xref: /openbsd-src/usr.bin/expand/expand.c (revision db3296cf5c1dd9058ceecc3a29fe4aaa0bd26000)
1 /*	$OpenBSD: expand.c,v 1.7 2003/07/03 03:09:39 deraadt Exp $	*/
2 /*	$NetBSD: expand.c,v 1.5 1995/09/02 06:19:46 jtc Exp $	*/
3 
4 /*
5  * Copyright (c) 1980, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #ifndef lint
34 static char copyright[] =
35 "@(#) Copyright (c) 1980, 1993\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)expand.c	8.1 (Berkeley) 6/9/93";
42 #endif
43 static char rcsid[] = "$OpenBSD: expand.c,v 1.7 2003/07/03 03:09:39 deraadt Exp $";
44 #endif /* not lint */
45 
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <ctype.h>
49 #include <unistd.h>
50 
51 /*
52  * expand - expand tabs to equivalent spaces
53  */
54 int	nstops;
55 int	tabstops[100];
56 
57 static void getstops(char *);
58 static void usage(void);
59 
60 int
61 main(int argc, char *argv[])
62 {
63 	int c, column;
64 	int n;
65 
66 	/* handle obsolete syntax */
67 	while (argc > 1 && argv[1][0] == '-' && isdigit(argv[1][1])) {
68 		getstops(&argv[1][1]);
69 		argc--; argv++;
70 	}
71 
72 	while ((c = getopt (argc, argv, "t:")) != -1) {
73 		switch (c) {
74 		case 't':
75 			getstops(optarg);
76 			break;
77 		case '?':
78 		default:
79 			usage();
80 			/* NOTREACHED */
81 		}
82 	}
83 	argc -= optind;
84 	argv += optind;
85 
86 	do {
87 		if (argc > 0) {
88 			if (freopen(argv[0], "r", stdin) == NULL) {
89 				perror(argv[0]);
90 				exit(1);
91 			}
92 			argc--, argv++;
93 		}
94 		column = 0;
95 		while ((c = getchar()) != EOF) {
96 			switch (c) {
97 			case '\t':
98 				if (nstops == 0) {
99 					do {
100 						putchar(' ');
101 						column++;
102 					} while (column & 07);
103 					continue;
104 				}
105 				if (nstops == 1) {
106 					do {
107 						putchar(' ');
108 						column++;
109 					} while (((column - 1) %
110 					    tabstops[0]) != (tabstops[0] - 1));
111 					continue;
112 				}
113 				for (n = 0; n < nstops; n++)
114 					if (tabstops[n] > column)
115 						break;
116 				if (n == nstops) {
117 					putchar(' ');
118 					column++;
119 					continue;
120 				}
121 				while (column < tabstops[n]) {
122 					putchar(' ');
123 					column++;
124 				}
125 				continue;
126 
127 			case '\b':
128 				if (column)
129 					column--;
130 				putchar('\b');
131 				continue;
132 
133 			default:
134 				putchar(c);
135 				column++;
136 				continue;
137 
138 			case '\n':
139 				putchar(c);
140 				column = 0;
141 				continue;
142 			}
143 		}
144 	} while (argc > 0);
145 	exit(0);
146 }
147 
148 static void
149 getstops(char *cp)
150 {
151 	int i;
152 
153 	nstops = 0;
154 	for (;;) {
155 		i = 0;
156 		while (*cp >= '0' && *cp <= '9')
157 			i = i * 10 + *cp++ - '0';
158 		if (i <= 0 || i > 256) {
159 bad:
160 			fprintf(stderr, "Bad tab stop spec\n");
161 			exit(1);
162 		}
163 		if (nstops > 0 && i <= tabstops[nstops-1])
164 			goto bad;
165 		tabstops[nstops++] = i;
166 		if (*cp == 0)
167 			break;
168 		if (*cp != ',' && *cp != ' ')
169 			goto bad;
170 		cp++;
171 	}
172 }
173 
174 static void
175 usage(void)
176 {
177 	(void)fprintf (stderr, "usage: expand [-t tablist] [file ...]\n");
178 	exit(1);
179 }
180