xref: /openbsd/usr.bin/expand/expand.c (revision 3cab2bb3)
1 /*	$OpenBSD: expand.c,v 1.14 2015/10/09 01:37:07 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 #include <stdio.h>
34 #include <stdlib.h>
35 #include <ctype.h>
36 #include <unistd.h>
37 #include <err.h>
38 
39 /*
40  * expand - expand tabs to equivalent spaces
41  */
42 int	nstops;
43 int	tabstops[100];
44 
45 static void getstops(char *);
46 static void usage(void);
47 
48 int
49 main(int argc, char *argv[])
50 {
51 	int c, column;
52 	int n;
53 
54 	if (pledge("stdio rpath", NULL) == -1)
55 		err(1, "pledge");
56 
57 	/* handle obsolete syntax */
58 	while (argc > 1 && argv[1][0] == '-' &&
59 	    isdigit((unsigned char)argv[1][1])) {
60 		getstops(&argv[1][1]);
61 		argc--; argv++;
62 	}
63 
64 	while ((c = getopt (argc, argv, "t:")) != -1) {
65 		switch (c) {
66 		case 't':
67 			getstops(optarg);
68 			break;
69 		case '?':
70 		default:
71 			usage();
72 			/* NOTREACHED */
73 		}
74 	}
75 	argc -= optind;
76 	argv += optind;
77 
78 	do {
79 		if (argc > 0) {
80 			if (freopen(argv[0], "r", stdin) == NULL)
81 				err(1, "%s", argv[0]);
82 			argc--, argv++;
83 		}
84 		column = 0;
85 		while ((c = getchar()) != EOF) {
86 			switch (c) {
87 			case '\t':
88 				if (nstops == 0) {
89 					do {
90 						putchar(' ');
91 						column++;
92 					} while (column & 07);
93 					continue;
94 				}
95 				if (nstops == 1) {
96 					do {
97 						putchar(' ');
98 						column++;
99 					} while (((column - 1) %
100 					    tabstops[0]) != (tabstops[0] - 1));
101 					continue;
102 				}
103 				for (n = 0; n < nstops; n++)
104 					if (tabstops[n] > column)
105 						break;
106 				if (n == nstops) {
107 					putchar(' ');
108 					column++;
109 					continue;
110 				}
111 				while (column < tabstops[n]) {
112 					putchar(' ');
113 					column++;
114 				}
115 				continue;
116 
117 			case '\b':
118 				if (column)
119 					column--;
120 				putchar('\b');
121 				continue;
122 
123 			default:
124 				putchar(c);
125 				column++;
126 				continue;
127 
128 			case '\n':
129 				putchar(c);
130 				column = 0;
131 				continue;
132 			}
133 		}
134 	} while (argc > 0);
135 	exit(0);
136 }
137 
138 static void
139 getstops(char *cp)
140 {
141 	int i;
142 
143 	nstops = 0;
144 	for (;;) {
145 		i = 0;
146 		while (*cp >= '0' && *cp <= '9')
147 			i = i * 10 + *cp++ - '0';
148 		if (i <= 0 || i > 256) {
149 bad:
150 			errx(1, "Bad tab stop spec");
151 		}
152 		if (nstops > 0 && i <= tabstops[nstops-1])
153 			goto bad;
154 		if (nstops >= sizeof(tabstops) / sizeof(tabstops[0]))
155 			errx(1, "Too many tab stops");
156 		tabstops[nstops++] = i;
157 		if (*cp == 0)
158 			break;
159 		if (*cp != ',' && *cp != ' ')
160 			goto bad;
161 		cp++;
162 	}
163 }
164 
165 static void
166 usage(void)
167 {
168 	extern char *__progname;
169 	fprintf (stderr, "usage: %s [-t tablist] [file ...]\n", __progname);
170 	exit(1);
171 }
172