xref: /netbsd-src/usr.bin/comm/comm.c (revision da9817918ec7e88db2912a2882967c7570a83f47)
1 /*	$NetBSD: comm.c,v 1.17 2009/04/11 12:18:45 lukem 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\
38  The Regents of the University of California.  All rights reserved.");
39 #endif /* not lint */
40 
41 #ifndef lint
42 #if 0
43 static char sccsid[] = "@(#)comm.c	8.4 (Berkeley) 5/4/95";
44 #endif
45 __RCSID("$NetBSD: comm.c,v 1.17 2009/04/11 12:18:45 lukem 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 
58 const char *tabs[] = { "", "\t", "\t\t" };
59 
60 FILE   *file(const char *);
61 void	show(FILE *, const char *, char *);
62 void	usage(void);
63 
64 int
65 main(int argc, char **argv)
66 {
67 	int comp, file1done, file2done, read1, read2;
68 	int ch, flag1, flag2, flag3;
69 	FILE *fp1, *fp2;
70 	const char *col1, *col2, *col3, **p;
71 	char 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 
166 void
167 show(FILE *fp, const char *offset, char *buf)
168 {
169 	while (printf("%s%s", offset, buf) >= 0 && fgets(buf, MAXLINELEN, fp))
170 		;
171 }
172 
173 FILE *
174 file(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 
185 void
186 usage(void)
187 {
188 
189 	(void)fprintf(stderr, "usage: comm [-123f] file1 file2\n");
190 	exit(1);
191 }
192