Common: Add helpers for enum classes

common/CMakeLists.txt

@@ -72,6 +72,7 @@ target_sources(common PRIVATE
 	boost_spsc_queue.hpp
 	Console.h
 	Dependencies.h
+	EnumOps.h
 	EventSource.h
 	Exceptions.h
 	FastJmp.h

common/EnumOps.h

@@ -0,0 +1,96 @@
+/*  PCSX2 - PS2 Emulator for PCs
+ *  Copyright (C) 2002-2022 PCSX2 Dev Team
+ *
+ *  PCSX2 is free software: you can redistribute it and/or modify it under the terms
+ *  of the GNU Lesser General Public License as published by the Free Software Found-
+ *  ation, either version 3 of the License, or (at your option) any later version.
+ *
+ *  PCSX2 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ *  PURPOSE.  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with PCSX2.
+ *  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <type_traits>
+
+namespace detail
+{
+	/// Marks an enum as supporting boolean operators
+	template <typename T>
+	struct enum_is_flags : public std::false_type {};
+
+	/// For return types that should be convertible to bool
+	template <typename Enum>
+	struct enum_bool_helper
+	{
+		Enum value;
+		constexpr enum_bool_helper(Enum value): value(value) {}
+		constexpr operator Enum() const { return value; }
+		constexpr operator bool() const { return static_cast<bool>(static_cast<typename std::underlying_type<Enum>::type>(value)); }
+	};
+};
+
+#define MARK_ENUM_AS_FLAGS(T) template<> struct detail::enum_is_flags<T> : public std::true_type {}
+
+template <typename Enum>
+constexpr typename std::enable_if<detail::enum_is_flags<Enum>::value, Enum>::type
+operator|(Enum lhs, Enum rhs) noexcept
+{
+	using underlying = typename std::underlying_type<Enum>::type;
+	return static_cast<Enum>(static_cast<underlying>(lhs) | static_cast<underlying>(rhs));
+}
+
+template <typename Enum>
+constexpr typename std::enable_if<detail::enum_is_flags<Enum>::value, detail::enum_bool_helper<Enum>>::type
+operator&(Enum lhs, Enum rhs) noexcept
+{
+	using underlying = typename std::underlying_type<Enum>::type;
+	return static_cast<Enum>(static_cast<underlying>(lhs) & static_cast<underlying>(rhs));
+}
+
+template <typename Enum>
+constexpr typename std::enable_if<detail::enum_is_flags<Enum>::value, Enum>::type
+operator^(Enum lhs, Enum rhs) noexcept
+{
+	using underlying = typename std::underlying_type<Enum>::type;
+	return static_cast<Enum>(static_cast<underlying>(lhs) ^ static_cast<underlying>(rhs));
+}
+
+template <typename Enum>
+constexpr typename std::enable_if<detail::enum_is_flags<Enum>::value, Enum&>::type
+operator|=(Enum& lhs, Enum rhs) noexcept
+{
+	return lhs = lhs | rhs;
+}
+
+template <typename Enum>
+constexpr typename std::enable_if<detail::enum_is_flags<Enum>::value, Enum&>::type
+operator&=(Enum& lhs, Enum rhs) noexcept
+{
+	return lhs = lhs & rhs;
+}
+
+template <typename Enum>
+constexpr typename std::enable_if<detail::enum_is_flags<Enum>::value, Enum&>::type
+operator^=(Enum& lhs, Enum rhs) noexcept
+{
+	return lhs = lhs ^ rhs;
+}
+
+template<typename Enum>
+constexpr typename std::enable_if<detail::enum_is_flags<Enum>::value, bool>::type
+operator!(Enum e) noexcept
+{
+	return !static_cast<typename std::underlying_type<Enum>::type>(e);
+}
+
+template<typename Enum>
+constexpr typename std::enable_if<detail::enum_is_flags<Enum>::value, Enum>::type
+operator~(Enum e) noexcept
+{
+	return static_cast<Enum>(~static_cast<typename std::underlying_type<Enum>::type>(e));
+}