tr1_impl/type_traits

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// TR1 type_traits -*- C++ -*-

// Copyright (C) 2007, 2008, 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 tr1_impl/type_traits
*  This is an internal header file, included by other library headers.
*  You should not attempt to use it directly.
*/

namespace std
{
_GLIBCXX_BEGIN_NAMESPACE_TR1

  /**
   * @defgroup metaprogramming Type Traits
   * @ingroup utilities
   *
   * Compile time type transformation and information.
   * @{
   */

  // For use in __is_convertible_simple.
  struct __sfinae_types
  {
    typedef char __one;
    typedef struct { char __arr[2]; } __two;
  };

#define _DEFINE_SPEC_0_HELPER                          \
  template<>

#define _DEFINE_SPEC_1_HELPER                          \
  template<typename _Tp>

#define _DEFINE_SPEC_2_HELPER                          \
  template<typename _Tp, typename _Cp>

#define _DEFINE_SPEC(_Order, _Trait, _Type, _Value)    \
  _DEFINE_SPEC_##_Order##_HELPER                       \
    struct _Trait<_Type>                               \
    : public integral_constant<bool, _Value> { };

  // helper classes [4.3].

  /// integral_constant
  template<typename _Tp, _Tp __v>
    struct integral_constant
    {
      static const _Tp                      value = __v;
      typedef _Tp                           value_type;
      typedef integral_constant<_Tp, __v>   type;
    };
  
  /// typedef for true_type
  typedef integral_constant<bool, true>     true_type;

  /// typedef for false_type
  typedef integral_constant<bool, false>    false_type;

  template<typename _Tp, _Tp __v>
    const _Tp integral_constant<_Tp, __v>::value;

  /// remove_cv
  template<typename>
    struct remove_cv;

  template<typename>
    struct __is_void_helper
    : public false_type { };
  _DEFINE_SPEC(0, __is_void_helper, void, true)

  // primary type categories [4.5.1].

  /// is_void
  template<typename _Tp>
    struct is_void
    : public integral_constant<bool, (__is_void_helper<typename
                      remove_cv<_Tp>::type>::value)>
    { };

  template<typename>
    struct __is_integral_helper
    : public false_type { };
  _DEFINE_SPEC(0, __is_integral_helper, bool, true)
  _DEFINE_SPEC(0, __is_integral_helper, char, true)
  _DEFINE_SPEC(0, __is_integral_helper, signed char, true)
  _DEFINE_SPEC(0, __is_integral_helper, unsigned char, true)
#ifdef _GLIBCXX_USE_WCHAR_T
  _DEFINE_SPEC(0, __is_integral_helper, wchar_t, true)
#endif
#ifdef _GLIBCXX_INCLUDE_AS_CXX0X
  _DEFINE_SPEC(0, __is_integral_helper, char16_t, true)
  _DEFINE_SPEC(0, __is_integral_helper, char32_t, true)
#endif
  _DEFINE_SPEC(0, __is_integral_helper, short, true)
  _DEFINE_SPEC(0, __is_integral_helper, unsigned short, true)
  _DEFINE_SPEC(0, __is_integral_helper, int, true)
  _DEFINE_SPEC(0, __is_integral_helper, unsigned int, true)
  _DEFINE_SPEC(0, __is_integral_helper, long, true)
  _DEFINE_SPEC(0, __is_integral_helper, unsigned long, true)
  _DEFINE_SPEC(0, __is_integral_helper, long long, true)
  _DEFINE_SPEC(0, __is_integral_helper, unsigned long long, true)

  /// is_integral
  template<typename _Tp>
    struct is_integral
    : public integral_constant<bool, (__is_integral_helper<typename
                      remove_cv<_Tp>::type>::value)>
    { };

  template<typename>
    struct __is_floating_point_helper
    : public false_type { };
  _DEFINE_SPEC(0, __is_floating_point_helper, float, true)
  _DEFINE_SPEC(0, __is_floating_point_helper, double, true)
  _DEFINE_SPEC(0, __is_floating_point_helper, long double, true)

  /// is_floating_point
  template<typename _Tp>
    struct is_floating_point
    : public integral_constant<bool, (__is_floating_point_helper<typename
                      remove_cv<_Tp>::type>::value)>
    { };

  /// is_array
  template<typename>
    struct is_array
    : public false_type { };

  template<typename _Tp, std::size_t _Size>
    struct is_array<_Tp[_Size]>
    : public true_type { };

  template<typename _Tp>
    struct is_array<_Tp[]>
    : public true_type { };

  template<typename>
    struct __is_pointer_helper
    : public false_type { };
  _DEFINE_SPEC(1, __is_pointer_helper, _Tp*, true)

  /// is_pointer
  template<typename _Tp>
    struct is_pointer
    : public integral_constant<bool, (__is_pointer_helper<typename
                      remove_cv<_Tp>::type>::value)>
    { };

  /// is_reference
  template<typename _Tp>
    struct is_reference;

  /// is_function
  template<typename _Tp>
    struct is_function;

  template<typename>
    struct __is_member_object_pointer_helper
    : public false_type { };
  _DEFINE_SPEC(2, __is_member_object_pointer_helper, _Tp _Cp::*,
           !is_function<_Tp>::value)

  /// is_member_object_pointer
  template<typename _Tp>
    struct is_member_object_pointer
    : public integral_constant<bool, (__is_member_object_pointer_helper<
                      typename remove_cv<_Tp>::type>::value)>
    { };

  template<typename>
    struct __is_member_function_pointer_helper
    : public false_type { };
  _DEFINE_SPEC(2, __is_member_function_pointer_helper, _Tp _Cp::*,
           is_function<_Tp>::value)

  /// is_member_function_pointer
  template<typename _Tp>
    struct is_member_function_pointer
    : public integral_constant<bool, (__is_member_function_pointer_helper<
                      typename remove_cv<_Tp>::type>::value)>
    { };

  /// is_enum
  template<typename _Tp>
    struct is_enum
    : public integral_constant<bool, __is_enum(_Tp)>
    { };

  /// is_union
  template<typename _Tp>
    struct is_union
    : public integral_constant<bool, __is_union(_Tp)>
    { };

  /// is_class
  template<typename _Tp>
    struct is_class
    : public integral_constant<bool, __is_class(_Tp)>
    { };

  /// is_function
  template<typename>
    struct is_function
    : public false_type { };
  template<typename _Res, typename... _ArgTypes>
    struct is_function<_Res(_ArgTypes...)>
    : public true_type { };
  template<typename _Res, typename... _ArgTypes>
    struct is_function<_Res(_ArgTypes......)>
    : public true_type { };
  template<typename _Res, typename... _ArgTypes>
    struct is_function<_Res(_ArgTypes...) const>
    : public true_type { };
  template<typename _Res, typename... _ArgTypes>
    struct is_function<_Res(_ArgTypes......) const>
    : public true_type { };
  template<typename _Res, typename... _ArgTypes>
    struct is_function<_Res(_ArgTypes...) volatile>
    : public true_type { };
  template<typename _Res, typename... _ArgTypes>
    struct is_function<_Res(_ArgTypes......) volatile>
    : public true_type { };
  template<typename _Res, typename... _ArgTypes>
    struct is_function<_Res(_ArgTypes...) const volatile>
    : public true_type { };
  template<typename _Res, typename... _ArgTypes>
    struct is_function<_Res(_ArgTypes......) const volatile>
    : public true_type { };

  // composite type traits [4.5.2].
  
  /// is_arithmetic
  template<typename _Tp>
    struct is_arithmetic
    : public integral_constant<bool, (is_integral<_Tp>::value
                      || is_floating_point<_Tp>::value)>
    { };

  /// is_fundamental
  template<typename _Tp>
    struct is_fundamental
    : public integral_constant<bool, (is_arithmetic<_Tp>::value
                      || is_void<_Tp>::value)>
    { };

  /// is_object
  template<typename _Tp>
    struct is_object
    : public integral_constant<bool, !(is_function<_Tp>::value
                       || is_reference<_Tp>::value
                       || is_void<_Tp>::value)>
    { };

  /// is_member_pointer
  template<typename _Tp>
    struct is_member_pointer;

  /// is_scalar
  template<typename _Tp>
    struct is_scalar
    : public integral_constant<bool, (is_arithmetic<_Tp>::value
                      || is_enum<_Tp>::value
                      || is_pointer<_Tp>::value
                      || is_member_pointer<_Tp>::value)>
    { };

  /// is_compound
  template<typename _Tp>
    struct is_compound
    : public integral_constant<bool, !is_fundamental<_Tp>::value> { };

  /// is_member_pointer
  template<typename _Tp>
    struct __is_member_pointer_helper
    : public false_type { };
  _DEFINE_SPEC(2, __is_member_pointer_helper, _Tp _Cp::*, true)

  template<typename _Tp>
  struct is_member_pointer
    : public integral_constant<bool, (__is_member_pointer_helper<
                      typename remove_cv<_Tp>::type>::value)>
    { };

  // type properties [4.5.3].
  /// is_const
  template<typename>
    struct is_const
    : public false_type { };

  template<typename _Tp>
    struct is_const<_Tp const>
    : public true_type { };
  
  /// is_volatile
  template<typename>
    struct is_volatile
    : public false_type { };

  template<typename _Tp>
    struct is_volatile<_Tp volatile>
    : public true_type { };

  /// is_empty
  template<typename _Tp>
    struct is_empty
    : public integral_constant<bool, __is_empty(_Tp)>
    { };

  /// is_polymorphic
  template<typename _Tp>
    struct is_polymorphic
    : public integral_constant<bool, __is_polymorphic(_Tp)>
    { };

  /// is_abstract
  template<typename _Tp>
    struct is_abstract
    : public integral_constant<bool, __is_abstract(_Tp)>
    { };

  /// has_virtual_destructor
  template<typename _Tp>
    struct has_virtual_destructor
    : public integral_constant<bool, __has_virtual_destructor(_Tp)>
    { };

  /// alignment_of
  template<typename _Tp>
    struct alignment_of
    : public integral_constant<std::size_t, __alignof__(_Tp)> { };
  
  /// rank
  template<typename>
    struct rank
    : public integral_constant<std::size_t, 0> { };
   
  template<typename _Tp, std::size_t _Size>
    struct rank<_Tp[_Size]>
    : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };

  template<typename _Tp>
    struct rank<_Tp[]>
    : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };

  /// extent
  template<typename, unsigned _Uint = 0>
    struct extent
    : public integral_constant<std::size_t, 0> { };
  
  template<typename _Tp, unsigned _Uint, std::size_t _Size>
    struct extent<_Tp[_Size], _Uint>
    : public integral_constant<std::size_t,
                   _Uint == 0 ? _Size : extent<_Tp,
                               _Uint - 1>::value>
    { };

  template<typename _Tp, unsigned _Uint>
    struct extent<_Tp[], _Uint>
    : public integral_constant<std::size_t,
                   _Uint == 0 ? 0 : extent<_Tp,
                               _Uint - 1>::value>
    { };

  // relationships between types [4.6].

  /// is_same
  template<typename, typename>
    struct is_same
    : public false_type { };

  template<typename _Tp>
    struct is_same<_Tp, _Tp>
    : public true_type { };

  // const-volatile modifications [4.7.1].

  /// remove_const
  template<typename _Tp>
    struct remove_const
    { typedef _Tp     type; };

  template<typename _Tp>
    struct remove_const<_Tp const>
    { typedef _Tp     type; };
  
  /// remove_volatile
  template<typename _Tp>
    struct remove_volatile
    { typedef _Tp     type; };

  template<typename _Tp>
    struct remove_volatile<_Tp volatile>
    { typedef _Tp     type; };
  
  /// remove_cv
  template<typename _Tp>
    struct remove_cv
    {
      typedef typename
      remove_const<typename remove_volatile<_Tp>::type>::type     type;
    };
  
  /// add_const
  template<typename _Tp>
    struct add_const
    { typedef _Tp const     type; };
   
  /// add_volatile
  template<typename _Tp>
    struct add_volatile
    { typedef _Tp volatile     type; };
  
  /// add_cv
  template<typename _Tp>
    struct add_cv
    {
      typedef typename
      add_const<typename add_volatile<_Tp>::type>::type     type;
    };

  // array modifications [4.7.3].

  /// remove_extent
  template<typename _Tp>
    struct remove_extent
    { typedef _Tp     type; };

  template<typename _Tp, std::size_t _Size>
    struct remove_extent<_Tp[_Size]>
    { typedef _Tp     type; };

  template<typename _Tp>
    struct remove_extent<_Tp[]>
    { typedef _Tp     type; };

  /// remove_all_extents
  template<typename _Tp>
    struct remove_all_extents
    { typedef _Tp     type; };

  template<typename _Tp, std::size_t _Size>
    struct remove_all_extents<_Tp[_Size]>
    { typedef typename remove_all_extents<_Tp>::type     type; };

  template<typename _Tp>
    struct remove_all_extents<_Tp[]>
    { typedef typename remove_all_extents<_Tp>::type     type; };

  // pointer modifications [4.7.4].

  template<typename _Tp, typename>
    struct __remove_pointer_helper
    { typedef _Tp     type; };

  template<typename _Tp, typename _Up>
    struct __remove_pointer_helper<_Tp, _Up*>
    { typedef _Up     type; };

  /// remove_pointer
  template<typename _Tp>
    struct remove_pointer
    : public __remove_pointer_helper<_Tp, typename remove_cv<_Tp>::type>
    { };

  template<typename>
    struct remove_reference;

  /// add_pointer
  template<typename _Tp>
    struct add_pointer
    { typedef typename remove_reference<_Tp>::type*     type; };

#undef _DEFINE_SPEC_0_HELPER
#undef _DEFINE_SPEC_1_HELPER
#undef _DEFINE_SPEC_2_HELPER
#undef _DEFINE_SPEC

  // @} group metaprogramming
_GLIBCXX_END_NAMESPACE_TR1
}