src/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2    Copyright (C) 91, 1995-2002 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 "closeout.h"
  28 #include "error.h"
  29 #include "posixver.h"
  30 #include "xstrtol.h"
  31
  32 /* The official name of this program (e.g., no `g' prefix).  */
  33 #define PROGRAM_NAME "fold"
  34
  35 #define AUTHORS "David MacKenzie"
  36
  37 /* The name this program was run with. */
  38 char *program_name;
  39
  40 /* If nonzero, try to break on whitespace. */
  41 static int break_spaces;
  42
  43 /* If nonzero, count bytes, not column positions. */
  44 static int count_bytes;
  45
  46 /* If nonzero, at least one of the files we read was standard input. */
  47 static int have_read_stdin;
  48
  49 static struct option const longopts[] =
  50 {
  51   {"bytes", no_argument, NULL, 'b'},
  52   {"spaces", no_argument, NULL, 's'},
  53   {"width", required_argument, NULL, 'w'},
  54   {GETOPT_HELP_OPTION_DECL},
  55   {GETOPT_VERSION_OPTION_DECL},
  56   {NULL, 0, NULL, 0}
  57 };
  58
  59 void
  60 usage (int status)
  61 {
  62   if (status != 0)
  63     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  64              program_name);
  65   else
  66     {
  67       printf (_("\
  68 Usage: %s [OPTION]... [FILE]...\n\
  69 "),
  70               program_name);
  71       fputs (_("\
  72 Wrap input lines in each FILE (standard input by default), writing to\n\
  73 standard output.\n\
  74 \n\
  75 "), stdout);
  76       fputs (_("\
  77 Mandatory arguments to long options are mandatory for short options too.\n\
  78 "), stdout);
  79       fputs (_("\
  80   -b, --bytes         count bytes rather than columns\n\
  81   -s, --spaces        break at spaces\n\
  82   -w, --width=WIDTH   use WIDTH columns instead of 80\n\
  83 "), stdout);
  84       fputs (HELP_OPTION_DESCRIPTION, stdout);
  85       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  86       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  87     }
  88   exit (status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
  89 }
  90
  91 /* Assuming the current column is COLUMN, return the column that
  92    printing C will move the cursor to.
  93    The first column is 0. */
  94
  95 static int
  96 adjust_column (int column, char c)
  97 {
  98   if (!count_bytes)
  99     {
 100       if (c == '\b')
 101         {
 102           if (column > 0)
 103             column--;
 104         }
 105       else if (c == '\r')
 106         column = 0;
 107       else if (c == '\t')
 108         column = column + 8 - column % 8;
 109       else /* if (isprint (c)) */
 110         column++;
 111     }
 112   else
 113     column++;
 114   return column;
 115 }
 116
 117 /* Fold file FILENAME, or standard input if FILENAME is "-",
 118    to stdout, with maximum line length WIDTH.
 119    Return 0 if successful, 1 if an error occurs. */
 120
 121 static int
 122 fold_file (char *filename, int width)
 123 {
 124   FILE *istream;
 125   register int c;
 126   int column = 0;               /* Screen column where next char will go. */
 127   int offset_out = 0;   /* Index in `line_out' for next char. */
 128   static char *line_out = NULL;
 129   static int allocated_out = 0;
 130
 131   if (STREQ (filename, "-"))
 132     {
 133       istream = stdin;
 134       have_read_stdin = 1;
 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         {
 149           allocated_out += 1024;
 150           line_out = xrealloc (line_out, allocated_out);
 151         }
 152
 153       if (c == '\n')
 154         {
 155           line_out[offset_out++] = c;
 156           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 157           column = offset_out = 0;
 158           continue;
 159         }
 160
 161     rescan:
 162       column = adjust_column (column, c);
 163
 164       if (column > width)
 165         {
 166           /* This character would make the line too long.
 167              Print the line plus a newline, and make this character
 168              start the next line. */
 169           if (break_spaces)
 170             {
 171               /* Look for the last blank. */
 172               int logical_end;
 173
 174               for (logical_end = offset_out - 1; logical_end >= 0;
 175                    logical_end--)
 176                 if (ISBLANK (line_out[logical_end]))
 177                   break;
 178               if (logical_end >= 0)
 179                 {
 180                   int i;
 181
 182                   /* Found a blank.  Don't output the part after it. */
 183                   logical_end++;
 184                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 185                           stdout);
 186                   putchar ('\n');
 187                   /* Move the remainder to the beginning of the next line.
 188                      The areas being copied here might overlap. */
 189                   memmove (line_out, line_out + logical_end,
 190                            offset_out - logical_end);
 191                   offset_out -= logical_end;
 192                   for (column = i = 0; i < offset_out; i++)
 193                     column = adjust_column (column, line_out[i]);
 194                   goto rescan;
 195                 }
 196             }
 197           else
 198             {
 199               if (offset_out == 0)
 200                 {
 201                   line_out[offset_out++] = c;
 202                   continue;
 203                 }
 204             }
 205           line_out[offset_out++] = '\n';
 206           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 207           column = offset_out = 0;
 208           goto rescan;
 209         }
 210
 211       line_out[offset_out++] = c;
 212     }
 213
 214   if (offset_out)
 215     fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 216
 217   if (ferror (istream))
 218     {
 219       error (0, errno, "%s", filename);
 220       if (!STREQ (filename, "-"))
 221         fclose (istream);
 222       return 1;
 223     }
 224   if (!STREQ (filename, "-") && fclose (istream) == EOF)
 225     {
 226       error (0, errno, "%s", filename);
 227       return 1;
 228     }
 229
 230   return 0;
 231 }
 232
 233 int
 234 main (int argc, char **argv)
 235 {
 236   int width = 80;
 237   int i;
 238   int optc;
 239   int errs = 0;
 240
 241   program_name = argv[0];
 242   setlocale (LC_ALL, "");
 243   bindtextdomain (PACKAGE, LOCALEDIR);
 244   textdomain (PACKAGE);
 245
 246   atexit (close_stdout);
 247
 248   break_spaces = count_bytes = have_read_stdin = 0;
 249
 250   /* Turn any numeric options into -w options.  */
 251   for (i = 1; i < argc; i++)
 252     {
 253       char const *a = argv[i];
 254       if (a[0] == '-')
 255         {
 256           if (a[1] == '-' && ! a[2])
 257             break;
 258           if (ISDIGIT (a[1]))
 259             {
 260               char *s = xmalloc (strlen (a) + 2);
 261               s[0] = '-';
 262               s[1] = 'w';
 263               strcpy (s + 2, a + 1);
 264               argv[i] = s;
 265               if (200112 <= posix2_version ())
 266                 {
 267                   error (0, 0, _("`%s' option is obsolete; use `%s'"), a, s);
 268                   usage (EXIT_FAILURE);
 269                 }
 270             }
 271         }
 272     }
 273
 274   while ((optc = getopt_long (argc, argv, "bsw:", longopts, NULL)) != -1)
 275     {
 276       switch (optc)
 277         {
 278         case 0:
 279           break;
 280
 281         case 'b':               /* Count bytes rather than columns. */
 282           count_bytes = 1;
 283           break;
 284
 285         case 's':               /* Break at word boundaries. */
 286           break_spaces = 1;
 287           break;
 288
 289         case 'w':               /* Line width. */
 290           {
 291             long int tmp_long;
 292             if (xstrtol (optarg, NULL, 10, &tmp_long, "") != LONGINT_OK
 293                 || tmp_long <= 0 || tmp_long > INT_MAX)
 294               error (EXIT_FAILURE, 0,
 295                      _("invalid number of columns: `%s'"), optarg);
 296             width = (int) tmp_long;
 297           }
 298           break;
 299
 300         case_GETOPT_HELP_CHAR;
 301
 302         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 303
 304         default:
 305           usage (1);
 306         }
 307     }
 308
 309   if (argc == optind)
 310     errs |= fold_file ("-", width);
 311   else
 312     for (i = optind; i < argc; i++)
 313       errs |= fold_file (argv[i], width);
 314
 315   if (have_read_stdin && fclose (stdin) == EOF)
 316     error (EXIT_FAILURE, errno, "-");
 317
 318   exit (errs == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
 319 }