xref: /freebsd/usr.bin/expand/expand.c (revision 4cf49a43559ed9fdad601bdcccd2c55963008675)
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 #else
44 static const char rcsid[] =
45   "$FreeBSD$";
46 #endif
47 #endif /* not lint */
48 
49 #include <ctype.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 				perror(argv[0]);
95 				exit(1);
96 			}
97 			argc--, argv++;
98 		}
99 		column = 0;
100 		while ((c = getchar()) != EOF) {
101 			switch (c) {
102 			case '\t':
103 				if (nstops == 0) {
104 					do {
105 						putchar(' ');
106 						column++;
107 					} while (column & 07);
108 					continue;
109 				}
110 				if (nstops == 1) {
111 					do {
112 						putchar(' ');
113 						column++;
114 					} while (((column - 1) % tabstops[0]) != (tabstops[0] - 1));
115 					continue;
116 				}
117 				for (n = 0; n < nstops; n++)
118 					if (tabstops[n] > column)
119 						break;
120 				if (n == nstops) {
121 					putchar(' ');
122 					column++;
123 					continue;
124 				}
125 				while (column < tabstops[n]) {
126 					putchar(' ');
127 					column++;
128 				}
129 				continue;
130 
131 			case '\b':
132 				if (column)
133 					column--;
134 				putchar('\b');
135 				continue;
136 
137 			default:
138 				putchar(c);
139 				column++;
140 				continue;
141 
142 			case '\n':
143 				putchar(c);
144 				column = 0;
145 				continue;
146 			}
147 		}
148 	} while (argc > 0);
149 	exit(0);
150 }
151 
152 static void
153 getstops(cp)
154 	register char *cp;
155 {
156 	register int i;
157 
158 	nstops = 0;
159 	for (;;) {
160 		i = 0;
161 		while (*cp >= '0' && *cp <= '9')
162 			i = i * 10 + *cp++ - '0';
163 		if (i <= 0 || i > 256) {
164 bad:
165 			fprintf(stderr, "Bad tab stop spec\n");
166 			exit(1);
167 		}
168 		if (nstops > 0 && i <= tabstops[nstops-1])
169 			goto bad;
170 		tabstops[nstops++] = i;
171 		if (*cp == 0)
172 			break;
173 		if (*cp != ',' && *cp != ' ')
174 			goto bad;
175 		cp++;
176 	}
177 }
178 
179 static void
180 usage()
181 {
182 	(void)fprintf (stderr, "usage: expand [-t tablist] [file ...]\n");
183 	exit(1);
184 }
185