xref: /freebsd/usr.bin/tabs/tabs.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2002 Tim J. Robbins.
5  * 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  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 /*
30  * tabs -- set terminal tabs
31  *
32  * This utility displays a series of characters that clears the terminal
33  * hardware tab settings, then initialises them to specified values,
34  * and optionally sets a soft margin.
35  */
36 
37 #include <sys/cdefs.h>
38 #include <sys/types.h>
39 #include <sys/tty.h>
40 
41 #include <ctype.h>
42 #include <err.h>
43 #include <errno.h>
44 #include <locale.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <term.h>
49 #include <unistd.h>
50 
51 /* Maximum number of tab stops allowed in table. */
52 #define NSTOPS		20
53 
54 #define NELEMS(a) (sizeof(a) / sizeof(a[0]))
55 
56 /* Predefined formats, taken from IEEE Std 1003.1-2001. */
57 static const struct {
58 	const char	*name;		/* Format name used on cmd. line */
59 	long		stops[NSTOPS];	/* Column positions */
60 } formats[] = {
61 	{ "a",	{ 1, 10, 16, 36, 72 } },
62 	{ "a2",	{ 1, 10, 16, 40, 72 } },
63 	{ "c",	{ 1, 8, 12, 16, 20, 55 } },
64 	{ "c2",	{ 1, 6, 10, 14, 49 } },
65 	{ "c3", { 1, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58,
66 		62, 67 } },
67 	{ "f",	{ 1, 7, 11, 15, 19, 23 } },
68 	{ "p",	{ 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57,
69 		61 } },
70 	{ "s",	{ 1, 10, 55 } },
71 	{ "u",	{ 1, 12, 20, 44 } }
72 };
73 
74 static void	 gettabs(char *, long *, long *);
75 static int	 ttywidth(void);
76 static void	 usage(void);
77 
78 int
79 main(int argc __unused, char *argv[])
80 {
81 	long cols, i, inc, j, margin, nstops, stops[NSTOPS];
82 	const char *cr, *ct, *st, *ML;
83 	char area[1024], *ap, *arg, *end;
84 
85 	setlocale(LC_ALL, "");
86 
87 	inc = 8;
88 	margin = 0;
89 	nstops = -1;
90 	while ((arg = *++argv) != NULL && (*arg == '-' || *arg == '+')) {
91 		if (*arg == '+') {
92 			/* +m[n] or +[n] */
93 			if (*++arg == 'm')
94 				arg++;
95 			if (*arg != '\0') {
96 				errno = 0;
97 				margin = strtol(arg, &end, 10);
98 				if (errno != 0 || *end != '\0' || margin < 0)
99 					errx(1, "%s: invalid margin width",
100 					    arg);
101 			} else
102 				margin = 10;
103 		} else if (isdigit(arg[1])) {
104 			/* -n */
105 			errno = 0;
106 			inc = strtol(arg + 1, &end, 10);
107 			if (errno != 0 || *end != '\0' || inc < 0)
108 				errx(1, "%s: invalid increment", arg + 1);
109 		} else if (arg[1] == 'T') {
110 			/* -Ttype or -T type */
111 			if (arg[2] != '\0')
112 				setenv("TERM", arg + 2, 1);
113 			else {
114 				if ((arg = *++argv) == NULL)
115 					usage();
116 				setenv("TERM", arg, 1);
117 			}
118 		} else if (arg[1] == '-') {
119 			arg = *++argv;
120 			break;
121 		} else {
122 			/* Predefined format */
123 			for (i = 0; i < (int)NELEMS(formats); i++)
124 				if (strcmp(formats[i].name, arg + 1) == 0)
125 					break;
126 			if (i == NELEMS(formats))
127 				usage();
128 			for (j = nstops = 0; j < NSTOPS &&
129 			    formats[i].stops[j] != 0; j++)
130 				stops[nstops++] = formats[i].stops[j];
131 		}
132 	}
133 
134 	if (arg != NULL) {
135 		if (nstops != -1)
136 			usage();
137 		gettabs(arg, stops, &nstops);
138 	}
139 
140 	/* Initialise terminal, get the strings we need */
141 	setupterm(NULL, 1, NULL);
142 	ap = area;
143 	if ((ct = tgetstr("ct", &ap)) == NULL)
144 		errx(1, "terminal cannot clear tabs");
145 	if ((st = tgetstr("st", &ap)) == NULL)
146 		errx(1, "terminal cannot set tabs");
147 	if ((cr = tgetstr("cr", &ap)) == NULL)
148 		cr = "\r";
149 	ML = tgetstr("ML", &ap);
150 	cols = ttywidth();
151 
152 	/* Clear all tabs. */
153 	putp(cr);
154 	putp(ct);
155 
156 	/*
157 	 * Set soft margin.
158 	 * XXX Does this actually work?
159 	 */
160 	if (ML != NULL) {
161 		printf("%*s", (int)margin, "");
162 		putp(ML);
163 	} else if (margin != 0)
164 		warnx("terminal cannot set left margin");
165 
166 	/* Optionally output new tab stops. */
167 	if (nstops >= 0) {
168 		printf("%*s", (int)stops[0] - 1, "");
169 		putp(st);
170 		for (i = 1; i < nstops; i++) {
171 			printf("%*s", (int)(stops[i] - stops[i - 1]), "");
172 			putp(st);
173 		}
174 	} else if (inc > 0) {
175 		for (i = 0; i < cols / inc; i++) {
176 			putp(st);
177 			printf("%*s", (int)inc, "");
178 		}
179 		putp(st);
180 	}
181 	putp(cr);
182 
183 	exit(0);
184 }
185 
186 static void
187 usage(void)
188 {
189 
190 	fprintf(stderr,
191 "usage: tabs [-n|-a|-a2|-c|-c2|-c3|-f|-p|-s|-u] [+m[n]] [-T type]\n");
192 	fprintf(stderr,
193 "       tabs [-T type] [+[n]] n1,[n2,...]\n");
194 	exit(1);
195 }
196 
197 static void
198 gettabs(char *arg, long stops[], long *nstops)
199 {
200 	char *tok, *end;
201 	long last, stop;
202 
203 	for (last = *nstops = 0, tok = strtok(arg, ","); tok != NULL;
204 	    tok = strtok(NULL, ",")) {
205 		if (*nstops >= NSTOPS)
206 			errx(1, "too many tab stops (limit %d)", NSTOPS);
207 		errno = 0;
208 		stop = strtol(tok, &end, 10);
209 		if (errno != 0 || *end != '\0' || stop <= 0)
210 			errx(1, "%s: invalid tab stop", tok);
211 		if (*tok == '+') {
212 			if (tok == arg)
213 				errx(1, "%s: first tab may not be relative",
214 				    tok);
215 			stop += last;
216 		}
217 		if (last > stop)
218 			errx(1, "cannot go backwards");
219 		last = stops[(*nstops)++] = stop;
220 	}
221 }
222 
223 static int
224 ttywidth(void)
225 {
226 	struct winsize ws;
227 	int width;
228 
229 	if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1)
230 		width = ws.ws_col;
231 	else if ((width = tgetnum("co")) == 0) {
232 		width = 80;
233 		warnx("cannot find terminal width; defaulted to %d", width);
234 	}
235 
236 	return (width);
237 }
238