#ifndef DOUBLEBUFFER_H
#define DOUBLEBUFFER_H

template <typename Scalar, int size> class DoubleBuffer {

private:

	Scalar data[size*2];
	Scalar* ptr1;
	Scalar* ptr2;

	volatile uint32_t head;
	volatile bool _needsFlush;

public:

	void init() {
		ptr1 = &data[0];
		ptr2 = &data[size];
		head = 0;
		_needsFlush = false;
	}

	/** add new values to buffer A. swaps A and B if A is full */
	void add(const Scalar value) {

		ptr1[head] = value; // ptr1
		++head;

		if (head >= size) {
			head = 0;
			swap();
			_needsFlush = true;
		}

	}

	/** get data from buffer B */
	const Scalar* getData() const {
		return ptr2;
	}

	/** true if the buffer is currently empty */
	bool isEmpty() const {
		return head == 0;
	}

	bool needsFlush() const {
		return _needsFlush;
	}

	void markFlushed() {
		_needsFlush = false;
	}

	uint32_t getSize() const {
		return size;
	}

private:

	void swap() {
		Scalar* tmp = ptr1;
		ptr1 = ptr2;
		ptr2 = tmp;
	}

};

#endif // DOUBLEBUFFER_H