/* hard-locale.c -- Determine whether a locale is hard.

   Copyright (C) 1997-1999, 2002-2004, 2006-2007, 2009-2017 Free Software
   Foundation, Inc.

   This program is free software: you can redistribute it and/or
   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at your
       option) any later version.

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at your
       option) any later version.

   or both in parallel, as here.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

#include "hard-locale.h"

#include <locale.h>
#include <stdlib.h>
#include <string.h>

#ifdef __GLIBC__
# define GLIBC_VERSION __GLIBC__
#elif defined __UCLIBC__
# define GLIBC_VERSION 2
#else
# define GLIBC_VERSION 0
#endif

/* Return true if the current CATEGORY locale is hard, i.e. if you
   can't get away with assuming traditional C or POSIX behavior.  */
bool
hard_locale (int category)
{
  bool hard = true;
  char const *p = setlocale (category, NULL);

  if (p)
    {
      if (2 <= GLIBC_VERSION)
        {
          if (strcmp (p, "C") == 0 || strcmp (p, "POSIX") == 0)
            hard = false;
        }
      else
        {
          char *locale = strdup (p);
          if (locale)
            {
              /* Temporarily set the locale to the "C" and "POSIX" locales
                 to find their names, so that we can determine whether one
                 or the other is the caller's locale.  */
              if (((p = setlocale (category, "C"))
                   && strcmp (p, locale) == 0)
                  || ((p = setlocale (category, "POSIX"))
                      && strcmp (p, locale) == 0))
                hard = false;

              /* Restore the caller's locale.  */
              setlocale (category, locale);
              free (locale);
            }
        }
    }

  return hard;
}