xref: /openbsd-src/usr.bin/unexpand/unexpand.c (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
1 /*	$OpenBSD: unexpand.c,v 1.9 2003/07/10 00:06:51 david Exp $	*/
2 /*	$NetBSD: unexpand.c,v 1.5 1994/12/24 17:08:05 cgd 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 #ifndef lint
34 static char copyright[] =
35 "@(#) Copyright (c) 1980, 1993\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)unexpand.c	8.1 (Berkeley) 6/6/93";
42 #endif
43 static char rcsid[] = "$OpenBSD: unexpand.c,v 1.9 2003/07/10 00:06:51 david Exp $";
44 #endif /* not lint */
45 
46 /*
47  * unexpand - put tabs into a file replacing blanks
48  */
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 
53 char	genbuf[BUFSIZ];
54 char	linebuf[BUFSIZ];
55 int	all;
56 
57 void tabify(char);
58 
59 int
60 main(int argc, char *argv[])
61 {
62 	char *cp;
63 
64 	argc--, argv++;
65 	if (argc > 0 && argv[0][0] == '-') {
66 		if (strcmp(argv[0], "-a") != 0) {
67 			fprintf(stderr, "usage: unexpand [-a] [file ...]\n");
68 			exit(1);
69 		}
70 		all++;
71 		argc--, argv++;
72 	}
73 	do {
74 		if (argc > 0) {
75 			if (freopen(argv[0], "r", stdin) == NULL) {
76 				perror(argv[0]);
77 				exit(1);
78 			}
79 			argc--, argv++;
80 		}
81 		while (fgets(genbuf, BUFSIZ, stdin) != NULL) {
82 			for (cp = linebuf; *cp; cp++)
83 				continue;
84 			if (cp > linebuf)
85 				cp[-1] = 0;
86 			tabify(all);
87 			printf("%s", linebuf);
88 		}
89 	} while (argc > 0);
90 	exit(0);
91 }
92 
93 void
94 tabify(char c)
95 {
96 	char *cp, *dp;
97 	int dcol;
98 	int ocol;
99 	size_t len;
100 
101 	ocol = 0;
102 	dcol = 0;
103 	cp = genbuf;
104 	dp = linebuf;
105 	len = sizeof linebuf;
106 
107 	for (;;) {
108 		switch (*cp) {
109 
110 		case ' ':
111 			dcol++;
112 			break;
113 
114 		case '\t':
115 			dcol += 8;
116 			dcol &= ~07;
117 			break;
118 
119 		default:
120 			while (((ocol + 8) &~ 07) <= dcol) {
121 				if (ocol + 1 == dcol)
122 					break;
123 				if (len > 1) {
124 					*dp++ = '\t';
125 					len--;
126 				}
127 				ocol += 8;
128 				ocol &= ~07;
129 			}
130 			while (ocol < dcol) {
131 				if (len > 1) {
132 					*dp++ = ' ';
133 					len--;
134 				}
135 				ocol++;
136 			}
137 			if (*cp == 0 || c == 0) {
138 				strlcpy(dp, cp, len);
139 				return;
140 			}
141 			*dp++ = *cp;
142 			len--;
143 			ocol++;
144 			dcol++;
145 		}
146 		cp++;
147 	}
148 }
149