Added is_trivially_copyable traits

include/boost/fusion/support/detail/is_trivially_copyable.hpp

@@ -0,0 +1,95 @@
+/*=============================================================================
+    Copyright (c) 2018 Kohei Takahashi
+
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
+    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+==============================================================================*/
+#ifndef BOOST_FUSION_SUPPORT_DETAIL_IS_TRIVIALLY_COPYABLE
+#define BOOST_FUSION_SUPPORT_DETAIL_IS_TRIVIALLY_COPYABLE
+
+#include <boost/fusion/support/config.hpp>
+
+#if BOOST_WORKAROUND(BOOST_GCC, BOOST_TESTED_AT(90000))
+    // GCC treats volatile qualified scalar type as non trivially copyable,
+    // so to be fail safe, we also treat it as non trivially copyable type.
+    // http://wg21.link/cwg2094
+    // https://gcc.gnu.org/PR85679
+#   define BOOST_FUSION_DETAIL_VOLATILE_SCALAR_IS_NON_TRIVIALLY_COPYABLE
+#endif
+
+#ifndef BOOST_NO_CXX11_HDR_TYPE_TRAITS
+#   include <type_traits>
+#else
+#   include <boost/config/workaround.hpp>
+#   include <boost/mpl/bool.hpp>
+#   include <boost/mpl/if.hpp>
+#   include <boost/type_traits/remove_cv.hpp>
+#   include <boost/type_traits/remove_all_extents.hpp>
+#   include <boost/type_traits/is_scalar.hpp>
+#   include <boost/type_traits/is_constructible.hpp>
+#   include <boost/type_traits/is_assignable.hpp>
+#   include <boost/type_traits/is_copy_constructible.hpp>
+#   include <boost/type_traits/is_copy_assignable.hpp>
+#   include <boost/type_traits/has_trivial_assign.hpp>
+#   include <boost/type_traits/has_trivial_copy.hpp>
+#   include <boost/type_traits/has_trivial_destructor.hpp>
+#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
+#   include <boost/type_traits/has_trivial_move_assign.hpp>
+#   include <boost/type_traits/has_trivial_move_constructor.hpp>
+#endif
+#ifdef BOOST_FUSION_DETAIL_VOLATILE_SCALAR_IS_NON_TRIVIALLY_COPYABLE
+#   include <boost/mpl/not.hpp>
+#   include <boost/type_traits/is_volatile.hpp>
+#endif
+#endif // <type_traits>
+
+#ifndef BOOST_NO_CXX11_HDR_TYPE_TRAITS
+#   define BOOST_FUSION_DETAIL_IS_TRIVIALLY_COPYABLE_CONFORMING 2
+#elif defined(BOOST_SFINAE_EXPR) && !defined(BOOST_NO_CXX11_DECLTYPE) && \
+      defined(BOOST_HAS_TRIVIAL_ASSIGN) && defined(BOOST_HAS_TRIVIAL_COPY) && \
+      defined(BOOST_HAS_TRIVIAL_MOVE_ASSIGN) && defined(BOOST_HAS_TRIVIAL_MOVE_CONSTRUCTOR) && \
+      defined(BOOST_HAS_TRIVIAL_DESTRUCTOR) && defined(BOOST_TT_IS_CONSTRUCTIBLE_CONFORMING)
+#   define BOOST_FUSION_DETAIL_IS_TRIVIALLY_COPYABLE_CONFORMING 1
+#endif
+
+namespace boost { namespace fusion { namespace detail
+{
+
+#ifdef BOOST_NO_CXX11_HDR_TYPE_TRAITS
+template <typename T>
+struct is_trivially_copyable_class
+  : mpl::bool_<
+        (has_trivial_copy<T>::value   || !is_copy_constructible<T>::value) &&
+        (has_trivial_assign<T>::value || !is_copy_assignable<T>::value) &&
+#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
+        (has_trivial_move_constructor<T>::value || !is_constructible<T, T&&>::value) &&
+        (has_trivial_move_assign<T>::value      || !is_assignable<T, T&&>::value) &&
+#endif // rv-ref
+        (is_constructible<T, T>::value || is_assignable<T, T>::value) &&
+        has_trivial_destructor<T>::value
+    > { };
+
+template <typename T>
+struct is_trivially_copyable_impl
+  : mpl::if_c<is_scalar<T>::value
+#ifdef BOOST_FUSION_DETAIL_VOLATILE_SCALAR_IS_NON_TRIVIALLY_COPYABLE
+    , mpl::not_<is_volatile<T> >
+#else
+    , mpl::true_
+#endif
+    , is_trivially_copyable_class<typename remove_cv<T>::type> >::type { };
+#endif // <type_traits>
+
+template <typename T>
+struct is_trivially_copyable
+#ifndef BOOST_NO_CXX11_HDR_TYPE_TRAITS
+  : std::is_trivially_copyable<T>
+#else
+  : is_trivially_copyable_impl<typename remove_all_extents<T>::type>
+#endif // <type_traits>
+{ };
+
+}}} // namespace boost::fusion::detail
+
+#endif
+