xref: /freebsd/usr.bin/colrm/colrm.c (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb)
1 /*-
2  * Copyright (c) 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	$Id: colrm.c,v 1.5 1997/12/29 00:08:59 alex Exp $
34  */
35 
36 #ifndef lint
37 static const char copyright[] =
38 "@(#) Copyright (c) 1991, 1993\n\
39 	The Regents of the University of California.  All rights reserved.\n";
40 #endif /* not lint */
41 
42 #ifndef lint
43 static const char sccsid[] = "@(#)colrm.c	8.2 (Berkeley) 5/4/95";
44 #endif /* not lint */
45 
46 #include <sys/types.h>
47 #include <limits.h>
48 #include <err.h>
49 #include <errno.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54 
55 #define	TAB	8
56 
57 void check __P((FILE *));
58 static void usage __P((void));
59 
60 int
61 main(argc, argv)
62 	int argc;
63 	char *argv[];
64 {
65 	register u_long column, start, stop;
66 	register int ch;
67 	char *p;
68 
69 	while ((ch = getopt(argc, argv, "")) != -1)
70 		switch(ch) {
71 		case '?':
72 		default:
73 			usage();
74 		}
75 	argc -= optind;
76 	argv += optind;
77 
78 	start = stop = 0;
79 	switch(argc) {
80 	case 2:
81 		stop = strtol(argv[1], &p, 10);
82 		if (stop <= 0 || *p)
83 			errx(1, "illegal column -- %s", argv[1]);
84 		/* FALLTHROUGH */
85 	case 1:
86 		start = strtol(argv[0], &p, 10);
87 		if (start <= 0 || *p)
88 			errx(1, "illegal column -- %s", argv[0]);
89 		break;
90 	case 0:
91 		break;
92 	default:
93 		usage();
94 	}
95 
96 	if (stop && start > stop)
97 		errx(1, "illegal start and stop columns");
98 
99 	for (column = 0;;) {
100 		switch (ch = getchar()) {
101 		case EOF:
102 			check(stdin);
103 			break;
104 		case '\b':
105 			if (column)
106 				--column;
107 			break;
108 		case '\n':
109 			column = 0;
110 			break;
111 		case '\t':
112 			column = (column + TAB) & ~(TAB - 1);
113 			break;
114 		default:
115 			++column;
116 			break;
117 		}
118 
119 		if ((!start || column < start || (stop && column > stop)) &&
120 		    putchar(ch) == EOF)
121 			check(stdout);
122 	}
123 }
124 
125 void
126 check(stream)
127 	FILE *stream;
128 {
129 	if (feof(stream))
130 		exit(0);
131 	if (ferror(stream))
132 		err(1, "%s", stream == stdin ? "stdin" : "stdout");
133 }
134 
135 void
136 usage()
137 {
138 	(void)fprintf(stderr, "usage: colrm [start [stop]]\n");
139 	exit(1);
140 }
141 
142