/*      $NetBSD: foldit.c,v 1.7 2009/02/10 23:06:31 christos Exp $      */

/*-
* Copyright (c) 1990, 1993
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)foldit.c    8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: foldit.c,v 1.7 2009/02/10 23:06:31 christos Exp $");
#endif /* not lint */

#include <stdio.h>
#include <vis.h>
#include "extern.h"

int
foldit(const char *chunk, int col, int max, int flags)
{
       const char *cp;

       /*
        * Keep track of column position. Insert hidden newline
        * if this chunk puts us over the limit.
        */
again:
       cp = chunk;
       while (*cp) {
               switch(*cp) {
               case '\n':
               case '\r':
                       col = 0;
                       break;
               case '\t':
                       col = (col + 8) &~ 07;
                       break;
               case '\b':
                       col = col ? col - 1 : 0;
                       break;
               default:
                       col++;
               }
               if (col > (max - 2)) {
                       printf(flags & VIS_MIMESTYLE ? "=\n" : "\\\n");
                       col = 0;
                       goto again;
               }
               cp++;
       }
       return (col);
}