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      1 /*	$NetBSD: foldit.c,v 1.7 2009/02/10 23:06:31 christos 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. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)foldit.c	8.1 (Berkeley) 6/6/93";
     36 #endif
     37 __RCSID("$NetBSD: foldit.c,v 1.7 2009/02/10 23:06:31 christos Exp $");
     38 #endif /* not lint */
     39 
     40 #include <stdio.h>
     41 #include <vis.h>
     42 #include "extern.h"
     43 
     44 int
     45 foldit(const char *chunk, int col, int max, int flags)
     46 {
     47 	const char *cp;
     48 
     49 	/*
     50 	 * Keep track of column position. Insert hidden newline
     51 	 * if this chunk puts us over the limit.
     52 	 */
     53 again:
     54 	cp = chunk;
     55 	while (*cp) {
     56 		switch(*cp) {
     57 		case '\n':
     58 		case '\r':
     59 			col = 0;
     60 			break;
     61 		case '\t':
     62 			col = (col + 8) &~ 07;
     63 			break;
     64 		case '\b':
     65 			col = col ? col - 1 : 0;
     66 			break;
     67 		default:
     68 			col++;
     69 		}
     70 		if (col > (max - 2)) {
     71 			printf(flags & VIS_MIMESTYLE ? "=\n" : "\\\n");
     72 			col = 0;
     73 			goto again;
     74 		}
     75 		cp++;
     76 	}
     77 	return (col);
     78 }
     79