package ac.essex.ecj.util;

import ec.gp.*;
import ec.EvolutionState;
import ec.Problem;
import ec.util.Code;
import ec.util.DecodeReturn;
import ac.essex.ecj.data.DoubleData;

/**
 * <p/>
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version,
 * provided that any use properly credits the author.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details at http://www.gnu.org
 * </p>
 *
 * @author Olly Oechsle, University of Essex, Date: 17-Aug-2006
 * @version 1.0
 */
public abstract class ERCAdapter extends ERC {

    protected double value;
    protected String name;

    public abstract double setNumber(final EvolutionState state, final int thread);

    public void resetNode(final EvolutionState state, final int thread) {
        value = setNumber(state, thread);
    }

    public int nodeHashCode() {
        // a reasonable hash code
        return this.getClass().hashCode() + Float.floatToIntBits((float) value);
    }

    public boolean nodeEquals(final GPNode node) {
        // check first to see if we're the same kind of ERC --
        // won't work for subclasses; in that case you'll need
        // to change this to isAssignableTo(...)
        if (this.getClass() != node.getClass()) return false;
        // now check to see if the ERCs hold the same value
        return (((ERCAdapter) node).value == value);
    }

    public String encode() {
        return Code.encode(value);
    }

    public boolean decode(DecodeReturn dret) {
        // store the position and the string in case they
        // get modified by Code.java
        int pos = dret.pos;
        String data = dret.data;

        // decode
        Code.decode(dret);

        if (dret.type != DecodeReturn.T_DOUBLE) // uh oh!
        {
            // restore the position and the string; it was an error
            dret.data = data;
            dret.pos = pos;
            return false;
        }

        // store the data
        value = dret.d;
        return true;
    }

    public void eval(final EvolutionState state, final int thread, final GPData input, final ADFStack stack, final GPIndividual individual, final Problem problem) {
        DoubleData rd = ((DoubleData) (input));
        rd.value = value;
    }

}