xref: /freebsd/usr.bin/comm/comm.c (revision afe61c15161c324a7af299a9b8457aba5afc92db)
1 /*
2  * Copyright (c) 1989, 1993, 1994
3  *	The Regents of the University of California.  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
38 static char copyright[] =
39 "@(#) Copyright (c) 1989, 1993, 1994\n\
40 	The Regents of the University of California.  All rights reserved.\n";
41 #endif /* not lint */
42 
43 #ifndef lint
44 static char sccsid[] = "@(#)comm.c	8.3 (Berkeley) 4/2/94";
45 #endif /* not lint */
46 
47 #include <fcntl.h>
48 #include <limits.h>
49 #include <errno.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 
54 #define	MAXLINELEN	(LINE_MAX + 1)
55 
56 char *tabs[] = { "", "\t", "\t\t" };
57 
58 FILE   *file __P((char *));
59 void	show __P((FILE *, char *, char *));
60 void	usage __P((void));
61 
62 int
63 main(argc, argv)
64 	int argc;
65 	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 
73 	flag1 = flag2 = flag3 = 1;
74 	while ((ch = getopt(argc, argv, "-123")) != EOF)
75 		switch(ch) {
76 		case '-':
77 			--optind;
78 			goto done;
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 done:	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 = strcmp(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 
154 void
155 show(fp, offset, buf)
156 	FILE *fp;
157 	char *offset, *buf;
158 {
159 
160 	do {
161 		(void)printf("%s%s", offset, buf);
162 	} while (fgets(buf, MAXLINELEN, fp));
163 }
164 
165 FILE *
166 file(name)
167 	char *name;
168 {
169 	FILE *fp;
170 
171 	if (!strcmp(name, "-"))
172 		return (stdin);
173 	if ((fp = fopen(name, "r")) == NULL) {
174 		(void)fprintf(stderr, "comm: %s: %s\n", name, strerror(errno));
175 		exit(1);
176 	}
177 	return (fp);
178 }
179 
180 void
181 usage()
182 {
183 
184 	(void)fprintf(stderr, "usage: comm [-123] file1 file2\n");
185 	exit(1);
186 }
187