colrm.c revision 41568 
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
37static 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
43static 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
57void check __P((FILE *));
58static void usage __P((void));
59
60int
61main(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
125void
126check(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
135void
136usage()
137{
138	(void)fprintf(stderr, "usage: colrm [start [stop]]\n");
139	exit(1);
140}
141
142