/*
  Copyright 2006 by Sean Luke
  Licensed under the Academic Free License version 3.0
  See the file "LICENSE" for more information
*/


package ec.app.edge.func;
import ec.*;
import ec.app.edge.*;
import ec.gp.*;
import ec.util.*;

/* 
 * BLoop.java
 * 
 * Created: Wed Nov  3 18:26:37 1999
 * By: Sean Luke
 */

/**
 * @author Sean Luke
 * @version 1.0 
 */

public class BLoop extends GPNode
    {
    public String toString() { return "loop2"; }

    /*
      public void checkConstraints(final EvolutionState state,
      final int tree,
      final GPIndividual typicalIndividual,
      final Parameter individualBase)
      {
      super.checkConstraints(state,tree,typicalIndividual,individualBase);
      if (children.length!=2)
      state.output.error("Incorrect number of children for node " + 
      toStringForError() + " at " +
      individualBase);
      }
    */
    public int expectedChildren() { return 2; }

    public void eval(final EvolutionState state,
        final int thread,
        final GPData input,
        final ADFStack stack,
        final GPIndividual individual,
        final Problem problem)
        {
        int edge = ((EdgeData)(input)).edge;
        Edge prob = (Edge)problem;

        if (prob.from.length==prob.numEdges)  // we're full, need to expand
            {
            int[] from_ = new int[prob.numEdges*2];
            int[] to_ = new int[prob.numEdges*2];
            int[] reading_ = new int[prob.numEdges*2];
            System.arraycopy(prob.from,0,from_,0,prob.from.length);
            System.arraycopy(prob.to,0,to_,0,prob.to.length);
            System.arraycopy(prob.reading,0,reading_,0,prob.reading.length);
            prob.from = from_;
            prob.to = to_;
            prob.reading = reading_;
            }

        int newedge = prob.numEdges;
        prob.numEdges++;
        prob.from[newedge] = prob.from[edge];
        prob.to[newedge] = prob.from[edge];  // same
        prob.reading[newedge] = prob.reading[edge];
        
        // pass the original edge down the left child

        children[0].eval(state,thread,input,stack,individual,problem);

        // reset input for right child
        ((EdgeData)(input)).edge = newedge;

        // pass the new edge down the right child
        
        children[1].eval(state,thread,input,stack,individual,problem);
        }
    }