comm.c revision 1.15 
1/*	$NetBSD: comm.c,v 1.15 2005/02/17 17:31:28 xtraeme Exp $	*/
2
3/*
4 * Copyright (c) 1989, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Case Larsen.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36#ifndef lint
37__COPYRIGHT("@(#) Copyright (c) 1989, 1993, 1994\n\
38	The Regents of the University of California.  All rights reserved.\n");
39#endif /* not lint */
40
41#ifndef lint
42#if 0
43static char sccsid[] = "@(#)comm.c	8.4 (Berkeley) 5/4/95";
44#endif
45__RCSID("$NetBSD: comm.c,v 1.15 2005/02/17 17:31:28 xtraeme Exp $");
46#endif /* not lint */
47
48#include <err.h>
49#include <limits.h>
50#include <locale.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include <string.h>
54#include <unistd.h>
55
56#define	MAXLINELEN	(LINE_MAX + 1)
57
58char *tabs[] = { "", "\t", "\t\t" };
59
60FILE   *file(const char *);
61void	show(FILE *, char *, char *);
62void	usage(void);
63
64int
65main(int argc, char **argv)
66{
67	int comp, file1done, file2done, read1, read2;
68	int ch, flag1, flag2, flag3;
69	FILE *fp1, *fp2;
70	char *col1, *col2, *col3;
71	char **p, line1[MAXLINELEN], line2[MAXLINELEN];
72	int (*compare)(const char*,const char*);
73
74	(void)setlocale(LC_ALL, "");
75
76	file1done = file2done = 0;
77	flag1 = flag2 = flag3 = 1;
78	compare = strcoll;
79	while ((ch = getopt(argc, argv, "123f")) != -1)
80		switch(ch) {
81		case '1':
82			flag1 = 0;
83			break;
84		case '2':
85			flag2 = 0;
86			break;
87		case '3':
88			flag3 = 0;
89			break;
90		case 'f':
91			compare = strcasecmp;
92			break;
93		case '?':
94		default:
95			usage();
96		}
97	argc -= optind;
98	argv += optind;
99
100	if (argc != 2)
101		usage();
102
103	fp1 = file(argv[0]);
104	fp2 = file(argv[1]);
105
106	/* for each column printed, add another tab offset */
107	p = tabs;
108	col1 = col2 = col3 = NULL;
109	if (flag1)
110		col1 = *p++;
111	if (flag2)
112		col2 = *p++;
113	if (flag3)
114		col3 = *p;
115
116	for (read1 = read2 = 1;;) {
117		/* read next line, check for EOF */
118		if (read1)
119			file1done = !fgets(line1, MAXLINELEN, fp1);
120		if (read2)
121			file2done = !fgets(line2, MAXLINELEN, fp2);
122
123		/* if one file done, display the rest of the other file */
124		if (file1done) {
125			if (!file2done && col2)
126				show(fp2, col2, line2);
127			break;
128		}
129		if (file2done) {
130			if (!file1done && col1)
131				show(fp1, col1, line1);
132			break;
133		}
134
135		/* lines are the same */
136		if (!(comp = compare(line1, line2))) {
137			read1 = read2 = 1;
138			if (col3)
139				if (printf("%s%s", col3, line1) < 0)
140					break;
141			continue;
142		}
143
144		/* lines are different */
145		if (comp < 0) {
146			read1 = 1;
147			read2 = 0;
148			if (col1)
149				if (printf("%s%s", col1, line1) < 0)
150					break;
151		} else {
152			read1 = 0;
153			read2 = 1;
154			if (col2)
155				if (printf("%s%s", col2, line2) < 0)
156					break;
157		}
158	}
159
160	if (ferror (stdout) || fclose (stdout) == EOF)
161		err(1, "stdout");
162
163	exit(0);
164}
165
166void
167show(FILE *fp, char *offset, char *buf)
168{
169	while (printf("%s%s", offset, buf) >= 0 && fgets(buf, MAXLINELEN, fp))
170		;
171}
172
173FILE *
174file(const char *name)
175{
176	FILE *fp;
177
178	if (!strcmp(name, "-"))
179		return (stdin);
180	if ((fp = fopen(name, "r")) == NULL)
181		err(1, "%s", name);
182	return (fp);
183}
184
185void
186usage(void)
187{
188
189	(void)fprintf(stderr, "usage: comm [-123f] file1 file2\n");
190	exit(1);
191}
192