comm.c revision 1.4 
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 1.4 1993/10/13 18:33:45 jtc Exp $";
46#endif /* not lint */
47
48#include <stdio.h>
49#include <stdlib.h>
50#include <string.h>
51#include <limits.h>
52#include <locale.h>
53#include <unistd.h>
54
55#define	MAXLINELEN	(_POSIX2_LINE_MAX + 1)
56
57char *tabs[] = { "", "\t", "\t\t" };
58
59FILE *file __P((const char *));
60void  show __P((FILE *, char *, char *));
61void  usage __P((void));
62
63int
64main(argc,argv)
65	int argc;
66	char **argv;
67{
68	register int comp, file1done, file2done, read1, read2;
69	register char *col1, *col2, *col3;
70	int ch, flag1, flag2, flag3;
71	FILE *fp1, *fp2;
72	char **p, line1[MAXLINELEN], line2[MAXLINELEN];
73
74	setlocale(LC_ALL, "");
75
76	flag1 = flag2 = flag3 = 1;
77	while ((ch = getopt(argc, argv, "123")) != -1)
78		switch(ch) {
79		case '1':
80			flag1 = 0;
81			break;
82		case '2':
83			flag2 = 0;
84			break;
85		case '3':
86			flag3 = 0;
87			break;
88		case '?':
89		default:
90			usage();
91		}
92	argc -= optind;
93	argv += optind;
94
95	if (argc != 2)
96		usage();
97
98	fp1 = file(argv[0]);
99	fp2 = file(argv[1]);
100
101	/* for each column printed, add another tab offset */
102	p = tabs;
103	col1 = col2 = col3 = NULL;
104	if (flag1)
105		col1 = *p++;
106	if (flag2)
107		col2 = *p++;
108	if (flag3)
109		col3 = *p;
110
111	for (read1 = read2 = 1;;) {
112		/* read next line, check for EOF */
113		if (read1)
114			file1done = !fgets(line1, MAXLINELEN, fp1);
115		if (read2)
116			file2done = !fgets(line2, MAXLINELEN, fp2);
117
118		/* if one file done, display the rest of the other file */
119		if (file1done) {
120			if (!file2done && col2)
121				show(fp2, col2, line2);
122			break;
123		}
124		if (file2done) {
125			if (!file1done && col1)
126				show(fp1, col1, line1);
127			break;
128		}
129
130		/* lines are the same */
131		if (!(comp = strcoll(line1, line2))) {
132			read1 = read2 = 1;
133			if (col3)
134				(void)printf("%s%s", col3, line1);
135			continue;
136		}
137
138		/* lines are different */
139		if (comp < 0) {
140			read1 = 1;
141			read2 = 0;
142			if (col1)
143				(void)printf("%s%s", col1, line1);
144		} else {
145			read1 = 0;
146			read2 = 1;
147			if (col2)
148				(void)printf("%s%s", col2, line2);
149		}
150	}
151	exit(0);
152}
153
154void
155show(fp, offset, buf)
156	FILE *fp;
157	char *offset, *buf;
158{
159	do {
160		(void)printf("%s%s", offset, buf);
161	} while (fgets(buf, MAXLINELEN, fp));
162}
163
164FILE *
165file(name)
166	const char *name;
167{
168	FILE *fp;
169
170	if (!strcmp(name, "-"))
171		return(stdin);
172	if (!(fp = fopen(name, "r"))) {
173		(void)fprintf(stderr, "comm: can't read %s.\n", name);
174		exit(1);
175	}
176	return(fp);
177}
178
179void
180usage()
181{
182	(void)fprintf(stderr, "usage: comm [-123] file1 file2\n");
183	exit(1);
184}
185