IteratorAdapter.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Templates/UnrealTemplate.h"
 
template <typename Base>
class TIteratorAdapter;
 
template <typename Base>
class TIteratorAdapter : public Base
{
public:
    using BaseType = Base;
    using ThisType = TIteratorAdapter<Base>;
    using ElementType = typename BaseType::ElementType;
    using SizeType = typename BaseType::SizeType;
 
    [[nodiscard]] TIteratorAdapter() = default;
 
    template < typename... Args>
    [[nodiscard]] TIteratorAdapter(EInPlace, Args&&... InArgs) : BaseType(Forward<Args>(InArgs)...)
    {
    }
 
    [[nodiscard]] ElementType& operator*() const
    {
        return this->Dereference();
    }
 
    [[nodiscard]] ElementType* operator->() const
    {
        return &this->Dereference();
    }
 
    ThisType& operator++()
    {
        this->Increment();
        return *this;
    }
 
    ThisType operator++(int)
    {
        ThisType Temp = *this;
        ++*this;
        return Temp;
    }
 
    ThisType& operator--()
    {
        this->Decrement();
        return *this;
    }
 
    ThisType operator--(int)
    {
        ThisType Temp = *this;
        --*this;
        return Temp;
    }
 
    ThisType& operator+=(SizeType Offset)
    {
        this->Increment(Offset);
        return *this;
    }
 
    ThisType& operator-=(SizeType Offset)
    {
        this->Decrement(Offset);
        return *this;
    }
 
    ThisType operator+(SizeType Offset) const
    {
        ThisType Temp = *this;
        return Temp += Offset;
    }
 
    ThisType operator-(SizeType Offset) const
    {
        ThisType Temp = *this;
        return Temp -= Offset;
    }
 
protected:
    // BaseType MUST implement at least forward iteration which is enforced with the "using" declaration.
    using BaseType::Dereference;
    using BaseType::Equals;
    using BaseType::Increment;
 
    template <typename AnyElementType>
    friend class TIteratorAdapter;
 
public:
    [[nodiscard]] bool operator==(const TIteratorAdapter& Right) const
    {
        return Equals(Right);
    }
 
    [[nodiscard]] bool operator!=(const TIteratorAdapter& Right) const
    {
        return !Equals(Right);
    }
};