xref: /openbsd-src/usr.bin/unexpand/unexpand.c (revision f2da64fbbbf1b03f09f390ab01267c93dfd77c4c)
1 /*	$OpenBSD: unexpand.c,v 1.12 2015/11/11 02:52:46 deraadt 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 /*
34  * unexpand - put tabs into a file replacing blanks
35  */
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <unistd.h>
40 
41 char	genbuf[BUFSIZ];
42 char	linebuf[BUFSIZ];
43 int	all;
44 
45 void tabify(char);
46 
47 int
48 main(int argc, char *argv[])
49 {
50 	char *cp;
51 
52 	if (pledge("stdio rpath", NULL) == -1) {
53 		perror("pledge");
54 		exit(1);
55 	}
56 
57 	argc--, argv++;
58 	if (argc > 0 && argv[0][0] == '-') {
59 		if (strcmp(argv[0], "-a") != 0) {
60 			fprintf(stderr, "usage: unexpand [-a] [file ...]\n");
61 			exit(1);
62 		}
63 		all++;
64 		argc--, argv++;
65 	}
66 	do {
67 		if (argc > 0) {
68 			if (freopen(argv[0], "r", stdin) == NULL) {
69 				perror(argv[0]);
70 				exit(1);
71 			}
72 			argc--, argv++;
73 		}
74 		while (fgets(genbuf, BUFSIZ, stdin) != NULL) {
75 			for (cp = linebuf; *cp; cp++)
76 				continue;
77 			if (cp > linebuf)
78 				cp[-1] = 0;
79 			tabify(all);
80 			printf("%s", linebuf);
81 		}
82 	} while (argc > 0);
83 	exit(0);
84 }
85 
86 void
87 tabify(char c)
88 {
89 	char *cp, *dp;
90 	int dcol;
91 	int ocol;
92 	size_t len;
93 
94 	ocol = 0;
95 	dcol = 0;
96 	cp = genbuf;
97 	dp = linebuf;
98 	len = sizeof linebuf;
99 
100 	for (;;) {
101 		switch (*cp) {
102 
103 		case ' ':
104 			dcol++;
105 			break;
106 
107 		case '\t':
108 			dcol += 8;
109 			dcol &= ~07;
110 			break;
111 
112 		default:
113 			while (((ocol + 8) &~ 07) <= dcol) {
114 				if (ocol + 1 == dcol)
115 					break;
116 				if (len > 1) {
117 					*dp++ = '\t';
118 					len--;
119 				}
120 				ocol += 8;
121 				ocol &= ~07;
122 			}
123 			while (ocol < dcol) {
124 				if (len > 1) {
125 					*dp++ = ' ';
126 					len--;
127 				}
128 				ocol++;
129 			}
130 			if (*cp == 0 || c == 0) {
131 				strlcpy(dp, cp, len);
132 				return;
133 			}
134 			*dp++ = *cp;
135 			len--;
136 			ocol++;
137 			dcol++;
138 		}
139 		cp++;
140 	}
141 }
142