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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #ifndef lint 31 #if 0 32 static char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93"; 33 #endif 34 #endif /* not lint */ 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <sys/types.h> 39 40 #include <unistd.h> 41 #include <stdint.h> 42 43 #include "extern.h" 44 45 int 46 csum2(int fd, uint32_t *cval, off_t *clen) 47 { 48 uint32_t lcrc; 49 int nr; 50 off_t total; 51 u_char *p; 52 u_char buf[8192]; 53 54 /* 55 * Draft 8 POSIX 1003.2: 56 * 57 * s = sum of all bytes 58 * r = s % 2^16 + (s % 2^32) / 2^16 59 * lcrc = (r % 2^16) + r / 2^16 60 */ 61 lcrc = total = 0; 62 while ((nr = read(fd, buf, sizeof(buf))) > 0) 63 for (total += nr, p = buf; nr--; ++p) 64 lcrc += *p; 65 if (nr < 0) 66 return (1); 67 68 lcrc = (lcrc & 0xffff) + (lcrc >> 16); 69 lcrc = (lcrc & 0xffff) + (lcrc >> 16); 70 71 *cval = lcrc; 72 *clen = total; 73 return (0); 74 } 75