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// -*- C++ -*-

// Copyright (C) 2005, 2006, 2007, 2009 Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the terms

// of the GNU General Public License as published by the Free Software

// Foundation; either version 3, or (at your option) any later

// version.

// This 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

// General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional

// permissions described in the GCC Runtime Library Exception, version

// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and

// a copy of the GCC Runtime Library Exception along with this program;

// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

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

/** @file ext/type_traits.h

 *  This file is a GNU extension to the Standard C++ Library.

 */

#ifndef _EXT_TYPE_TRAITS

#define _EXT_TYPE_TRAITS 1

#pragma GCC system_header

#include <bits/c++config.h>

#include <bits/cpp_type_traits.h>

namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // Define a nested type if some predicate holds.

  template<bool, typename>

    struct __enable_if

    { };

  template<typename _Tp>

    struct __enable_if<true, _Tp>

    { typedef _Tp __type; };

  // Conditional expression for types. If true, first, if false, second.

  template<bool _Cond, typename _Iftrue, typename _Iffalse>

    struct __conditional_type

    { typedef _Iftrue __type; };

  template<typename _Iftrue, typename _Iffalse>

    struct __conditional_type<false, _Iftrue, _Iffalse>

    { typedef _Iffalse __type; };

  // Given an integral builtin type, return the corresponding unsigned type.

  template<typename _Tp>

    struct __add_unsigned

    {

    private:

      typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type;

    public:

      typedef typename __if_type::__type __type;

    };

  template<>

    struct __add_unsigned<char>

    { typedef unsigned char __type; };

  template<>

    struct __add_unsigned<signed char>

    { typedef unsigned char __type; };

  template<>

    struct __add_unsigned<short>

    { typedef unsigned short __type; };

  template<>

    struct __add_unsigned<int>

    { typedef unsigned int __type; };

  template<>

    struct __add_unsigned<long>

    { typedef unsigned long __type; };

  template<>

    struct __add_unsigned<long long>

    { typedef unsigned long long __type; };

  // Declare but don't define.

  template<>

    struct __add_unsigned<bool>;

  template<>

    struct __add_unsigned<wchar_t>;

  // Given an integral builtin type, return the corresponding signed type.

  template<typename _Tp>

    struct __remove_unsigned

    {

    private:

      typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type;

    public:

      typedef typename __if_type::__type __type;

    };

  template<>

    struct __remove_unsigned<char>

    { typedef signed char __type; };

  template<>

    struct __remove_unsigned<unsigned char>

    { typedef signed char __type; };

  template<>

    struct __remove_unsigned<unsigned short>

    { typedef short __type; };

  template<>

    struct __remove_unsigned<unsigned int>

    { typedef int __type; };

  template<>

    struct __remove_unsigned<unsigned long>

    { typedef long __type; };

  template<>

    struct __remove_unsigned<unsigned long long>

    { typedef long long __type; };

  // Declare but don't define.

  template<>

    struct __remove_unsigned<bool>;

  template<>

    struct __remove_unsigned<wchar_t>;

  // For use in string and vstring.

  template<typename _Type>

    inline bool

    __is_null_pointer(_Type* __ptr)

    { return __ptr == 0; }

  template<typename _Type>

    inline bool

    __is_null_pointer(_Type)

    { return false; }

  // For complex and cmath

  template<typename _Tp, bool = std::__is_integer<_Tp>::__value>

    struct __promote

    { typedef double __type; };

  // No nested __type member for non-integer non-floating point types,

  // allows this type to be used for SFINAE to constrain overloads in

  // <cmath> and <complex> to only the intended types.

  template<typename _Tp>

    struct __promote<_Tp, false>

    { };

  template<>

    struct __promote<long double>

    { typedef long double __type; };

  template<>

    struct __promote<double>

    { typedef double __type; };

  template<>

    struct __promote<float>

    { typedef float __type; };

  template<typename _Tp, typename _Up,

           typename _Tp2 = typename __promote<_Tp>::__type,

           typename _Up2 = typename __promote<_Up>::__type>

    struct __promote_2

    {

      typedef __typeof__(_Tp2() + _Up2()) __type;

    };

  template<typename _Tp, typename _Up, typename _Vp,

           typename _Tp2 = typename __promote<_Tp>::__type,

           typename _Up2 = typename __promote<_Up>::__type,

           typename _Vp2 = typename __promote<_Vp>::__type>

    struct __promote_3

    {

      typedef __typeof__(_Tp2() + _Up2() + _Vp2()) __type;

    };

  template<typename _Tp, typename _Up, typename _Vp, typename _Wp,

           typename _Tp2 = typename __promote<_Tp>::__type,

           typename _Up2 = typename __promote<_Up>::__type,

           typename _Vp2 = typename __promote<_Vp>::__type,

           typename _Wp2 = typename __promote<_Wp>::__type>

    struct __promote_4

    {

      typedef __typeof__(_Tp2() + _Up2() + _Vp2() + _Wp2()) __type;

    };

_GLIBCXX_END_NAMESPACE_VERSION

} // namespace

#endif