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[] = "@(#)sum1.c 8.1 (Berkeley) 6/6/93";
33 #endif
34 #endif /* not lint */
35
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38
39 #include <sys/types.h>
40
41 #include <unistd.h>
42 #include <stdint.h>
43
44 #include "extern.h"
45
46 int
csum1(int fd,uint32_t * cval,off_t * clen)47 csum1(int fd, uint32_t *cval, off_t *clen)
48 {
49 int nr;
50 u_int lcrc;
51 off_t total;
52 u_char *p;
53 u_char buf[8192];
54
55 /*
56 * 16-bit checksum, rotating right before each addition;
57 * overflow is discarded.
58 */
59 lcrc = total = 0;
60 while ((nr = read(fd, buf, sizeof(buf))) > 0)
61 for (total += nr, p = buf; nr--; ++p) {
62 if (lcrc & 1)
63 lcrc |= 0x10000;
64 lcrc = ((lcrc >> 1) + *p) & 0xffff;
65 }
66 if (nr < 0)
67 return (1);
68
69 *cval = lcrc;
70 *clen = total;
71 return (0);
72 }
73