src/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2    Copyright (C) 91, 1995-2004 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 "error.h"
  28 #include "posixver.h"
  29 #include "xstrtol.h"
  30
  31 /* The official name of this program (e.g., no `g' prefix).  */
  32 #define PROGRAM_NAME "fold"
  33
  34 #define AUTHORS "David MacKenzie"
  35
  36 /* The name this program was run with. */
  37 char *program_name;
  38
  39 /* If nonzero, try to break on whitespace. */
  40 static bool break_spaces;
  41
  42 /* If nonzero, count bytes, not column positions. */
  43 static bool count_bytes;
  44
  45 /* If nonzero, at least one of the files we read was standard input. */
  46 static bool have_read_stdin;
  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   {GETOPT_HELP_OPTION_DECL},
  54   {GETOPT_VERSION_OPTION_DECL},
  55   {NULL, 0, NULL, 0}
  56 };
  57
  58 void
  59 usage (int status)
  60 {
  61   if (status != EXIT_SUCCESS)
  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       fputs (_("\
  71 Wrap input lines in each FILE (standard input by default), writing to\n\
  72 standard output.\n\
  73 \n\
  74 "), stdout);
  75       fputs (_("\
  76 Mandatory arguments to long options are mandatory for short options too.\n\
  77 "), stdout);
  78       fputs (_("\
  79   -b, --bytes         count bytes rather than columns\n\
  80   -s, --spaces        break at spaces\n\
  81   -w, --width=WIDTH   use WIDTH columns instead of 80\n\
  82 "), stdout);
  83       fputs (HELP_OPTION_DESCRIPTION, stdout);
  84       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  85       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  86     }
  87   exit (status);
  88 }
  89
  90 /* Assuming the current column is COLUMN, return the column that
  91    printing C will move the cursor to.
  92    The first column is 0. */
  93
  94 static size_t
  95 adjust_column (size_t column, char c)
  96 {
  97   if (!count_bytes)
  98     {
  99       if (c == '\b')
 100         {
 101           if (column > 0)
 102             column--;
 103         }
 104       else if (c == '\r')
 105         column = 0;
 106       else if (c == '\t')
 107         column = column + 8 - column % 8;
 108       else /* if (isprint (c)) */
 109         column++;
 110     }
 111   else
 112     column++;
 113   return column;
 114 }
 115
 116 /* Fold file FILENAME, or standard input if FILENAME is "-",
 117    to stdout, with maximum line length WIDTH.
 118    Return 0 if successful, 1 if an error occurs. */
 119
 120 static int
 121 fold_file (char *filename, int width)
 122 {
 123   FILE *istream;
 124   register int c;
 125   size_t column = 0;            /* Screen column where next char will go. */
 126   size_t offset_out = 0;        /* Index in `line_out' for next char. */
 127   static char *line_out = NULL;
 128   static size_t allocated_out = 0;
 129   int saved_errno;
 130
 131   if (STREQ (filename, "-"))
 132     {
 133       istream = stdin;
 134       have_read_stdin = true;
 135     }
 136   else
 137     istream = fopen (filename, "r");
 138
 139   if (istream == NULL)
 140     {
 141       error (0, errno, "%s", filename);
 142       return 1;
 143     }
 144
 145   while ((c = getc (istream)) != EOF)
 146     {
 147       if (offset_out + 1 >= allocated_out)
 148         line_out = x2nrealloc (line_out, &allocated_out, sizeof *line_out);
 149
 150       if (c == '\n')
 151         {
 152           line_out[offset_out++] = c;
 153           fwrite (line_out, sizeof (char), offset_out, stdout);
 154           column = offset_out = 0;
 155           continue;
 156         }
 157
 158     rescan:
 159       column = adjust_column (column, c);
 160
 161       if (column > width)
 162         {
 163           /* This character would make the line too long.
 164              Print the line plus a newline, and make this character
 165              start the next line. */
 166           if (break_spaces)
 167             {
 168               bool found_blank = false;
 169               size_t logical_end = offset_out;
 170
 171               /* Look for the last blank. */
 172               while (logical_end)
 173                 {
 174                   --logical_end;
 175                   if (ISBLANK (line_out[logical_end]))
 176                     {
 177                       found_blank = true;
 178                       break;
 179                     }
 180                 }
 181
 182               if (found_blank)
 183                 {
 184                   size_t i;
 185
 186                   /* Found a blank.  Don't output the part after it. */
 187                   logical_end++;
 188                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 189                           stdout);
 190                   putchar ('\n');
 191                   /* Move the remainder to the beginning of the next line.
 192                      The areas being copied here might overlap. */
 193                   memmove (line_out, line_out + logical_end,
 194                            offset_out - logical_end);
 195                   offset_out -= logical_end;
 196                   for (column = i = 0; i < offset_out; i++)
 197                     column = adjust_column (column, line_out[i]);
 198                   goto rescan;
 199                 }
 200             }
 201
 202           if (offset_out == 0)
 203             {
 204               line_out[offset_out++] = c;
 205               continue;
 206             }
 207
 208           line_out[offset_out++] = '\n';
 209           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 210           column = offset_out = 0;
 211           goto rescan;
 212         }
 213
 214       line_out[offset_out++] = c;
 215     }
 216
 217   saved_errno = errno;
 218
 219   if (offset_out)
 220     fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 221
 222   if (ferror (istream))
 223     {
 224       error (0, saved_errno, "%s", filename);
 225       if (!STREQ (filename, "-"))
 226         fclose (istream);
 227       return 1;
 228     }
 229   if (!STREQ (filename, "-") && fclose (istream) == EOF)
 230     {
 231       error (0, errno, "%s", filename);
 232       return 1;
 233     }
 234
 235   return 0;
 236 }
 237
 238 int
 239 main (int argc, char **argv)
 240 {
 241   int width = 80;
 242   int i;
 243   int optc;
 244   int errs = 0;
 245
 246   initialize_main (&argc, &argv);
 247   program_name = argv[0];
 248   setlocale (LC_ALL, "");
 249   bindtextdomain (PACKAGE, LOCALEDIR);
 250   textdomain (PACKAGE);
 251
 252   atexit (close_stdout);
 253
 254   break_spaces = count_bytes = have_read_stdin = false;
 255
 256   /* Turn any numeric options into -w options.  */
 257   for (i = 1; i < argc; i++)
 258     {
 259       char const *a = argv[i];
 260       if (a[0] == '-')
 261         {
 262           if (a[1] == '-' && ! a[2])
 263             break;
 264           if (ISDIGIT (a[1]))
 265             {
 266               size_t len_a = strlen (a);
 267               char *s = xmalloc (len_a + 2);
 268               s[0] = '-';
 269               s[1] = 'w';
 270               memcpy (s + 2, a + 1, len_a);
 271               argv[i] = s;
 272               if (200112 <= posix2_version ())
 273                 {
 274                   error (0, 0, _("`%s' option is obsolete; use `%s'"), a, s);
 275                   usage (EXIT_FAILURE);
 276                 }
 277             }
 278         }
 279     }
 280
 281   while ((optc = getopt_long (argc, argv, "bsw:", longopts, NULL)) != -1)
 282     {
 283       switch (optc)
 284         {
 285         case 0:
 286           break;
 287
 288         case 'b':               /* Count bytes rather than columns. */
 289           count_bytes = true;
 290           break;
 291
 292         case 's':               /* Break at word boundaries. */
 293           break_spaces = true;
 294           break;
 295
 296         case 'w':               /* Line width. */
 297           {
 298             long int tmp_long;
 299             if (xstrtol (optarg, NULL, 10, &tmp_long, "") != LONGINT_OK
 300                 || tmp_long <= 0 || tmp_long > INT_MAX)
 301               error (EXIT_FAILURE, 0,
 302                      _("invalid number of columns: `%s'"), optarg);
 303             width = (int) tmp_long;
 304           }
 305           break;
 306
 307         case_GETOPT_HELP_CHAR;
 308
 309         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 310
 311         default:
 312           usage (EXIT_FAILURE);
 313         }
 314     }
 315
 316   if (argc == optind)
 317     errs |= fold_file ("-", width);
 318   else
 319     for (i = optind; i < argc; i++)
 320       errs |= fold_file (argv[i], width);
 321
 322   if (have_read_stdin && fclose (stdin) == EOF)
 323     error (EXIT_FAILURE, errno, "-");
 324
 325   exit (errs == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
 326 }