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
47 void fold(int);
48 static int newpos(int, wint_t);
49 static void usage(void) __dead2;
50
51 static int bflag; /* Count bytes, not columns */
52 static int sflag; /* Split on word boundaries */
53
54 int
main(int argc,char ** argv)55 main(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
123 static void
usage(void)124 usage(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 */
141 void
fold(int width)142 fold(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 */
193 static int
newpos(int col,wint_t ch)194 newpos(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