fold.c revision 65427 
1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kevin Ruddy.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38static const char copyright[] =
39"@(#) Copyright (c) 1990, 1993\n\
40	The Regents of the University of California.  All rights reserved.\n";
41#endif /* not lint */
42
43#ifndef lint
44#if 0
45static char sccsid[] = "@(#)fold.c	8.1 (Berkeley) 6/6/93";
46#endif
47static const char rcsid[] =
48  "$FreeBSD: head/usr.bin/fold/fold.c 65427 2000-09-04 05:59:25Z imp $";
49#endif /* not lint */
50
51#include <err.h>
52#include <stdio.h>
53#include <stdlib.h>
54#include <string.h>
55#include <unistd.h>
56
57#define	DEFLINEWIDTH	80
58
59void fold __P((int));
60static void usage __P((void));
61
62int
63main(argc, argv)
64	int argc;
65	char **argv;
66{
67	register int ch;
68	int width;
69	char *p;
70
71	width = -1;
72	while ((ch = getopt(argc, argv, "0123456789w:")) != -1)
73		switch (ch) {
74		case 'w':
75			if ((width = atoi(optarg)) <= 0) {
76				errx(1, "illegal width value");
77			}
78			break;
79		case '0': case '1': case '2': case '3': case '4':
80		case '5': case '6': case '7': case '8': case '9':
81			if (width == -1) {
82				p = argv[optind - 1];
83				if (p[0] == '-' && p[1] == ch && !p[2])
84					width = atoi(++p);
85				else
86					width = atoi(argv[optind] + 1);
87			}
88			break;
89		default:
90			usage();
91		}
92	argv += optind;
93	argc -= optind;
94
95	if (width == -1)
96		width = DEFLINEWIDTH;
97	if (!*argv)
98		fold(width);
99	else for (; *argv; ++argv)
100		if (!freopen(*argv, "r", stdin)) {
101			err(1, "%s", *argv);
102		} else
103			fold(width);
104	exit(0);
105}
106
107static void
108usage()
109{
110	(void)fprintf(stderr, "usage: fold [-w width] [file ...]\n");
111	exit(1);
112}
113
114void
115fold(width)
116	register int width;
117{
118	register int ch, col, new;
119
120	for (col = 0;;) {
121		switch (ch = getchar()) {
122		case EOF:
123			return;
124		case '\b':
125			new = col ? col - 1 : 0;
126			break;
127		case '\n':
128		case '\r':
129			new = 0;
130			break;
131		case '\t':
132			new = (col + 8) & ~7;
133			break;
134		default:
135			new = col + 1;
136			break;
137		}
138
139		if (new > width) {
140			putchar('\n');
141			col = 0;
142		}
143		putchar(ch);
144
145		switch (ch) {
146		case '\b':
147			if (col > 0)
148				--col;
149			break;
150		case '\n':
151		case '\r':
152			col = 0;
153			break;
154		case '\t':
155			col += 8;
156			col &= ~7;
157			break;
158		default:
159			++col;
160			break;
161		}
162	}
163}
164