xref: /dragonfly/usr.bin/fold/fold.c (revision 9b0ea272)
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. 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  * @(#) Copyright (c) 1990, 1993 The Regents of the University of California.  All rights reserved.
33  * @(#)fold.c	8.1 (Berkeley) 6/6/93
34  * $FreeBSD: head/usr.bin/fold/fold.c 227165 2011-11-06 08:15:23Z ed $
35  */
36 
37 #include <err.h>
38 #include <limits.h>
39 #include <locale.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44 #include <wchar.h>
45 #include <wctype.h>
46 
47 #define	DEFLINEWIDTH	80
48 
49 void fold(int);
50 static int newpos(int, wint_t);
51 static void usage(void);
52 
53 static int bflag;		/* Count bytes, not columns */
54 static int sflag;		/* Split on word boundaries */
55 
56 int
main(int argc,char ** argv)57 main(int argc, char **argv)
58 {
59 	int ch, previous_ch;
60 	int rval, width;
61 
62 	(void) setlocale(LC_CTYPE, "");
63 
64 	width = -1;
65 	previous_ch = 0;
66 	while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1) {
67 		switch (ch) {
68 		case 'b':
69 			bflag = 1;
70 			break;
71 		case 's':
72 			sflag = 1;
73 			break;
74 		case 'w':
75 			if ((width = atoi(optarg)) <= 0) {
76 				errx(1, "illegal width value");
77 			}
78 			break;
79 		case '0': case '1': case '2': case '3': case '4':
80 		case '5': case '6': case '7': case '8': case '9':
81 			/* Accept a width as eg. -30. Note that a width
82 			 * specified using the -w option is always used prior
83 			 * to this undocumented option. */
84 			switch (previous_ch) {
85 			case '0': case '1': case '2': case '3': case '4':
86 			case '5': case '6': case '7': case '8': case '9':
87 				/* The width is a number with multiple digits:
88 				 * add the last one. */
89 				width = width * 10 + (ch - '0');
90 				break;
91 			default:
92 				/* Set the width, unless it was previously
93 				 * set. For instance, the following options
94 				 * would all give a width of 5 and not 10:
95 				 *   -10 -w5
96 				 *   -5b10
97 				 *   -5 -10b */
98 				if (width == -1)
99 					width = ch - '0';
100 				break;
101 			}
102 			break;
103 		default:
104 			usage();
105 		}
106 		previous_ch = ch;
107 	}
108 	argv += optind;
109 	argc -= optind;
110 
111 	if (width == -1)
112 		width = DEFLINEWIDTH;
113 	rval = 0;
114 	if (!*argv)
115 		fold(width);
116 	else for (; *argv; ++argv)
117 		if (!freopen(*argv, "r", stdin)) {
118 			warn("%s", *argv);
119 			rval = 1;
120 		} else
121 			fold(width);
122 	exit(rval);
123 }
124 
125 static void
usage(void)126 usage(void)
127 {
128 	(void)fprintf(stderr, "usage: fold [-bs] [-w width] [file ...]\n");
129 	exit(1);
130 }
131 
132 /*
133  * Fold the contents of standard input to fit within WIDTH columns (or bytes)
134  * and write to standard output.
135  *
136  * If sflag is set, split the line at the last space character on the line.
137  * This flag necessitates storing the line in a buffer until the current
138  * column > width, or a newline or EOF is read.
139  *
140  * The buffer can grow larger than WIDTH due to backspaces and carriage
141  * returns embedded in the input stream.
142  */
143 void
fold(int width)144 fold(int width)
145 {
146 	static wchar_t *buf;
147 	static int buf_max;
148 	int col, i, indx, space;
149 	wint_t ch;
150 
151 	col = indx = 0;
152 	while ((ch = getwchar()) != WEOF) {
153 		if (ch == '\n') {
154 			wprintf(L"%.*ls\n", indx, buf);
155 			col = indx = 0;
156 			continue;
157 		}
158 		if ((col = newpos(col, ch)) > width) {
159 			if (sflag) {
160 				i = indx;
161 				while (--i >= 0 && !iswblank(buf[i]))
162 					;
163 				space = i;
164 			}
165 			if (sflag && space != -1) {
166 				space++;
167 				wprintf(L"%.*ls\n", space, buf);
168 				wmemmove(buf, buf + space, indx - space);
169 				indx -= space;
170 				col = 0;
171 				for (i = 0; i < indx; i++)
172 					col = newpos(col, buf[i]);
173 			} else {
174 				wprintf(L"%.*ls\n", indx, buf);
175 				col = indx = 0;
176 			}
177 			col = newpos(col, ch);
178 		}
179 		if (indx + 1 > buf_max) {
180 			buf_max += LINE_MAX;
181 			buf = realloc(buf, sizeof(*buf) * buf_max);
182 			if (buf == NULL)
183 				err(1, "realloc()");
184 		}
185 		buf[indx++] = ch;
186 	}
187 
188 	if (indx != 0)
189 		wprintf(L"%.*ls", indx, buf);
190 }
191 
192 /*
193  * Update the current column position for a character.
194  */
195 static int
newpos(int col,wint_t ch)196 newpos(int col, wint_t ch)
197 {
198 	char buf[MB_LEN_MAX];
199 	size_t len;
200 	int w;
201 
202 	if (bflag) {
203 		len = wcrtomb(buf, ch, NULL);
204 		col += len;
205 	} else
206 		switch (ch) {
207 		case '\b':
208 			if (col > 0)
209 				--col;
210 			break;
211 		case '\r':
212 			col = 0;
213 			break;
214 		case '\t':
215 			col = (col + 8) & ~7;
216 			break;
217 		default:
218 			if ((w = wcwidth(ch)) > 0)
219 				col += w;
220 			break;
221 		}
222 
223 	return (col);
224 }
225