Optimal.cpp

#include "Page.cpp"
#include <iostream>
#include <time.h>

using namespace std;
/** @author Jared Baker
    @date 12/01/2014
Implements Optimal algorithm used in virtual page replacement. The algorythm looks into the page's future to decide what will be used
-- OPTTableSize : value to keep track of the page table's size
-- OPTTable : pointer to an Page object; used in construction of page tables
-- func
*/
class OPT {
  private:
    int OPTTableSize;
    int loc;
    int g;
    int StringSize;
    Page * OPTTable;
    Page * OPTTableString;
  public:
/** Constructor to create a new Optimal page table using the Page class.
*/
    OPT( int size, int fsize){
      OPTTableSize = size;
      OPTTable = new Page[size];
      OPTTableString = new Page[fsize];
      loc = 0;
      g = 0;
      StringSize = 0;
    }

  int Value [10]; //holds value distances for table from current location.
  int getSize() { return OPTTableSize; }
/** Compares each value with similar values ahead of its current location. This returns
that value that is furthest from the current. That value is to be deleted.
*/
  int getFurthest(void){
    int furthestaway; //keeps track of current index of the furthest page
    for (int i = 0; i < getSize(); i ++) {
      for (int z = loc + 1; z < StringSize; z ++) {
          //compares the value
        if (OPTTable[i].getName() == OPTTableString[z].getName()) { //I need to compare with each value that is currently ahead of its location. On the list. Is there a simple way of doing this?
          Value[i] = z-loc; //If positive, this should store how far the next similar value is from current.
          break;
        }
        else{
          Value[i] = StringSize + 1; //If no value matches, returns the highest possible size value. Thus it will be replaced.
        }
      }
    }
    furthestaway = 0;
  //Compare each value in the array and then figure out which one is furthest away. It will then return the one that is and replace it.
  for (int i = 0; i < getSize(); i ++){
      if (Value[furthestaway] < Value[i]){
        furthestaway = i;
      }
    }
    return furthestaway;
  }

  void getstringsize(int string) {
    StringSize = string;
  }

  void stringpage(char page){
    for (int i = g; i < StringSize; i ++){
      OPTTableString[i].setName(page);
      break;
      }
    g = g + 1;
  }

  bool checkForPage(char page, int pos){
    loc = pos;
    for (int i = 0; i < getSize(); i ++){
      if(OPTTable[i].isSet() != true){ //checks whether the page was set or not
        OPTTable[i].setName(page); //sets name of the page at the table's current index to the name of the page replacing it
        return false;
      }
    if (OPTTable[i].getName() == page){
      return true;
      }
    }
    int furthest = getFurthest();
  //changes new index for furthest page, sets value using getFurthest method
    OPTTable[furthest].setName(page); //replaces furthest page with the needed page
    return false;
  }
};