/* Locale dependent transformation for comparison of Unicode strings.
   Copyright (C) 2009-2018 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 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
   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 <https://www.gnu.org/licenses/>.  */

char *
FUNC (const UNIT *s, size_t n, uninorm_t nf,
      char *resultbuf, size_t *lengthp)
{
  UNIT normsbuf[2048 / sizeof (UNIT)];
  UNIT *norms;
  size_t norms_length;
  char convsbuf[2048];
  char *convs;
  size_t convs_length;
  char *result;

  /* Normalize the Unicode string.  */
  norms_length = sizeof (normsbuf) / sizeof (UNIT);
  norms = U_NORMALIZE (nf, s, n, normsbuf, &norms_length);
  if (norms == NULL)
    /* errno is set here.  */
    return NULL;

  /* Convert it to locale encoding.  */
  convs_length = sizeof (convsbuf) - 1;
  convs = U_CONV_TO_ENCODING (locale_charset (),
                              iconveh_error,
                              norms, norms_length,
                              NULL,
                              convsbuf, &convs_length);
  if (convs == NULL)
    {
      if (norms != normsbuf)
        {
          int saved_errno = errno;
          free (norms);
          errno = saved_errno;
        }
      return NULL;
    }

  if (norms != normsbuf)
    free (norms);

  /* Ensure one more byte is available.  */
  if (convs != convsbuf)
    {
      char *memory = (char *) realloc (convs, convs_length + 1);
      if (memory == NULL)
        {
          free (convs);
          errno = ENOMEM;
          return NULL;
        }
      convs = memory;
    }

  /* Apply locale dependent transformations for comparison.  */
  result = amemxfrm (convs, convs_length, resultbuf, lengthp);
  if (result == NULL)
    {
      if (convs != convsbuf)
        {
          int saved_errno = errno;
          free (convs);
          errno = saved_errno;
        }
      return NULL;
    }

  if (convs != convsbuf)
    free (convs);
  return result;
}
