xref: /openbsd/usr.bin/comm/comm.c (revision a6445c1d)
1 /*	$OpenBSD: comm.c,v 1.8 2009/10/27 23:59:37 deraadt Exp $	*/
2 /*	$NetBSD: comm.c,v 1.10 1995/09/05 19:57:43 jtc Exp $	*/
3 
4 /*
5  * Copyright (c) 1989, 1993, 1994
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Case Larsen.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <err.h>
37 #include <limits.h>
38 #include <locale.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43 
44 #define	MAXLINELEN	(LINE_MAX + 1)
45 
46 char *tabs[] = { "", "\t", "\t\t" };
47 
48 FILE   *file(const char *);
49 void	show(FILE *, char *, char *);
50 void	usage(void);
51 
52 int
53 main(int argc, char *argv[])
54 {
55 	int comp, file1done, file2done, read1, read2;
56 	int ch, flag1, flag2, flag3;
57 	FILE *fp1, *fp2;
58 	char *col1, *col2, *col3;
59 	char **p, line1[MAXLINELEN], line2[MAXLINELEN];
60 	int (*compare)(const char * ,const char *);
61 
62 	setlocale(LC_ALL, "");
63 
64 	flag1 = flag2 = flag3 = 1;
65 	compare = strcoll;
66 	while ((ch = getopt(argc, argv, "123f")) != -1)
67 		switch(ch) {
68 		case '1':
69 			flag1 = 0;
70 			break;
71 		case '2':
72 			flag2 = 0;
73 			break;
74 		case '3':
75 			flag3 = 0;
76 			break;
77 		case 'f':
78 			compare = strcasecmp;
79 			break;
80 		case '?':
81 		default:
82 			usage();
83 		}
84 	argc -= optind;
85 	argv += optind;
86 
87 	if (argc != 2)
88 		usage();
89 
90 	fp1 = file(argv[0]);
91 	fp2 = file(argv[1]);
92 
93 	/* for each column printed, add another tab offset */
94 	p = tabs;
95 	col1 = col2 = col3 = NULL;
96 	if (flag1)
97 		col1 = *p++;
98 	if (flag2)
99 		col2 = *p++;
100 	if (flag3)
101 		col3 = *p;
102 
103 	for (read1 = read2 = 1;;) {
104 		/* read next line, check for EOF */
105 		if (read1)
106 			file1done = !fgets(line1, MAXLINELEN, fp1);
107 		if (read2)
108 			file2done = !fgets(line2, MAXLINELEN, fp2);
109 
110 		/* if one file done, display the rest of the other file */
111 		if (file1done) {
112 			if (!file2done && col2)
113 				show(fp2, col2, line2);
114 			break;
115 		}
116 		if (file2done) {
117 			if (!file1done && col1)
118 				show(fp1, col1, line1);
119 			break;
120 		}
121 
122 		/* lines are the same */
123 		if (!(comp = compare(line1, line2))) {
124 			read1 = read2 = 1;
125 			if (col3)
126 				if (printf("%s%s", col3, line1) < 0)
127 					break;
128 			continue;
129 		}
130 
131 		/* lines are different */
132 		if (comp < 0) {
133 			read1 = 1;
134 			read2 = 0;
135 			if (col1)
136 				if (printf("%s%s", col1, line1) < 0)
137 					break;
138 		} else {
139 			read1 = 0;
140 			read2 = 1;
141 			if (col2)
142 				if (printf("%s%s", col2, line2) < 0)
143 					break;
144 		}
145 	}
146 
147 	if (ferror (stdout) || fclose (stdout) == EOF)
148 		err(1, "stdout");
149 
150 	exit(0);
151 }
152 
153 void
154 show(FILE *fp, char *offset, char *buf)
155 {
156 	while (printf("%s%s", offset, buf) >= 0 && fgets(buf, MAXLINELEN, fp))
157 		;
158 }
159 
160 FILE *
161 file(const char *name)
162 {
163 	FILE *fp;
164 
165 	if (!strcmp(name, "-"))
166 		return (stdin);
167 	if ((fp = fopen(name, "r")) == NULL)
168 		err(1, "%s", name);
169 	return (fp);
170 }
171 
172 void
173 usage(void)
174 {
175 	(void)fprintf(stderr, "usage: comm [-123f] file1 file2\n");
176 	exit(1);
177 }
178