ceph/src/boost/boost/type_traits/is_default_constructible.hpp

   1
   2 //  (C) Copyright John Maddock 2015.
   3 //  Use, modification and distribution are subject to the Boost Software License,
   4 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 //  http://www.boost.org/LICENSE_1_0.txt).
   6 //
   7 //  See http://www.boost.org/libs/type_traits for most recent version including documentation.
   8
   9 #ifndef BOOST_TT_IS_DEFAULT_CONSTRUCTIBLE_HPP_INCLUDED
  10 #define BOOST_TT_IS_DEFAULT_CONSTRUCTIBLE_HPP_INCLUDED
  11
  12 #include <cstddef> // size_t
  13 #include <boost/type_traits/integral_constant.hpp>
  14 #include <boost/detail/workaround.hpp>
  15 #include <boost/type_traits/is_complete.hpp>
  16 #include <boost/static_assert.hpp>
  17
  18 #if BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40700)
  19 #include <boost/type_traits/is_abstract.hpp>
  20 #endif
  21 #if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ <= 5)) || (defined(BOOST_MSVC) && (BOOST_MSVC == 1800))
  22 #include <utility> // std::pair
  23 #endif
  24
  25 #if !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, < 1800) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40500)
  26
  27 #include <boost/type_traits/detail/yes_no_type.hpp>
  28
  29 namespace boost{
  30
  31    namespace detail{
  32
  33       struct is_default_constructible_imp
  34       {
  35          template<typename _Tp, typename = decltype(_Tp())>
  36          static boost::type_traits::yes_type test(int);
  37
  38          template<typename>
  39          static boost::type_traits::no_type test(...);
  40       };
  41 #if BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40700)
  42       template<class T, bool b>
  43       struct is_default_constructible_abstract_filter
  44       {
  45           static const bool value = sizeof(is_default_constructible_imp::test<T>(0)) == sizeof(boost::type_traits::yes_type);
  46       };
  47       template<class T>
  48       struct is_default_constructible_abstract_filter<T, true>
  49       {
  50           static const bool value = false;
  51       };
  52 #endif
  53    }
  54
  55 #if BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40700)
  56    template <class T> struct is_default_constructible : public integral_constant<bool, detail::is_default_constructible_abstract_filter<T, boost::is_abstract<T>::value>::value>
  57    {
  58       BOOST_STATIC_ASSERT_MSG(boost::is_complete<T>::value, "Arguments to is_default_constructible must be complete types");
  59    };
  60 #else
  61    template <class T> struct is_default_constructible : public integral_constant<bool, sizeof(boost::detail::is_default_constructible_imp::test<T>(0)) == sizeof(boost::type_traits::yes_type)>
  62    {
  63       BOOST_STATIC_ASSERT_MSG(boost::is_complete<T>::value, "Arguments to is_default_constructible must be complete types");
  64    };
  65 #endif
  66    template <class T, std::size_t N> struct is_default_constructible<T[N]> : public is_default_constructible<T>{};
  67    template <class T> struct is_default_constructible<T[]> : public is_default_constructible<T>{};
  68    template <class T> struct is_default_constructible<T&> : public integral_constant<bool, false>{};
  69 #if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ <= 5))|| (defined(BOOST_MSVC) && (BOOST_MSVC == 1800))
  70    template <class T, class U> struct is_default_constructible<std::pair<T,U> > : public integral_constant<bool, is_default_constructible<T>::value && is_default_constructible<U>::value>{};
  71 #endif
  72 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
  73    template <class T> struct is_default_constructible<T&&> : public integral_constant<bool, false>{};
  74 #endif
  75    template <> struct is_default_constructible<void> : public integral_constant<bool, false>{};
  76    template <> struct is_default_constructible<void const> : public integral_constant<bool, false>{};
  77    template <> struct is_default_constructible<void volatile> : public integral_constant<bool, false>{};
  78    template <> struct is_default_constructible<void const volatile> : public integral_constant<bool, false>{};
  79
  80 #else
  81
  82 #include <boost/type_traits/is_pod.hpp>
  83
  84 namespace boost{
  85
  86    // We don't know how to implement this, note we can not use has_trivial_constructor here
  87    // because the correct implementation of that trait requires this one:
  88    template <class T> struct is_default_constructible : public is_pod<T>{};
  89    template <> struct is_default_constructible<void> : public integral_constant<bool, false>{};
  90    template <> struct is_default_constructible<void const> : public integral_constant<bool, false>{};
  91    template <> struct is_default_constructible<void volatile> : public integral_constant<bool, false>{};
  92    template <> struct is_default_constructible<void const volatile> : public integral_constant<bool, false>{};
  93
  94 #endif
  95
  96 } // namespace boost
  97
  98 #endif // BOOST_TT_IS_DEFAULT_CONSTRUCTIBLE_HPP_INCLUDED