IsContiguousContainer.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Misc/StaticAssertCompleteType.h"
#include <initializer_list>
 
template <typename T>
struct TIsContiguousContainer
{
    UE_STATIC_ASSERT_COMPLETE_TYPE(T, "TIsContiguousContainer instantiated with an incomplete type");
    // This sizeof(T) == 0 test will let Clang treat zero-sized arrays as contiguous containers.
    // An alternate fix using a specialization of TIsContiguousContainer (which Clang doesn't support) can be found below.
    static constexpr bool Value = sizeof(T) == 0;
};
 
template <typename T> struct TIsContiguousContainer<             T& > : TIsContiguousContainer<T> {};
template <typename T> struct TIsContiguousContainer<             T&&> : TIsContiguousContainer<T> {};
template <typename T> struct TIsContiguousContainer<const          T> : TIsContiguousContainer<T> {};
template <typename T> struct TIsContiguousContainer<      volatile T> : TIsContiguousContainer<T> {};
template <typename T> struct TIsContiguousContainer<const volatile T> : TIsContiguousContainer<T> {};
 
template <typename T, size_t N> struct TIsContiguousContainer<               T[N]> { static constexpr bool Value = true; };
template <typename T, size_t N> struct TIsContiguousContainer<const          T[N]> { static constexpr bool Value = true; };
template <typename T, size_t N> struct TIsContiguousContainer<      volatile T[N]> { static constexpr bool Value = true; };
template <typename T, size_t N> struct TIsContiguousContainer<const volatile T[N]> { static constexpr bool Value = true; };
 
#ifndef __clang__
    template <typename T> struct TIsContiguousContainer<               T[0]> { static constexpr bool Value = true; };
    template <typename T> struct TIsContiguousContainer<const          T[0]> { static constexpr bool Value = true; };
    template <typename T> struct TIsContiguousContainer<      volatile T[0]> { static constexpr bool Value = true; };
    template <typename T> struct TIsContiguousContainer<const volatile T[0]> { static constexpr bool Value = true; };
#endif
 
template <typename T> struct TIsContiguousContainer<               T[]> { static constexpr bool Value = false; };
template <typename T> struct TIsContiguousContainer<const          T[]> { static constexpr bool Value = false; };
template <typename T> struct TIsContiguousContainer<      volatile T[]> { static constexpr bool Value = false; };
template <typename T> struct TIsContiguousContainer<const volatile T[]> { static constexpr bool Value = false; };
 
template <typename T>
struct TIsContiguousContainer<std::initializer_list<T>>
{
    static constexpr bool Value = true;
};
 
template <typename T>
inline constexpr bool TIsContiguousContainer_V = TIsContiguousContainer<T>::Value;