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 #define TAB_WIDTH 8
  32
  33 /* The official name of this program (e.g., no `g' prefix).  */
  34 #define PROGRAM_NAME "fold"
  35
  36 #define AUTHORS "David MacKenzie"
  37
  38 /* The name this program was run with. */
  39 char *program_name;
  40
  41 /* If nonzero, try to break on whitespace. */
  42 static bool break_spaces;
  43
  44 /* If nonzero, count bytes, not column positions. */
  45 static bool count_bytes;
  46
  47 /* If nonzero, at least one of the files we read was standard input. */
  48 static bool have_read_stdin;
  49
  50 static struct option const longopts[] =
  51 {
  52   {"bytes", no_argument, NULL, 'b'},
  53   {"spaces", no_argument, NULL, 's'},
  54   {"width", required_argument, NULL, 'w'},
  55   {GETOPT_HELP_OPTION_DECL},
  56   {GETOPT_VERSION_OPTION_DECL},
  57   {NULL, 0, NULL, 0}
  58 };
  59
  60 void
  61 usage (int status)
  62 {
  63   if (status != EXIT_SUCCESS)
  64     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  65              program_name);
  66   else
  67     {
  68       printf (_("\
  69 Usage: %s [OPTION]... [FILE]...\n\
  70 "),
  71               program_name);
  72       fputs (_("\
  73 Wrap input lines in each FILE (standard input by default), writing to\n\
  74 standard output.\n\
  75 \n\
  76 "), stdout);
  77       fputs (_("\
  78 Mandatory arguments to long options are mandatory for short options too.\n\
  79 "), stdout);
  80       fputs (_("\
  81   -b, --bytes         count bytes rather than columns\n\
  82   -s, --spaces        break at spaces\n\
  83   -w, --width=WIDTH   use WIDTH columns instead of 80\n\
  84 "), stdout);
  85       fputs (HELP_OPTION_DESCRIPTION, stdout);
  86       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  87       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  88     }
  89   exit (status);
  90 }
  91
  92 /* Assuming the current column is COLUMN, return the column that
  93    printing C will move the cursor to.
  94    The first column is 0. */
  95
  96 static size_t
  97 adjust_column (size_t column, char c)
  98 {
  99   if (!count_bytes)
 100     {
 101       if (c == '\b')
 102         {
 103           if (column > 0)
 104             column--;
 105         }
 106       else if (c == '\r')
 107         column = 0;
 108       else if (c == '\t')
 109         column += TAB_WIDTH - column % TAB_WIDTH;
 110       else /* if (isprint (c)) */
 111         column++;
 112     }
 113   else
 114     column++;
 115   return column;
 116 }
 117
 118 /* Fold file FILENAME, or standard input if FILENAME is "-",
 119    to stdout, with maximum line length WIDTH.
 120    Return true if successful.  */
 121
 122 static bool
 123 fold_file (char *filename, size_t width)
 124 {
 125   FILE *istream;
 126   register int c;
 127   size_t column = 0;            /* Screen column where next char will go. */
 128   size_t offset_out = 0;        /* Index in `line_out' for next char. */
 129   static char *line_out = NULL;
 130   static size_t allocated_out = 0;
 131   int saved_errno;
 132
 133   if (STREQ (filename, "-"))
 134     {
 135       istream = stdin;
 136       have_read_stdin = true;
 137     }
 138   else
 139     istream = fopen (filename, "r");
 140
 141   if (istream == NULL)
 142     {
 143       error (0, errno, "%s", filename);
 144       return false;
 145     }
 146
 147   while ((c = getc (istream)) != EOF)
 148     {
 149       if (offset_out + 1 >= allocated_out)
 150         line_out = x2nrealloc (line_out, &allocated_out, sizeof *line_out);
 151
 152       if (c == '\n')
 153         {
 154           line_out[offset_out++] = c;
 155           fwrite (line_out, sizeof (char), offset_out, stdout);
 156           column = offset_out = 0;
 157           continue;
 158         }
 159
 160     rescan:
 161       column = adjust_column (column, c);
 162
 163       if (column > width)
 164         {
 165           /* This character would make the line too long.
 166              Print the line plus a newline, and make this character
 167              start the next line. */
 168           if (break_spaces)
 169             {
 170               bool found_blank = false;
 171               size_t logical_end = offset_out;
 172
 173               /* Look for the last blank. */
 174               while (logical_end)
 175                 {
 176                   --logical_end;
 177                   if (ISBLANK (line_out[logical_end]))
 178                     {
 179                       found_blank = true;
 180                       break;
 181                     }
 182                 }
 183
 184               if (found_blank)
 185                 {
 186                   size_t i;
 187
 188                   /* Found a blank.  Don't output the part after it. */
 189                   logical_end++;
 190                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 191                           stdout);
 192                   putchar ('\n');
 193                   /* Move the remainder to the beginning of the next line.
 194                      The areas being copied here might overlap. */
 195                   memmove (line_out, line_out + logical_end,
 196                            offset_out - logical_end);
 197                   offset_out -= logical_end;
 198                   for (column = i = 0; i < offset_out; i++)
 199                     column = adjust_column (column, line_out[i]);
 200                   goto rescan;
 201                 }
 202             }
 203
 204           if (offset_out == 0)
 205             {
 206               line_out[offset_out++] = c;
 207               continue;
 208             }
 209
 210           line_out[offset_out++] = '\n';
 211           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 212           column = offset_out = 0;
 213           goto rescan;
 214         }
 215
 216       line_out[offset_out++] = c;
 217     }
 218
 219   saved_errno = errno;
 220
 221   if (offset_out)
 222     fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 223
 224   if (ferror (istream))
 225     {
 226       error (0, saved_errno, "%s", filename);
 227       if (!STREQ (filename, "-"))
 228         fclose (istream);
 229       return false;
 230     }
 231   if (!STREQ (filename, "-") && fclose (istream) == EOF)
 232     {
 233       error (0, errno, "%s", filename);
 234       return false;
 235     }
 236
 237   return true;
 238 }
 239
 240 int
 241 main (int argc, char **argv)
 242 {
 243   size_t width = 80;
 244   int i;
 245   int optc;
 246   bool ok;
 247
 248   initialize_main (&argc, &argv);
 249   program_name = argv[0];
 250   setlocale (LC_ALL, "");
 251   bindtextdomain (PACKAGE, LOCALEDIR);
 252   textdomain (PACKAGE);
 253
 254   atexit (close_stdout);
 255
 256   break_spaces = count_bytes = have_read_stdin = false;
 257
 258   /* Turn any numeric options into -w options.  */
 259   for (i = 1; i < argc; i++)
 260     {
 261       char const *a = argv[i];
 262       if (a[0] == '-')
 263         {
 264           if (a[1] == '-' && ! a[2])
 265             break;
 266           if (ISDIGIT (a[1]))
 267             {
 268               size_t len_a = strlen (a);
 269               char *s = xmalloc (len_a + 2);
 270               s[0] = '-';
 271               s[1] = 'w';
 272               memcpy (s + 2, a + 1, len_a);
 273               argv[i] = s;
 274               if (200112 <= posix2_version ())
 275                 {
 276                   error (0, 0, _("`%s' option is obsolete; use `%s'"), a, s);
 277                   usage (EXIT_FAILURE);
 278                 }
 279             }
 280         }
 281     }
 282
 283   while ((optc = getopt_long (argc, argv, "bsw:", longopts, NULL)) != -1)
 284     {
 285       switch (optc)
 286         {
 287         case 'b':               /* Count bytes rather than columns. */
 288           count_bytes = true;
 289           break;
 290
 291         case 's':               /* Break at word boundaries. */
 292           break_spaces = true;
 293           break;
 294
 295         case 'w':               /* Line width. */
 296           {
 297             unsigned long int tmp_ulong;
 298             if (! (xstrtoul (optarg, NULL, 10, &tmp_ulong, "") == LONGINT_OK
 299                    && 0 < tmp_ulong && tmp_ulong < SIZE_MAX - TAB_WIDTH))
 300               error (EXIT_FAILURE, 0,
 301                      _("invalid number of columns: `%s'"), optarg);
 302             width = tmp_ulong;
 303           }
 304           break;
 305
 306         case_GETOPT_HELP_CHAR;
 307
 308         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 309
 310         default:
 311           usage (EXIT_FAILURE);
 312         }
 313     }
 314
 315   if (argc == optind)
 316     ok = fold_file ("-", width);
 317   else
 318     {
 319       ok = true;
 320       for (i = optind; i < argc; i++)
 321         ok &= fold_file (argv[i], width);
 322     }
 323
 324   if (have_read_stdin && fclose (stdin) == EOF)
 325     error (EXIT_FAILURE, errno, "-");
 326
 327   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 328 }