/*
 * Least-recently used replacement algorithm.
 */

#ifndef _lru_h_
#define _lru_h_

#include "replacement.h"

class LRUReplacementAlg: public ReplacementAlg {
public:
	LRUReplacementAlg(unsigned long num_frame, int page_bits);
	~LRUReplacementAlg() { delete [] m_counts; }

	virtual string name() { return "LRU"; }

	// We need to keep track of each reference, so we replace this with
	// a version that does the record-keeping, then calls the base class
	// version.
	virtual void ref(const Ref &r);

	// Choose the least-recently-used page.
	virtual unsigned long fault(const Ref &r);
protected:
	unsigned long m_count;		// Virtual time (ref count).
	unsigned long *m_counts;	// Time for each frame.
};

#endif