1 /* $NetBSD: unexpand.c,v 1.18 2019/09/13 17:32:29 dyoung Exp $ */
2
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 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1980, 1993\
35 The Regents of the University of California. All rights reserved.");
36 #endif /* not lint */
37
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)unexpand.c 8.1 (Berkeley) 6/6/93";
41 #endif
42 __RCSID("$NetBSD: unexpand.c,v 1.18 2019/09/13 17:32:29 dyoung Exp $");
43 #endif /* not lint */
44
45 /*
46 * unexpand - put tabs into a file replacing blanks
47 */
48 #include <limits.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53 #include <errno.h>
54 #include <err.h>
55 #include <util.h>
56
57
58 #define DSTOP 8
59 static int all;
60 static size_t nstops;
61 static size_t maxstops;
62 static size_t *tabstops;
63
64 static void tabify(const char *, size_t);
65 static void usage(void) __attribute__((__noreturn__));
66
67 static void
usage(void)68 usage(void)
69 {
70 (void)fprintf(stderr, "Usage: %s [-a] [-t tabstop] [file ...]\n",
71 getprogname());
72 exit(EXIT_FAILURE);
73 }
74
75 int
main(int argc,char ** argv)76 main(int argc, char **argv)
77 {
78 int c;
79 char *ep, *tab;
80 char *line;
81 size_t len;
82 unsigned long i;
83
84 setprogname(argv[0]);
85
86 while ((c = getopt(argc, argv, "at:")) != -1) {
87 switch (c) {
88 case 'a':
89 all = 1;
90 break;
91 case 't':
92 while ((tab = strsep(&optarg, ", \t")) != NULL) {
93 if (*tab == '\0')
94 continue;
95 errno = 0;
96 i = strtoul(tab, &ep, 0);
97 if (*ep || (errno == ERANGE && i == ULONG_MAX))
98 errx(EXIT_FAILURE,
99 "Invalid tabstop `%s'", tab);
100 if (nstops >= maxstops) {
101 maxstops += 20;
102 tabstops = erealloc(tabstops, maxstops);
103 }
104 if (nstops && tabstops[nstops - 1] >= (size_t)i)
105 errx(EXIT_FAILURE,
106 "Bad tabstop spec `%s', must be "
107 "greater than the previous `%zu'",
108 tab, tabstops[nstops - 1]);
109 tabstops[nstops++] = i;
110 }
111 break;
112 case '?':
113 default:
114 usage();
115 }
116 }
117 argc -= optind;
118 argv += optind;
119
120 do {
121 if (argc > 0) {
122 if (freopen(argv[0], "r", stdin) == NULL)
123 err(EXIT_FAILURE, "Cannot open `%s'", argv[0]);
124 argc--, argv++;
125 }
126 while ((line = fgetln(stdin, &len)) != NULL)
127 tabify(line, len);
128 } while (argc > 0);
129 return EXIT_SUCCESS;
130 }
131
132 static void
tabify(const char * line,size_t len)133 tabify(const char *line, size_t len)
134 {
135 const size_t dstop = (nstops == 0) ? DSTOP : tabstops[0];
136 const char *e, *p;
137 size_t dcol, ocol, limit, n;
138
139 dcol = ocol = 0;
140 limit = nstops <= 1 ? UINT_MAX : tabstops[nstops - 1] - 1;
141 e = line + len;
142 for (p = line; p < e; p++) {
143 if (*p == ' ') {
144 dcol++;
145 continue;
146 } else if (*p == '\t') {
147 if (nstops <= 1) {
148 dcol = (1 + dcol / dstop) * dstop;
149 continue;
150 }
151 for (n = 0; n < nstops && tabstops[n] <= dcol; n++)
152 continue;
153 if (n < nstops - 1 && tabstops[n] - 1 < limit) {
154 dcol = tabstops[n];
155 continue;
156 }
157 }
158
159 /* Output our tabs */
160 if (nstops <= 1) {
161 while (((ocol + dstop) / dstop) <= (dcol / dstop)) {
162 if (dcol - ocol < 2)
163 break;
164 if (putchar('\t') == EOF)
165 goto out;
166 ocol = (1 + ocol / dstop) * dstop;
167 }
168 } else {
169 for (n = 0; n < nstops && tabstops[n] <= ocol; n++)
170 continue;
171 while (n < nstops && tabstops[n] <= dcol && ocol < dcol
172 && ocol < limit) {
173 if (putchar('\t') == EOF)
174 goto out;
175 ocol = tabstops[n++];
176 }
177 }
178
179 /* Output remaining spaces */
180 while (ocol < dcol && ocol < limit) {
181 if (putchar(' ') == EOF)
182 goto out;
183 ocol++;
184 }
185
186 /* Output our char */
187 if (putchar(*p) == EOF)
188 goto out;
189 if (*p == '\b') {
190 if (ocol > 0) {
191 ocol--;
192 dcol--;
193 }
194 } else {
195 ocol++;
196 dcol++;
197 }
198
199 if (all && dcol < limit)
200 continue; /* Collapse the rest of the line. */
201
202 /* Output remainder of line */
203 for (p++; p < e; p++) {
204 if (putchar(*p) == EOF)
205 goto out;
206 }
207 return;
208 }
209 return;
210 out:
211 err(EXIT_FAILURE, "write failed");
212 }
213