xref: /netbsd-src/usr.bin/comm/comm.c (revision ae9172d6cd9432a6a1a56760d86b32c57a66c39c)
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
38 char 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";*/
45 static 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 
58 char *tabs[] = { "", "\t", "\t\t" };
59 
60 FILE *file __P((const char *));
61 void  show __P((FILE *, char *, char *));
62 void  usage __P((void));
63 
64 int
65 main(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 
162 void
163 show(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 
171 FILE *
172 file(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 
186 void
187 usage()
188 {
189 	(void)fprintf(stderr, "usage: comm [-123] file1 file2\n");
190 	exit(1);
191 }
192