xref: /freebsd/usr.bin/unexpand/unexpand.c (revision f126890ac5386406dadf7c4cfa9566cbb56537c5)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * unexpand - put tabs into a file replacing blanks
34  */
35 #include <ctype.h>
36 #include <err.h>
37 #include <limits.h>
38 #include <locale.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43 #include <wchar.h>
44 #include <wctype.h>
45 
46 static int	all;
47 static int	nstops;
48 static int	tabstops[100];
49 
50 static void getstops(const char *);
51 static void usage(void) __dead2;
52 static int tabify(const char *);
53 
54 int
55 main(int argc, char *argv[])
56 {
57 	int ch, failed;
58 	char *filename;
59 
60 	setlocale(LC_CTYPE, "");
61 
62 	nstops = 1;
63 	tabstops[0] = 8;
64 	while ((ch = getopt(argc, argv, "at:")) != -1) {
65 		switch (ch) {
66 		case 'a':	/* Un-expand all spaces, not just leading. */
67 			all = 1;
68 			break;
69 		case 't':	/* Specify tab list, implies -a. */
70 			getstops(optarg);
71 			all = 1;
72 			break;
73 		default:
74 			usage();
75 			/*NOTREACHED*/
76 		}
77 	}
78 	argc -= optind;
79 	argv += optind;
80 
81 	failed = 0;
82 	if (argc == 0)
83 		failed |= tabify("stdin");
84 	else {
85 		while ((filename = *argv++) != NULL) {
86 			if (freopen(filename, "r", stdin) == NULL) {
87 				warn("%s", filename);
88 				failed = 1;
89 			} else
90 				failed |= tabify(filename);
91 		}
92 	}
93 	exit(failed != 0);
94 }
95 
96 static void
97 usage(void)
98 {
99 	fprintf(stderr, "usage: unexpand [-a | -t tablist] [file ...]\n");
100 	exit(1);
101 }
102 
103 static int
104 tabify(const char *curfile)
105 {
106 	int dcol, doneline, limit, n, ocol, width;
107 	wint_t ch;
108 
109 	limit = nstops == 1 ? INT_MAX : tabstops[nstops - 1] - 1;
110 
111 	doneline = ocol = dcol = 0;
112 	while ((ch = getwchar()) != WEOF) {
113 		if (ch == ' ' && !doneline) {
114 			if (++dcol >= limit)
115 				doneline = 1;
116 			continue;
117 		} else if (ch == '\t') {
118 			if (nstops == 1) {
119 				dcol = (1 + dcol / tabstops[0]) *
120 				    tabstops[0];
121 				continue;
122 			} else {
123 				for (n = 0; n < nstops &&
124 				    tabstops[n] - 1 < dcol; n++)
125 					;
126 				if (n < nstops - 1 && tabstops[n] - 1 < limit) {
127 					dcol = tabstops[n];
128 					continue;
129 				}
130 				doneline = 1;
131 			}
132 		}
133 
134 		/* Output maximal number of tabs. */
135 		if (nstops == 1) {
136 			while (((ocol + tabstops[0]) / tabstops[0])
137 			    <= (dcol / tabstops[0])) {
138 				if (dcol - ocol < 2)
139 					break;
140 				putwchar('\t');
141 				ocol = (1 + ocol / tabstops[0]) *
142 				    tabstops[0];
143 			}
144 		} else {
145 			for (n = 0; n < nstops && tabstops[n] - 1 < ocol; n++)
146 				;
147 			while (ocol < dcol && n < nstops && ocol < limit) {
148 				putwchar('\t');
149 				ocol = tabstops[n++];
150 			}
151 		}
152 
153 		/* Then spaces. */
154 		while (ocol < dcol && ocol < limit) {
155 			putwchar(' ');
156 			ocol++;
157 		}
158 
159 		if (ch == '\b') {
160 			putwchar('\b');
161 			if (ocol > 0)
162 				ocol--, dcol--;
163 		} else if (ch == '\n') {
164 			putwchar('\n');
165 			doneline = ocol = dcol = 0;
166 			continue;
167 		} else if (ch != ' ' || dcol > limit) {
168 			putwchar(ch);
169 			if ((width = wcwidth(ch)) > 0)
170 				ocol += width, dcol += width;
171 		}
172 
173 		/*
174 		 * Only processing leading blanks or we've gone past the
175 		 * last tab stop. Emit remainder of this line unchanged.
176 		 */
177 		if (!all || dcol >= limit) {
178 			while ((ch = getwchar()) != '\n' && ch != WEOF)
179 				putwchar(ch);
180 			if (ch == '\n')
181 				putwchar('\n');
182 			doneline = ocol = dcol = 0;
183 		}
184 	}
185 	if (ferror(stdin)) {
186 		warn("%s", curfile);
187 		return (1);
188 	}
189 	return (0);
190 }
191 
192 static void
193 getstops(const char *cp)
194 {
195 	int i;
196 
197 	nstops = 0;
198 	for (;;) {
199 		i = 0;
200 		while (*cp >= '0' && *cp <= '9')
201 			i = i * 10 + *cp++ - '0';
202 		if (i <= 0)
203 			errx(1, "bad tab stop spec");
204 		if (nstops > 0 && i <= tabstops[nstops-1])
205 			errx(1, "bad tab stop spec");
206 		if (nstops == sizeof(tabstops) / sizeof(*tabstops))
207 			errx(1, "too many tab stops");
208 		tabstops[nstops++] = i;
209 		if (*cp == 0)
210 			break;
211 		if (*cp != ',' && !isblank((unsigned char)*cp))
212 			errx(1, "bad tab stop spec");
213 		cp++;
214 	}
215 }
216