cmp.c revision 1.3 
1/*
2 * Copyright (c) 1987 Regents of the University of California.
3 * 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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35char copyright[] =
36"@(#) Copyright (c) 1987, 1990 Regents of the University of California.\n\
37 All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41/*static char sccsid[] = "from: @(#)cmp.c	5.3 (Berkeley) 6/1/90";*/
42static char rcsid[] = "$Id: cmp.c,v 1.3 1993/09/21 22:35:56 jtc Exp $";
43#endif /* not lint */
44
45#include <sys/param.h>
46#include <sys/file.h>
47#include <sys/stat.h>
48#include <stdio.h>
49#include <ctype.h>
50#include <errno.h>
51
52#define	EXITNODIFF	0
53#define	EXITDIFF	1
54#define	EXITERR		2
55
56int	all, fd1, fd2, silent;
57u_char	buf1[MAXBSIZE], buf2[MAXBSIZE];
58char	*file1, *file2;
59
60main(argc, argv)
61	int argc;
62	char **argv;
63{
64	extern char *optarg;
65	extern int optind;
66	int ch;
67	u_long otoi();
68
69	while ((ch = getopt(argc, argv, "ls")) != -1)
70		switch (ch) {
71		case 'l':		/* print all differences */
72			all = 1;
73			break;
74		case 's':		/* silent run */
75			silent = 1;
76			break;
77		case '?':
78		default:
79			usage();
80		}
81	argv += optind;
82	argc -= optind;
83
84	if (argc < 2 || argc > 4)
85		usage();
86
87	if (all && silent)
88		usage ();
89
90	if (strcmp(file1 = argv[0], "-") == 0)
91		fd1 = 0;
92	else if ((fd1 = open(file1, O_RDONLY, 0)) < 0)
93		error(file1);
94	if (strcmp(file2 = argv[1], "-") == 0)
95		fd2 = 0;
96	else if ((fd2 = open(file2, O_RDONLY, 0)) < 0)
97		error(file2);
98	if (fd1 == fd2) {
99		fprintf(stderr,
100		    "cmp: standard input may only be specified once.\n");
101		exit(EXITERR);
102	}
103
104	/* handle skip arguments */
105	if (argc > 2) {
106		skip(otoi(argv[2]), fd1, file1);
107		if (argc == 4)
108			skip(otoi(argv[3]), fd2, file2);
109	}
110	cmp();
111	/*NOTREACHED*/
112}
113
114/*
115 * skip --
116 *	skip first part of file
117 */
118skip(dist, fd, fname)
119	register u_long dist;
120	register int fd;
121	char *fname;
122{
123	register int rlen, nread;
124
125	for (; dist; dist -= rlen) {
126		rlen = MIN(dist, sizeof(buf1));
127		if ((nread = read(fd, buf1, rlen)) != rlen) {
128			if (nread < 0)
129				error(fname);
130			else
131				endoffile(fname);
132		}
133	}
134}
135
136cmp()
137{
138	register u_char	*p1, *p2;
139	register int cnt, len1, len2;
140	register long byte, line;
141	int dfound = 0;
142
143	for (byte = 0, line = 1; ; ) {
144		switch (len1 = read(fd1, buf1, MAXBSIZE)) {
145		case -1:
146			error(file1);
147		case 0:
148			/*
149			 * read of file 1 just failed, find out
150			 * if there's anything left in file 2
151			 */
152			switch (read(fd2, buf2, 1)) {
153				case -1:
154					error(file2);
155					/* NOTREACHED */
156				case 0:
157					exit(dfound ? EXITDIFF : EXITNODIFF);
158					/* NOTREACHED */
159				default:
160					endoffile(file1);
161					break;
162			}
163		}
164		/*
165		 * file1 might be stdio, which means that a read of less than
166		 * MAXBSIZE might not mean an EOF.  So, read whatever we read
167		 * from file1 from file2.
168		 */
169		if ((len2 = read(fd2, buf2, len1)) == -1)
170			error(file2);
171		if (bcmp(buf1, buf2, len2)) {
172			if (silent)
173				exit(EXITDIFF);
174			if (all) {
175				dfound = 1;
176				for (p1 = buf1, p2 = buf2, cnt = len2; cnt--;
177				    ++p1, ++p2) {
178					++byte;
179					if (*p1 != *p2)
180						printf("%6ld %3o %3o\n",
181						    byte, *p1, *p2);
182				}
183			} else for (p1 = buf1, p2 = buf2; ; ++p1, ++p2) {
184				++byte;
185				if (*p1 != *p2) {
186					printf("%s %s differ: char %ld, line %ld\n", file1, file2, byte, line);
187					exit(EXITDIFF);
188				}
189				if (*p1 == '\n')
190					++line;
191			}
192		} else {
193			byte += len2;
194			/*
195			 * here's the real performance problem, we've got to
196			 * count the stupid lines, which means that -l is a
197			 * *much* faster version, i.e., unless you really
198			 * *want* to know the line number, run -s or -l.
199			 */
200			if (!silent && !all)
201				for (p1 = buf1, cnt = len2; cnt--; )
202					if (*p1++ == '\n')
203						++line;
204		}
205		/*
206		 * couldn't read as much from file2 as from file1; checked
207		 * here because there might be a difference before we got
208		 * to this point, which would have precedence.
209		 */
210		if (len2 < len1)
211			endoffile(file2);
212	}
213}
214
215/*
216 * otoi --
217 *	octal/decimal string to u_long
218 */
219u_long
220otoi(s)
221	register char *s;
222{
223	register u_long val;
224	register int base;
225
226	base = (*s == '0') ? 8 : 10;
227	for (val = 0; isdigit(*s); ++s)
228		val = val * base + *s - '0';
229	return (val);
230}
231
232/*
233 * error --
234 *	print I/O error message and die
235 */
236error(filename)
237	char *filename;
238{
239	extern int errno;
240	char *strerror();
241
242	if (!silent)
243		(void) fprintf(stderr, "cmp: %s: %s\n",
244		    filename, strerror(errno));
245	exit(EXITERR);
246}
247
248/*
249 * endoffile --
250 *	print end-of-file message and exit indicating the files were different
251 */
252endoffile(filename)
253	char *filename;
254{
255	if (!silent)
256		(void) fprintf(stderr, "cmp: EOF on %s\n", filename);
257	exit(EXITDIFF);
258}
259
260/*
261 * usage --
262 *	print usage and die
263 */
264usage()
265{
266	fputs("usage: cmp [-l | -s] file1 file2 [skip1] [skip2]\n", stderr);
267	exit(EXITERR);
268}
269