/* Compare UTF-8/UTF-16/UTF-32 strings using the collation rules of the current
   locale.
   Copyright (C) 2009 Free Software Foundation, Inc.
   Written by Bruno Haible <bruno@clisp.org>, 2009.

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

   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
   Lesser General Public License for more details.

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

int
FUNC (const UNIT *s1, const UNIT *s2)
{
  /* When this function succeeds, it sets errno back to its original value.
     When it fails, it sets errno, but also returns a meaningful return value,
     for the sake of callers which ignore errno.  */
  int final_errno = errno;
  char *sl1;
  char *sl2;
  int result;

  sl1 = U_STRCONV_TO_LOCALE (s1);
  if (sl1 != NULL)
    {
      sl2 = U_STRCONV_TO_LOCALE (s2);
      if (sl2 != NULL)
	{
	  /* Compare sl1 and sl2.  */
	  errno = 0;
	  result = strcoll (sl1, sl2);
	  if (errno == 0)
	    {
	      /* strcoll succeeded.  */
	      free (sl1);
	      free (sl2);
	    }
	  else
	    {
	      /* strcoll failed.  */
	      final_errno = errno;
	      free (sl1);
	      free (sl2);
	      result = U_STRCMP (s1, s2);
	    }
	}
      else
	{
	  /* s1 could be converted to locale encoding, s2 not.  */
	  final_errno = errno;
	  free (sl1);
	  result = -1;
	}
    }
  else
    {
      final_errno = errno;
      sl2 = U_STRCONV_TO_LOCALE (s2);
      if (sl2 != NULL)
	{
	  /* s2 could be converted to locale encoding, s1 not.  */
	  free (sl2);
	  result = 1;
	}
      else
	{
	  /* Neither s1 nor s2 could be converted to locale encoding.  */
	  result = U_STRCMP (s1, s2);
	}
    }

  errno = final_errno;
  return result;
}