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 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34static const char copyright[] =
35"@(#) Copyright (c) 1990, 1993\n\
36	The Regents of the University of California.  All rights reserved.\n";
37#endif /* not lint */
38
39#ifndef lint
40#if 0
41static char sccsid[] = "@(#)fold.c	8.1 (Berkeley) 6/6/93";
42#endif
43#endif /* not lint */
44
45#include <sys/cdefs.h>
46__FBSDID("$FreeBSD$");
47
48#include <err.h>
49#include <limits.h>
50#include <locale.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include <string.h>
54#include <unistd.h>
55#include <wchar.h>
56#include <wctype.h>
57
58#define	DEFLINEWIDTH	80
59
60void fold(int);
61static int newpos(int, wint_t);
62static void usage(void);
63
64static int bflag;		/* Count bytes, not columns */
65static int sflag;		/* Split on word boundaries */
66
67int
68main(int argc, char **argv)
69{
70	int ch, previous_ch;
71	int rval, width;
72
73	(void) setlocale(LC_CTYPE, "");
74
75	width = -1;
76	previous_ch = 0;
77	while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1) {
78		switch (ch) {
79		case 'b':
80			bflag = 1;
81			break;
82		case 's':
83			sflag = 1;
84			break;
85		case 'w':
86			if ((width = atoi(optarg)) <= 0) {
87				errx(1, "illegal width value");
88			}
89			break;
90		case '0': case '1': case '2': case '3': case '4':
91		case '5': case '6': case '7': case '8': case '9':
92			/* Accept a width as eg. -30. Note that a width
93			 * specified using the -w option is always used prior
94			 * to this undocumented option. */
95			switch (previous_ch) {
96			case '0': case '1': case '2': case '3': case '4':
97			case '5': case '6': case '7': case '8': case '9':
98				/* The width is a number with multiple digits:
99				 * add the last one. */
100				width = width * 10 + (ch - '0');
101				break;
102			default:
103				/* Set the width, unless it was previously
104				 * set. For instance, the following options
105				 * would all give a width of 5 and not 10:
106				 *   -10 -w5
107				 *   -5b10
108				 *   -5 -10b */
109				if (width == -1)
110					width = ch - '0';
111				break;
112			}
113			break;
114		default:
115			usage();
116		}
117		previous_ch = ch;
118	}
119	argv += optind;
120	argc -= optind;
121
122	if (width == -1)
123		width = DEFLINEWIDTH;
124	rval = 0;
125	if (!*argv)
126		fold(width);
127	else for (; *argv; ++argv)
128		if (!freopen(*argv, "r", stdin)) {
129			warn("%s", *argv);
130			rval = 1;
131		} else
132			fold(width);
133	exit(rval);
134}
135
136static void
137usage(void)
138{
139	(void)fprintf(stderr, "usage: fold [-bs] [-w width] [file ...]\n");
140	exit(1);
141}
142
143/*
144 * Fold the contents of standard input to fit within WIDTH columns (or bytes)
145 * and write to standard output.
146 *
147 * If sflag is set, split the line at the last space character on the line.
148 * This flag necessitates storing the line in a buffer until the current
149 * column > width, or a newline or EOF is read.
150 *
151 * The buffer can grow larger than WIDTH due to backspaces and carriage
152 * returns embedded in the input stream.
153 */
154void
155fold(int width)
156{
157	static wchar_t *buf;
158	static int buf_max;
159	int col, i, indx, space;
160	wint_t ch;
161
162	col = indx = 0;
163	while ((ch = getwchar()) != WEOF) {
164		if (ch == '\n') {
165			wprintf(L"%.*ls\n", indx, buf);
166			col = indx = 0;
167			continue;
168		}
169		if ((col = newpos(col, ch)) > width) {
170			if (sflag) {
171				i = indx;
172				while (--i >= 0 && !iswblank(buf[i]))
173					;
174				space = i;
175			}
176			if (sflag && space != -1) {
177				space++;
178				wprintf(L"%.*ls\n", space, buf);
179				wmemmove(buf, buf + space, indx - space);
180				indx -= space;
181				col = 0;
182				for (i = 0; i < indx; i++)
183					col = newpos(col, buf[i]);
184			} else {
185				wprintf(L"%.*ls\n", indx, buf);
186				col = indx = 0;
187			}
188			col = newpos(col, ch);
189		}
190		if (indx + 1 > buf_max) {
191			buf_max += LINE_MAX;
192			buf = realloc(buf, sizeof(*buf) * buf_max);
193			if (buf == NULL)
194				err(1, "realloc()");
195		}
196		buf[indx++] = ch;
197	}
198
199	if (indx != 0)
200		wprintf(L"%.*ls", indx, buf);
201}
202
203/*
204 * Update the current column position for a character.
205 */
206static int
207newpos(int col, wint_t ch)
208{
209	char buf[MB_LEN_MAX];
210	size_t len;
211	int w;
212
213	if (bflag) {
214		len = wcrtomb(buf, ch, NULL);
215		col += len;
216	} else
217		switch (ch) {
218		case '\b':
219			if (col > 0)
220				--col;
221			break;
222		case '\r':
223			col = 0;
224			break;
225		case '\t':
226			col = (col + 8) & ~7;
227			break;
228		default:
229			if ((w = wcwidth(ch)) > 0)
230				col += w;
231			break;
232		}
233
234	return (col);
235}
236