src/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2    Copyright (C) 91, 1995-2000 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 "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 int break_spaces;
  41
  42 /* If nonzero, count bytes, not column positions. */
  43 static int count_bytes;
  44
  45 /* If nonzero, at least one of the files we read was standard input. */
  46 static int 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 != 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       --help          display this help and exit\n\
  78       --version       output version information and exit\n\
  79 "));
  80       puts (_("\nReport bugs to <bug-textutils@gnu.org>."));
  81     }
  82   exit (status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
  83 }
  84
  85 /* Assuming the current column is COLUMN, return the column that
  86    printing C will move the cursor to.
  87    The first column is 0. */
  88
  89 static int
  90 adjust_column (int column, char c)
  91 {
  92   if (!count_bytes)
  93     {
  94       if (c == '\b')
  95         {
  96           if (column > 0)
  97             column--;
  98         }
  99       else if (c == '\r')
 100         column = 0;
 101       else if (c == '\t')
 102         column = column + 8 - column % 8;
 103       else /* if (isprint (c)) */
 104         column++;
 105     }
 106   else
 107     column++;
 108   return column;
 109 }
 110
 111 /* Fold file FILENAME, or standard input if FILENAME is "-",
 112    to stdout, with maximum line length WIDTH.
 113    Return 0 if successful, 1 if an error occurs. */
 114
 115 static int
 116 fold_file (char *filename, int width)
 117 {
 118   FILE *istream;
 119   register int c;
 120   int column = 0;               /* Screen column where next char will go. */
 121   int offset_out = 0;   /* Index in `line_out' for next char. */
 122   static char *line_out = NULL;
 123   static int allocated_out = 0;
 124
 125   if (STREQ (filename, "-"))
 126     {
 127       istream = stdin;
 128       have_read_stdin = 1;
 129     }
 130   else
 131     istream = fopen (filename, "r");
 132
 133   if (istream == NULL)
 134     {
 135       error (0, errno, "%s", filename);
 136       return 1;
 137     }
 138
 139   while ((c = getc (istream)) != EOF)
 140     {
 141       if (offset_out + 1 >= allocated_out)
 142         {
 143           allocated_out += 1024;
 144           line_out = xrealloc (line_out, allocated_out);
 145         }
 146
 147       if (c == '\n')
 148         {
 149           line_out[offset_out++] = c;
 150           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 151           column = offset_out = 0;
 152           continue;
 153         }
 154
 155     rescan:
 156       column = adjust_column (column, c);
 157
 158       if (column > width)
 159         {
 160           /* This character would make the line too long.
 161              Print the line plus a newline, and make this character
 162              start the next line. */
 163           if (break_spaces)
 164             {
 165               /* Look for the last blank. */
 166               int logical_end;
 167
 168               for (logical_end = offset_out - 1; logical_end >= 0;
 169                    logical_end--)
 170                 if (ISBLANK (line_out[logical_end]))
 171                   break;
 172               if (logical_end >= 0)
 173                 {
 174                   int i;
 175
 176                   /* Found a blank.  Don't output the part after it. */
 177                   logical_end++;
 178                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 179                           stdout);
 180                   putchar ('\n');
 181                   /* Move the remainder to the beginning of the next line.
 182                      The areas being copied here might overlap. */
 183                   memmove (line_out, line_out + logical_end,
 184                            offset_out - logical_end);
 185                   offset_out -= logical_end;
 186                   for (column = i = 0; i < offset_out; i++)
 187                     column = adjust_column (column, line_out[i]);
 188                   goto rescan;
 189                 }
 190             }
 191           else
 192             {
 193               if (offset_out == 0)
 194                 {
 195                   line_out[offset_out++] = c;
 196                   continue;
 197                 }
 198             }
 199           line_out[offset_out++] = '\n';
 200           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 201           column = offset_out = 0;
 202           goto rescan;
 203         }
 204
 205       line_out[offset_out++] = c;
 206     }
 207
 208   if (offset_out)
 209     fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 210
 211   if (ferror (istream))
 212     {
 213       error (0, errno, "%s", filename);
 214       if (!STREQ (filename, "-"))
 215         fclose (istream);
 216       return 1;
 217     }
 218   if (!STREQ (filename, "-") && fclose (istream) == EOF)
 219     {
 220       error (0, errno, "%s", filename);
 221       return 1;
 222     }
 223
 224   return 0;
 225 }
 226
 227 int
 228 main (int argc, char **argv)
 229 {
 230   int width = 80;
 231   int i;
 232   int optc;
 233   int errs = 0;
 234
 235   program_name = argv[0];
 236   setlocale (LC_ALL, "");
 237   bindtextdomain (PACKAGE, LOCALEDIR);
 238   textdomain (PACKAGE);
 239
 240   atexit (close_stdout);
 241
 242   break_spaces = count_bytes = have_read_stdin = 0;
 243
 244   /* Turn any numeric options into -w options.  */
 245   for (i = 1; i < argc; i++)
 246     {
 247       if (argv[i][0] == '-' && ISDIGIT (argv[i][1]))
 248         {
 249           char *s;
 250
 251           s = xmalloc (strlen (argv[i]) + 2);
 252           s[0] = '-';
 253           s[1] = 'w';
 254           strcpy (s + 2, argv[i] + 1);
 255           argv[i] = s;
 256         }
 257     }
 258
 259   while ((optc = getopt_long (argc, argv, "bsw:", longopts, NULL)) != -1)
 260     {
 261       switch (optc)
 262         {
 263         case 0:
 264           break;
 265
 266         case 'b':               /* Count bytes rather than columns. */
 267           count_bytes = 1;
 268           break;
 269
 270         case 's':               /* Break at word boundaries. */
 271           break_spaces = 1;
 272           break;
 273
 274         case 'w':               /* Line width. */
 275           {
 276             long int tmp_long;
 277             if (xstrtol (optarg, NULL, 10, &tmp_long, "") != LONGINT_OK
 278                 || tmp_long <= 0 || tmp_long > INT_MAX)
 279               error (EXIT_FAILURE, 0,
 280                      _("invalid number of columns: `%s'"), optarg);
 281             width = (int) tmp_long;
 282           }
 283           break;
 284
 285         case_GETOPT_HELP_CHAR;
 286
 287         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 288
 289         default:
 290           usage (1);
 291         }
 292     }
 293
 294   if (argc == optind)
 295     errs |= fold_file ("-", width);
 296   else
 297     for (i = optind; i < argc; i++)
 298       errs |= fold_file (argv[i], width);
 299
 300   if (have_read_stdin && fclose (stdin) == EOF)
 301     error (EXIT_FAILURE, errno, "-");
 302
 303   exit (errs == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
 304 }