usr.bin/vis/foldit.c

   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 }