1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kevin Ruddy.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#ifndef lint
36static const char copyright[] =
37"@(#) Copyright (c) 1990, 1993\n\
38	The Regents of the University of California.  All rights reserved.\n";
39#endif /* not lint */
40
41#ifndef lint
42#if 0
43static char sccsid[] = "@(#)fold.c	8.1 (Berkeley) 6/6/93";
44#endif
45#endif /* not lint */
46
47#include <sys/cdefs.h>
48__FBSDID("$FreeBSD$");
49
50#include <err.h>
51#include <limits.h>
52#include <locale.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57#include <wchar.h>
58#include <wctype.h>
59
60#define	DEFLINEWIDTH	80
61
62void fold(int);
63static int newpos(int, wint_t);
64static void usage(void);
65
66static int bflag;		/* Count bytes, not columns */
67static int sflag;		/* Split on word boundaries */
68
69int
70main(int argc, char **argv)
71{
72	int ch, previous_ch;
73	int rval, width;
74
75	(void) setlocale(LC_CTYPE, "");
76
77	width = -1;
78	previous_ch = 0;
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			/* Accept a width as eg. -30. Note that a width
95			 * specified using the -w option is always used prior
96			 * to this undocumented option. */
97			switch (previous_ch) {
98			case '0': case '1': case '2': case '3': case '4':
99			case '5': case '6': case '7': case '8': case '9':
100				/* The width is a number with multiple digits:
101				 * add the last one. */
102				width = width * 10 + (ch - '0');
103				break;
104			default:
105				/* Set the width, unless it was previously
106				 * set. For instance, the following options
107				 * would all give a width of 5 and not 10:
108				 *   -10 -w5
109				 *   -5b10
110				 *   -5 -10b */
111				if (width == -1)
112					width = ch - '0';
113				break;
114			}
115			break;
116		default:
117			usage();
118		}
119		previous_ch = ch;
120	}
121	argv += optind;
122	argc -= optind;
123
124	if (width == -1)
125		width = DEFLINEWIDTH;
126	rval = 0;
127	if (!*argv)
128		fold(width);
129	else for (; *argv; ++argv)
130		if (!freopen(*argv, "r", stdin)) {
131			warn("%s", *argv);
132			rval = 1;
133		} else
134			fold(width);
135	exit(rval);
136}
137
138static void
139usage(void)
140{
141	(void)fprintf(stderr, "usage: fold [-bs] [-w width] [file ...]\n");
142	exit(1);
143}
144
145/*
146 * Fold the contents of standard input to fit within WIDTH columns (or bytes)
147 * and write to standard output.
148 *
149 * If sflag is set, split the line at the last space character on the line.
150 * This flag necessitates storing the line in a buffer until the current
151 * column > width, or a newline or EOF is read.
152 *
153 * The buffer can grow larger than WIDTH due to backspaces and carriage
154 * returns embedded in the input stream.
155 */
156void
157fold(int width)
158{
159	static wchar_t *buf;
160	static int buf_max;
161	int col, i, indx, space;
162	wint_t ch;
163
164	col = indx = 0;
165	while ((ch = getwchar()) != WEOF) {
166		if (ch == '\n') {
167			wprintf(L"%.*ls\n", indx, buf);
168			col = indx = 0;
169			continue;
170		}
171		if ((col = newpos(col, ch)) > width) {
172			if (sflag) {
173				i = indx;
174				while (--i >= 0 && !iswblank(buf[i]))
175					;
176				space = i;
177			}
178			if (sflag && space != -1) {
179				space++;
180				wprintf(L"%.*ls\n", space, buf);
181				wmemmove(buf, buf + space, indx - space);
182				indx -= space;
183				col = 0;
184				for (i = 0; i < indx; i++)
185					col = newpos(col, buf[i]);
186			} else {
187				wprintf(L"%.*ls\n", indx, buf);
188				col = indx = 0;
189			}
190			col = newpos(col, ch);
191		}
192		if (indx + 1 > buf_max) {
193			buf_max += LINE_MAX;
194			buf = realloc(buf, sizeof(*buf) * buf_max);
195			if (buf == NULL)
196				err(1, "realloc()");
197		}
198		buf[indx++] = ch;
199	}
200
201	if (indx != 0)
202		wprintf(L"%.*ls", indx, buf);
203}
204
205/*
206 * Update the current column position for a character.
207 */
208static int
209newpos(int col, wint_t ch)
210{
211	char buf[MB_LEN_MAX];
212	size_t len;
213	int w;
214
215	if (bflag) {
216		len = wcrtomb(buf, ch, NULL);
217		col += len;
218	} else
219		switch (ch) {
220		case '\b':
221			if (col > 0)
222				--col;
223			break;
224		case '\r':
225			col = 0;
226			break;
227		case '\t':
228			col = (col + 8) & ~7;
229			break;
230		default:
231			if ((w = wcwidth(ch)) > 0)
232				col += w;
233			break;
234		}
235
236	return (col);
237}
238