src/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2    Copyright (C) 91, 1995-1999 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 "xstrtol.h"
  29
  30 /* The official name of this program (e.g., no `g' prefix).  */
  31 #define PROGRAM_NAME "fold"
  32
  33 #define AUTHORS "David MacKenzie"
  34
  35 /* The name this program was run with. */
  36 char *program_name;
  37
  38 /* If nonzero, try to break on whitespace. */
  39 static int break_spaces;
  40
  41 /* If nonzero, count bytes, not column positions. */
  42 static int count_bytes;
  43
  44 /* If nonzero, at least one of the files we read was standard input. */
  45 static int have_read_stdin;
  46
  47 static struct option const longopts[] =
  48 {
  49   {"bytes", no_argument, NULL, 'b'},
  50   {"spaces", no_argument, NULL, 's'},
  51   {"width", required_argument, NULL, 'w'},
  52   {GETOPT_HELP_OPTION_DECL},
  53   {GETOPT_VERSION_OPTION_DECL},
  54   {NULL, 0, NULL, 0}
  55 };
  56
  57 void
  58 usage (int status)
  59 {
  60   if (status != 0)
  61     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  62              program_name);
  63   else
  64     {
  65       printf (_("\
  66 Usage: %s [OPTION]... [FILE]...\n\
  67 "),
  68               program_name);
  69       printf (_("\
  70 Wrap input lines in each FILE (standard input by default), writing to\n\
  71 standard output.\n\
  72 \n\
  73   -b, --bytes         count bytes rather than columns\n\
  74   -s, --spaces        break at spaces\n\
  75   -w, --width=WIDTH   use WIDTH columns instead of 80\n\
  76       --help          display this help and exit\n\
  77       --version       output version information and exit\n\
  78 "));
  79       puts (_("\nReport bugs to <bug-textutils@gnu.org>."));
  80     }
  81   exit (status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
  82 }
  83
  84 /* Assuming the current column is COLUMN, return the column that
  85    printing C will move the cursor to.
  86    The first column is 0. */
  87
  88 static int
  89 adjust_column (int column, char c)
  90 {
  91   if (!count_bytes)
  92     {
  93       if (c == '\b')
  94         {
  95           if (column > 0)
  96             column--;
  97         }
  98       else if (c == '\r')
  99         column = 0;
 100       else if (c == '\t')
 101         column = column + 8 - column % 8;
 102       else /* if (isprint (c)) */
 103         column++;
 104     }
 105   else
 106     column++;
 107   return column;
 108 }
 109
 110 /* Fold file FILENAME, or standard input if FILENAME is "-",
 111    to stdout, with maximum line length WIDTH.
 112    Return 0 if successful, 1 if an error occurs. */
 113
 114 static int
 115 fold_file (char *filename, int width)
 116 {
 117   FILE *istream;
 118   register int c;
 119   int column = 0;               /* Screen column where next char will go. */
 120   int offset_out = 0;   /* Index in `line_out' for next char. */
 121   static char *line_out = NULL;
 122   static int allocated_out = 0;
 123
 124   if (STREQ (filename, "-"))
 125     {
 126       istream = stdin;
 127       have_read_stdin = 1;
 128     }
 129   else
 130     istream = fopen (filename, "r");
 131
 132   if (istream == NULL)
 133     {
 134       error (0, errno, "%s", filename);
 135       return 1;
 136     }
 137
 138   while ((c = getc (istream)) != EOF)
 139     {
 140       if (offset_out + 1 >= allocated_out)
 141         {
 142           allocated_out += 1024;
 143           line_out = xrealloc (line_out, allocated_out);
 144         }
 145
 146       if (c == '\n')
 147         {
 148           line_out[offset_out++] = c;
 149           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 150           column = offset_out = 0;
 151           continue;
 152         }
 153
 154     rescan:
 155       column = adjust_column (column, c);
 156
 157       if (column > width)
 158         {
 159           /* This character would make the line too long.
 160              Print the line plus a newline, and make this character
 161              start the next line. */
 162           if (break_spaces)
 163             {
 164               /* Look for the last blank. */
 165               int logical_end;
 166
 167               for (logical_end = offset_out - 1; logical_end >= 0;
 168                    logical_end--)
 169                 if (ISBLANK (line_out[logical_end]))
 170                   break;
 171               if (logical_end >= 0)
 172                 {
 173                   int i;
 174
 175                   /* Found a blank.  Don't output the part after it. */
 176                   logical_end++;
 177                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 178                           stdout);
 179                   putchar ('\n');
 180                   /* Move the remainder to the beginning of the next line.
 181                      The areas being copied here might overlap. */
 182                   memmove (line_out, line_out + logical_end,
 183                            offset_out - logical_end);
 184                   offset_out -= logical_end;
 185                   for (column = i = 0; i < offset_out; i++)
 186                     column = adjust_column (column, line_out[i]);
 187                   goto rescan;
 188                 }
 189             }
 190           else
 191             {
 192               if (offset_out == 0)
 193                 {
 194                   line_out[offset_out++] = c;
 195                   continue;
 196                 }
 197             }
 198           line_out[offset_out++] = '\n';
 199           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 200           column = offset_out = 0;
 201           goto rescan;
 202         }
 203
 204       line_out[offset_out++] = c;
 205     }
 206
 207   if (offset_out)
 208     fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 209
 210   if (ferror (istream))
 211     {
 212       error (0, errno, "%s", filename);
 213       if (!STREQ (filename, "-"))
 214         fclose (istream);
 215       return 1;
 216     }
 217   if (!STREQ (filename, "-") && fclose (istream) == EOF)
 218     {
 219       error (0, errno, "%s", filename);
 220       return 1;
 221     }
 222
 223   if (ferror (stdout))
 224     {
 225       error (0, errno, _("write error"));
 226       return 1;
 227     }
 228
 229   return 0;
 230 }
 231
 232 int
 233 main (int argc, char **argv)
 234 {
 235   int width = 80;
 236   int i;
 237   int optc;
 238   int errs = 0;
 239
 240   program_name = argv[0];
 241   setlocale (LC_ALL, "");
 242   bindtextdomain (PACKAGE, LOCALEDIR);
 243   textdomain (PACKAGE);
 244
 245   break_spaces = count_bytes = have_read_stdin = 0;
 246
 247   /* Turn any numeric options into -w options.  */
 248   for (i = 1; i < argc; i++)
 249     {
 250       if (argv[i][0] == '-' && ISDIGIT (argv[i][1]))
 251         {
 252           char *s;
 253
 254           s = xmalloc (strlen (argv[i]) + 2);
 255           s[0] = '-';
 256           s[1] = 'w';
 257           strcpy (s + 2, argv[i] + 1);
 258           argv[i] = s;
 259         }
 260     }
 261
 262   while ((optc = getopt_long (argc, argv, "bsw:", longopts, NULL)) != -1)
 263     {
 264       switch (optc)
 265         {
 266         case 0:
 267           break;
 268
 269         case 'b':               /* Count bytes rather than columns. */
 270           count_bytes = 1;
 271           break;
 272
 273         case 's':               /* Break at word boundaries. */
 274           break_spaces = 1;
 275           break;
 276
 277         case 'w':               /* Line width. */
 278           {
 279             long int tmp_long;
 280             if (xstrtol (optarg, NULL, 10, &tmp_long, "") != LONGINT_OK
 281                 || tmp_long <= 0 || tmp_long > INT_MAX)
 282               error (EXIT_FAILURE, 0,
 283                      _("invalid number of columns: `%s'"), optarg);
 284             width = (int) tmp_long;
 285           }
 286           break;
 287
 288         case_GETOPT_HELP_CHAR;
 289
 290         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 291
 292         default:
 293           usage (1);
 294         }
 295     }
 296
 297   if (argc == optind)
 298     errs |= fold_file ("-", width);
 299   else
 300     for (i = optind; i < argc; i++)
 301       errs |= fold_file (argv[i], width);
 302
 303   if (have_read_stdin && fclose (stdin) == EOF)
 304     error (EXIT_FAILURE, errno, "-");
 305   if (fclose (stdout) == EOF)
 306     error (EXIT_FAILURE, errno, _("write error"));
 307
 308   exit (errs == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
 309 }