xref: /freebsd/usr.bin/expand/expand.c (revision 2e3507c25e42292b45a5482e116d278f5515d04d)
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 #include <ctype.h>
33 #include <err.h>
34 #include <locale.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <unistd.h>
38 #include <wchar.h>
39 #include <wctype.h>
40 
41 /*
42  * expand - expand tabs to equivalent spaces
43  */
44 static int	nstops;
45 static int	tabstops[100];
46 
47 static void getstops(char *);
48 static void usage(void) __dead2;
49 
50 int
51 main(int argc, char *argv[])
52 {
53 	const char *curfile;
54 	wint_t wc;
55 	int c, column;
56 	int n;
57 	int rval;
58 	int width;
59 
60 	setlocale(LC_CTYPE, "");
61 
62 	/* handle obsolete syntax */
63 	while (argc > 1 && argv[1][0] == '-' &&
64 	    isdigit((unsigned char)argv[1][1])) {
65 		getstops(&argv[1][1]);
66 		argc--; argv++;
67 	}
68 
69 	while ((c = getopt (argc, argv, "t:")) != -1) {
70 		switch (c) {
71 		case 't':
72 			getstops(optarg);
73 			break;
74 		case '?':
75 		default:
76 			usage();
77 			/* NOTREACHED */
78 		}
79 	}
80 	argc -= optind;
81 	argv += optind;
82 
83 	rval = 0;
84 	do {
85 		if (argc > 0) {
86 			if (freopen(argv[0], "r", stdin) == NULL) {
87 				warn("%s", argv[0]);
88 				rval = 1;
89 				argc--, argv++;
90 				continue;
91 			}
92 			curfile = argv[0];
93 			argc--, argv++;
94 		} else
95 			curfile = "stdin";
96 		column = 0;
97 		while ((wc = getwchar()) != WEOF) {
98 			switch (wc) {
99 			case '\t':
100 				if (nstops == 0) {
101 					do {
102 						putwchar(' ');
103 						column++;
104 					} while (column & 07);
105 					continue;
106 				}
107 				if (nstops == 1) {
108 					do {
109 						putwchar(' ');
110 						column++;
111 					} while (((column - 1) % tabstops[0]) != (tabstops[0] - 1));
112 					continue;
113 				}
114 				for (n = 0; n < nstops; n++)
115 					if (tabstops[n] > column)
116 						break;
117 				if (n == nstops) {
118 					putwchar(' ');
119 					column++;
120 					continue;
121 				}
122 				while (column < tabstops[n]) {
123 					putwchar(' ');
124 					column++;
125 				}
126 				continue;
127 
128 			case '\b':
129 				if (column)
130 					column--;
131 				putwchar('\b');
132 				continue;
133 
134 			default:
135 				putwchar(wc);
136 				if ((width = wcwidth(wc)) > 0)
137 					column += width;
138 				continue;
139 
140 			case '\n':
141 				putwchar(wc);
142 				column = 0;
143 				continue;
144 			}
145 		}
146 		if (ferror(stdin)) {
147 			warn("%s", curfile);
148 			rval = 1;
149 		}
150 	} while (argc > 0);
151 	exit(rval);
152 }
153 
154 static void
155 getstops(char *cp)
156 {
157 	int i;
158 
159 	nstops = 0;
160 	for (;;) {
161 		i = 0;
162 		while (*cp >= '0' && *cp <= '9')
163 			i = i * 10 + *cp++ - '0';
164 		if (i <= 0)
165 			errx(1, "bad tab stop spec");
166 		if (nstops > 0 && i <= tabstops[nstops-1])
167 			errx(1, "bad tab stop spec");
168 		if (nstops == sizeof(tabstops) / sizeof(*tabstops))
169 			errx(1, "too many tab stops");
170 		tabstops[nstops++] = i;
171 		if (*cp == 0)
172 			break;
173 		if (*cp != ',' && !isblank((unsigned char)*cp))
174 			errx(1, "bad tab stop spec");
175 		cp++;
176 	}
177 }
178 
179 static void
180 usage(void)
181 {
182 	(void)fprintf (stderr, "usage: expand [-t tablist] [file ...]\n");
183 	exit(1);
184 }
185