src/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2    Copyright (C) 1991, 1995 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 "version.h"
  43 #include "xstrtol.h"
  44 #include "error.h"
  45
  46 char *xrealloc ();
  47 char *xmalloc ();
  48
  49 /* The name this program was run with. */
  50 char *program_name;
  51
  52 /* If nonzero, try to break on whitespace. */
  53 static int break_spaces;
  54
  55 /* If nonzero, count bytes, not column positions. */
  56 static int count_bytes;
  57
  58 /* If nonzero, at least one of the files we read was standard input. */
  59 static int have_read_stdin;
  60
  61 /* If nonzero, display usage information and exit.  */
  62 static int show_help;
  63
  64 /* If nonzero, print the version on standard output then exit.  */
  65 static int show_version;
  66
  67 static struct option const longopts[] =
  68 {
  69   {"bytes", no_argument, NULL, 'b'},
  70   {"spaces", no_argument, NULL, 's'},
  71   {"width", required_argument, NULL, 'w'},
  72   {"help", no_argument, &show_help, 1},
  73   {"version", no_argument, &show_version, 1},
  74   {NULL, 0, NULL, 0}
  75 };
  76
  77 static void
  78 usage (int status)
  79 {
  80   if (status != 0)
  81     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  82              program_name);
  83   else
  84     {
  85       printf (_("\
  86 Usage: %s [OPTION]... [FILE]...\n\
  87 "),
  88               program_name);
  89       printf (_("\
  90 Wrap input lines in each FILE (standard input by default), writing to\n\
  91 standard output.\n\
  92 \n\
  93   -b, --bytes         count bytes rather than columns\n\
  94   -s, --spaces        break at spaces\n\
  95   -w, --width=WIDTH   use WIDTH columns instead of 80\n\
  96 "));
  97     }
  98   exit (status);
  99 }
 100
 101 /* Assuming the current column is COLUMN, return the column that
 102    printing C will move the cursor to.
 103    The first column is 0. */
 104
 105 static int
 106 adjust_column (int column, char c)
 107 {
 108   if (!count_bytes)
 109     {
 110       if (c == '\b')
 111         {
 112           if (column > 0)
 113             column--;
 114         }
 115       else if (c == '\r')
 116         column = 0;
 117       else if (c == '\t')
 118         column = column + 8 - column % 8;
 119       else /* if (isprint (c)) */
 120         column++;
 121     }
 122   else
 123     column++;
 124   return column;
 125 }
 126
 127 /* Fold file FILENAME, or standard input if FILENAME is "-",
 128    to stdout, with maximum line length WIDTH.
 129    Return 0 if successful, 1 if an error occurs. */
 130
 131 static int
 132 fold_file (char *filename, int width)
 133 {
 134   FILE *istream;
 135   register int c;
 136   int column = 0;               /* Screen column where next char will go. */
 137   int offset_out = 0;   /* Index in `line_out' for next char. */
 138   static char *line_out = NULL;
 139   static int allocated_out = 0;
 140
 141   if (!strcmp (filename, "-"))
 142     {
 143       istream = stdin;
 144       have_read_stdin = 1;
 145     }
 146   else
 147     istream = fopen (filename, "r");
 148
 149   if (istream == NULL)
 150     {
 151       error (0, errno, "%s", filename);
 152       return 1;
 153     }
 154
 155   while ((c = getc (istream)) != EOF)
 156     {
 157       if (offset_out + 1 >= allocated_out)
 158         {
 159           allocated_out += 1024;
 160           line_out = xrealloc (line_out, allocated_out);
 161         }
 162
 163       if (c == '\n')
 164         {
 165           line_out[offset_out++] = c;
 166           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 167           column = offset_out = 0;
 168           continue;
 169         }
 170
 171     rescan:
 172       column = adjust_column (column, c);
 173
 174       if (column > width)
 175         {
 176           /* This character would make the line too long.
 177              Print the line plus a newline, and make this character
 178              start the next line. */
 179           if (break_spaces)
 180             {
 181               /* Look for the last blank. */
 182               int logical_end;
 183
 184               for (logical_end = offset_out - 1; logical_end >= 0;
 185                    logical_end--)
 186                 if (ISBLANK (line_out[logical_end]))
 187                   break;
 188               if (logical_end >= 0)
 189                 {
 190                   int i;
 191
 192                   /* Found a blank.  Don't output the part after it. */
 193                   logical_end++;
 194                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 195                           stdout);
 196                   putchar ('\n');
 197                   /* Move the remainder to the beginning of the next line.
 198                      The areas being copied here might overlap. */
 199                   memmove (line_out, line_out + logical_end,
 200                            offset_out - logical_end);
 201                   offset_out -= logical_end;
 202                   for (column = i = 0; i < offset_out; i++)
 203                     column = adjust_column (column, line_out[i]);
 204                   goto rescan;
 205                 }
 206             }
 207           else
 208             {
 209               if (offset_out == 0)
 210                 {
 211                   line_out[offset_out++] = c;
 212                   continue;
 213                 }
 214             }
 215           line_out[offset_out++] = '\n';
 216           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 217           column = offset_out = 0;
 218           goto rescan;
 219         }
 220
 221       line_out[offset_out++] = c;
 222     }
 223
 224   if (offset_out)
 225     fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 226
 227   if (ferror (istream))
 228     {
 229       error (0, errno, "%s", filename);
 230       if (strcmp (filename, "-"))
 231         fclose (istream);
 232       return 1;
 233     }
 234   if (strcmp (filename, "-") && fclose (istream) == EOF)
 235     {
 236       error (0, errno, "%s", filename);
 237       return 1;
 238     }
 239
 240   if (ferror (stdout))
 241     {
 242       error (0, errno, _("write error"));
 243       return 1;
 244     }
 245
 246   return 0;
 247 }
 248
 249 void
 250 main (int argc, char **argv)
 251 {
 252   int width = 80;
 253   int i;
 254   int optc;
 255   int errs = 0;
 256
 257   program_name = argv[0];
 258   setlocale (LC_ALL, "");
 259   bindtextdomain (PACKAGE, LOCALEDIR);
 260   textdomain (PACKAGE);
 261
 262   break_spaces = count_bytes = have_read_stdin = 0;
 263
 264   /* Turn any numeric options into -w options.  */
 265   for (i = 1; i < argc; i++)
 266     {
 267       if (argv[i][0] == '-' && ISDIGIT (argv[i][1]))
 268         {
 269           char *s;
 270
 271           s = xmalloc (strlen (argv[i]) + 2);
 272           s[0] = '-';
 273           s[1] = 'w';
 274           strcpy (s + 2, argv[i] + 1);
 275           argv[i] = s;
 276         }
 277     }
 278
 279   while ((optc = getopt_long (argc, argv, "bsw:", longopts, (int *) 0))
 280          != EOF)
 281     {
 282       switch (optc)
 283         {
 284         case 0:
 285           break;
 286
 287         case 'b':               /* Count bytes rather than columns. */
 288           count_bytes = 1;
 289           break;
 290
 291         case 's':               /* Break at word boundaries. */
 292           break_spaces = 1;
 293           break;
 294
 295         case 'w':               /* Line width. */
 296           {
 297             long int tmp_long;
 298             if (xstrtol (optarg, NULL, 10, &tmp_long, NULL) != LONGINT_OK
 299                 || tmp_long <= 0 || tmp_long > INT_MAX)
 300               error (1, 0, _("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", version_string);
 313       exit (0);
 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 (1, errno, "-");
 327   if (fclose (stdout) == EOF)
 328     error (1, errno, _("write error"));
 329
 330   exit (errs);
 331 }