yuzu/src/common/parent_of_member.h
Morph 99ceb03a1c general: Convert source file copyright comments over to SPDX
This formats all copyright comments according to SPDX formatting guidelines.
Additionally, this resolves the remaining GPLv2 only licensed files by relicensing them to GPLv2.0-or-later.
2022-04-23 05:55:32 -04:00

190 lines
6.8 KiB
C++

// SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <type_traits>
#include "common/assert.h"
namespace Common {
namespace detail {
template <typename T, size_t Size, size_t Align>
struct TypedStorageImpl {
std::aligned_storage_t<Size, Align> storage_;
};
} // namespace detail
template <typename T>
using TypedStorage = detail::TypedStorageImpl<T, sizeof(T), alignof(T)>;
template <typename T>
static constexpr T* GetPointer(TypedStorage<T>& ts) {
return static_cast<T*>(static_cast<void*>(std::addressof(ts.storage_)));
}
template <typename T>
static constexpr const T* GetPointer(const TypedStorage<T>& ts) {
return static_cast<const T*>(static_cast<const void*>(std::addressof(ts.storage_)));
}
namespace impl {
template <size_t MaxDepth>
struct OffsetOfUnionHolder {
template <typename ParentType, typename MemberType, size_t Offset>
union UnionImpl {
using PaddingMember = char;
static constexpr size_t GetOffset() {
return Offset;
}
#pragma pack(push, 1)
struct {
PaddingMember padding[Offset];
MemberType members[(sizeof(ParentType) / sizeof(MemberType)) + 1];
} data;
#pragma pack(pop)
UnionImpl<ParentType, MemberType, Offset + 1> next_union;
};
template <typename ParentType, typename MemberType>
union UnionImpl<ParentType, MemberType, 0> {
static constexpr size_t GetOffset() {
return 0;
}
struct {
MemberType members[(sizeof(ParentType) / sizeof(MemberType)) + 1];
} data;
UnionImpl<ParentType, MemberType, 1> next_union;
};
template <typename ParentType, typename MemberType>
union UnionImpl<ParentType, MemberType, MaxDepth> {};
};
template <typename ParentType, typename MemberType>
struct OffsetOfCalculator {
using UnionHolder =
typename OffsetOfUnionHolder<sizeof(MemberType)>::template UnionImpl<ParentType, MemberType,
0>;
union Union {
char c{};
UnionHolder first_union;
TypedStorage<ParentType> parent;
constexpr Union() : c() {}
};
static constexpr Union U = {};
static constexpr const MemberType* GetNextAddress(const MemberType* start,
const MemberType* target) {
while (start < target) {
start++;
}
return start;
}
static constexpr std::ptrdiff_t GetDifference(const MemberType* start,
const MemberType* target) {
return (target - start) * sizeof(MemberType);
}
template <typename CurUnion>
static constexpr std::ptrdiff_t OffsetOfImpl(MemberType ParentType::*member,
CurUnion& cur_union) {
constexpr size_t Offset = CurUnion::GetOffset();
const auto target = std::addressof(GetPointer(U.parent)->*member);
const auto start = std::addressof(cur_union.data.members[0]);
const auto next = GetNextAddress(start, target);
if (next != target) {
if constexpr (Offset < sizeof(MemberType) - 1) {
return OffsetOfImpl(member, cur_union.next_union);
} else {
UNREACHABLE();
}
}
return static_cast<ptrdiff_t>(static_cast<size_t>(next - start) * sizeof(MemberType) +
Offset);
}
static constexpr std::ptrdiff_t OffsetOf(MemberType ParentType::*member) {
return OffsetOfImpl(member, U.first_union);
}
};
template <typename T>
struct GetMemberPointerTraits;
template <typename P, typename M>
struct GetMemberPointerTraits<M P::*> {
using Parent = P;
using Member = M;
};
template <auto MemberPtr>
using GetParentType = typename GetMemberPointerTraits<decltype(MemberPtr)>::Parent;
template <auto MemberPtr>
using GetMemberType = typename GetMemberPointerTraits<decltype(MemberPtr)>::Member;
template <auto MemberPtr, typename RealParentType = GetParentType<MemberPtr>>
constexpr std::ptrdiff_t OffsetOf() {
using DeducedParentType = GetParentType<MemberPtr>;
using MemberType = GetMemberType<MemberPtr>;
static_assert(std::is_base_of<DeducedParentType, RealParentType>::value ||
std::is_same<RealParentType, DeducedParentType>::value);
return OffsetOfCalculator<RealParentType, MemberType>::OffsetOf(MemberPtr);
};
} // namespace impl
template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
constexpr RealParentType& GetParentReference(impl::GetMemberType<MemberPtr>* member) {
std::ptrdiff_t Offset = impl::OffsetOf<MemberPtr, RealParentType>();
return *static_cast<RealParentType*>(
static_cast<void*>(static_cast<uint8_t*>(static_cast<void*>(member)) - Offset));
}
template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
constexpr RealParentType const& GetParentReference(impl::GetMemberType<MemberPtr> const* member) {
std::ptrdiff_t Offset = impl::OffsetOf<MemberPtr, RealParentType>();
return *static_cast<const RealParentType*>(static_cast<const void*>(
static_cast<const uint8_t*>(static_cast<const void*>(member)) - Offset));
}
template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
constexpr RealParentType* GetParentPointer(impl::GetMemberType<MemberPtr>* member) {
return std::addressof(GetParentReference<MemberPtr, RealParentType>(member));
}
template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
constexpr RealParentType const* GetParentPointer(impl::GetMemberType<MemberPtr> const* member) {
return std::addressof(GetParentReference<MemberPtr, RealParentType>(member));
}
template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
constexpr RealParentType& GetParentReference(impl::GetMemberType<MemberPtr>& member) {
return GetParentReference<MemberPtr, RealParentType>(std::addressof(member));
}
template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
constexpr RealParentType const& GetParentReference(impl::GetMemberType<MemberPtr> const& member) {
return GetParentReference<MemberPtr, RealParentType>(std::addressof(member));
}
template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
constexpr RealParentType* GetParentPointer(impl::GetMemberType<MemberPtr>& member) {
return std::addressof(GetParentReference<MemberPtr, RealParentType>(member));
}
template <auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
constexpr RealParentType const* GetParentPointer(impl::GetMemberType<MemberPtr> const& member) {
return std::addressof(GetParentReference<MemberPtr, RealParentType>(member));
}
} // namespace Common