xref: /netbsd-src/usr.bin/vis/foldit.c (revision ce0bb6e8d2e560ecacbe865a848624f94498063b)
1 /*	$NetBSD: foldit.c,v 1.4 1994/12/20 16:13:02 jtc Exp $	*/
2 
3 /*-
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)foldit.c	8.1 (Berkeley) 6/6/93";
39 #endif
40 static char rcsid[] = "$NetBSD: foldit.c,v 1.4 1994/12/20 16:13:02 jtc Exp $";
41 #endif /* not lint */
42 
43 #include <stdio.h>
44 
45 int
46 foldit(chunk, col, max)
47 	char *chunk;
48 	int col, max;
49 {
50 	register char *cp;
51 
52 	/*
53 	 * Keep track of column position. Insert hidden newline
54 	 * if this chunk puts us over the limit.
55 	 */
56 again:
57 	cp = chunk;
58 	while (*cp) {
59 		switch(*cp) {
60 		case '\n':
61 		case '\r':
62 			col = 0;
63 			break;
64 		case '\t':
65 			col = col + 8 &~ 07;
66 			break;
67 		case '\b':
68 			col = col ? col - 1 : 0;
69 			break;
70 		default:
71 			col++;
72 		}
73 		if (col > (max - 2)) {
74 			printf("\\\n");
75 			col = 0;
76 			goto again;
77 		}
78 		cp++;
79 	}
80 	return (col);
81 }
82