mirror of
https://github.com/Atmosphere-NX/Atmosphere
synced 2024-11-10 07:06:34 +00:00
274 lines
13 KiB
C++
274 lines
13 KiB
C++
/*
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* Copyright (c) 2018-2020 Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <vapours/common.hpp>
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#include <vapours/assert.hpp>
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#include <vapours/util/util_typed_storage.hpp>
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namespace ams::util {
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namespace impl {
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#define AMS_UTIL_OFFSET_OF_STANDARD_COMPLIANT 0
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#if AMS_UTIL_OFFSET_OF_STANDARD_COMPLIANT
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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() { return Offset; }
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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() { return 0; }
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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> { /* Empty ... */ };
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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 = typename OffsetOfUnionHolder<sizeof(MemberType)>::template UnionImpl<ParentType, MemberType, 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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/* This coerces the active member to be c. */
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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, 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, 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, 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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__builtin_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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#else
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template<typename ParentType, typename MemberType>
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struct OffsetOfCalculator {
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static constexpr std::ptrdiff_t OffsetOf(MemberType ParentType::*member) {
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constexpr TypedStorage<ParentType> Holder = {};
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const auto *parent = GetPointer(Holder);
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const auto *target = std::addressof(parent->*member);
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return static_cast<const uint8_t *>(static_cast<const void *>(target)) - static_cast<const uint8_t *>(static_cast<const void *>(parent));
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}
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};
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#endif
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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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constexpr 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 || std::is_same<RealParentType, DeducedParentType>::value);
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/* DEPRECATED: static_assert(std::is_literal_type<MemberType>::value); */
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return OffsetOfCalculator<RealParentType, MemberType>::OffsetOf(MemberPtr);
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}();
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}
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template<auto MemberPtr, typename RealParentType = impl::GetParentType<MemberPtr>>
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constexpr ALWAYS_INLINE RealParentType &GetParentReference(impl::GetMemberType<MemberPtr> *member) {
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constexpr std::ptrdiff_t Offset = impl::OffsetOf<MemberPtr, RealParentType>;
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return *static_cast<RealParentType *>(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 ALWAYS_INLINE RealParentType const &GetParentReference(impl::GetMemberType<MemberPtr> const *member) {
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constexpr std::ptrdiff_t Offset = impl::OffsetOf<MemberPtr, RealParentType>;
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return *static_cast<const RealParentType *>(static_cast<const void *>(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 ALWAYS_INLINE 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 ALWAYS_INLINE 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 ALWAYS_INLINE 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 ALWAYS_INLINE 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 ALWAYS_INLINE 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 ALWAYS_INLINE 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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/* Defines, for use by other code. */
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#define OFFSETOF(parent, member) (::ams::util::impl::OffsetOf<&parent::member, parent>)
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#define GET_PARENT_PTR(parent, member, _arg) (::ams::util::GetParentPointer<&parent::member, parent>(_arg))
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#define GET_PARENT_REF(parent, member, _arg) (::ams::util::GetParentReference<&parent::member, parent>(_arg))
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namespace test {
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struct Struct1 {
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uint32_t a;
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};
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struct Struct2 {
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uint32_t b;
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};
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struct Struct3 : public Struct1, Struct2 {
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uint32_t c;
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};
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static_assert(impl::OffsetOf<&Struct1::a> == 0);
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static_assert(impl::OffsetOf<&Struct2::b> == 0);
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static_assert(impl::OffsetOf<&Struct3::a> == 0);
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static_assert(impl::OffsetOf<&Struct3::b> == 0);
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static_assert(impl::OffsetOf<&Struct3::a, Struct3> == 0 || impl::OffsetOf<&Struct3::b, Struct3> == 0);
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static_assert(impl::OffsetOf<&Struct3::a, Struct3> == sizeof(Struct2) || impl::OffsetOf<&Struct3::b, Struct3> == sizeof(Struct1));
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static_assert(impl::OffsetOf<&Struct3::c> == sizeof(Struct1) + sizeof(Struct2));
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constexpr Struct3 TestStruct3 = {};
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static_assert(std::addressof(TestStruct3) == GET_PARENT_PTR(Struct3, a, TestStruct3.a));
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static_assert(std::addressof(TestStruct3) == GET_PARENT_PTR(Struct3, a, std::addressof(TestStruct3.a)));
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static_assert(std::addressof(TestStruct3) == GET_PARENT_PTR(Struct3, b, TestStruct3.b));
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static_assert(std::addressof(TestStruct3) == GET_PARENT_PTR(Struct3, b, std::addressof(TestStruct3.b)));
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static_assert(std::addressof(TestStruct3) == GET_PARENT_PTR(Struct3, c, TestStruct3.c));
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static_assert(std::addressof(TestStruct3) == GET_PARENT_PTR(Struct3, c, std::addressof(TestStruct3.c)));
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struct CharArray {
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char c0;
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char c1;
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char c2;
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char c3;
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char c4;
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char c5;
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char c6;
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char c7;
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};
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static_assert(impl::OffsetOf<&CharArray::c0> == 0);
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static_assert(impl::OffsetOf<&CharArray::c1> == 1);
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static_assert(impl::OffsetOf<&CharArray::c2> == 2);
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static_assert(impl::OffsetOf<&CharArray::c3> == 3);
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static_assert(impl::OffsetOf<&CharArray::c4> == 4);
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static_assert(impl::OffsetOf<&CharArray::c5> == 5);
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static_assert(impl::OffsetOf<&CharArray::c6> == 6);
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static_assert(impl::OffsetOf<&CharArray::c7> == 7);
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constexpr CharArray TestCharArray = {};
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c0, TestCharArray.c0));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c0, std::addressof(TestCharArray.c0)));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c1, TestCharArray.c1));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c1, std::addressof(TestCharArray.c1)));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c2, TestCharArray.c2));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c2, std::addressof(TestCharArray.c2)));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c3, TestCharArray.c3));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c3, std::addressof(TestCharArray.c3)));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c4, TestCharArray.c4));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c4, std::addressof(TestCharArray.c4)));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c5, TestCharArray.c5));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c5, std::addressof(TestCharArray.c5)));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c6, TestCharArray.c6));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c6, std::addressof(TestCharArray.c6)));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c7, TestCharArray.c7));
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static_assert(std::addressof(TestCharArray) == GET_PARENT_PTR(CharArray, c7, std::addressof(TestCharArray.c7)));
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}
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}
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