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[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93";
35 #endif
36 #endif /* not lint */
37 #include <sys/cdefs.h>
38 #include <sys/types.h>
39
40 #include <unistd.h>
41 #include <stdint.h>
42
43 #include "extern.h"
44
45 int
csum2(int fd,uint32_t * cval,off_t * clen)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