expand.c revision 1.12 
1/*	$NetBSD: expand.c,v 1.12 2008/07/21 14:19:22 lukem Exp $	*/
2
3/*
4 * Copyright (c) 1980, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#ifndef lint
34__COPYRIGHT("@(#) Copyright (c) 1980, 1993\
35 The Regents of the University of California.  All rights reserved.");
36#endif /* not lint */
37
38#ifndef lint
39#if 0
40static char sccsid[] = "@(#)expand.c	8.1 (Berkeley) 6/9/93";
41#endif
42__RCSID("$NetBSD: expand.c,v 1.12 2008/07/21 14:19:22 lukem Exp $");
43#endif /* not lint */
44
45#include <stdio.h>
46#include <stdlib.h>
47#include <ctype.h>
48#include <unistd.h>
49#include <err.h>
50
51/*
52 * expand - expand tabs to equivalent spaces
53 */
54size_t	nstops;
55size_t	tabstops[100];
56
57static	void	getstops(const char *);
58	int	main(int, char **);
59static	void	usage(void) __dead;
60
61int
62main(int argc, char *argv[])
63{
64	int c;
65	size_t n, column;
66
67	setprogname(argv[0]);
68
69	/* handle obsolete syntax */
70	while (argc > 1 &&
71	    argv[1][0] == '-' && isdigit((unsigned char)argv[1][1])) {
72		getstops(&argv[1][1]);
73		argc--; argv++;
74	}
75
76	while ((c = getopt (argc, argv, "t:")) != -1) {
77		switch (c) {
78		case 't':
79			getstops(optarg);
80			break;
81		case '?':
82		default:
83			usage();
84			/* NOTREACHED */
85		}
86	}
87	argc -= optind;
88	argv += optind;
89
90	do {
91		if (argc > 0) {
92			if (freopen(argv[0], "r", stdin) == NULL)
93				err(EXIT_FAILURE, "Cannot open `%s'", argv[0]);
94			argc--, argv++;
95		}
96		column = 0;
97		while ((c = getchar()) != EOF) {
98			switch (c) {
99			case '\t':
100				if (nstops == 0) {
101					do {
102						putchar(' ');
103						column++;
104					} while (column & 07);
105					continue;
106				}
107				if (nstops == 1) {
108					do {
109						putchar(' ');
110						column++;
111					} while (((column - 1) % tabstops[0])
112					    != (tabstops[0] - 1));
113					continue;
114				}
115				for (n = 0; n < nstops; n++)
116					if (tabstops[n] > column)
117						break;
118				if (n == nstops) {
119					putchar(' ');
120					column++;
121					continue;
122				}
123				while (column < tabstops[n]) {
124					putchar(' ');
125					column++;
126				}
127				continue;
128
129			case '\b':
130				if (column)
131					column--;
132				putchar('\b');
133				continue;
134
135			default:
136				putchar(c);
137				column++;
138				continue;
139
140			case '\n':
141				putchar(c);
142				column = 0;
143				continue;
144			}
145		}
146	} while (argc > 0);
147	return EXIT_SUCCESS;
148}
149
150static void
151getstops(const char *spec)
152{
153	int i;
154	const char *cp = spec;
155
156	nstops = 0;
157	for (;;) {
158		i = 0;
159		while (*cp >= '0' && *cp <= '9')
160			i = i * 10 + *cp++ - '0';
161		if (i <= 0 || i > 256)
162			errx(EXIT_FAILURE, "Too large tab stop spec `%d'", i);
163		if (nstops > 0 && i <= tabstops[nstops-1])
164			errx(EXIT_FAILURE, "Out of order tabstop spec `%d'", i);
165		if (nstops == sizeof(tabstops) / sizeof(tabstops[0]) - 1)
166			errx(EXIT_FAILURE, "Too many tabstops");
167		tabstops[nstops++] = i;
168		if (*cp == '\0')
169			break;
170		if (*cp != ',' && *cp != ' ')
171			errx(EXIT_FAILURE, "Illegal tab stop spec `%s'", spec);
172		cp++;
173	}
174}
175
176static void
177usage(void)
178{
179
180	(void)fprintf(stderr, "Usage: %s [-t tablist] [file ...]\n",
181	    getprogname());
182	exit(EXIT_FAILURE);
183}
184