1/* vi: set sw=4 ts=4: */
2/*
3 * sum -- checksum and count the blocks in a file
4 *     Like BSD sum or SysV sum -r, except like SysV sum if -s option is given.
5 *
6 * Copyright (C) 86, 89, 91, 1995-2002, 2004 Free Software Foundation, Inc.
7 * Copyright (C) 2005 by Erik Andersen <andersen@codepoet.org>
8 * Copyright (C) 2005 by Mike Frysinger <vapier@gentoo.org>
9 *
10 * Written by Kayvan Aghaiepour and David MacKenzie
11 * Taken from coreutils and turned into a busybox applet by Mike Frysinger
12 *
13 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
14 */
15
16#include "libbb.h"
17
18enum { SUM_BSD, PRINT_NAME, SUM_SYSV };
19
20/* BSD: calculate and print the rotated checksum and the size in 1K blocks
21   The checksum varies depending on sizeof (int). */
22/* SYSV: calculate and print the checksum and the size in 512-byte blocks */
23/* Return 1 if successful.  */
24static unsigned sum_file(const char *file, const unsigned type)
25{
26#define buf bb_common_bufsiz1
27	uintmax_t total_bytes = 0;
28	int fd = 0, r;
29
30	/* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
31	unsigned s = 0;
32
33	if (NOT_LONE_DASH(file)) {
34		fd = open(file, O_RDONLY);
35		if (fd == -1)
36			goto ret_bad;
37	}
38
39	while (1) {
40		size_t bytes_read = safe_read(fd, buf, BUFSIZ);
41
42		if ((ssize_t)bytes_read <= 0) {
43			r = (fd && close(fd) != 0);
44			if (!bytes_read && !r)
45				/* no error */
46				break;
47 ret_bad:
48			bb_perror_msg(file);
49			return 0;
50		}
51
52		total_bytes += bytes_read;
53		if (type >= SUM_SYSV) {
54			do s += buf[--bytes_read]; while (bytes_read);
55		} else {
56			r = 0;
57			do {
58				s = (s >> 1) + ((s & 1) << 15);
59				s += buf[r++];
60				s &= 0xffff; /* Keep it within bounds. */
61			} while (--bytes_read);
62		}
63	}
64
65	if (type < PRINT_NAME)
66		file = "";
67	if (type >= SUM_SYSV) {
68		r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
69		s = (r & 0xffff) + (r >> 16);
70		printf("%d %ju %s\n", s, (total_bytes+511)/512, file);
71	} else
72		printf("%05d %5ju %s\n", s, (total_bytes+1023)/1024, file);
73	return 1;
74#undef buf
75}
76
77int sum_main(int argc, char **argv);
78int sum_main(int argc, char **argv)
79{
80	unsigned n;
81	unsigned type = SUM_BSD;
82
83	n = getopt32(argv, "sr");
84	if (n & 1) type = SUM_SYSV;
85	/* give the bsd priority over sysv func */
86	if (n & 2) type = SUM_BSD;
87
88	if (argc == optind) {
89		/* Do not print the name */
90		n = sum_file("-", type);
91	} else {
92		/* Need to print the name if either
93		   - more than one file given
94		   - doing sysv */
95		type += argc - 1 > optind || type == SUM_SYSV;
96		for (n = 1; optind < argc; optind++)
97			n &= sum_file(argv[optind], type);
98	}
99	return !n;
100}
101