src/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2    Copyright (C) 91, 95, 1996 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
  16    Foundation, 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 /* Get isblank from GNU libc.  */
  23 #define _GNU_SOURCE
  24
  25 #include <stdio.h>
  26 #include <getopt.h>
  27 #include <sys/types.h>
  28
  29 #if HAVE_LIMITS_H
  30 # include <limits.h>
  31 #endif
  32
  33 #ifndef UINT_MAX
  34 # define UINT_MAX ((unsigned int) ~(unsigned int) 0)
  35 #endif
  36
  37 #ifndef INT_MAX
  38 # define INT_MAX ((int) (UINT_MAX >> 1))
  39 #endif
  40
  41 #include "system.h"
  42 #include "xstrtol.h"
  43 #include "error.h"
  44
  45 char *xrealloc ();
  46 char *xmalloc ();
  47
  48 /* The name this program was run with. */
  49 char *program_name;
  50
  51 /* If nonzero, try to break on whitespace. */
  52 static int break_spaces;
  53
  54 /* If nonzero, count bytes, not column positions. */
  55 static int count_bytes;
  56
  57 /* If nonzero, at least one of the files we read was standard input. */
  58 static int have_read_stdin;
  59
  60 /* If nonzero, display usage information and exit.  */
  61 static int show_help;
  62
  63 /* If nonzero, print the version on standard output then exit.  */
  64 static int show_version;
  65
  66 static struct option const longopts[] =
  67 {
  68   {"bytes", no_argument, NULL, 'b'},
  69   {"spaces", no_argument, NULL, 's'},
  70   {"width", required_argument, NULL, 'w'},
  71   {"help", no_argument, &show_help, 1},
  72   {"version", no_argument, &show_version, 1},
  73   {NULL, 0, NULL, 0}
  74 };
  75
  76 static void
  77 usage (int status)
  78 {
  79   if (status != 0)
  80     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  81              program_name);
  82   else
  83     {
  84       printf (_("\
  85 Usage: %s [OPTION]... [FILE]...\n\
  86 "),
  87               program_name);
  88       printf (_("\
  89 Wrap input lines in each FILE (standard input by default), writing to\n\
  90 standard output.\n\
  91 \n\
  92   -b, --bytes         count bytes rather than columns\n\
  93   -s, --spaces        break at spaces\n\
  94   -w, --width=WIDTH   use WIDTH columns instead of 80\n\
  95 "));
  96     }
  97   exit (status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
  98 }
  99
 100 /* Assuming the current column is COLUMN, return the column that
 101    printing C will move the cursor to.
 102    The first column is 0. */
 103
 104 static int
 105 adjust_column (int column, char c)
 106 {
 107   if (!count_bytes)
 108     {
 109       if (c == '\b')
 110         {
 111           if (column > 0)
 112             column--;
 113         }
 114       else if (c == '\r')
 115         column = 0;
 116       else if (c == '\t')
 117         column = column + 8 - column % 8;
 118       else /* if (isprint (c)) */
 119         column++;
 120     }
 121   else
 122     column++;
 123   return column;
 124 }
 125
 126 /* Fold file FILENAME, or standard input if FILENAME is "-",
 127    to stdout, with maximum line length WIDTH.
 128    Return 0 if successful, 1 if an error occurs. */
 129
 130 static int
 131 fold_file (char *filename, int width)
 132 {
 133   FILE *istream;
 134   register int c;
 135   int column = 0;               /* Screen column where next char will go. */
 136   int offset_out = 0;   /* Index in `line_out' for next char. */
 137   static char *line_out = NULL;
 138   static int allocated_out = 0;
 139
 140   if (!strcmp (filename, "-"))
 141     {
 142       istream = stdin;
 143       have_read_stdin = 1;
 144     }
 145   else
 146     istream = fopen (filename, "r");
 147
 148   if (istream == NULL)
 149     {
 150       error (0, errno, "%s", filename);
 151       return 1;
 152     }
 153
 154   while ((c = getc (istream)) != EOF)
 155     {
 156       if (offset_out + 1 >= allocated_out)
 157         {
 158           allocated_out += 1024;
 159           line_out = xrealloc (line_out, allocated_out);
 160         }
 161
 162       if (c == '\n')
 163         {
 164           line_out[offset_out++] = c;
 165           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 166           column = offset_out = 0;
 167           continue;
 168         }
 169
 170     rescan:
 171       column = adjust_column (column, c);
 172
 173       if (column > width)
 174         {
 175           /* This character would make the line too long.
 176              Print the line plus a newline, and make this character
 177              start the next line. */
 178           if (break_spaces)
 179             {
 180               /* Look for the last blank. */
 181               int logical_end;
 182
 183               for (logical_end = offset_out - 1; logical_end >= 0;
 184                    logical_end--)
 185                 if (ISBLANK (line_out[logical_end]))
 186                   break;
 187               if (logical_end >= 0)
 188                 {
 189                   int i;
 190
 191                   /* Found a blank.  Don't output the part after it. */
 192                   logical_end++;
 193                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 194                           stdout);
 195                   putchar ('\n');
 196                   /* Move the remainder to the beginning of the next line.
 197                      The areas being copied here might overlap. */
 198                   memmove (line_out, line_out + logical_end,
 199                            offset_out - logical_end);
 200                   offset_out -= logical_end;
 201                   for (column = i = 0; i < offset_out; i++)
 202                     column = adjust_column (column, line_out[i]);
 203                   goto rescan;
 204                 }
 205             }
 206           else
 207             {
 208               if (offset_out == 0)
 209                 {
 210                   line_out[offset_out++] = c;
 211                   continue;
 212                 }
 213             }
 214           line_out[offset_out++] = '\n';
 215           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 216           column = offset_out = 0;
 217           goto rescan;
 218         }
 219
 220       line_out[offset_out++] = c;
 221     }
 222
 223   if (offset_out)
 224     fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 225
 226   if (ferror (istream))
 227     {
 228       error (0, errno, "%s", filename);
 229       if (strcmp (filename, "-"))
 230         fclose (istream);
 231       return 1;
 232     }
 233   if (strcmp (filename, "-") && fclose (istream) == EOF)
 234     {
 235       error (0, errno, "%s", filename);
 236       return 1;
 237     }
 238
 239   if (ferror (stdout))
 240     {
 241       error (0, errno, _("write error"));
 242       return 1;
 243     }
 244
 245   return 0;
 246 }
 247
 248 int
 249 main (int argc, char **argv)
 250 {
 251   int width = 80;
 252   int i;
 253   int optc;
 254   int errs = 0;
 255
 256   program_name = argv[0];
 257   setlocale (LC_ALL, "");
 258   bindtextdomain (PACKAGE, LOCALEDIR);
 259   textdomain (PACKAGE);
 260
 261   break_spaces = count_bytes = have_read_stdin = 0;
 262
 263   /* Turn any numeric options into -w options.  */
 264   for (i = 1; i < argc; i++)
 265     {
 266       if (argv[i][0] == '-' && ISDIGIT (argv[i][1]))
 267         {
 268           char *s;
 269
 270           s = xmalloc (strlen (argv[i]) + 2);
 271           s[0] = '-';
 272           s[1] = 'w';
 273           strcpy (s + 2, argv[i] + 1);
 274           argv[i] = s;
 275         }
 276     }
 277
 278   while ((optc = getopt_long (argc, argv, "bsw:", longopts, (int *) 0))
 279          != EOF)
 280     {
 281       switch (optc)
 282         {
 283         case 0:
 284           break;
 285
 286         case 'b':               /* Count bytes rather than columns. */
 287           count_bytes = 1;
 288           break;
 289
 290         case 's':               /* Break at word boundaries. */
 291           break_spaces = 1;
 292           break;
 293
 294         case 'w':               /* Line width. */
 295           {
 296             long int tmp_long;
 297             if (xstrtol (optarg, NULL, 10, &tmp_long, NULL) != LONGINT_OK
 298                 || tmp_long <= 0 || tmp_long > INT_MAX)
 299               error (EXIT_FAILURE, 0,
 300                      _("invalid number of columns: `%s'"), optarg);
 301             width = (int) tmp_long;
 302           }
 303           break;
 304
 305         default:
 306           usage (1);
 307         }
 308     }
 309
 310   if (show_version)
 311     {
 312       printf ("fold - %s\n", PACKAGE_VERSION);
 313       exit (EXIT_SUCCESS);
 314     }
 315
 316   if (show_help)
 317     usage (0);
 318
 319   if (argc == optind)
 320     errs |= fold_file ("-", width);
 321   else
 322     for (i = optind; i < argc; i++)
 323       errs |= fold_file (argv[i], width);
 324
 325   if (have_read_stdin && fclose (stdin) == EOF)
 326     error (EXIT_FAILURE, errno, "-");
 327   if (fclose (stdout) == EOF)
 328     error (EXIT_FAILURE, errno, _("write error"));
 329
 330   exit (errs == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
 331 }