xref: /netbsd-src/usr.bin/comm/comm.c (revision 809c33aadd4d94bd1b06b18dd5833f589564329b)
1 /*	$NetBSD: comm.c,v 1.20 2012/09/05 04:01:23 simonb 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 1.20 2012/09/05 04:01:23 simonb 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 static const char *tabs[] = { "", "\t", "\t\t" };
59 
60 static FILE   *file(const char *);
61 static void	show(FILE *, const char *, char *);
62 __dead static void	usage(void);
63 static char   *getnextln(char *buf, FILE *);
64 
65 int
main(int argc,char ** argv)66 main(int argc, char **argv)
67 {
68 	int comp, file1done, file2done, read1, read2;
69 	int ch, flag1, flag2, flag3;
70 	FILE *fp1, *fp2;
71 	const char *col1, *col2, *col3, **p;
72 	char line1[MAXLINELEN], line2[MAXLINELEN];
73 	int (*compare)(const char*,const char*);
74 
75 	(void)setlocale(LC_ALL, "");
76 
77 	file1done = file2done = 0;
78 	flag1 = flag2 = flag3 = 1;
79 	compare = strcoll;
80 	while ((ch = getopt(argc, argv, "123f")) != -1)
81 		switch(ch) {
82 		case '1':
83 			flag1 = 0;
84 			break;
85 		case '2':
86 			flag2 = 0;
87 			break;
88 		case '3':
89 			flag3 = 0;
90 			break;
91 		case 'f':
92 			compare = strcasecmp;
93 			break;
94 		case '?':
95 		default:
96 			usage();
97 		}
98 	argc -= optind;
99 	argv += optind;
100 
101 	if (argc != 2)
102 		usage();
103 
104 	fp1 = file(argv[0]);
105 	fp2 = file(argv[1]);
106 
107 	/* for each column printed, add another tab offset */
108 	p = tabs;
109 	col1 = col2 = col3 = NULL;
110 	if (flag1)
111 		col1 = *p++;
112 	if (flag2)
113 		col2 = *p++;
114 	if (flag3)
115 		col3 = *p;
116 
117 	for (read1 = read2 = 1;;) {
118 		/* read next line, check for EOF */
119 		if (read1)
120 			file1done = !getnextln(line1, fp1);
121 		if (read2)
122 			file2done = !getnextln(line2, fp2);
123 
124 		/* if one file done, display the rest of the other file */
125 		if (file1done) {
126 			if (!file2done && col2)
127 				show(fp2, col2, line2);
128 			break;
129 		}
130 		if (file2done) {
131 			if (!file1done && col1)
132 				show(fp1, col1, line1);
133 			break;
134 		}
135 
136 		/* lines are the same */
137 		if (!(comp = compare(line1, line2))) {
138 			read1 = read2 = 1;
139 			if (col3)
140 				if (printf("%s%s\n", col3, line1) < 0)
141 					break;
142 			continue;
143 		}
144 
145 		/* lines are different */
146 		if (comp < 0) {
147 			read1 = 1;
148 			read2 = 0;
149 			if (col1)
150 				if (printf("%s%s\n", col1, line1) < 0)
151 					break;
152 		} else {
153 			read1 = 0;
154 			read2 = 1;
155 			if (col2)
156 				if (printf("%s%s\n", col2, line2) < 0)
157 					break;
158 		}
159 	}
160 
161 	if (ferror (stdout) || fclose (stdout) == EOF)
162 		err(1, "stdout");
163 
164 	exit(0);
165 }
166 
167 static void
show(FILE * fp,const char * offset,char * buf)168 show(FILE *fp, const char *offset, char *buf)
169 {
170 	while (printf("%s%s\n", offset, buf) >= 0 && getnextln(buf, fp))
171 		;
172 }
173 
174 static FILE *
file(const char * name)175 file(const char *name)
176 {
177 	FILE *fp;
178 
179 	if (!strcmp(name, "-"))
180 		return (stdin);
181 	if ((fp = fopen(name, "r")) == NULL)
182 		err(1, "%s", name);
183 	return (fp);
184 }
185 
186 static void
usage(void)187 usage(void)
188 {
189 
190 	(void)fprintf(stderr, "usage: comm [-123f] file1 file2\n");
191 	exit(1);
192 }
193 
194 static char *
getnextln(char * buf,FILE * fp)195 getnextln(char *buf, FILE *fp)
196 {
197 	size_t i = 0;
198 	int c;
199 
200 	while ((c = getc(fp)) != '\n' && c != EOF) {
201 		buf[i++] = c;
202 
203 		if (i >= MAXLINELEN)
204 			i--; /* consumes extra characters till newline */
205 	}
206 
207 	if (c == EOF && !i)
208 		return NULL;
209 
210 	buf[i] = 0;
211 	return buf;
212 }
213 
214