p) 67 crc += *p; 68 if (nr < 0) 69 return(1); 70 71 crc = (crc & 0xffff) + (crc >> 16); 72 crc = (crc & 0xffff) + (crc >> 16); 73 74 *cval = crc; 75 *clen = total; 76 return(0); 77 } 78