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foldit.c revision 1.5 
      1 /*	$NetBSD: foldit.c,v 1.5 1997/10/20 03:06:47 lukem 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 #include <sys/cdefs.h>
     37 #ifndef lint
     38 #if 0
     39 static char sccsid[] = "@(#)foldit.c	8.1 (Berkeley) 6/6/93";
     40 #endif
     41 __RCSID("$NetBSD: foldit.c,v 1.5 1997/10/20 03:06:47 lukem Exp $");
     42 #endif /* not lint */
     43 
     44 #include <stdio.h>
     45 
     46 int foldit __P((char *, int, int));
     47 
     48 int
     49 foldit(chunk, col, max)
     50 	char *chunk;
     51 	int col, max;
     52 {
     53 	char *cp;
     54 
     55 	/*
     56 	 * Keep track of column position. Insert hidden newline
     57 	 * if this chunk puts us over the limit.
     58 	 */
     59 again:
     60 	cp = chunk;
     61 	while (*cp) {
     62 		switch(*cp) {
     63 		case '\n':
     64 		case '\r':
     65 			col = 0;
     66 			break;
     67 		case '\t':
     68 			col = (col + 8) &~ 07;
     69 			break;
     70 		case '\b':
     71 			col = col ? col - 1 : 0;
     72 			break;
     73 		default:
     74 			col++;
     75 		}
     76 		if (col > (max - 2)) {
     77 			printf("\\\n");
     78 			col = 0;
     79 			goto again;
     80 		}
     81 		cp++;
     82 	}
     83 	return (col);
     84 }
     85