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- /*=============================================================================
- Copyright (c) 2015 Agustin K-ballo Berge
- Copyright (c) 2015 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_INDEX_SEQUENCE_06232015_1038
- #define BOOST_FUSION_SUPPORT_DETAIL_INDEX_SEQUENCE_06232015_1038
- #include <boost/fusion/support/config.hpp>
- #include <cstddef>
- // GCC5 has O(logN) implementation, see https://gcc.gnu.org/PR66059 .
- #if (defined(__cpp_lib_integer_sequence) && __cpp_lib_integer_sequence >= 201304) \
- || (defined(BOOST_LIBSTDCXX_VERSION) \
- && BOOST_LIBSTDCXX_VERSION >= 500000 && __cplusplus >= 201402)
- #include <utility>
- #define BOOST_FUSION_STDLIB_HAS_INTEGER_SEQUENCE
- #endif
- namespace boost { namespace fusion { namespace detail
- {
- #ifdef BOOST_FUSION_STDLIB_HAS_INTEGER_SEQUENCE
- // Use aliasing templates without checking availability, the compiler should work.
- template <std::size_t ...Ints>
- using index_sequence = std::index_sequence<Ints...>;
- template <std::size_t N>
- struct make_index_sequence
- {
- using type = std::make_index_sequence<N>;
- };
- #else
- template <std::size_t ...Ints>
- struct index_sequence
- {
- typedef std::size_t value_type;
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- static std::size_t size() BOOST_NOEXCEPT
- { return sizeof...(Ints); }
- // non standard extension
- typedef index_sequence type;
- };
- template <typename Left, typename Right>
- struct _make_index_sequence_join;
- template <std::size_t... Left, std::size_t... Right>
- struct _make_index_sequence_join<
- index_sequence<Left...>, index_sequence<Right...>
- > : index_sequence<Left..., (sizeof...(Left) + Right)...>
- {};
- template <std::size_t N>
- struct make_index_sequence
- : _make_index_sequence_join<
- typename make_index_sequence<N / 2>::type
- , typename make_index_sequence<N - N / 2>::type
- >
- {};
- template <>
- struct make_index_sequence<1>
- : index_sequence<0>
- {};
- template <>
- struct make_index_sequence<0>
- : index_sequence<>
- {};
- #endif
- }}}
- #endif
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