src/fold.c

   1 /* fold -- wrap each input line to fit in specified width.
   2    Copyright (C) 91, 1995-2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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 "quote.h"
  29 #include "xstrtol.h"
  30
  31 #define TAB_WIDTH 8
  32
  33 /* The official name of this program (e.g., no `g' prefix).  */
  34 #define PROGRAM_NAME "fold"
  35
  36 #define AUTHORS "David MacKenzie"
  37
  38 /* The name this program was run with. */
  39 char *program_name;
  40
  41 /* If nonzero, try to break on whitespace. */
  42 static bool break_spaces;
  43
  44 /* If nonzero, count bytes, not column positions. */
  45 static bool count_bytes;
  46
  47 /* If nonzero, at least one of the files we read was standard input. */
  48 static bool have_read_stdin;
  49
  50 static char const shortopts[] = "bsw:0::1::2::3::4::5::6::7::8::9::";
  51
  52 static struct option const longopts[] =
  53 {
  54   {"bytes", no_argument, NULL, 'b'},
  55   {"spaces", no_argument, NULL, 's'},
  56   {"width", required_argument, NULL, 'w'},
  57   {GETOPT_HELP_OPTION_DECL},
  58   {GETOPT_VERSION_OPTION_DECL},
  59   {NULL, 0, NULL, 0}
  60 };
  61
  62 void
  63 usage (int status)
  64 {
  65   if (status != EXIT_SUCCESS)
  66     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  67              program_name);
  68   else
  69     {
  70       printf (_("\
  71 Usage: %s [OPTION]... [FILE]...\n\
  72 "),
  73               program_name);
  74       fputs (_("\
  75 Wrap input lines in each FILE (standard input by default), writing to\n\
  76 standard output.\n\
  77 \n\
  78 "), stdout);
  79       fputs (_("\
  80 Mandatory arguments to long options are mandatory for short options too.\n\
  81 "), stdout);
  82       fputs (_("\
  83   -b, --bytes         count bytes rather than columns\n\
  84   -s, --spaces        break at spaces\n\
  85   -w, --width=WIDTH   use WIDTH columns instead of 80\n\
  86 "), stdout);
  87       fputs (HELP_OPTION_DESCRIPTION, stdout);
  88       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  89       emit_bug_reporting_address ();
  90     }
  91   exit (status);
  92 }
  93
  94 /* Assuming the current column is COLUMN, return the column that
  95    printing C will move the cursor to.
  96    The first column is 0. */
  97
  98 static size_t
  99 adjust_column (size_t column, char c)
 100 {
 101   if (!count_bytes)
 102     {
 103       if (c == '\b')
 104         {
 105           if (column > 0)
 106             column--;
 107         }
 108       else if (c == '\r')
 109         column = 0;
 110       else if (c == '\t')
 111         column += TAB_WIDTH - column % TAB_WIDTH;
 112       else /* if (isprint (c)) */
 113         column++;
 114     }
 115   else
 116     column++;
 117   return column;
 118 }
 119
 120 /* Fold file FILENAME, or standard input if FILENAME is "-",
 121    to stdout, with maximum line length WIDTH.
 122    Return true if successful.  */
 123
 124 static bool
 125 fold_file (char const *filename, size_t width)
 126 {
 127   FILE *istream;
 128   int c;
 129   size_t column = 0;            /* Screen column where next char will go. */
 130   size_t offset_out = 0;        /* Index in `line_out' for next char. */
 131   static char *line_out = NULL;
 132   static size_t allocated_out = 0;
 133   int saved_errno;
 134
 135   if (STREQ (filename, "-"))
 136     {
 137       istream = stdin;
 138       have_read_stdin = true;
 139     }
 140   else
 141     istream = fopen (filename, "r");
 142
 143   if (istream == NULL)
 144     {
 145       error (0, errno, "%s", filename);
 146       return false;
 147     }
 148
 149   while ((c = getc (istream)) != EOF)
 150     {
 151       if (offset_out + 1 >= allocated_out)
 152         line_out = X2REALLOC (line_out, &allocated_out);
 153
 154       if (c == '\n')
 155         {
 156           line_out[offset_out++] = c;
 157           fwrite (line_out, sizeof (char), offset_out, stdout);
 158           column = offset_out = 0;
 159           continue;
 160         }
 161
 162     rescan:
 163       column = adjust_column (column, c);
 164
 165       if (column > width)
 166         {
 167           /* This character would make the line too long.
 168              Print the line plus a newline, and make this character
 169              start the next line. */
 170           if (break_spaces)
 171             {
 172               bool found_blank = false;
 173               size_t logical_end = offset_out;
 174
 175               /* Look for the last blank. */
 176               while (logical_end)
 177                 {
 178                   --logical_end;
 179                   if (isblank (to_uchar (line_out[logical_end])))
 180                     {
 181                       found_blank = true;
 182                       break;
 183                     }
 184                 }
 185
 186               if (found_blank)
 187                 {
 188                   size_t i;
 189
 190                   /* Found a blank.  Don't output the part after it. */
 191                   logical_end++;
 192                   fwrite (line_out, sizeof (char), (size_t) logical_end,
 193                           stdout);
 194                   putchar ('\n');
 195                   /* Move the remainder to the beginning of the next line.
 196                      The areas being copied here might overlap. */
 197                   memmove (line_out, line_out + logical_end,
 198                            offset_out - logical_end);
 199                   offset_out -= logical_end;
 200                   for (column = i = 0; i < offset_out; i++)
 201                     column = adjust_column (column, line_out[i]);
 202                   goto rescan;
 203                 }
 204             }
 205
 206           if (offset_out == 0)
 207             {
 208               line_out[offset_out++] = c;
 209               continue;
 210             }
 211
 212           line_out[offset_out++] = '\n';
 213           fwrite (line_out, sizeof (char), (size_t) offset_out, stdout);
 214           column = offset_out = 0;
 215           goto rescan;
 216         }
 217
 218       line_out[offset_out++] = c;
 219     }
 220
 221   saved_errno = errno;
 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, saved_errno, "%s", filename);
 229       if (!STREQ (filename, "-"))
 230         fclose (istream);
 231       return false;
 232     }
 233   if (!STREQ (filename, "-") && fclose (istream) == EOF)
 234     {
 235       error (0, errno, "%s", filename);
 236       return false;
 237     }
 238
 239   return true;
 240 }
 241
 242 int
 243 main (int argc, char **argv)
 244 {
 245   size_t width = 80;
 246   int i;
 247   int optc;
 248   bool ok;
 249
 250   initialize_main (&argc, &argv);
 251   program_name = argv[0];
 252   setlocale (LC_ALL, "");
 253   bindtextdomain (PACKAGE, LOCALEDIR);
 254   textdomain (PACKAGE);
 255
 256   atexit (close_stdout);
 257
 258   break_spaces = count_bytes = have_read_stdin = false;
 259
 260   while ((optc = getopt_long (argc, argv, shortopts, longopts, NULL)) != -1)
 261     {
 262       char optargbuf[2];
 263
 264       switch (optc)
 265         {
 266         case 'b':               /* Count bytes rather than columns. */
 267           count_bytes = true;
 268           break;
 269
 270         case 's':               /* Break at word boundaries. */
 271           break_spaces = true;
 272           break;
 273
 274         case '0': case '1': case '2': case '3': case '4':
 275         case '5': case '6': case '7': case '8': case '9':
 276           if (optarg)
 277             optarg--;
 278           else
 279             {
 280               optargbuf[0] = optc;
 281               optargbuf[1] = '\0';
 282               optarg = optargbuf;
 283             }
 284           /* Fall through.  */
 285         case 'w':               /* Line width. */
 286           {
 287             unsigned long int tmp_ulong;
 288             if (! (xstrtoul (optarg, NULL, 10, &tmp_ulong, "") == LONGINT_OK
 289                    && 0 < tmp_ulong && tmp_ulong < SIZE_MAX - TAB_WIDTH))
 290               error (EXIT_FAILURE, 0,
 291                      _("invalid number of columns: %s"), quote (optarg));
 292             width = tmp_ulong;
 293           }
 294           break;
 295
 296         case_GETOPT_HELP_CHAR;
 297
 298         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 299
 300         default:
 301           usage (EXIT_FAILURE);
 302         }
 303     }
 304
 305   if (argc == optind)
 306     ok = fold_file ("-", width);
 307   else
 308     {
 309       ok = true;
 310       for (i = optind; i < argc; i++)
 311         ok &= fold_file (argv[i], width);
 312     }
 313
 314   if (have_read_stdin && fclose (stdin) == EOF)
 315     error (EXIT_FAILURE, errno, "-");
 316
 317   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 318 }