/*
 * Recycler.h
 *
 *  Created on: 2 Jan 2016
 *      Author: hieu
 */
#pragma once

#include <cstddef>
#include <deque>
#include <vector>

namespace Moses2 {

template<typename T>
class Recycler {
public:
	Recycler()
	:m_currInd(0)
    {}
	virtual ~Recycler()
	{}

	T Get()
	{
		if (!m_coll.empty()) {
			T &obj = m_coll.back();
			m_coll.pop_back();
			return obj;
		}
		else if (m_currInd) {
			--m_currInd;
			T &obj = m_all[m_currInd];
			return obj;
		}
		else {
			return NULL;
		}
	}

	void Clear()
	{
		m_coll.clear();
		m_currInd = m_all.size();
	}

	void Keep(const T& val) {
		m_all.push_back(val);
	}

	void Recycle(const T& val)
	{
		m_coll.push_back(val);
	}

protected:
	// all objects we're looking after
	std::vector<T> m_all;

	// pointer to the object that's just been given out.
	// to give out another obj, must decrement THEN give out
	size_t m_currInd;

	// objects that have been give back to us
	std::deque<T> m_coll;
};

} /* namespace Moses2 */