/*****************************************************
 *                                                   *
 *					CSC468H1  2000  Fall             *
 *				     Assignment 2 -- Problem 2       *
 *                                                   *
 *				 	Student Name:    Wei Wang        *
 *						      	:    Jeff Xing       *
 *					Student Number: 984336700        *
 *								  : 990555323        *
 *                                                   *
 *****************************************************/


import java.io.*;
import java.util.*;

/**
 * A simulation on performance of three different page-replacement 
 * algorithms:  FIFO (first in, first out),
 *			    LFU (least frequently used) and
 *			    PFF (page fault frequency)
 * with different memory sizes (or thresholds), by giving a page
 * reference string, which contains s series of page refencece 
 * calls. By comapring the performance of each case, a better 
 * algorithm with a specific memory size (threshold) could be 
 * concluded.
 *
 */

class a2q2 {
/**
 * a2q2 constructor
 */
public a2q2() {
	super();
}
public static void main(String[] args) {
	String filename = "a2_data.txt";
	int pageReference[] = new int[1000];
	int i = 0;

	// initialize the page reference to -1 (invalid page reference)
	for (int j=0; j<1000; j++) {
		pageReference[j] = -1;
	}
	
	// get input from command line
	if (args.length > 0) {
		filename = args[0];
	}
	
	// read page reference strings from file and store into pageReference array
	try {
		RandomAccessFile inFile = new RandomAccessFile(filename, "r");
		String inString;
		while ((inString = inFile.readLine()) != null) {
			if (i >= 1000) {
				System.out.println("More than 1000 page reference strings");
				System.exit(0);
			}
			StringTokenizer st = new StringTokenizer(inString);
			while (st.hasMoreTokens()) {
				pageReference[i] = Integer.parseInt(st.nextToken());
				i++;
			}
		}
	} catch (Exception e) {
		System.out.println("Exception: " + e);
	}
	
	Fifo fifo = new Fifo();
	double x1 = fifo.run(pageReference, 6);
	double x2 = fifo.run(pageReference, 10);
	double x3 = fifo.run(pageReference, 16);

	Lfu lfu = new Lfu();
	double[] y = lfu.run(pageReference);
	
	Pff pff = new Pff();
	double z1[] = pff.run(pageReference, 8);
	double z2[] = pff.run(pageReference, 12);
	double z3[] = pff.run(pageReference, 16);
	
	Format x = new Format();

	System.out.println("# of page references = " + i);
	System.out.println("==========================================================");
	System.out.println("FIFO");
	System.out.println("==========================================================");
	System.out.println("Frames               6              10               16");
	System.out.println("----------------------------------------------------------");
	x.print(System.out, "Page faults	%10.4f", x1);
	x.print(System.out, "	%10.4f", x2);
	x.print(System.out, "	%10.4f\n", x3);
	x.print(System.out, "Faults/frames	%10.4f", x1/6);
	x.print(System.out, "	%10.4f", x2/10);
	x.print(System.out, "	%10.4f\n", x3/16);
	System.out.println("==========================================================");
	System.out.println("LFU");
	System.out.println("==========================================================");
	System.out.println("Frames               6               10              16");
	System.out.println("----------------------------------------------------------");
	x.print(System.out, "Page faults	%10.4f", y[0]);
	x.print(System.out, "	%10.4f", y[1]);
	x.print(System.out, "	%10.4f\n", y[2]);
	x.print(System.out, "Faults/frames	%10.4f", y[0]/6);
	x.print(System.out, "	%10.4f", y[1]/10);
	x.print(System.out, "	%10.4f\n", y[2]/16);
	System.out.println("==========================================================");
	System.out.println("PFF");
	System.out.println("==========================================================");
	System.out.println("Threshold            8               12              16");
	System.out.println("----------------------------------------------------------");
	x.print(System.out, "Frames (total)	%10.4f", z1[1]);
	x.print(System.out, "	%10.4f", z2[1]);
	x.print(System.out, "	%10.4f\n", z3[1]);
	x.print(System.out, "Frames (mean)	%10.4f", z1[1]/i);
	x.print(System.out, "	%10.4f", z2[1]/i);
	x.print(System.out, "	%10.4f\n", z3[1]/i);
	x.print(System.out, "Page faults	%10.4f", z1[0]);
	x.print(System.out, "	%10.4f", z2[0]);
	x.print(System.out, "	%10.4f\n", z3[0]);
	x.print(System.out, "Faults/frames	%10.4f", z1[0]/(z1[1]/i));
	x.print(System.out, "	%10.4f", z2[0]/(z2[1]/i));
	x.print(System.out, "	%10.4f\n", z3[0]/(z3[1]/i));
}
}