fold.c revision 102944 
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 102944 2002-09-04 23:29:10Z dwmalone $");
51
52#include <ctype.h>
53#include <err.h>
54#include <limits.h>
55#include <locale.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include <unistd.h>
60
61#define	DEFLINEWIDTH	80
62
63void fold(int);
64static int newpos(int, int);
65static void usage(void);
66
67int bflag;			/* Count bytes, not columns */
68int sflag;			/* Split on word boundaries */
69
70int
71main(int argc, char **argv)
72{
73	int ch;
74	int rval, width;
75	char *p;
76
77	(void) setlocale(LC_CTYPE, "");
78
79	width = -1;
80	while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1)
81		switch (ch) {
82		case 'b':
83			bflag = 1;
84			break;
85		case 's':
86			sflag = 1;
87			break;
88		case 'w':
89			if ((width = atoi(optarg)) <= 0) {
90				errx(1, "illegal width value");
91			}
92			break;
93		case '0': case '1': case '2': case '3': case '4':
94		case '5': case '6': case '7': case '8': case '9':
95			if (width == -1) {
96				p = argv[optind - 1];
97				if (p[0] == '-' && p[1] == ch && !p[2])
98					width = atoi(++p);
99				else
100					width = atoi(argv[optind] + 1);
101			}
102			break;
103		default:
104			usage();
105		}
106	argv += optind;
107	argc -= optind;
108
109	if (width == -1)
110		width = DEFLINEWIDTH;
111	rval = 0;
112	if (!*argv)
113		fold(width);
114	else for (; *argv; ++argv)
115		if (!freopen(*argv, "r", stdin)) {
116			warn("%s", *argv);
117			rval = 1;
118		} else
119			fold(width);
120	exit(rval);
121}
122
123static void
124usage(void)
125{
126	(void)fprintf(stderr, "usage: fold [-bs] [-w width] [file ...]\n");
127	exit(1);
128}
129
130/*
131 * Fold the contents of standard input to fit within WIDTH columns (or bytes)
132 * and write to standard output.
133 *
134 * If sflag is set, split the line at the last space character on the line.
135 * This flag necessitates storing the line in a buffer until the current
136 * column > width, or a newline or EOF is read.
137 *
138 * The buffer can grow larger than WIDTH due to backspaces and carriage
139 * returns embedded in the input stream.
140 */
141void
142fold(int width)
143{
144	static char *buf;
145	static int buf_max;
146	int ch, col, i, indx, space;
147
148	col = indx = 0;
149	while ((ch = getchar()) != EOF) {
150		if (ch == '\n') {
151			if (indx != 0)
152				fwrite(buf, 1, indx, stdout);
153			putchar('\n');
154			col = indx = 0;
155			continue;
156		}
157		if ((col = newpos(col, ch)) > width) {
158			if (sflag) {
159				i = indx;
160				while (--i >= 0 && !isblank((unsigned char)buf[i]))
161					;
162				space = i;
163			}
164			if (sflag && space != -1) {
165				space++;
166				fwrite(buf, 1, space, stdout);
167				memmove(buf, buf + space, indx - space);
168				indx -= space;
169				col = 0;
170				for (i = 0; i < indx; i++)
171					col = newpos(col,
172					    (unsigned char)buf[i]);
173			} else {
174				fwrite(buf, 1, indx, stdout);
175				col = indx = 0;
176			}
177			putchar('\n');
178			col = newpos(col, ch);
179		}
180		if (indx + 1 > buf_max) {
181			buf_max += LINE_MAX;
182			if ((buf = realloc(buf, buf_max)) == NULL)
183				err(1, "realloc()");
184		}
185		buf[indx++] = ch;
186	}
187
188	if (indx != 0)
189		fwrite(buf, 1, indx, stdout);
190}
191
192/*
193 * Update the current column position for a character.
194 */
195static int
196newpos(int col, int ch)
197{
198
199	if (bflag)
200		++col;
201	else
202		switch (ch) {
203		case '\b':
204			if (col > 0)
205				--col;
206			break;
207		case '\r':
208			col = 0;
209			break;
210		case '\t':
211			col = (col + 8) & ~7;
212			break;
213		default:
214			if (isprint(ch))
215				++col;
216			break;
217		}
218
219	return (col);
220}
221