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