#ifndef RING_BUFFER_H
#define RING_BUFFER_H

#include <vector>
#include <mutex>
#include <condition_variable>

template<typename T>
class RingBuffer {
   public:
      RingBuffer(unsigned int size) :
	 read_index(0), write_index(0), filled(0), buf(size) {
      }
      void write(T item) {
	 std::unique_lock<std::mutex> lock(mutex);
	 while (filled == buf.capacity()) {
	    ready_for_writing.wait(lock);
	 }
	 buf[write_index] = item;
	 write_index = (write_index + 1) % buf.capacity();
	 ++filled;
	 ready_for_reading.notify_one();
      }
      void read(T& item) {
	 std::unique_lock<std::mutex> lock(mutex);
	 while (filled == 0) {
	    ready_for_reading.wait(lock);
	 }
	 item = buf[read_index];
	 read_index = (read_index + 1) % buf.capacity();
	 --filled;
	 ready_for_writing.notify_one();
      }
   private:
      unsigned int read_index;
      unsigned int write_index;
      unsigned int filled;
      std::vector<T> buf;
      std::mutex mutex;
      std::condition_variable ready_for_reading;
      std::condition_variable ready_for_writing;
};

#endif