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#include <err.h>
36#include <limits.h>
37#include <locale.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <unistd.h>
42#include <wchar.h>
43#include <wctype.h>
44
45#define	DEFLINEWIDTH	80
46
47void fold(int);
48static int newpos(int, wint_t);
49static void usage(void) __dead2;
50
51static int bflag;		/* Count bytes, not columns */
52static int sflag;		/* Split on word boundaries */
53
54int
55main(int argc, char **argv)
56{
57	int ch, previous_ch;
58	int rval, width;
59
60	(void) setlocale(LC_CTYPE, "");
61
62	width = -1;
63	previous_ch = 0;
64	while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1) {
65		switch (ch) {
66		case 'b':
67			bflag = 1;
68			break;
69		case 's':
70			sflag = 1;
71			break;
72		case 'w':
73			if ((width = atoi(optarg)) <= 0) {
74				errx(1, "illegal width value");
75			}
76			break;
77		case '0': case '1': case '2': case '3': case '4':
78		case '5': case '6': case '7': case '8': case '9':
79			/* Accept a width as eg. -30. Note that a width
80			 * specified using the -w option is always used prior
81			 * to this undocumented option. */
82			switch (previous_ch) {
83			case '0': case '1': case '2': case '3': case '4':
84			case '5': case '6': case '7': case '8': case '9':
85				/* The width is a number with multiple digits:
86				 * add the last one. */
87				width = width * 10 + (ch - '0');
88				break;
89			default:
90				/* Set the width, unless it was previously
91				 * set. For instance, the following options
92				 * would all give a width of 5 and not 10:
93				 *   -10 -w5
94				 *   -5b10
95				 *   -5 -10b */
96				if (width == -1)
97					width = ch - '0';
98				break;
99			}
100			break;
101		default:
102			usage();
103		}
104		previous_ch = ch;
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 wchar_t *buf;
145	static int buf_max;
146	int col, i, indx, space;
147	wint_t ch;
148
149	col = indx = 0;
150	while ((ch = getwchar()) != WEOF) {
151		if (ch == '\n') {
152			wprintf(L"%.*ls\n", indx, buf);
153			col = indx = 0;
154			continue;
155		}
156		if ((col = newpos(col, ch)) > width) {
157			if (sflag) {
158				i = indx;
159				while (--i >= 0 && !iswblank(buf[i]))
160					;
161				space = i;
162			}
163			if (sflag && space != -1) {
164				space++;
165				wprintf(L"%.*ls\n", space, buf);
166				wmemmove(buf, buf + space, indx - space);
167				indx -= space;
168				col = 0;
169				for (i = 0; i < indx; i++)
170					col = newpos(col, buf[i]);
171			} else {
172				wprintf(L"%.*ls\n", indx, buf);
173				col = indx = 0;
174			}
175			col = newpos(col, ch);
176		}
177		if (indx + 1 > buf_max) {
178			buf_max += LINE_MAX;
179			buf = realloc(buf, sizeof(*buf) * buf_max);
180			if (buf == NULL)
181				err(1, "realloc()");
182		}
183		buf[indx++] = ch;
184	}
185
186	if (indx != 0)
187		wprintf(L"%.*ls", indx, buf);
188}
189
190/*
191 * Update the current column position for a character.
192 */
193static int
194newpos(int col, wint_t ch)
195{
196	char buf[MB_LEN_MAX];
197	size_t len;
198	int w;
199
200	if (bflag) {
201		len = wcrtomb(buf, ch, NULL);
202		col += len;
203	} else
204		switch (ch) {
205		case '\b':
206			if (col > 0)
207				--col;
208			break;
209		case '\r':
210			col = 0;
211			break;
212		case '\t':
213			col = (col + 8) & ~7;
214			break;
215		default:
216			if ((w = wcwidth(ch)) > 0)
217				col += w;
218			break;
219		}
220
221	return (col);
222}
223