comm.c revision 1.5 
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 1.5 1994/11/08 18:37:10 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#include <err.h>
55
56#define	MAXLINELEN	(_POSIX2_LINE_MAX + 1)
57
58char *tabs[] = { "", "\t", "\t\t" };
59
60FILE *file __P((const char *));
61void  show __P((FILE *, char *, char *));
62void  usage __P((void));
63
64int
65main(argc,argv)
66	int argc;
67	char **argv;
68{
69	register int comp, file1done, file2done, read1, read2;
70	register char *col1, *col2, *col3;
71	int ch, flag1, flag2, flag3;
72	FILE *fp1, *fp2;
73	char **p, line1[MAXLINELEN], line2[MAXLINELEN];
74
75	setlocale(LC_ALL, "");
76
77	flag1 = flag2 = flag3 = 1;
78	while ((ch = getopt(argc, argv, "123")) != -1)
79		switch(ch) {
80		case '1':
81			flag1 = 0;
82			break;
83		case '2':
84			flag2 = 0;
85			break;
86		case '3':
87			flag3 = 0;
88			break;
89		case '?':
90		default:
91			usage();
92		}
93	argc -= optind;
94	argv += optind;
95
96	if (argc != 2)
97		usage();
98
99	fp1 = file(argv[0]);
100	fp2 = file(argv[1]);
101
102	/* for each column printed, add another tab offset */
103	p = tabs;
104	col1 = col2 = col3 = NULL;
105	if (flag1)
106		col1 = *p++;
107	if (flag2)
108		col2 = *p++;
109	if (flag3)
110		col3 = *p;
111
112	for (read1 = read2 = 1;;) {
113		/* read next line, check for EOF */
114		if (read1)
115			file1done = !fgets(line1, MAXLINELEN, fp1);
116		if (read2)
117			file2done = !fgets(line2, MAXLINELEN, fp2);
118
119		/* if one file done, display the rest of the other file */
120		if (file1done) {
121			if (!file2done && col2)
122				show(fp2, col2, line2);
123			break;
124		}
125		if (file2done) {
126			if (!file1done && col1)
127				show(fp1, col1, line1);
128			break;
129		}
130
131		/* lines are the same */
132		if (!(comp = strcoll(line1, line2))) {
133			read1 = read2 = 1;
134			if (col3)
135				if (printf("%s%s", col3, line1) == EOF)
136					break;
137			continue;
138		}
139
140		/* lines are different */
141		if (comp < 0) {
142			read1 = 1;
143			read2 = 0;
144			if (col1)
145				if (printf("%s%s", col1, line1) == EOF)
146					break;
147		} else {
148			read1 = 0;
149			read2 = 1;
150			if (col2)
151				if (printf("%s%s", col2, line2) == EOF)
152					break;
153		}
154	}
155
156	if (ferror (stdout) || fclose (stdout) == EOF)
157		err(1, "stdout");
158
159	exit(0);
160}
161
162void
163show(fp, offset, buf)
164	FILE *fp;
165	char *offset, *buf;
166{
167	while (printf("%s%s", offset, buf) != EOF && fgets(buf, MAXLINELEN, fp))
168		;
169}
170
171FILE *
172file(name)
173	const char *name;
174{
175	FILE *fp;
176
177	if (!strcmp(name, "-"))
178		return(stdin);
179	if (!(fp = fopen(name, "r"))) {
180		(void)fprintf(stderr, "comm: can't read %s.\n", name);
181		exit(1);
182	}
183	return(fp);
184}
185
186void
187usage()
188{
189	(void)fprintf(stderr, "usage: comm [-123] file1 file2\n");
190	exit(1);
191}
192