/* Classify a domain name for IDNA purposes.

   Copyright (C) 2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library 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 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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 the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <inet/net-internal.h>

#include <stdbool.h>

#include <string.h>

#include <wchar.h>

enum idna_name_classification

__idna_name_classify (const char *name)

{

  mbstate_t mbs;

  memset (&mbs, 0, sizeof (mbs));

  const char *p = name;

  const char *end = p + strlen (p) + 1;

  bool nonascii = false;

  bool backslash = false;

  while (true)

    {

      wchar_t wc;

      size_t result = mbrtowc (&wc, p, end - p, &mbs);

      if (result == 0)

        /* NUL terminator was reached.  */

        break;

      else if (result == (size_t) -2)

        /* Incomplete trailing multi-byte character.  This is an

           encoding error becaue we received the full name.  */

        return idna_name_encoding_error;

      else if (result == (size_t) -1)

        {

          /* Other error, including EILSEQ.  */

          if (errno == EILSEQ)

            return idna_name_encoding_error;

          else if (errno == ENOMEM)

            return idna_name_memory_error;

          else

            return idna_name_error;

        }

      else

        {

          /* A wide character was decoded.  */

          p += result;

          if (wc == L'\\')

            backslash = true;

          else if (wc > 127)

            nonascii = true;

        }

    }

  if (nonascii)

    {

      if (backslash)

        return idna_name_nonascii_backslash;

      else

        return idna_name_nonascii;

    }

  else

    return idna_name_ascii;

}