xref: /freebsd/usr.bin/expand/expand.c (revision 817420dc8eac7df799c78f5309b75092b7f7cd40)
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 <unistd.h>
52 
53 /*
54  * expand - expand tabs to equivalent spaces
55  */
56 int	nstops;
57 int	tabstops[100];
58 
59 static void getstops __P((char *));
60 static void usage __P((void));
61 
62 int
63 main(argc, argv)
64 	int argc;
65 	char *argv[];
66 {
67 	register int c, column;
68 	register int n;
69 
70 	/* handle obsolete syntax */
71 	while (argc > 1 && argv[1][0] == '-' && isdigit(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 				errx(1, "%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]) != (tabstops[0] - 1));
112 					continue;
113 				}
114 				for (n = 0; n < nstops; n++)
115 					if (tabstops[n] > column)
116 						break;
117 				if (n == nstops) {
118 					putchar(' ');
119 					column++;
120 					continue;
121 				}
122 				while (column < tabstops[n]) {
123 					putchar(' ');
124 					column++;
125 				}
126 				continue;
127 
128 			case '\b':
129 				if (column)
130 					column--;
131 				putchar('\b');
132 				continue;
133 
134 			default:
135 				putchar(c);
136 				column++;
137 				continue;
138 
139 			case '\n':
140 				putchar(c);
141 				column = 0;
142 				continue;
143 			}
144 		}
145 	} while (argc > 0);
146 	exit(0);
147 }
148 
149 static void
150 getstops(cp)
151 	register char *cp;
152 {
153 	register int i;
154 
155 	nstops = 0;
156 	for (;;) {
157 		i = 0;
158 		while (*cp >= '0' && *cp <= '9')
159 			i = i * 10 + *cp++ - '0';
160 		if (i <= 0 || i > 256)
161 			errx(1, "bad tab stop spec");
162 		if (nstops > 0 && i <= tabstops[nstops-1])
163 			errx(1, "bad tab stop spec");
164 		tabstops[nstops++] = i;
165 		if (*cp == 0)
166 			break;
167 		if (*cp != ',' && *cp != ' ')
168 			errx(1, "bad tab stop spec");
169 		cp++;
170 	}
171 }
172 
173 static void
174 usage()
175 {
176 	(void)fprintf (stderr, "usage: expand [-t tablist] [file ...]\n");
177 	exit(1);
178 }
179