/usr.bin/vis/foldit.c

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