NazaraEngine/include/Nazara/Core/OffsetOf.hpp

31 lines
950 B
C++

// Copyright (C) 2021 Jérôme "Lynix" Leclercq (lynix680@gmail.com)
// This file is part of the "Nazara Engine - Core module"
// For conditions of distribution and use, see copyright notice in Config.hpp
#pragma once
#ifndef NAZARA_OFFSETOF_HPP
#define NAZARA_OFFSETOF_HPP
// By "Jesse Good" from SO:
// http://stackoverflow.com/questions/12811330/c-compile-time-offsetof-inside-a-template?answertab=votes#tab-top
namespace Nz
{
namespace Detail
{
template <typename T, typename M> T GetClassType(M T::*);
template <typename T, typename M> M GetMemberType(M T::*);
template <typename T, typename R, R T::*M>
constexpr std::size_t OffsetOf()
{
return reinterpret_cast<std::size_t>(&((static_cast<T*>(0))->*M));
}
}
}
#define NazaraOffsetOf(type, member) Nz::Detail::OffsetOf<decltype(Nz::Detail::GetClassType(&type::member)), decltype(Nz::Detail::GetMemberType(&type::member)), &type::member>()
#endif // NAZARA_OFFSETOF_HPP