xref: /netbsd-src/usr.bin/fold/fold.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: fold.c,v 1.16 2009/07/21 01:35:02 ahoka Exp $	*/
2 
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 <sys/cdefs.h>
36 #ifndef lint
37 __COPYRIGHT("@(#) Copyright (c) 1990, 1993\
38  The Regents of the University of California.  All rights reserved.");
39 #endif /* not lint */
40 
41 #ifndef lint
42 #if 0
43 static char sccsid[] = "@(#)fold.c	8.1 (Berkeley) 6/6/93";
44 #endif
45 __RCSID("$NetBSD: fold.c,v 1.16 2009/07/21 01:35:02 ahoka Exp $");
46 #endif /* not lint */
47 
48 #include <limits.h>
49 #include <locale.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <unistd.h>
53 #include <wchar.h>
54 #include <err.h>
55 
56 #define	DEFLINEWIDTH	80
57 
58 	int	main(int, char **);
59 static	void	fold(int);
60 static	int	new_column_position(int, wint_t);
61 static	void	usage(void);
62 
63 int count_bytes = 0;
64 int split_words = 0;
65 
66 int
67 main(int argc, char **argv)
68 {
69 	int ch;
70 	int width;
71 	char *p;
72 
73 	setlocale(LC_CTYPE, "");
74 	setprogname(argv[0]);
75 
76 	width = -1;
77 	while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1)
78 		switch (ch) {
79 		case 'b':
80 			count_bytes = 1;
81 			break;
82 		case 's':
83 			split_words = 1;
84 			break;
85 		case 'w':
86 			if ((width = atoi(optarg)) <= 0)
87 				errx(1, "illegal width value");
88 			break;
89 		case '0': case '1': case '2': case '3': case '4':
90 		case '5': case '6': case '7': case '8': case '9':
91 			if (width == -1) {
92 				p = argv[optind - 1];
93 				if (p[0] == '-' && p[1] == ch && !p[2])
94 					width = atoi(++p);
95 				else
96 					width = atoi(argv[optind] + 1);
97 			}
98 			break;
99 		default:
100 			usage();
101 		}
102 	argv += optind;
103 	argc -= optind;
104 
105 	if (width == -1)
106 		width = DEFLINEWIDTH;
107 
108 	if (!*argv)
109 		fold(width);
110 	else for (; *argv; ++argv)
111 		if (!freopen(*argv, "r", stdin)) {
112 			err (1, "%s", *argv);
113 			/* NOTREACHED */
114 		} else
115 			fold(width);
116 	exit(0);
117 }
118 
119 /*
120  * Fold the contents of standard input to fit within WIDTH columns
121  * (or bytes) and write to standard output.
122  *
123  * If split_words is set, split the line at the last space character
124  * on the line.  This flag necessitates storing the line in a buffer
125  * until the current column > width, or a newline or EOF is read.
126  *
127  * The buffer can grow larger than WIDTH due to backspaces and carriage
128  * returns embedded in the input stream.
129  */
130 static void
131 fold(int width)
132 {
133 	static wchar_t *buf = NULL;
134 	wchar_t *nbuf;
135 	static int   buf_max = 0;
136 	wint_t ch;
137 	int col, indx, i;
138 
139 	col = indx = 0;
140 	while ((ch = getwchar()) != WEOF) {
141 		if (ch == L'\n') {
142 			if (indx != 0) {
143 				for (i = 0; i < indx; i++)
144 					putwchar(buf[i]);
145 			}
146 			putwchar(L'\n');
147 			col = indx = 0;
148 			continue;
149 		}
150 
151 		col = new_column_position (col, ch);
152 		if (col > width) {
153 			int last_space;
154 
155 #ifdef __GNUC__
156 			last_space = 0;	/* XXX gcc */
157 #endif
158 			if (split_words) {
159 				for (i = 0, last_space = -1; i < indx; i++)
160 					if (buf[i] == L' ')
161 						last_space = i;
162 			}
163 
164 			if (split_words && last_space != -1) {
165 				for (i = 0; i < last_space; i++)
166 					putwchar(buf[i]);
167 
168 				/* increase last_space here, so we skip trailing whitespace */
169 				last_space++;
170 				wmemmove (buf, buf+last_space, indx-last_space);
171 
172 				indx -= last_space;
173 				col = 0;
174 				for (i = 0; i < indx; i++) {
175 					col = new_column_position (col, buf[i]);
176 				}
177 			} else {
178 				for (i = 0; i < indx; i++)
179 					putwchar(buf[i]);
180 				col = indx = 0;
181 			}
182 			putwchar('\n');
183 
184 			/* calculate the column position for the next line. */
185 			col = new_column_position (col, ch);
186 		}
187 
188 		if (indx + 1 > buf_max) {
189 			/* Allocate buffer in LINE_MAX increments */
190 			if ((nbuf = realloc (buf, buf_max + 2048)) == NULL) {
191 				err (1, "realloc");
192 				/* NOTREACHED */
193 			}
194 			buf = nbuf;
195 			buf_max += 2048;
196 		}
197 		buf[indx++] = ch;
198 	}
199 
200 	if (indx != 0) {
201 		for (i = 0; i < indx; i++)
202 			putwchar(buf[i]);
203 	}
204 }
205 
206 /*
207  * calculate the column position
208  */
209 static int
210 new_column_position (int col, wint_t ch)
211 {
212 	int w;
213 
214 	if (!count_bytes) {
215 		switch (ch) {
216 		case L'\b':
217 			if (col > 0)
218 				--col;
219 			break;
220 		case L'\r':
221 			col = 0;
222 			break;
223 		case L'\t':
224 			col = (col + 8) & ~7;
225 			break;
226 		default:
227 			w = wcwidth(ch);
228 			if (w > 0)
229 				col += w;
230 			break;
231 		}
232 	} else {
233 		char dummy[MB_LEN_MAX];
234 
235 		/* XXX: we assume stateless encoding */
236 		col += wcrtomb(dummy, ch, NULL);
237 	}
238 
239 	return col;
240 }
241 
242 static void
243 usage(void)
244 {
245 	(void)fprintf(stderr,
246 	    "usage: %s [-bs] [-w width] [file ...]\n", getprogname());
247 	exit(1);
248 }
249 
250