xref: /freebsd/usr.bin/unexpand/unexpand.c (revision 2a4a1db342263067035ce69a4017c645da63455d)
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 #include <sys/cdefs.h>
35 
36 __FBSDID("$FreeBSD$");
37 
38 #ifndef lint
39 static const char copyright[] =
40 "@(#) Copyright (c) 1980, 1993\n\
41 	The Regents of the University of California.  All rights reserved.\n";
42 #endif
43 
44 #ifndef lint
45 static const char sccsid[] = "@(#)unexpand.c	8.1 (Berkeley) 6/6/93";
46 #endif
47 
48 /*
49  * unexpand - put tabs into a file replacing blanks
50  */
51 #include <err.h>
52 #include <limits.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <unistd.h>
57 
58 int	all;
59 int	nstops;
60 int	tabstops[100];
61 
62 static void getstops(const char *);
63 static void usage(void);
64 static void tabify(void);
65 
66 int
67 main(argc, argv)
68 	int argc;
69 	char *argv[];
70 {
71 	int ch, failed;
72 	char *filename;
73 
74 	nstops = 1;
75 	tabstops[0] = 8;
76 	while ((ch = getopt(argc, argv, "at:")) != -1) {
77 		switch (ch) {
78 		case 'a':	/* Un-expand all spaces, not just leading. */
79 			all = 1;
80 			break;
81 		case 't':	/* Specify tab list, implies -a. */
82 			getstops(optarg);
83 			all = 1;
84 			break;
85 		default:
86 			usage();
87 			/*NOTREACHED*/
88 		}
89 	}
90 	argc -= optind;
91 	argv += optind;
92 
93 	failed = 0;
94 	if (argc == 0)
95 		tabify();
96 	else {
97 		while ((filename = *argv++) != NULL) {
98 			if (freopen(filename, "r", stdin) == NULL) {
99 				warn("%s", filename);
100 				failed++;
101 			} else
102 				tabify();
103 		}
104 	}
105 	exit(failed != 0);
106 }
107 
108 static void
109 usage()
110 {
111 	fprintf(stderr, "usage: unexpand [-a] [-t tablist] [file ...]\n");
112 	exit(1);
113 }
114 
115 static void
116 tabify()
117 {
118 	int ch, dcol, doneline, limit, n, ocol;
119 
120 	limit = nstops == 1 ? INT_MAX : tabstops[nstops - 1] - 1;
121 
122 	doneline = ocol = dcol = 0;
123 	while ((ch = getchar()) != EOF) {
124 		if (ch == ' ' && !doneline) {
125 			if (++dcol >= limit)
126 				doneline = 1;
127 			continue;
128 		} else if (ch == '\t') {
129 			if (nstops == 1) {
130 				dcol = (1 + dcol / tabstops[0]) *
131 				    tabstops[0];
132 				continue;
133 			} else {
134 				for (n = 0; tabstops[n] - 1 < dcol &&
135 				    n < nstops; n++)
136 					;
137 				if (n < nstops - 1 && tabstops[n] - 1 < limit) {
138 					dcol = tabstops[n];
139 					continue;
140 				}
141 				doneline = 1;
142 			}
143 		}
144 
145 		/* Output maximal number of tabs. */
146 		if (nstops == 1) {
147 			while (((ocol + tabstops[0]) / tabstops[0])
148 			    <= (dcol / tabstops[0])) {
149 				if (dcol - ocol < 2)
150 					break;
151 				putchar('\t');
152 				ocol = (1 + ocol / tabstops[0]) *
153 				    tabstops[0];
154 			}
155 		} else {
156 			for (n = 0; tabstops[n] - 1 < ocol && n < nstops; n++)
157 				;
158 			while (ocol < dcol && n < nstops && ocol < limit) {
159 				putchar('\t');
160 				ocol = tabstops[n++];
161 			}
162 		}
163 
164 		/* Then spaces. */
165 		while (ocol < dcol && ocol < limit) {
166 			putchar(' ');
167 			ocol++;
168 		}
169 
170 		if (ch == '\b') {
171 			putchar('\b');
172 			if (ocol > 0)
173 				ocol--, dcol--;
174 		} else if (ch == '\n') {
175 			putchar('\n');
176 			doneline = ocol = dcol = 0;
177 		} else if (ch != ' ' || dcol > limit) {
178 			putchar(ch);
179 			ocol++, dcol++;
180 		}
181 
182 		/*
183 		 * Only processing leading blanks or we've gone past the
184 		 * last tab stop. Emit remainder of this line unchanged.
185 		 */
186 		if (!all || dcol >= limit) {
187 			while ((ch = getchar()) != '\n' && ch != EOF)
188 				putchar(ch);
189 			if (ch == '\n')
190 				putchar('\n');
191 			doneline = ocol = dcol = 0;
192 		}
193 	}
194 }
195 
196 static void
197 getstops(cp)
198 	const char *cp;
199 {
200 	int i;
201 
202 	nstops = 0;
203 	for (;;) {
204 		i = 0;
205 		while (*cp >= '0' && *cp <= '9')
206 			i = i * 10 + *cp++ - '0';
207 		if (i <= 0)
208 			errx(1, "bad tab stop spec");
209 		if (nstops > 0 && i <= tabstops[nstops-1])
210 			errx(1, "bad tab stop spec");
211 		if (nstops == sizeof(tabstops) / sizeof(*tabstops))
212 			errx(1, "too many tab stops");
213 		tabstops[nstops++] = i;
214 		if (*cp == 0)
215 			break;
216 		if (*cp != ',' && *cp != ' ')
217 			errx(1, "bad tab stop spec");
218 		cp++;
219 	}
220 }
221