290 lines
8.9 KiB
C++
290 lines
8.9 KiB
C++
#pragma once
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#include "CoreTypes.h"
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#include "Templates/Utility.h"
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#include "Templates/TypeHash.h"
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#include "Concepts/Comparable.h"
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#include "TypeTraits/TypeTraits.h"
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#include "Miscellaneous/AssertionMacros.h"
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NAMESPACE_REDCRAFT_BEGIN
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NAMESPACE_MODULE_BEGIN(Redcraft)
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NAMESPACE_MODULE_BEGIN(Utility)
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template <typename OptionalType> requires TIsObject<OptionalType>::Value && (!TIsArray<OptionalType>::Value) && TIsDestructible<OptionalType>::Value
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struct TOptional
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{
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public:
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using ValueType = OptionalType;
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constexpr TOptional() : bIsValid(false) { }
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constexpr TOptional(FInvalid) : TOptional() { }
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template <typename... Types> requires TIsConstructible<OptionalType, Types...>::Value
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constexpr explicit TOptional(FInPlace, Types&&... Args)
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: bIsValid(true)
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{
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new(&Value) OptionalType(Forward<Types>(Args)...);
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}
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template <typename T = OptionalType> requires TIsConstructible<OptionalType, T&&>::Value
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&& (!TIsSame<typename TRemoveCVRef<T>::Type, FInPlace>::Value) && (!TIsSame<typename TRemoveCVRef<T>::Type, TOptional>::Value)
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constexpr explicit (!TIsConvertible<T&&, OptionalType>::Value) TOptional(T&& InValue)
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: TOptional(InPlace, Forward<T>(InValue))
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{ }
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constexpr TOptional(const TOptional& InValue) requires TIsCopyConstructible<OptionalType>::Value
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: bIsValid(InValue.IsValid())
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{
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if (InValue.IsValid()) new(&Value) OptionalType(InValue.GetValue());
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}
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constexpr TOptional(TOptional&& InValue) requires TIsMoveConstructible<OptionalType>::Value
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: bIsValid(InValue.IsValid())
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{
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if (InValue.IsValid()) new(&Value) OptionalType(MoveTemp(InValue.GetValue()));
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}
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template <typename T = OptionalType> requires TIsConstructible<OptionalType, const T&>::Value
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constexpr explicit (!TIsConvertible<const T&, OptionalType>::Value) TOptional(const TOptional<T>& InValue)
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: bIsValid(InValue.IsValid())
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{
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if (InValue.IsValid()) new(&Value) OptionalType(InValue.GetValue());
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}
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template <typename T = OptionalType> requires TIsConstructible<OptionalType, T&&>::Value
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constexpr explicit (!TIsConvertible<T&&, OptionalType>::Value) TOptional(TOptional<T>&& InValue)
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: bIsValid(InValue.IsValid())
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{
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if (InValue.IsValid()) new(&Value) OptionalType(MoveTemp(InValue.GetValue()));
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}
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constexpr ~TOptional()
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{
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if constexpr (!TIsTriviallyDestructible<OptionalType>::Value) Reset();
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}
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constexpr TOptional& operator=(const TOptional& InValue) requires TIsCopyConstructible<OptionalType>::Value && TIsCopyAssignable<OptionalType>::Value
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{
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if (&InValue == this) return *this;
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if (!InValue.IsValid())
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{
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Reset();
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return *this;
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}
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if (IsValid()) GetValue() = InValue.GetValue();
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else
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{
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new(&Value) OptionalType(InValue.GetValue());
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bIsValid = true;
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}
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return *this;
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}
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constexpr TOptional& operator=(TOptional&& InValue) requires TIsMoveConstructible<OptionalType>::Value && TIsMoveAssignable<OptionalType>::Value
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{
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if (&InValue == this) return *this;
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if (!InValue.IsValid())
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{
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Reset();
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return *this;
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}
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if (IsValid()) GetValue() = MoveTemp(InValue.GetValue());
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else
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{
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new(&Value) OptionalType(MoveTemp(InValue.GetValue()));
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bIsValid = true;
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}
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return *this;
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}
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template <typename T = OptionalType> requires TIsConstructible<OptionalType, const T&>::Value && TIsAssignable<OptionalType, const T&>::Value
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constexpr TOptional& operator=(const TOptional<T>& InValue)
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{
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if (&InValue == this) return *this;
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if (!InValue.IsValid())
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{
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Reset();
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return *this;
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}
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if (IsValid()) GetValue() = InValue.GetValue();
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else
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{
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new(&Value) OptionalType(InValue.GetValue());
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bIsValid = true;
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}
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return *this;
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}
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template <typename T = OptionalType> requires TIsConstructible<OptionalType, T&&>::Value && TIsAssignable<OptionalType, T&&>::Value
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constexpr TOptional& operator=(TOptional<T>&& InValue)
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{
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if (&InValue == this) return *this;
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if (!InValue.IsValid())
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{
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Reset();
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return *this;
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}
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if (IsValid()) GetValue() = MoveTemp(InValue.GetValue());
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else
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{
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new(&Value) OptionalType(MoveTemp(InValue.GetValue()));
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bIsValid = true;
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}
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return *this;
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}
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template <typename T = OptionalType> requires TIsConstructible<OptionalType, T&&>::Value && TIsAssignable<OptionalType, T&&>::Value
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constexpr TOptional& operator=(T&& InValue)
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{
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if (IsValid()) GetValue() = Forward<T>(InValue);
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else
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{
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new(&Value) OptionalType(Forward<T>(InValue));
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bIsValid = true;
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}
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return *this;
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}
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template <typename... ArgTypes> requires TIsConstructible<OptionalType, ArgTypes...>::Value
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constexpr OptionalType& Emplace(ArgTypes&&... Args)
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{
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Reset();
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OptionalType* Result = new(&Value) OptionalType(Forward<ArgTypes>(Args)...);
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bIsValid = true;
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return *Result;
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}
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constexpr bool IsValid() const { return bIsValid; }
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constexpr explicit operator bool() const { return bIsValid; }
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constexpr void* GetData() { return &Value; }
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constexpr const void* GetData() const { return &Value; }
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constexpr OptionalType& GetValue() & { checkf(IsValid(), TEXT("It is an error to call GetValue() on an unset TOptional. Please either check IsValid() or use Get(DefaultValue) instead.")); return *reinterpret_cast< OptionalType*>(&Value); }
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constexpr OptionalType&& GetValue() && { checkf(IsValid(), TEXT("It is an error to call GetValue() on an unset TOptional. Please either check IsValid() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast< OptionalType*>(&Value)); }
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constexpr const OptionalType& GetValue() const& { checkf(IsValid(), TEXT("It is an error to call GetValue() on an unset TOptional. Please either check IsValid() or use Get(DefaultValue) instead.")); return *reinterpret_cast<const OptionalType*>(&Value); }
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constexpr const OptionalType&& GetValue() const&& { checkf(IsValid(), TEXT("It is an error to call GetValue() on an unset TOptional. Please either check IsValid() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast<const OptionalType*>(&Value)); }
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constexpr const OptionalType* operator->() const { return &GetValue(); }
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constexpr OptionalType* operator->() { return &GetValue(); }
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constexpr OptionalType& operator*() & { return GetValue(); }
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constexpr OptionalType&& operator*() && { return GetValue(); }
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constexpr const OptionalType& operator*() const& { return GetValue(); }
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constexpr const OptionalType&& operator*() const&& { return GetValue(); }
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constexpr OptionalType& Get( OptionalType& DefaultValue) & { return IsValid() ? GetValue() : DefaultValue; }
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constexpr const OptionalType& Get(const OptionalType& DefaultValue) const& { return IsValid() ? GetValue() : DefaultValue; }
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constexpr size_t GetTypeHash() const requires CHashable<OptionalType>
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{
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if (!IsValid()) return NAMESPACE_REDCRAFT::GetTypeHash(nullptr);
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return NAMESPACE_REDCRAFT::GetTypeHash(GetValue());
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}
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constexpr void Reset()
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{
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if (bIsValid)
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{
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bIsValid = false;
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typedef OptionalType DestructOptionalType;
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((OptionalType*)&Value)->DestructOptionalType::~DestructOptionalType();
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}
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}
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private:
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TAlignedStorage<sizeof(OptionalType), alignof(OptionalType)>::Type Value;
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bool bIsValid;
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};
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template <typename T>
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TOptional(T) ->TOptional<T>;
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template <typename T, typename U> requires CWeaklyEqualityComparableWith<T, U>
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constexpr bool operator==(const TOptional<T>& LHS, const TOptional<U>& RHS)
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{
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if (LHS.IsValid() != RHS.IsValid()) return false;
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if (LHS.IsValid() == false) return true;
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return *LHS == *RHS;
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}
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template <typename T, typename U> requires CWeaklyEqualityComparableWith<T, U>
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constexpr bool operator==(const TOptional<T>& LHS, const U& RHS)
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{
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return LHS.IsValid() ? *LHS == RHS : false;
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}
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template <typename T>
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constexpr bool operator==(const TOptional<T>& LHS, FInvalid)
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{
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return !LHS.IsValid();
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}
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template <typename T> requires (TIsObject<T>::Value && !TIsArray<T>::Value && TIsDestructible<T>::Value)
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constexpr TOptional<typename TDecay<T>::Type> MakeOptional(FInvalid)
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{
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return TOptional<typename TDecay<T>::Type>(Invalid);
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}
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template <typename T> requires (TIsObject<T>::Value && !TIsArray<T>::Value && TIsDestructible<T>::Value)
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constexpr TOptional<typename TDecay<T>::Type> MakeOptional(T&& InValue)
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{
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return TOptional<typename TDecay<T>::Type>(Forward<T>(InValue));
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}
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template <typename T, typename... Types> requires (TIsObject<T>::Value && !TIsArray<T>::Value && TIsDestructible<T>::Value)
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constexpr TOptional<T> MakeOptional(Types&&... Args)
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{
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return TOptional<T>(InPlace, Forward<T>(Args)...);
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}
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template <typename T> requires TIsMoveConstructible<T>::Value&& TIsSwappable<T>::Value
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constexpr void Swap(TOptional<T>& A, TOptional<T>& B)
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{
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if (!A && !B) return;
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if (A && !B)
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{
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B = MoveTemp(A);
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A.Reset();
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return;
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}
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if (B && !A)
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{
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A = MoveTemp(B);
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B.Reset();
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return;
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}
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Swap(*A, *B);
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}
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template <typename T> struct TIsTOptional : FFalse { };
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template <typename T> struct TIsTOptional<TOptional<T>> : FTrue { };
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NAMESPACE_MODULE_END(Utility)
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NAMESPACE_MODULE_END(Redcraft)
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NAMESPACE_REDCRAFT_END
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