xref: /dragonfly/usr.bin/colrm/colrm.c (revision c9f721c2)
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  * $FreeBSD: src/usr.bin/colrm/colrm.c,v 1.7.2.1 2001/08/02 01:33:29 obrien Exp $
34  * $DragonFly: src/usr.bin/colrm/colrm.c,v 1.4 2003/11/03 19:31:29 eirikn Exp $
35  *
36  * @(#) Copyright (c) 1991, 1993 The Regents of the University of California.  All rights reserved.
37  * @(#)colrm.c	8.2 (Berkeley) 5/4/95
38  */
39 
40 #include <sys/types.h>
41 #include <limits.h>
42 #include <err.h>
43 #include <errno.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <unistd.h>
48 
49 #define	TAB	8
50 
51 int main(int, char *[]);
52 void check(FILE *);
53 static void usage(void);
54 
55 int
56 main(int argc, char **argv)
57 {
58 	register u_long column, start, stop;
59 	register int ch;
60 	char *p;
61 
62 	while ((ch = getopt(argc, argv, "")) != -1)
63 		switch(ch) {
64 		case '?':
65 		default:
66 			usage();
67 		}
68 	argc -= optind;
69 	argv += optind;
70 
71 	start = stop = 0;
72 	switch(argc) {
73 	case 2:
74 		stop = strtol(argv[1], &p, 10);
75 		if (stop <= 0 || *p)
76 			errx(1, "illegal column -- %s", argv[1]);
77 		/* FALLTHROUGH */
78 	case 1:
79 		start = strtol(argv[0], &p, 10);
80 		if (start <= 0 || *p)
81 			errx(1, "illegal column -- %s", argv[0]);
82 		break;
83 	case 0:
84 		break;
85 	default:
86 		usage();
87 	}
88 
89 	if (stop && start > stop)
90 		errx(1, "illegal start and stop columns");
91 
92 	for (column = 0;;) {
93 		switch (ch = getchar()) {
94 		case EOF:
95 			check(stdin);
96 			break;
97 		case '\b':
98 			if (column)
99 				--column;
100 			break;
101 		case '\n':
102 			column = 0;
103 			break;
104 		case '\t':
105 			column = (column + TAB) & ~(TAB - 1);
106 			break;
107 		default:
108 			++column;
109 			break;
110 		}
111 
112 		if ((!start || column < start || (stop && column > stop)) &&
113 		    putchar(ch) == EOF)
114 			check(stdout);
115 	}
116 }
117 
118 void
119 check(FILE *stream)
120 {
121 	if (feof(stream))
122 		exit(0);
123 	if (ferror(stream))
124 		err(1, "%s", stream == stdin ? "stdin" : "stdout");
125 }
126 
127 void
128 usage(void)
129 {
130 	(void)fprintf(stderr, "usage: colrm [start [stop]]\n");
131 	exit(1);
132 }
133 
134