include/cmn/blockingCircularFifo.h

/*
 * Copyright (c) 2019, Infosys Ltd.
 *
 * 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 INCLUDE_CMN_BLOCKINGCIRCULARFIFO_H_
#define INCLUDE_CMN_BLOCKINGCIRCULARFIFO_H_

#include <cstddef>
#include <semaphore.h>
#include "circularFifo.h"

namespace cmn {
	namespace utils {

		template<typename Element, size_t size>
		class BlockingCircularFifo
		{
		public:
			BlockingCircularFifo():circularQueue()
			{
				sem_init(&pop_semaphore, 0, 0);
				sem_init(&push_semaphore, 0, size);
			}

			~BlockingCircularFifo()
			{
				sem_destroy(&pop_semaphore);
				sem_destroy(&push_semaphore);
			}

			bool push(Element* item)
			{
				sem_wait(&push_semaphore);
				bool ret = circularQueue.push(item);
				if (ret)
					sem_post(&pop_semaphore);
				else
					sem_post(&push_semaphore);
				return ret;
			}

			bool pop(Element*& item)
			{
				sem_wait(&pop_semaphore);
				bool ret = circularQueue.pop(item);
				if (ret)
					sem_post(&push_semaphore);
				else
					sem_post(&pop_semaphore);
				return ret;
			}

		private:
			CircularFifo<Element, size> circularQueue;
			sem_t pop_semaphore;
			sem_t push_semaphore;
		};
	}
}
#endif /* INCLUDE_CMN_BLOCKINGCIRCULARFIFO_H_ */