/*=============================================================================
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Copyright (c) 2015 Agustin K-ballo Berge
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Copyright (c) 2015 Kohei Takahashi
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#ifndef BOOST_FUSION_SUPPORT_DETAIL_INDEX_SEQUENCE_06232015_1038
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#define BOOST_FUSION_SUPPORT_DETAIL_INDEX_SEQUENCE_06232015_1038
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#include <boost/fusion/support/config.hpp>
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#include <cstddef>
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// GCC5 has O(logN) implementation, see https://gcc.gnu.org/PR66059 .
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#if (defined(__cpp_lib_integer_sequence) && __cpp_lib_integer_sequence >= 201304) \
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|| (defined(BOOST_LIBSTDCXX_VERSION) \
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&& BOOST_LIBSTDCXX_VERSION >= 500000 && __cplusplus >= 201402)
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#include <utility>
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#define BOOST_FUSION_STDLIB_HAS_INTEGER_SEQUENCE
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#endif
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namespace boost { namespace fusion { namespace detail
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{
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#ifdef BOOST_FUSION_STDLIB_HAS_INTEGER_SEQUENCE
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// Use aliasing templates without checking availability, the compiler should work.
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template <std::size_t ...Ints>
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using index_sequence = std::index_sequence<Ints...>;
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template <std::size_t N>
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struct make_index_sequence
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{
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using type = std::make_index_sequence<N>;
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};
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#else
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template <std::size_t ...Ints>
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struct index_sequence
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{
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typedef std::size_t value_type;
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static std::size_t size() BOOST_NOEXCEPT
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{ return sizeof...(Ints); }
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// non standard extension
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typedef index_sequence type;
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};
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template <typename Left, typename Right>
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struct _make_index_sequence_join;
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template <std::size_t... Left, std::size_t... Right>
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struct _make_index_sequence_join<
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index_sequence<Left...>, index_sequence<Right...>
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> : index_sequence<Left..., (sizeof...(Left) + Right)...>
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{};
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template <std::size_t N>
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struct make_index_sequence
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: _make_index_sequence_join<
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typename make_index_sequence<N / 2>::type
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, typename make_index_sequence<N - N / 2>::type
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>
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{};
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template <>
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struct make_index_sequence<1>
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: index_sequence<0>
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{};
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template <>
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struct make_index_sequence<0>
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: index_sequence<>
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{};
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#endif
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}}}
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#endif
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