// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef rr_Routine_hpp
#define rr_Routine_hpp

#include <memory>

namespace rr
{
	class Routine
	{
	public:
		Routine() = default;
		virtual ~Routine() = default;

		virtual const void *getEntry(int index = 0) = 0;
	};

	// RoutineT is a type-safe wrapper around a Routine and its callable entry, returned by FunctionT
	template<typename FunctionType>
	class RoutineT;

	template<typename Return, typename... Arguments>
	class RoutineT<Return(Arguments...)>
	{
	public:
		RoutineT() = default;

		explicit RoutineT(const std::shared_ptr<Routine>& routine)
			: routine(routine)
		{
			if (routine)
			{
				callable = reinterpret_cast<CallableType>(const_cast<void*>(routine->getEntry(0)));
			}
		}

		operator bool() const
		{
			return callable != nullptr;
		}

		template <typename... Args>
		Return operator()(Args&&... args) const
		{
			return callable(std::forward<Args>(args)...);
		}

		const void* getEntry() const
		{
			return reinterpret_cast<void*>(callable);
		}

	private:
		std::shared_ptr<Routine> routine;
		using CallableType = Return(*)(Arguments...);
		CallableType callable = nullptr;
	};
}

#endif   // rr_Routine_hpp