comm.c revision 1.2 
1/*
2 * Copyright (c) 1989 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Case Larsen.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38char copyright[] =
39"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
40 All rights reserved.\n";
41#endif /* not lint */
42
43#ifndef lint
44/*static char sccsid[] = "from: @(#)comm.c	5.7 (Berkeley) 11/1/90";*/
45static char rcsid[] = "$Id: comm.c,v 1.2 1993/08/01 18:17:21 mycroft Exp $";
46#endif /* not lint */
47
48#include <sys/file.h>
49#include <limits.h>
50#include <stdio.h>
51
52#define	MAXLINELEN	(_POSIX2_LINE_MAX + 1)
53
54char *tabs[] = { "", "\t", "\t\t" };
55
56main(argc,argv)
57	int argc;
58	char *argv[];
59{
60	register int comp, file1done, file2done, read1, read2;
61	register char *col1, *col2, *col3;
62	int ch, flag1, flag2, flag3;
63	FILE *fp1, *fp2, *file();
64	char **p, line1[MAXLINELEN], line2[MAXLINELEN];
65	extern int optind;
66
67	flag1 = flag2 = flag3 = 1;
68	while ((ch = getopt(argc, argv, "-123")) != EOF)
69		switch(ch) {
70		case '-':
71			--optind;
72			goto done;
73		case '1':
74			flag1 = 0;
75			break;
76		case '2':
77			flag2 = 0;
78			break;
79		case '3':
80			flag3 = 0;
81			break;
82		case '?':
83		default:
84			usage();
85		}
86done:	argc -= optind;
87	argv += optind;
88
89	if (argc != 2)
90		usage();
91
92	fp1 = file(argv[0]);
93	fp2 = file(argv[1]);
94
95	/* for each column printed, add another tab offset */
96	p = tabs;
97	col1 = col2 = col3 = NULL;
98	if (flag1)
99		col1 = *p++;
100	if (flag2)
101		col2 = *p++;
102	if (flag3)
103		col3 = *p;
104
105	for (read1 = read2 = 1;;) {
106		/* read next line, check for EOF */
107		if (read1)
108			file1done = !fgets(line1, MAXLINELEN, fp1);
109		if (read2)
110			file2done = !fgets(line2, MAXLINELEN, fp2);
111
112		/* if one file done, display the rest of the other file */
113		if (file1done) {
114			if (!file2done && col2)
115				show(fp2, col2, line2);
116			break;
117		}
118		if (file2done) {
119			if (!file1done && col1)
120				show(fp1, col1, line1);
121			break;
122		}
123
124		/* lines are the same */
125		if (!(comp = strcmp(line1, line2))) {
126			read1 = read2 = 1;
127			if (col3)
128				(void)printf("%s%s", col3, line1);
129			continue;
130		}
131
132		/* lines are different */
133		if (comp < 0) {
134			read1 = 1;
135			read2 = 0;
136			if (col1)
137				(void)printf("%s%s", col1, line1);
138		} else {
139			read1 = 0;
140			read2 = 1;
141			if (col2)
142				(void)printf("%s%s", col2, line2);
143		}
144	}
145	exit(0);
146}
147
148show(fp, offset, buf)
149	FILE *fp;
150	char *offset, *buf;
151{
152	do {
153		(void)printf("%s%s", offset, buf);
154	} while (fgets(buf, MAXLINELEN, fp));
155}
156
157FILE *
158file(name)
159	char *name;
160{
161	FILE *fp;
162
163	if (!strcmp(name, "-"))
164		return(stdin);
165	if (!(fp = fopen(name, "r"))) {
166		(void)fprintf(stderr, "comm: can't read %s.\n", name);
167		exit(1);
168	}
169	return(fp);
170}
171
172usage()
173{
174	(void)fprintf(stderr, "usage: comm [-123] [ - ] file1 file2\n");
175	exit(1);
176}
177