usr.bin/fold/fold.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kevin Ruddy.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * @(#) Copyright (c) 1990, 1993 The Regents of the University of California.  All rights reserved.
  33  * @(#)fold.c   8.1 (Berkeley) 6/6/93
  34  * $FreeBSD: src/usr.bin/fold/fold.c,v 1.4.2.3 2002/07/11 01:01:44 tjr Exp $
  35  * $DragonFly: src/usr.bin/fold/fold.c,v 1.5 2006/08/13 02:15:07 swildner Exp $
  36  */
  37
  38 #include <ctype.h>
  39 #include <err.h>
  40 #include <limits.h>
  41 #include <locale.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <unistd.h>
  46
  47 #define DEFLINEWIDTH    80
  48
  49 void fold(int);
  50 static int newpos(int, int);
  51 static void usage(void);
  52
  53 int bflag;                      /* Count bytes, not columns */
  54 int sflag;                      /* Split on word boundaries */
  55
  56 int
  57 main(int argc, char **argv)
  58 {
  59         int ch;
  60         int rval, width;
  61         char *p;
  62
  63         (void) setlocale(LC_CTYPE, "");
  64
  65         width = -1;
  66         while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1)
  67                 switch (ch) {
  68                 case 'b':
  69                         bflag = 1;
  70                         break;
  71                 case 's':
  72                         sflag = 1;
  73                         break;
  74                 case 'w':
  75                         if ((width = atoi(optarg)) <= 0) {
  76                                 errx(1, "illegal width value");
  77                         }
  78                         break;
  79                 case '0': case '1': case '2': case '3': case '4':
  80                 case '5': case '6': case '7': case '8': case '9':
  81                         if (width == -1) {
  82                                 p = argv[optind - 1];
  83                                 if (p[0] == '-' && p[1] == ch && !p[2])
  84                                         width = atoi(++p);
  85                                 else
  86                                         width = atoi(argv[optind] + 1);
  87                         }
  88                         break;
  89                 default:
  90                         usage();
  91                 }
  92         argv += optind;
  93         argc -= optind;
  94
  95         if (width == -1)
  96                 width = DEFLINEWIDTH;
  97         rval = 0;
  98         if (!*argv)
  99                 fold(width);
 100         else for (; *argv; ++argv)
 101                 if (!freopen(*argv, "r", stdin)) {
 102                         warn("%s", *argv);
 103                         rval = 1;
 104                 } else
 105                         fold(width);
 106         exit(rval);
 107 }
 108
 109 static void
 110 usage(void)
 111 {
 112         (void)fprintf(stderr, "usage: fold [-bs] [-w width] [file ...]\n");
 113         exit(1);
 114 }
 115
 116 /*
 117  * Fold the contents of standard input to fit within WIDTH columns (or bytes)
 118  * and write to standard output.
 119  *
 120  * If sflag is set, split the line at the last space character on the line.
 121  * This flag necessitates storing the line in a buffer until the current
 122  * column > width, or a newline or EOF is read.
 123  *
 124  * The buffer can grow larger than WIDTH due to backspaces and carriage
 125  * returns embedded in the input stream.
 126  */
 127 void
 128 fold(int width)
 129 {
 130         static char *buf;
 131         static int buf_max;
 132         int ch, col, i, indx, space;
 133
 134         col = indx = space = 0;
 135         while ((ch = getchar()) != EOF) {
 136                 if (ch == '\n') {
 137                         if (indx != 0)
 138                                 fwrite(buf, 1, indx, stdout);
 139                         putchar('\n');
 140                         col = indx = 0;
 141                         continue;
 142                 }
 143                 if ((col = newpos(col, ch)) > width) {
 144                         if (sflag) {
 145                                 i = indx;
 146                                 while (--i >= 0 && !isblank((unsigned char)buf[i]))
 147                                         ;
 148                                 space = i;
 149                         }
 150                         if (sflag && space != -1) {
 151                                 space++;
 152                                 fwrite(buf, 1, space, stdout);
 153                                 memmove(buf, buf + space, indx - space);
 154                                 indx -= space;
 155                                 col = 0;
 156                                 for (i = 0; i < indx; i++)
 157                                         col = newpos(col,
 158                                             (unsigned char)buf[i]);
 159                         } else {
 160                                 fwrite(buf, 1, indx, stdout);
 161                                 col = indx = 0;
 162                         }
 163                         putchar('\n');
 164                         col = newpos(col, ch);
 165                 }
 166                 if (indx + 1 > buf_max) {
 167                         buf_max += LINE_MAX;
 168                         if ((buf = realloc(buf, buf_max)) == NULL)
 169                                 err(1, "realloc()");
 170                 }
 171                 buf[indx++] = ch;
 172         }
 173
 174         if (indx != 0)
 175                 fwrite(buf, 1, indx, stdout);
 176 }
 177
 178 /*
 179  * Update the current column position for a character.
 180  */
 181 static int
 182 newpos(int col, int ch)
 183 {
 184
 185         if (bflag)
 186                 ++col;
 187         else
 188                 switch (ch) {
 189                 case '\b':
 190                         if (col > 0)
 191                                 --col;
 192                         break;
 193                 case '\r':
 194                         col = 0;
 195                         break;
 196                 case '\t':
 197                         col = (col + 8) & ~7;
 198                         break;
 199                 default:
 200                         if (isprint(ch))
 201                                 ++col;
 202                         break;
 203                 }
 204
 205         return (col);
 206 }