usr.bin/fold/fold.c

   1 /*      $NetBSD: fold.c,v 1.14 2008/07/21 14:19:22 lukem Exp $  */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Kevin Ruddy.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 __COPYRIGHT("@(#) Copyright (c) 1990, 1993\
  38  The Regents of the University of California.  All rights reserved.");
  39 #endif /* not lint */
  40
  41 #ifndef lint
  42 #if 0
  43 static char sccsid[] = "@(#)fold.c      8.1 (Berkeley) 6/6/93";
  44 #endif
  45 __RCSID("$NetBSD: fold.c,v 1.14 2008/07/21 14:19:22 lukem Exp $");
  46 #endif /* not lint */
  47
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <unistd.h>
  52 #include <err.h>
  53
  54 #define DEFLINEWIDTH    80
  55
  56         int     main(int, char **);
  57 static  void    fold(int);
  58 static  int     new_column_position(int, int);
  59 static  void    usage(void);
  60
  61 int count_bytes = 0;
  62 int split_words = 0;
  63
  64 int
  65 main(int argc, char **argv)
  66 {
  67         int ch;
  68         int width;
  69         char *p;
  70
  71         width = -1;
  72         while ((ch = getopt(argc, argv, "0123456789bsw:")) != -1)
  73                 switch (ch) {
  74                 case 'b':
  75                         count_bytes = 1;
  76                         break;
  77                 case 's':
  78                         split_words = 1;
  79                         break;
  80                 case 'w':
  81                         if ((width = atoi(optarg)) <= 0)
  82                                 errx(1, "illegal width value");
  83                         break;
  84                 case '0': case '1': case '2': case '3': case '4':
  85                 case '5': case '6': case '7': case '8': case '9':
  86                         if (width == -1) {
  87                                 p = argv[optind - 1];
  88                                 if (p[0] == '-' && p[1] == ch && !p[2])
  89                                         width = atoi(++p);
  90                                 else
  91                                         width = atoi(argv[optind] + 1);
  92                         }
  93                         break;
  94                 default:
  95                         usage();
  96                 }
  97         argv += optind;
  98         argc -= optind;
  99
 100         if (width == -1)
 101                 width = DEFLINEWIDTH;
 102
 103         if (!*argv)
 104                 fold(width);
 105         else for (; *argv; ++argv)
 106                 if (!freopen(*argv, "r", stdin)) {
 107                         err (1, "%s", *argv);
 108                         /* NOTREACHED */
 109                 } else
 110                         fold(width);
 111         exit(0);
 112 }
 113
 114 /*
 115  * Fold the contents of standard input to fit within WIDTH columns
 116  * (or bytes) and write to standard output.
 117  *
 118  * If split_words is set, split the line at the last space character
 119  * on the line.  This flag necessitates storing the line in a buffer
 120  * until the current column > width, or a newline or EOF is read.
 121  *
 122  * The buffer can grow larger than WIDTH due to backspaces and carriage
 123  * returns embedded in the input stream.
 124  */
 125 static void
 126 fold(int width)
 127 {
 128         static char *buf = NULL;
 129         char *nbuf;
 130         static int   buf_max = 0;
 131         int ch, col;
 132         int indx;
 133
 134         col = indx = 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
 144                 col = new_column_position (col, ch);
 145                 if (col > width) {
 146                         int i, last_space;
 147
 148 #ifdef __GNUC__
 149                         last_space = 0; /* XXX gcc */
 150 #endif
 151                         if (split_words) {
 152                                 for (i = 0, last_space = -1; i < indx; i++)
 153                                         if (buf[i] == ' ')
 154                                                 last_space = i;
 155                         }
 156
 157                         if (split_words && last_space != -1) {
 158                                 fwrite (buf, 1, last_space, stdout);
 159
 160                                 /* increase last_space here, so we skip trailing whitespace */
 161                                 last_space++;
 162                                 memmove (buf, buf+last_space, indx-last_space);
 163
 164                                 indx -= last_space;
 165                                 col = 0;
 166                                 for (i = 0; i < indx; i++) {
 167                                         col = new_column_position (col, buf[i]);
 168                                 }
 169                         } else {
 170                                 fwrite (buf, 1, indx, stdout);
 171                                 col = indx = 0;
 172                         }
 173                         putchar('\n');
 174
 175                         /* calculate the column position for the next line. */
 176                         col = new_column_position (col, ch);
 177                 }
 178
 179                 if (indx + 1 > buf_max) {
 180                         /* Allocate buffer in LINE_MAX increments */
 181                         if ((nbuf = realloc (buf, buf_max + 2048)) == NULL) {
 182                                 err (1, "realloc");
 183                                 /* NOTREACHED */
 184                         }
 185                         buf = nbuf;
 186                         buf_max += 2048;
 187                 }
 188                 buf[indx++] = ch;
 189         }
 190
 191         if (indx != 0)
 192                 fwrite (buf, 1, indx, stdout);
 193 }
 194
 195 /*
 196  * calculate the column position
 197  */
 198 static int
 199 new_column_position (int col, int ch)
 200 {
 201         if (!count_bytes) {
 202                 switch (ch) {
 203                 case '\b':
 204                         if (col > 0)
 205                                 --col;
 206                         break;
 207                 case '\r':
 208                         col = 0;
 209                         break;
 210                 case '\t':
 211                         col = (col + 8) & ~7;
 212                         break;
 213                 default:
 214                         ++col;
 215                         break;
 216                 }
 217         } else {
 218                 ++col;
 219         }
 220
 221         return col;
 222 }
 223
 224 static void
 225 usage(void)
 226         {
 227         (void)fprintf(stderr,
 228                     "usage: fold [-bs] [-w width] [file ...]\n");
 229         exit(1);
 230         }
 231