colrm.c revision 100817 
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
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1991, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif
39
40#if 0
41#ifndef lint
42static char sccsid[] = "@(#)colrm.c	8.2 (Berkeley) 5/4/95";
43#endif
44#endif
45
46#include <sys/cdefs.h>
47__FBSDID("$FreeBSD: head/usr.bin/colrm/colrm.c 100817 2002-07-28 15:22:43Z dwmalone $");
48
49#include <sys/types.h>
50#include <err.h>
51#include <errno.h>
52#include <limits.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57
58#define	TAB	8
59
60void check(FILE *);
61static void usage(void);
62
63int
64main(int argc, char *argv[])
65{
66	u_long column, start, stop;
67	int ch;
68	char *p;
69
70	while ((ch = getopt(argc, argv, "")) != -1)
71		switch(ch) {
72		case '?':
73		default:
74			usage();
75		}
76	argc -= optind;
77	argv += optind;
78
79	start = stop = 0;
80	switch(argc) {
81	case 2:
82		stop = strtol(argv[1], &p, 10);
83		if (stop <= 0 || *p)
84			errx(1, "illegal column -- %s", argv[1]);
85		/* FALLTHROUGH */
86	case 1:
87		start = strtol(argv[0], &p, 10);
88		if (start <= 0 || *p)
89			errx(1, "illegal column -- %s", argv[0]);
90		break;
91	case 0:
92		break;
93	default:
94		usage();
95	}
96
97	if (stop && start > stop)
98		errx(1, "illegal start and stop columns");
99
100	for (column = 0;;) {
101		switch (ch = getchar()) {
102		case EOF:
103			check(stdin);
104			break;
105		case '\b':
106			if (column)
107				--column;
108			break;
109		case '\n':
110			column = 0;
111			break;
112		case '\t':
113			column = (column + TAB) & ~(TAB - 1);
114			break;
115		default:
116			++column;
117			break;
118		}
119
120		if ((!start || column < start || (stop && column > stop)) &&
121		    putchar(ch) == EOF)
122			check(stdout);
123	}
124}
125
126void
127check(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(void)
137{
138	(void)fprintf(stderr, "usage: colrm [start [stop]]\n");
139	exit(1);
140}
141
142