1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #ifndef lint
33 #if 0
34 static char sccsid[] = "@(#)sum1.c 8.1 (Berkeley) 6/6/93";
35 #endif
36 #endif /* not lint */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <sys/types.h>
42
43 #include <unistd.h>
44 #include <stdint.h>
45
46 #include "extern.h"
47
48 int
csum1(int fd,uint32_t * cval,off_t * clen)49 csum1(int fd, uint32_t *cval, off_t *clen)
50 {
51 int nr;
52 u_int lcrc;
53 off_t total;
54 u_char *p;
55 u_char buf[8192];
56
57 /*
58 * 16-bit checksum, rotating right before each addition;
59 * overflow is discarded.
60 */
61 lcrc = total = 0;
62 while ((nr = read(fd, buf, sizeof(buf))) > 0)
63 for (total += nr, p = buf; nr--; ++p) {
64 if (lcrc & 1)
65 lcrc |= 0x10000;
66 lcrc = ((lcrc >> 1) + *p) & 0xffff;
67 }
68 if (nr < 0)
69 return (1);
70
71 *cval = lcrc;
72 *clen = total;
73 return (0);
74 }
75