/*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* Copyright (c) 2009 Helge Bahmann
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* Copyright (c) 2012 Tim Blechmann
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* Copyright (c) 2013 - 2020 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/storage_traits.hpp
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*
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* This header defines underlying types used as storage
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*/
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#ifndef BOOST_ATOMIC_DETAIL_STORAGE_TRAITS_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_STORAGE_TRAITS_HPP_INCLUDED_
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#include <cstddef>
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#include <boost/cstdint.hpp>
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#include <boost/atomic/detail/config.hpp>
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#include <boost/atomic/detail/string_ops.hpp>
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#include <boost/atomic/detail/aligned_variable.hpp>
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#include <boost/atomic/detail/type_traits/alignment_of.hpp>
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#include <boost/atomic/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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namespace atomics {
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namespace detail {
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template< typename T >
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BOOST_FORCEINLINE void non_atomic_load(T const volatile& from, T& to) BOOST_NOEXCEPT
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{
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to = from;
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}
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template< std::size_t Size, std::size_t Alignment = 1u >
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struct BOOST_ATOMIC_DETAIL_MAY_ALIAS buffer_storage
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{
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typedef unsigned char data_type[Size];
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BOOST_ATOMIC_DETAIL_ALIGNED_VAR_TPL(Alignment, data_type, data);
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BOOST_FORCEINLINE bool operator! () const BOOST_NOEXCEPT
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{
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return (data[0] == 0u && BOOST_ATOMIC_DETAIL_MEMCMP(data, data + 1, Size - 1u) == 0);
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}
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BOOST_FORCEINLINE bool operator== (buffer_storage const& that) const BOOST_NOEXCEPT
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{
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return BOOST_ATOMIC_DETAIL_MEMCMP(data, that.data, Size) == 0;
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}
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BOOST_FORCEINLINE bool operator!= (buffer_storage const& that) const BOOST_NOEXCEPT
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{
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return BOOST_ATOMIC_DETAIL_MEMCMP(data, that.data, Size) != 0;
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}
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};
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template< std::size_t Size, std::size_t Alignment >
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BOOST_FORCEINLINE void non_atomic_load(buffer_storage< Size, Alignment > const volatile& from, buffer_storage< Size, Alignment >& to) BOOST_NOEXCEPT
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{
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BOOST_ATOMIC_DETAIL_MEMCPY(to.data, const_cast< unsigned char const* >(from.data), Size);
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}
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template< std::size_t Size >
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struct storage_traits
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{
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typedef buffer_storage< Size, 1u > type;
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static BOOST_CONSTEXPR_OR_CONST std::size_t native_alignment = 1u;
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// By default, prefer the maximum supported alignment
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static BOOST_CONSTEXPR_OR_CONST std::size_t alignment = 16u;
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};
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template< >
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struct storage_traits< 1u >
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{
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typedef boost::uint8_t BOOST_ATOMIC_DETAIL_MAY_ALIAS type;
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static BOOST_CONSTEXPR_OR_CONST std::size_t native_alignment = 1u;
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static BOOST_CONSTEXPR_OR_CONST std::size_t alignment = 1u;
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};
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template< >
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struct storage_traits< 2u >
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{
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typedef boost::uint16_t BOOST_ATOMIC_DETAIL_MAY_ALIAS type;
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static BOOST_CONSTEXPR_OR_CONST std::size_t native_alignment = atomics::detail::alignment_of< boost::uint16_t >::value;
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static BOOST_CONSTEXPR_OR_CONST std::size_t alignment = 2u;
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};
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template< >
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struct storage_traits< 4u >
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{
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typedef boost::uint32_t BOOST_ATOMIC_DETAIL_MAY_ALIAS type;
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static BOOST_CONSTEXPR_OR_CONST std::size_t native_alignment = atomics::detail::alignment_of< boost::uint32_t >::value;
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static BOOST_CONSTEXPR_OR_CONST std::size_t alignment = 4u;
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};
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template< >
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struct storage_traits< 8u >
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{
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typedef boost::uint64_t BOOST_ATOMIC_DETAIL_MAY_ALIAS type;
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static BOOST_CONSTEXPR_OR_CONST std::size_t native_alignment = atomics::detail::alignment_of< boost::uint64_t >::value;
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static BOOST_CONSTEXPR_OR_CONST std::size_t alignment = 8u;
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};
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#if defined(BOOST_HAS_INT128)
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template< >
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struct storage_traits< 16u >
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{
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typedef boost::uint128_type BOOST_ATOMIC_DETAIL_MAY_ALIAS type;
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static BOOST_CONSTEXPR_OR_CONST std::size_t native_alignment = atomics::detail::alignment_of< boost::uint128_type >::value;
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static BOOST_CONSTEXPR_OR_CONST std::size_t alignment = 16u;
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};
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#else
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#if (__cplusplus >= 201103L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201103L)) &&\
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(!defined(BOOST_GCC_VERSION) || BOOST_GCC_VERSION >= 40900)
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using std::max_align_t;
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#else
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#if defined(BOOST_MSVC)
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#pragma warning(push)
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// alignment is sensitive to packing
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#pragma warning(disable: 4121)
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#endif
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class max_align_helper;
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union max_align_t
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{
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void* ptr;
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void (*fun_ptr)();
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int max_align_helper::*mem_ptr;
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void (max_align_helper::*mem_fun_ptr)();
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long long ll;
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long double ld;
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#if defined(BOOST_HAS_INT128)
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boost::int128_type i128;
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#endif
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#if defined(BOOST_HAS_FLOAT128)
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boost::float128_type f128;
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#endif
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};
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#if defined(BOOST_MSVC)
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#pragma warning(pop)
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#endif
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#endif // __cplusplus >= 201103L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201103L)
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template< >
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struct storage_traits< 16u >
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{
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typedef buffer_storage< 16u, atomics::detail::alignment_of< atomics::detail::max_align_t >::value > type;
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static BOOST_CONSTEXPR_OR_CONST std::size_t native_alignment = atomics::detail::alignment_of< atomics::detail::max_align_t >::value;
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static BOOST_CONSTEXPR_OR_CONST std::size_t alignment = 16u;
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};
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#endif
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template< typename T >
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struct storage_size_of
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{
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static BOOST_CONSTEXPR_OR_CONST std::size_t size = sizeof(T);
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static BOOST_CONSTEXPR_OR_CONST std::size_t value = (size == 3u ? 4u : (size >= 5u && size <= 7u ? 8u : (size >= 9u && size <= 15u ? 16u : size)));
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};
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} // namespace detail
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} // namespace atomics
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} // namespace boost
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#include <boost/atomic/detail/footer.hpp>
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#endif // BOOST_ATOMIC_DETAIL_STORAGE_TRAITS_HPP_INCLUDED_
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