src/expand-common.c

   1 /* expand-common - common functionality for expand/unexpand
   2    Copyright (C) 1989-2024 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 3 of the License, or
   7    (at your option) 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, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 #include <ctype.h>
  20 #include <stdio.h>
  21 #include <sys/types.h>
  22 #include "system.h"
  23 #include "fadvise.h"
  24 #include "quote.h"
  25
  26 #include "expand-common.h"
  27
  28 /* If true, convert blanks even after nonblank characters have been
  29    read on the line.  */
  30 bool convert_entire_line = false;
  31
  32 /* If nonzero, the size of all tab stops.  If zero, use 'tab_list' instead.  */
  33 static uintmax_t tab_size = 0;
  34
  35 /* If nonzero, the size of all tab stops after the last specified.  */
  36 static uintmax_t extend_size = 0;
  37
  38 /* If nonzero, an increment for additional tab stops after the last specified.*/
  39 static uintmax_t increment_size = 0;
  40
  41 /* The maximum distance between tab stops.  */
  42 size_t max_column_width;
  43
  44 /* Array of the explicit column numbers of the tab stops;
  45    after 'tab_list' is exhausted, each additional tab is replaced
  46    by a space.  The first column is column 0.  */
  47 static uintmax_t *tab_list = nullptr;
  48
  49 /* The number of allocated entries in 'tab_list'.  */
  50 static size_t n_tabs_allocated = 0;
  51
  52 /* The index of the first invalid element of 'tab_list',
  53    where the next element can be added.  */
  54 static size_t first_free_tab = 0;
  55
  56 /* Null-terminated array of input filenames.  */
  57 static char **file_list = nullptr;
  58
  59 /* Default for 'file_list' if no files are given on the command line.  */
  60 static char *stdin_argv[] =
  61 {
  62   (char *) "-", nullptr
  63 };
  64
  65 /* True if we have ever read standard input.  */
  66 static bool have_read_stdin = false;
  67
  68 /* The desired exit status.  */
  69 int exit_status = EXIT_SUCCESS;
  70
  71
  72
  73 /* Add tab stop TABVAL to the end of 'tab_list'.  */
  74 extern void
  75 add_tab_stop (uintmax_t tabval)
  76 {
  77   uintmax_t prev_column = first_free_tab ? tab_list[first_free_tab - 1] : 0;
  78   uintmax_t column_width = prev_column <= tabval ? tabval - prev_column : 0;
  79
  80   if (first_free_tab == n_tabs_allocated)
  81     tab_list = X2NREALLOC (tab_list, &n_tabs_allocated);
  82   tab_list[first_free_tab++] = tabval;
  83
  84   if (max_column_width < column_width)
  85     {
  86       if (SIZE_MAX < column_width)
  87         error (EXIT_FAILURE, 0, _("tabs are too far apart"));
  88       max_column_width = column_width;
  89     }
  90 }
  91
  92 static bool
  93 set_extend_size (uintmax_t tabval)
  94 {
  95   bool ok = true;
  96
  97   if (extend_size)
  98     {
  99       error (0, 0,
 100              _("'/' specifier only allowed"
 101                " with the last value"));
 102       ok = false;
 103     }
 104   extend_size = tabval;
 105
 106   return ok;
 107 }
 108
 109 static bool
 110 set_increment_size (uintmax_t tabval)
 111 {
 112   bool ok = true;
 113
 114   if (increment_size)
 115     {
 116       error (0,0,
 117              _("'+' specifier only allowed"
 118                " with the last value"));
 119       ok = false;
 120     }
 121   increment_size = tabval;
 122
 123   return ok;
 124 }
 125
 126 /* Add the comma or blank separated list of tab stops STOPS
 127    to the list of tab stops.  */
 128 extern void
 129 parse_tab_stops (char const *stops)
 130 {
 131   bool have_tabval = false;
 132   uintmax_t tabval = 0;
 133   bool extend_tabval = false;
 134   bool increment_tabval = false;
 135   char const *num_start = nullptr;
 136   bool ok = true;
 137
 138   for (; *stops; stops++)
 139     {
 140       if (*stops == ',' || isblank (to_uchar (*stops)))
 141         {
 142           if (have_tabval)
 143             {
 144               if (extend_tabval)
 145                 {
 146                   if (! set_extend_size (tabval))
 147                     {
 148                       ok = false;
 149                       break;
 150                     }
 151                 }
 152               else if (increment_tabval)
 153                 {
 154                   if (! set_increment_size (tabval))
 155                     {
 156                       ok = false;
 157                       break;
 158                     }
 159                 }
 160               else
 161                 add_tab_stop (tabval);
 162             }
 163           have_tabval = false;
 164         }
 165       else if (*stops == '/')
 166         {
 167           if (have_tabval)
 168             {
 169               error (0, 0, _("'/' specifier not at start of number: %s"),
 170                      quote (stops));
 171               ok = false;
 172             }
 173           extend_tabval = true;
 174           increment_tabval = false;
 175         }
 176       else if (*stops == '+')
 177         {
 178           if (have_tabval)
 179             {
 180               error (0, 0, _("'+' specifier not at start of number: %s"),
 181                      quote (stops));
 182               ok = false;
 183             }
 184           increment_tabval = true;
 185           extend_tabval = false;
 186         }
 187       else if (ISDIGIT (*stops))
 188         {
 189           if (!have_tabval)
 190             {
 191               tabval = 0;
 192               have_tabval = true;
 193               num_start = stops;
 194             }
 195
 196           /* Detect overflow.  */
 197           if (!DECIMAL_DIGIT_ACCUMULATE (tabval, *stops - '0'))
 198             {
 199               size_t len = strspn (num_start, "0123456789");
 200               char *bad_num = ximemdup0 (num_start, len);
 201               error (0, 0, _("tab stop is too large %s"), quote (bad_num));
 202               free (bad_num);
 203               ok = false;
 204               stops = num_start + len - 1;
 205             }
 206         }
 207       else
 208         {
 209           error (0, 0, _("tab size contains invalid character(s): %s"),
 210                  quote (stops));
 211           ok = false;
 212           break;
 213         }
 214     }
 215
 216   if (ok && have_tabval)
 217     {
 218       if (extend_tabval)
 219         ok &= set_extend_size (tabval);
 220       else if (increment_tabval)
 221         ok &= set_increment_size (tabval);
 222       else
 223         add_tab_stop (tabval);
 224     }
 225
 226   if (! ok)
 227     exit (EXIT_FAILURE);
 228 }
 229
 230 /* Check that the list of tab stops TABS, with ENTRIES entries,
 231    contains only nonzero, ascending values.  */
 232
 233 static void
 234 validate_tab_stops (uintmax_t const *tabs, size_t entries)
 235 {
 236   uintmax_t prev_tab = 0;
 237
 238   for (size_t i = 0; i < entries; i++)
 239     {
 240       if (tabs[i] == 0)
 241         error (EXIT_FAILURE, 0, _("tab size cannot be 0"));
 242       if (tabs[i] <= prev_tab)
 243         error (EXIT_FAILURE, 0, _("tab sizes must be ascending"));
 244       prev_tab = tabs[i];
 245     }
 246
 247   if (increment_size && extend_size)
 248     error (EXIT_FAILURE, 0, _("'/' specifier is mutually exclusive with '+'"));
 249 }
 250
 251 /* Called after all command-line options have been parsed,
 252    and add_tab_stop/parse_tab_stops have been called.
 253    Will validate the tab-stop values,
 254    and set the final values to:
 255    tab-stops = 8 (if no tab-stops given on command line)
 256    tab-stops = N (if value N specified as the only value).
 257    tab-stops = distinct values given on command line (if multiple values given).
 258 */
 259 extern void
 260 finalize_tab_stops (void)
 261 {
 262   validate_tab_stops (tab_list, first_free_tab);
 263
 264   if (first_free_tab == 0)
 265     tab_size = max_column_width = extend_size
 266                                   ? extend_size : increment_size
 267                                                   ? increment_size : 8;
 268   else if (first_free_tab == 1 && ! extend_size && ! increment_size)
 269     tab_size = tab_list[0];
 270   else
 271     tab_size = 0;
 272 }
 273
 274
 275 extern uintmax_t
 276 get_next_tab_column (const uintmax_t column, size_t *tab_index,
 277                      bool *last_tab)
 278 {
 279   *last_tab = false;
 280
 281   /* single tab-size - return multiples of it */
 282   if (tab_size)
 283     return column + (tab_size - column % tab_size);
 284
 285   /* multiple tab-sizes - iterate them until the tab position is beyond
 286      the current input column. */
 287   for ( ; *tab_index < first_free_tab ; (*tab_index)++ )
 288     {
 289         uintmax_t tab = tab_list[*tab_index];
 290         if (column < tab)
 291             return tab;
 292     }
 293
 294   /* relative last tab - return multiples of it */
 295   if (extend_size)
 296     return column + (extend_size - column % extend_size);
 297
 298   /* incremental last tab - add increment_size to the previous tab stop */
 299   if (increment_size)
 300     {
 301       uintmax_t end_tab = tab_list[first_free_tab - 1];
 302
 303       return column + (increment_size - ((column - end_tab) % increment_size));
 304     }
 305
 306   *last_tab = true;
 307   return 0;
 308 }
 309
 310
 311
 312
 313 /* Sets new file-list */
 314 extern void
 315 set_file_list (char **list)
 316 {
 317   have_read_stdin = false;
 318
 319   if (!list)
 320     file_list = stdin_argv;
 321   else
 322     file_list = list;
 323 }
 324
 325 /* Close the old stream pointer FP if it is non-null,
 326    and return a new one opened to read the next input file.
 327    Open a filename of '-' as the standard input.
 328    Return nullptr if there are no more input files.  */
 329
 330 extern FILE *
 331 next_file (FILE *fp)
 332 {
 333   static char *prev_file;
 334   char *file;
 335
 336   if (fp)
 337     {
 338       int err = errno;
 339       if (!ferror (fp))
 340         err = 0;
 341       if (STREQ (prev_file, "-"))
 342         clearerr (fp);          /* Also clear EOF.  */
 343       else if (fclose (fp) != 0)
 344         err = errno;
 345       if (err)
 346         {
 347           error (0, err, "%s", quotef (prev_file));
 348           exit_status = EXIT_FAILURE;
 349         }
 350     }
 351
 352   while ((file = *file_list++) != nullptr)
 353     {
 354       if (STREQ (file, "-"))
 355         {
 356           have_read_stdin = true;
 357           fp = stdin;
 358         }
 359       else
 360         fp = fopen (file, "r");
 361       if (fp)
 362         {
 363           prev_file = file;
 364           fadvise (fp, FADVISE_SEQUENTIAL);
 365           return fp;
 366         }
 367       error (0, errno, "%s", quotef (file));
 368       exit_status = EXIT_FAILURE;
 369     }
 370   return nullptr;
 371 }
 372
 373 /* */
 374 extern void
 375 cleanup_file_list_stdin (void)
 376 {
 377     if (have_read_stdin && fclose (stdin) != 0)
 378       error (EXIT_FAILURE, errno, "-");
 379 }
 380
 381
 382 extern void
 383 emit_tab_list_info (void)
 384 {
 385   /* suppress syntax check for emit_mandatory_arg_note() */
 386   fputs (_("\
 387   -t, --tabs=LIST  use comma separated list of tab positions.\n\
 388 "), stdout);
 389   fputs (_("\
 390                      The last specified position can be prefixed with '/'\n\
 391                      to specify a tab size to use after the last\n\
 392                      explicitly specified tab stop.  Also a prefix of '+'\n\
 393                      can be used to align remaining tab stops relative to\n\
 394                      the last specified tab stop instead of the first column\n\
 395 "), stdout);
 396 }