IsCharEncodingCompatibleWith.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include <type_traits>
#include "Traits/IsCharType.h"
 
#ifndef PLATFORM_TCHAR_IS_CHAR16
    #error "Traits/IsCharEncodingCompatibleWith.h should be included after platform headers"
#endif
 
namespace UE::Core::Private
{
    template <typename SrcEncoding, typename DestEncoding>
    constexpr bool IsCharEncodingCompatibleWithImpl()
    {
        if constexpr (!TIsCharType_V<SrcEncoding> || !TIsCharType_V<DestEncoding>)
        {
            return false;
        }
        else if constexpr (std::is_same_v<SrcEncoding, DestEncoding>)
        {
            return true;
        }
        else if constexpr (std::is_same_v<SrcEncoding, ANSICHAR> && std::is_same_v<DestEncoding, UTF8CHAR>)
        {
            return true;
        }
        else if constexpr (std::is_same_v<SrcEncoding, UCS2CHAR> && std::is_same_v<DestEncoding, UTF16CHAR>)
        {
            return true;
        }
        else if constexpr (std::is_same_v<SrcEncoding, WIDECHAR> && std::is_same_v<DestEncoding, UCS2CHAR>)
        {
            return true;
        }
        else if constexpr (std::is_same_v<SrcEncoding, UCS2CHAR> && std::is_same_v<DestEncoding, WIDECHAR>)
        {
            return true;
        }
#if PLATFORM_TCHAR_IS_CHAR16
        else if constexpr (std::is_same_v<SrcEncoding, WIDECHAR> && std::is_same_v<DestEncoding, wchar_t>)
        {
            return true;
        }
        else if constexpr (std::is_same_v<SrcEncoding, wchar_t> && std::is_same_v<DestEncoding, WIDECHAR>)
        {
            return true;
        }
#endif
        else
        {
            return false;
        }
    };
}
 
template <typename SrcEncoding, typename DestEncoding>
struct TIsCharEncodingCompatibleWith
{
    static constexpr bool Value = UE::Core::Private::IsCharEncodingCompatibleWithImpl<std::remove_cv_t<SrcEncoding>, std::remove_cv_t<DestEncoding>>();
};
 
template <typename SrcEncoding, typename DestEncoding>
constexpr inline bool TIsCharEncodingCompatibleWith_V = TIsCharEncodingCompatibleWith<SrcEncoding, DestEncoding>::Value;
 
template <typename SrcEncoding>
using TIsCharEncodingCompatibleWithTCHAR = TIsCharEncodingCompatibleWith<SrcEncoding, TCHAR>;