BansheeEngine/Source/BansheeUtility/Include/BsEnumClassHash.h

//********************************** Banshee Engine (www.banshee3d.com) **************************************************//
//**************** Copyright (c) 2016 Marko Pintera ([email protected]). All rights reserved. **********************//
#pragma once

namespace BansheeEngine
{
	/**
	 * Hash for enum types, to be used instead of std::hash<T> when T is an enum.
	 *
	 * Until C++14, std::hash<T> is not defined if T is a enum (see
	 * http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148).  But
	 * even with C++14, as of october 2016, std::hash for enums is not widely
	 * implemented by compilers, so here when T is a enum, we use EnumClassHash
	 * instead of std::hash. (For instance, in BansheeEngine::hash_combine(), or
	 * BansheeEngine::UnorderedMap.)
	 */
	struct EnumClassHash
	{
		template <typename T>
		std::size_t operator()(T t) const
		{
			return static_cast<std::size_t>(t);
		}
	};
}