191 lines
6.8 KiB
C++
191 lines
6.8 KiB
C++
// Copyright 2021 yuzu Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <type_traits>
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#include "common/assert.h"
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#include "common/common_types.h"
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namespace Common {
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namespace detail {
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template <typename T, size_t Size, size_t Align>
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struct TypedStorageImpl {
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std::aligned_storage_t<Size, Align> storage_;
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};
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} // namespace detail
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template <typename T>
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using TypedStorage = detail::TypedStorageImpl<T, sizeof(T), alignof(T)>;
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template <typename T>
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static constexpr T* GetPointer(TypedStorage<T>& ts) {
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return static_cast<T*>(static_cast<void*>(std::addressof(ts.storage_)));
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}
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template <typename T>
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static constexpr const T* GetPointer(const TypedStorage<T>& ts) {
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return static_cast<const T*>(static_cast<const void*>(std::addressof(ts.storage_)));
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}
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namespace impl {
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template <size_t MaxDepth>
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struct OffsetOfUnionHolder {
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template <typename ParentType, typename MemberType, size_t Offset>
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union UnionImpl {
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using PaddingMember = char;
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static constexpr size_t GetOffset() {
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return Offset;
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}
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#pragma pack(push, 1)
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struct {
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PaddingMember padding[Offset];
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MemberType members[(sizeof(ParentType) / sizeof(MemberType)) + 1];
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} data;
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#pragma pack(pop)
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UnionImpl<ParentType, MemberType, Offset + 1> next_union;
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};
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template <typename ParentType, typename MemberType>
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union UnionImpl<ParentType, MemberType, 0> {
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static constexpr size_t GetOffset() {
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return 0;
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}
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struct {
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MemberType members[(sizeof(ParentType) / sizeof(MemberType)) + 1];
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} data;
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UnionImpl<ParentType, MemberType, 1> next_union;
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};
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template <typename ParentType, typename MemberType>
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union UnionImpl<ParentType, MemberType, MaxDepth> {};
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};
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template <typename ParentType, typename MemberType>
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struct OffsetOfCalculator {
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using UnionHolder =
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typename OffsetOfUnionHolder<sizeof(MemberType)>::template UnionImpl<ParentType, MemberType,
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0>;
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union Union {
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char c{};
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UnionHolder first_union;
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TypedStorage<ParentType> parent;
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constexpr Union() : c() {}
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};
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static constexpr Union U = {};
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static constexpr const MemberType* GetNextAddress(const MemberType* start,
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const MemberType* target) {
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while (start < target) {
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start++;
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}
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return start;
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}
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static constexpr std::ptrdiff_t GetDifference(const MemberType* start,
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const MemberType* target) {
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return (target - start) * sizeof(MemberType);
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}
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template <typename CurUnion>
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static constexpr std::ptrdiff_t OffsetOfImpl(MemberType ParentType::*member,
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CurUnion& cur_union) {
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constexpr size_t Offset = CurUnion::GetOffset();
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const auto target = std::addressof(GetPointer(U.parent)->*member);
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const auto start = std::addressof(cur_union.data.members[0]);
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const auto next = GetNextAddress(start, target);
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if (next != target) {
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if constexpr (Offset < sizeof(MemberType) - 1) {
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return OffsetOfImpl(member, cur_union.next_union);
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} else {
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UNREACHABLE();
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}
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}
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return (next - start) * sizeof(MemberType) + Offset;
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}
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static constexpr std::ptrdiff_t OffsetOf(MemberType ParentType::*member) {
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return OffsetOfImpl(member, U.first_union);
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}
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};
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template <typename T>
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struct GetMemberPointerTraits;
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template <typename P, typename M>
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struct GetMemberPointerTraits<M P::*> {
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using Parent = P;
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using Member = M;
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};
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template <auto MemberPtr>
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using GetParentType = typename GetMemberPointerTraits<decltype(MemberPtr)>::Parent;
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template <auto MemberPtr>
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using GetMemberType = typename GetMemberPointerTraits<decltype(MemberPtr)>::Member;
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template <auto MemberPtr, typename RealParentType = GetParentType<MemberPtr>>
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static inline std::ptrdiff_t OffsetOf = [] {
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using DeducedParentType = GetParentType<MemberPtr>;
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using MemberType = GetMemberType<MemberPtr>;
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static_assert(std::is_base_of<DeducedParentType, RealParentType>::value ||
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std::is_same<RealParentType, DeducedParentType>::value);
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return OffsetOfCalculator<RealParentType, MemberType>::OffsetOf(MemberPtr);
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}();
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} // namespace impl
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template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr RealParentType& GetParentReference(impl::GetMemberType<MemberPtr>* member) {
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std::ptrdiff_t Offset = impl::OffsetOf<MemberPtr, RealParentType>;
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return *static_cast<RealParentType*>(
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static_cast<void*>(static_cast<uint8_t*>(static_cast<void*>(member)) - Offset));
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}
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template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr RealParentType const& GetParentReference(impl::GetMemberType<MemberPtr> const* member) {
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std::ptrdiff_t Offset = impl::OffsetOf<MemberPtr, RealParentType>;
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return *static_cast<const RealParentType*>(static_cast<const void*>(
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static_cast<const uint8_t*>(static_cast<const void*>(member)) - Offset));
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}
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template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr RealParentType* GetParentPointer(impl::GetMemberType<MemberPtr>* member) {
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return std::addressof(GetParentReference<MemberPtr, RealParentType>(member));
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}
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template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr RealParentType const* GetParentPointer(impl::GetMemberType<MemberPtr> const* member) {
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return std::addressof(GetParentReference<MemberPtr, RealParentType>(member));
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}
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template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr RealParentType& GetParentReference(impl::GetMemberType<MemberPtr>& member) {
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return GetParentReference<MemberPtr, RealParentType>(std::addressof(member));
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}
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template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr RealParentType const& GetParentReference(impl::GetMemberType<MemberPtr> const& member) {
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return GetParentReference<MemberPtr, RealParentType>(std::addressof(member));
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}
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template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr RealParentType* GetParentPointer(impl::GetMemberType<MemberPtr>& member) {
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return std::addressof(GetParentReference<MemberPtr, RealParentType>(member));
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}
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template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr RealParentType const* GetParentPointer(impl::GetMemberType<MemberPtr> const& member) {
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return std::addressof(GetParentReference<MemberPtr, RealParentType>(member));
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}
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} // namespace Common
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