fold.c revision 24360 
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 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
44static char sccsid[] = "@(#)fold.c	8.1 (Berkeley) 6/6/93";
45#endif /* not lint */
46
47#include <stdio.h>
48#include <string.h>
49
50#define	DEFLINEWIDTH	80
51
52main(argc, argv)
53	int argc;
54	char **argv;
55{
56	extern int errno, optind;
57	extern char *optarg;
58	register int ch;
59	int width;
60	char *p;
61
62	width = -1;
63	while ((ch = getopt(argc, argv, "0123456789w:")) != -1)
64		switch (ch) {
65		case 'w':
66			if ((width = atoi(optarg)) <= 0) {
67				(void)fprintf(stderr,
68				    "fold: illegal width value.\n");
69				exit(1);
70			}
71			break;
72		case '0': case '1': case '2': case '3': case '4':
73		case '5': case '6': case '7': case '8': case '9':
74			if (width == -1) {
75				p = argv[optind - 1];
76				if (p[0] == '-' && p[1] == ch && !p[2])
77					width = atoi(++p);
78				else
79					width = atoi(argv[optind] + 1);
80			}
81			break;
82		default:
83			(void)fprintf(stderr,
84			    "usage: fold [-w width] [file ...]\n");
85			exit(1);
86		}
87	argv += optind;
88	argc -= optind;
89
90	if (width == -1)
91		width = DEFLINEWIDTH;
92	if (!*argv)
93		fold(width);
94	else for (; *argv; ++argv)
95		if (!freopen(*argv, "r", stdin)) {
96			(void)fprintf(stderr,
97			    "fold: %s: %s\n", *argv, strerror(errno));
98			exit(1);
99		} else
100			fold(width);
101	exit(0);
102}
103
104fold(width)
105	register int width;
106{
107	register int ch, col, new;
108
109	for (col = 0;;) {
110		switch (ch = getchar()) {
111		case EOF:
112			return;
113		case '\b':
114			new = col ? col - 1 : 0;
115			break;
116		case '\n':
117		case '\r':
118			new = 0;
119			break;
120		case '\t':
121			new = (col + 8) & ~7;
122			break;
123		default:
124			new = col + 1;
125			break;
126		}
127
128		if (new > width) {
129			putchar('\n');
130			col = 0;
131		}
132		putchar(ch);
133
134		switch (ch) {
135		case '\b':
136			if (col > 0)
137				--col;
138			break;
139		case '\n':
140		case '\r':
141			col = 0;
142			break;
143		case '\t':
144			col += 8;
145			col &= ~7;
146			break;
147		default:
148			++col;
149			break;
150		}
151	}
152}
153