/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package cache;

import java.util.ArrayList;

/**
 *
 * @author Juninho Carlos
 */
public class LRU {    
    ArrayList<Integer> traceLRU;
    private boolean firstTime;
    private int TAM;
    
    public LRU(){
        this.TAM = 4;
        this.firstTime = true;
        this.traceLRU = new ArrayList<>(); 
        
    }
    
    public ArrayList<Integer> getTraceLRU(){
        return this.traceLRU;
    }
    
    private boolean isCheio(){        
        return this.traceLRU.size() == TAM;
    }
    
    private int getIndexFromBloco(int num_bloco){
        for(int i = 0; i < this.traceLRU.size(); i++){
            if(this.traceLRU.get(i) == num_bloco){
                return i;
            }            
        }
        return -1;
    }
    
    private boolean containsBloco(int num_bloco){
        for(int i = 0; i < this.traceLRU.size(); i++){
            if(this.traceLRU.get(i) == num_bloco){
                return true;
            }
        }
        return false;
    }
    
    private void atualizaTraceLRU(int indexDoAcesso){
        int bloco = this.traceLRU.get(indexDoAcesso);
        
        for(; indexDoAcesso < this.traceLRU.size()-1; indexDoAcesso++){
            this.traceLRU.set(indexDoAcesso,this.traceLRU.get(indexDoAcesso+1));
        }        
        this.traceLRU.set(indexDoAcesso, bloco);
    }
    
    private void insereNoFinal(int numBloco){
        this.traceLRU.add(numBloco);
    }
    
    public void atualizaLRU(int bloco){        
        //Caso o trace ainda não tenha sido preenchido
        if(!isCheio() && containsBloco(bloco)){
            this.atualizaTraceLRU(getIndexFromBloco(bloco));
            return;
        }else if(!isCheio()){
            
            this.insereNoFinal(bloco);
            return;
        }
        
        
        //Caso já tenha sido preenchido
        int indiceBloco = 0;
        for(; indiceBloco < this.traceLRU.size(); indiceBloco++){
            if(this.traceLRU.get(indiceBloco) == bloco){
                break;
            }
        }
        
        for(; indiceBloco < this.traceLRU.size()-1;indiceBloco++){
            this.traceLRU.set(indiceBloco, this.traceLRU.get(indiceBloco+1));
        }
        
        this.traceLRU.set(this.traceLRU.size()-1, bloco);        
    }
    
    public int getBlocoFromLru(){
        if(this.firstTime){
            this.firstTime = false;
            this.TAM = this.traceLRU.size();
        }
        if(this.traceLRU.isEmpty()){
            return -1;
        }
        return this.traceLRU.get(0);
    }    

    @Override
    public String toString() {
        String s = this.traceLRU.toString();        
        s += "\n";
        
        return s; //To change body of generated methods, choose Tools | Templates.
    }
    
    
    
}