xref: /freebsd/usr.bin/expand/expand.c (revision 5521ff5a4d1929056e7ffc982fac3341ca54df7c)
1 /*
2  * Copyright (c) 1980, 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
35 static const char copyright[] =
36 "@(#) Copyright (c) 1980, 1993\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 #if 0
42 static char sccsid[] = "@(#)expand.c	8.1 (Berkeley) 6/9/93";
43 #endif
44 static const char rcsid[] =
45   "$FreeBSD$";
46 #endif /* not lint */
47 
48 #include <ctype.h>
49 #include <err.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <unistd.h>
53 
54 /*
55  * expand - expand tabs to equivalent spaces
56  */
57 int	nstops;
58 int	tabstops[100];
59 
60 static void getstops __P((char *));
61 static void usage __P((void));
62 
63 int
64 main(argc, argv)
65 	int argc;
66 	char *argv[];
67 {
68 	register int c, column;
69 	register int n;
70 
71 	/* handle obsolete syntax */
72 	while (argc > 1 && argv[1][0] == '-' && isdigit(argv[1][1])) {
73 		getstops(&argv[1][1]);
74 		argc--; argv++;
75 	}
76 
77 	while ((c = getopt (argc, argv, "t:")) != -1) {
78 		switch (c) {
79 		case 't':
80 			getstops(optarg);
81 			break;
82 		case '?':
83 		default:
84 			usage();
85 			/* NOTREACHED */
86 		}
87 	}
88 	argc -= optind;
89 	argv += optind;
90 
91 	do {
92 		if (argc > 0) {
93 			if (freopen(argv[0], "r", stdin) == NULL)
94 				errx(1, "%s", argv[0]);
95 			argc--, argv++;
96 		}
97 		column = 0;
98 		while ((c = getchar()) != EOF) {
99 			switch (c) {
100 			case '\t':
101 				if (nstops == 0) {
102 					do {
103 						putchar(' ');
104 						column++;
105 					} while (column & 07);
106 					continue;
107 				}
108 				if (nstops == 1) {
109 					do {
110 						putchar(' ');
111 						column++;
112 					} while (((column - 1) % tabstops[0]) != (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 	exit(0);
148 }
149 
150 static void
151 getstops(cp)
152 	register char *cp;
153 {
154 	register int i;
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)
162 			errx(1, "bad tab stop spec");
163 		if (nstops > 0 && i <= tabstops[nstops-1])
164 			errx(1, "bad tab stop spec");
165 		tabstops[nstops++] = i;
166 		if (*cp == 0)
167 			break;
168 		if (*cp != ',' && *cp != ' ')
169 			errx(1, "bad tab stop spec");
170 		cp++;
171 	}
172 }
173 
174 static void
175 usage()
176 {
177 	(void)fprintf (stderr, "usage: expand [-t tablist] [file ...]\n");
178 	exit(1);
179 }
180