fold.c revision 94978 
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
47#endif /* not lint */
48
49#include <sys/cdefs.h>
50__FBSDID("$FreeBSD: head/usr.bin/fold/fold.c 94978 2002-04-18 03:33:51Z tjr $");
51
52#include <ctype.h>
53#include <err.h>
54#include <limits.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <string.h>
58#include <unistd.h>
59
60#define	DEFLINEWIDTH	80
61
62void fold(int);
63static int newpos(int, int);
64static void usage(void);
65
66int bflag;			/* Count bytes, not columns */
67int sflag;			/* Split on word boundaries */
68
69int
70main(argc, argv)
71	int argc;
72	char **argv;
73{
74	register int ch;
75	int width;
76	char *p;
77
78	width = -1;
79	while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1)
80		switch (ch) {
81		case 'b':
82			bflag = 1;
83			break;
84		case 's':
85			sflag = 1;
86			break;
87		case 'w':
88			if ((width = atoi(optarg)) <= 0) {
89				errx(1, "illegal width value");
90			}
91			break;
92		case '0': case '1': case '2': case '3': case '4':
93		case '5': case '6': case '7': case '8': case '9':
94			if (width == -1) {
95				p = argv[optind - 1];
96				if (p[0] == '-' && p[1] == ch && !p[2])
97					width = atoi(++p);
98				else
99					width = atoi(argv[optind] + 1);
100			}
101			break;
102		default:
103			usage();
104		}
105	argv += optind;
106	argc -= optind;
107
108	if (width == -1)
109		width = DEFLINEWIDTH;
110	if (!*argv)
111		fold(width);
112	else for (; *argv; ++argv)
113		if (!freopen(*argv, "r", stdin)) {
114			err(1, "%s", *argv);
115		} else
116			fold(width);
117	exit(0);
118}
119
120static void
121usage()
122{
123	(void)fprintf(stderr, "usage: fold [-bs] [-w width] [file ...]\n");
124	exit(1);
125}
126
127/*
128 * Fold the contents of standard input to fit within WIDTH columns (or bytes)
129 * and write to standard output.
130 *
131 * If sflag is set, split the line at the last space character on the line.
132 * This flag necessitates storing the line in a buffer until the current
133 * column > width, or a newline or EOF is read.
134 *
135 * The buffer can grow larger than WIDTH due to backspaces and carriage
136 * returns embedded in the input stream.
137 */
138void
139fold(width)
140	register int width;
141{
142	static char *buf;
143	static int buf_max;
144	int ch, col, i, indx, space;
145
146	col = indx = 0;
147	while ((ch = getchar()) != EOF) {
148		if (ch == '\n') {
149			if (indx != 0)
150				fwrite(buf, 1, indx, stdout);
151			putchar('\n');
152			col = indx = 0;
153			continue;
154		}
155		if ((col = newpos(col, ch)) > width) {
156			if (sflag) {
157				i = indx;
158				while (--i >= 0 && !isblank(buf[i]))
159					;
160				space = i;
161			}
162			if (sflag && space != -1) {
163				space++;
164				fwrite(buf, 1, space, stdout);
165				memmove(buf, buf + space, indx - space);
166				indx -= space;
167				col = 0;
168				for (i = 0; i < indx; i++)
169					col = newpos(col, buf[i]);
170			} else {
171				fwrite(buf, 1, indx, stdout);
172				col = indx = 0;
173			}
174			putchar('\n');
175			col = newpos(col, ch);
176		}
177		if (indx + 1 > buf_max) {
178			buf_max += LINE_MAX;
179			if ((buf = realloc(buf, buf_max)) == NULL)
180				err(1, "realloc()");
181		}
182		buf[indx++] = ch;
183	}
184
185	if (indx != 0)
186		fwrite(buf, 1, indx, stdout);
187}
188
189/*
190 * Update the current column position for a character.
191 */
192static int
193newpos(col, ch)
194	int col, ch;
195{
196
197	if (bflag)
198		++col;
199	else
200		switch (ch) {
201		case '\b':
202			if (col > 0)
203				--col;
204			break;
205		case '\r':
206			col = 0;
207			break;
208		case '\t':
209			col = (col + 8) & ~7;
210			break;
211		default:
212			++col;
213			break;
214		}
215
216	return (col);
217}
218