xref: /freebsd/usr.bin/expand/expand.c (revision 17ee9d00bc1ae1e598c38f25826f861e4bc6c3ce)
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 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 static char sccsid[] = "@(#)expand.c	8.1 (Berkeley) 6/9/93";
42 #endif /* not lint */
43 
44 #include <stdio.h>
45 /*
46  * expand - expand tabs to equivalent spaces
47  */
48 int	nstops;
49 int	tabstops[100];
50 
51 main(argc, argv)
52 	int argc;
53 	char *argv[];
54 {
55 	register int c, column;
56 	register int n;
57 
58 	argc--, argv++;
59 	do {
60 		while (argc > 0 && argv[0][0] == '-') {
61 			getstops(argv[0]);
62 			argc--, argv++;
63 		}
64 		if (argc > 0) {
65 			if (freopen(argv[0], "r", stdin) == NULL) {
66 				perror(argv[0]);
67 				exit(1);
68 			}
69 			argc--, argv++;
70 		}
71 		column = 0;
72 		for (;;) {
73 			c = getc(stdin);
74 			if (c == -1)
75 				break;
76 			switch (c) {
77 
78 			case '\t':
79 				if (nstops == 0) {
80 					do {
81 						putchar(' ');
82 						column++;
83 					} while (column & 07);
84 					continue;
85 				}
86 				if (nstops == 1) {
87 					do {
88 						putchar(' ');
89 						column++;
90 					} while (((column - 1) % tabstops[0]) != (tabstops[0] - 1));
91 					continue;
92 				}
93 				for (n = 0; n < nstops; n++)
94 					if (tabstops[n] > column)
95 						break;
96 				if (n == nstops) {
97 					putchar(' ');
98 					column++;
99 					continue;
100 				}
101 				while (column < tabstops[n]) {
102 					putchar(' ');
103 					column++;
104 				}
105 				continue;
106 
107 			case '\b':
108 				if (column)
109 					column--;
110 				putchar('\b');
111 				continue;
112 
113 			default:
114 				putchar(c);
115 				column++;
116 				continue;
117 
118 			case '\n':
119 				putchar(c);
120 				column = 0;
121 				continue;
122 			}
123 		}
124 	} while (argc > 0);
125 	exit(0);
126 }
127 
128 getstops(cp)
129 	register char *cp;
130 {
131 	register int i;
132 
133 	nstops = 0;
134 	cp++;
135 	for (;;) {
136 		i = 0;
137 		while (*cp >= '0' && *cp <= '9')
138 			i = i * 10 + *cp++ - '0';
139 		if (i <= 0 || i > 256) {
140 bad:
141 			fprintf(stderr, "Bad tab stop spec\n");
142 			exit(1);
143 		}
144 		if (nstops > 0 && i <= tabstops[nstops-1])
145 			goto bad;
146 		tabstops[nstops++] = i;
147 		if (*cp == 0)
148 			break;
149 		if (*cp++ != ',')
150 			goto bad;
151 	}
152 }
153