src/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2    Copyright (C) 91, 95, 96, 1997, 1998 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by David MacKenzie, djm@gnu.ai.mit.edu. */
  19
  20 #include <config.h>
  21
  22 #include <stdio.h>
  23 #include <getopt.h>
  24 #include <sys/types.h>
  25
  26 #include "system.h"
  27 #include "xstrtol.h"
  28 #include "error.h"
  29
  30 /* The name this program was run with. */
  31 char *program_name;
  32
  33 /* If nonzero, try to break on whitespace. */
  34 static int break_spaces;
  35
  36 /* If nonzero, count bytes, not column positions. */
  37 static int count_bytes;
  38
  39 /* If nonzero, at least one of the files we read was standard input. */
  40 static int have_read_stdin;
  41
  42 /* If nonzero, display usage information and exit.  */
  43 static int show_help;
  44
  45 /* If nonzero, print the version on standard output then exit.  */
  46 static int show_version;
  47
  48 static struct option const longopts[] =
  49 {
  50   {"bytes", no_argument, NULL, 'b'},
  51   {"spaces", no_argument, NULL, 's'},
  52   {"width", required_argument, NULL, 'w'},
  53   {"help", no_argument, &show_help, 1},
  54   {"version", no_argument, &show_version, 1},
  55   {NULL, 0, NULL, 0}
  56 };
  57
  58 static void
  59 usage (int status)
  60 {
  61   if (status != 0)
  62     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  63              program_name);
  64   else
  65     {
  66       printf (_("\
  67 Usage: %s [OPTION]... [FILE]...\n\
  68 "),
  69               program_name);
  70       printf (_("\
  71 Wrap input lines in each FILE (standard input by default), writing to\n\
  72 standard output.\n\
  73 \n\
  74   -b, --bytes         count bytes rather than columns\n\
  75   -s, --spaces        break at spaces\n\
  76   -w, --width=WIDTH   use WIDTH columns instead of 80\n\
  77 "));
  78       puts (_("\nReport bugs to <bug-textutils@gnu.org>."));
  79     }
  80   exit (status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
  81 }
  82
  83 /* Assuming the current column is COLUMN, return the column that
  84    printing C will move the cursor to.
  85    The first column is 0. */
  86
  87 static int
  88 adjust_column (int column, char c)
  89 {
  90   if (!count_bytes)
  91     {
  92       if (c == '\b')
  93         {
  94           if (column > 0)
  95             column--;
  96         }
  97       else if (c == '\r')
  98         column = 0;
  99       else if (c == '\t')
 100         column = column + 8 - column % 8;
 101       else /* if (isprint (c)) */
 102         column++;
 103     }
 104   else
 105     column++;
 106   return column;
 107 }
 108
 109 /* Fold file FILENAME, or standard input if FILENAME is "-",
 110    to stdout, with maximum line length WIDTH.
 111    Return 0 if successful, 1 if an error occurs. */
 112
 113 static int
 114 fold_file (char *filename, int width)
 115 {
 116   FILE *istream;
 117   register int c;
 118   int column = 0;               /* Screen column where next char will go. */
 119   int offset_out = 0;   /* Index in `line_out' for next char. */
 120   static char *line_out = NULL;
 121   static int allocated_out = 0;
 122
 123   if (STREQ (filename, "-"))
 124     {
 125       istream = stdin;
 126       have_read_stdin = 1;
 127     }
 128   else
 129     istream = fopen (filename, "r");
 130
 131   if (istream == NULL)
 132     {
 133       error (0, errno, "%s", filename);
 134       return 1;
 135     }
 136
 137   while ((c = getc (istream)) != EOF)
 138     {
 139       if (offset_out + 1 >= allocated_out)
 140         {
 141           allocated_out += 1024;
 142           line_out = xrealloc (line_out, allocated_out);
 143         }
 144
 145       if (c == '\n')
 146         {
 147           line_out[offset_out++] = c;
 148           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 149           column = offset_out = 0;
 150           continue;
 151         }
 152
 153     rescan:
 154       column = adjust_column (column, c);
 155
 156       if (column > width)
 157         {
 158           /* This character would make the line too long.
 159              Print the line plus a newline, and make this character
 160              start the next line. */
 161           if (break_spaces)
 162             {
 163               /* Look for the last blank. */
 164               int logical_end;
 165
 166               for (logical_end = offset_out - 1; logical_end >= 0;
 167                    logical_end--)
 168                 if (ISBLANK (line_out[logical_end]))
 169                   break;
 170               if (logical_end >= 0)
 171                 {
 172                   int i;
 173
 174                   /* Found a blank.  Don't output the part after it. */
 175                   logical_end++;
 176                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 177                           stdout);
 178                   putchar ('\n');
 179                   /* Move the remainder to the beginning of the next line.
 180                      The areas being copied here might overlap. */
 181                   memmove (line_out, line_out + logical_end,
 182                            offset_out - logical_end);
 183                   offset_out -= logical_end;
 184                   for (column = i = 0; i < offset_out; i++)
 185                     column = adjust_column (column, line_out[i]);
 186                   goto rescan;
 187                 }
 188             }
 189           else
 190             {
 191               if (offset_out == 0)
 192                 {
 193                   line_out[offset_out++] = c;
 194                   continue;
 195                 }
 196             }
 197           line_out[offset_out++] = '\n';
 198           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 199           column = offset_out = 0;
 200           goto rescan;
 201         }
 202
 203       line_out[offset_out++] = c;
 204     }
 205
 206   if (offset_out)
 207     fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 208
 209   if (ferror (istream))
 210     {
 211       error (0, errno, "%s", filename);
 212       if (!STREQ (filename, "-"))
 213         fclose (istream);
 214       return 1;
 215     }
 216   if (!STREQ (filename, "-") && fclose (istream) == EOF)
 217     {
 218       error (0, errno, "%s", filename);
 219       return 1;
 220     }
 221
 222   if (ferror (stdout))
 223     {
 224       error (0, errno, _("write error"));
 225       return 1;
 226     }
 227
 228   return 0;
 229 }
 230
 231 int
 232 main (int argc, char **argv)
 233 {
 234   int width = 80;
 235   int i;
 236   int optc;
 237   int errs = 0;
 238
 239   program_name = argv[0];
 240   setlocale (LC_ALL, "");
 241   bindtextdomain (PACKAGE, LOCALEDIR);
 242   textdomain (PACKAGE);
 243
 244   break_spaces = count_bytes = have_read_stdin = 0;
 245
 246   /* Turn any numeric options into -w options.  */
 247   for (i = 1; i < argc; i++)
 248     {
 249       if (argv[i][0] == '-' && ISDIGIT (argv[i][1]))
 250         {
 251           char *s;
 252
 253           s = xmalloc (strlen (argv[i]) + 2);
 254           s[0] = '-';
 255           s[1] = 'w';
 256           strcpy (s + 2, argv[i] + 1);
 257           argv[i] = s;
 258         }
 259     }
 260
 261   while ((optc = getopt_long (argc, argv, "bsw:", longopts, NULL)) != -1)
 262     {
 263       switch (optc)
 264         {
 265         case 0:
 266           break;
 267
 268         case 'b':               /* Count bytes rather than columns. */
 269           count_bytes = 1;
 270           break;
 271
 272         case 's':               /* Break at word boundaries. */
 273           break_spaces = 1;
 274           break;
 275
 276         case 'w':               /* Line width. */
 277           {
 278             long int tmp_long;
 279             if (xstrtol (optarg, NULL, 10, &tmp_long, "") != LONGINT_OK
 280                 || tmp_long <= 0 || tmp_long > INT_MAX)
 281               error (EXIT_FAILURE, 0,
 282                      _("invalid number of columns: `%s'"), optarg);
 283             width = (int) tmp_long;
 284           }
 285           break;
 286
 287         default:
 288           usage (1);
 289         }
 290     }
 291
 292   if (show_version)
 293     {
 294       printf ("fold (%s) %s\n", GNU_PACKAGE, VERSION);
 295       exit (EXIT_SUCCESS);
 296     }
 297
 298   if (show_help)
 299     usage (0);
 300
 301   if (argc == optind)
 302     errs |= fold_file ("-", width);
 303   else
 304     for (i = optind; i < argc; i++)
 305       errs |= fold_file (argv[i], width);
 306
 307   if (have_read_stdin && fclose (stdin) == EOF)
 308     error (EXIT_FAILURE, errno, "-");
 309   if (fclose (stdout) == EOF)
 310     error (EXIT_FAILURE, errno, _("write error"));
 311
 312   exit (errs == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
 313 }