/*
 * © Copyright 2014 – Urheberrechtshinweis
 * Alle Rechte vorbehalten / All Rights Reserved
 *
 * Programmcode ist urheberrechtlich geschuetzt.
 * Das Urheberrecht liegt, soweit nicht ausdruecklich anders gekennzeichnet, bei Frank Ebner.
 * Keine Verwendung ohne explizite Genehmigung.
 * (vgl. § 106 ff UrhG / § 97 UrhG)
 */

#ifndef RINGBUFFER_H
#define RINGBUFFER_H

#include <vector>
#include "../Assertions.h"

template <typename Element> class RingBuffer {

private:

	std::vector<Element> data;

	int iWrite;
	int iRead;
	int available;

public:

	/** ctor with the size of the buffer */
	RingBuffer(const int size) : data(size), iWrite(0), iRead(0), available(0) {
		;
	}

	/** add a new element WITH overflow check! */
	void addSafe(const Element& element) {
		Assert::isTrue(available != (int)data.size(), "buffer overflow");
		add(element);
	}

	/** add a new element WIUTHOUT checking for overflows */
	void add(const Element& element) {
		data[iWrite] = element;
		++iWrite;
		iWrite %= data.size();
		++available;
	}

	/** get the next element */
	const Element& get() {
		Assert::isNot0(available, "buffer is empty");
		const Element& tmp = data[iRead];
		++iRead;
		iRead %= data.size();
		--available;
		if (available < 0) {available = 0;}
		return tmp;
	}

	/** peek into the given element without removing it */
	const Element& peek(const int idx) const {
		const Element& tmp = data[(iRead + idx) % data.size()];
		return tmp;
	}

	/** peek into the given element without removing it */
	const Element& operator [] (const int idx) const {
		return peek(idx);
	}

	/** does the buffer contain the given element? */
	bool contains(const Element& e) const {
		for (int i = 0; i < available; ++i) {
			if (peek(i) == e) {return true;}
		}
		return false;
	}

	/** reset the ringbuffer */
	void reset() {
		iWrite = 0;
		iRead = 0;
		available = 0;
	}

	/** is the buffer empty? */
	bool empty() const {
		return available == 0;
	}

	/** get the number of available entries */
	int size() const {
		return available;
	}

	struct Iterator {

		int idx;
		int available;
		const std::vector<Element>& data;

		/** ctor */
		Iterator(const int idx, const int available, const std::vector<Element>& data) : idx(idx), available(available), data(data) {;}

		bool operator != (const Iterator& other) {return other.available != available;}
		void operator ++ () {idx = (idx+1) % data.size(); --available;}
		const Element& operator * () const {return data[idx];}


	};


	Iterator begin() const {return Iterator(iRead, available, data);}
	Iterator end() const {return Iterator(iWrite, 0, data);}

};

#endif // RINGBUFFER_H