Bound.java

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/*
    Synthia, a data structure generator
    Copyright (C) 2019-2021 Laboratoire d'informatique formelle
    Université du Québec à Chicoutimi, Canada
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    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 Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package ca.uqac.lif.synthia.enumerative;
 
import ca.uqac.lif.synthia.Bounded;
import ca.uqac.lif.synthia.CannotShrinkException;
import ca.uqac.lif.synthia.NoMoreElementException;
import ca.uqac.lif.synthia.Picker;
import ca.uqac.lif.synthia.Shrinkable;
import ca.uqac.lif.synthia.random.RandomFloat;
import ca.uqac.lif.synthia.util.Constant;
import ca.uqac.lif.synthia.util.Mutator;
 
/**
 * Return the value picked by a picker a defined number of times.
 * @ingroup API
 */
public class Bound<T> extends Mutator<T> implements Bounded<T>, Shrinkable<T>
{
    /*@ non_null @*/ protected Picker<Integer> m_length;
    
    protected int m_chosenLength;
    
    protected int m_currentLength;
    
    public Bound(Picker<? extends T> source, Picker<Integer> length)
    {
        super(source);
        m_length = length;
        m_chosenLength = m_length.pick();
        m_currentLength = 0;
    }
    
    public Bound(Picker<T> source, int length)
    {
        this(source, new Constant<Integer>(length));
    }
    
    @Override
    public void reset()
    {
        m_picker.reset();
        m_length.reset();
        m_currentLength = 0;
    }
 
    @Override
    public T pick()
    {
        if (m_chosenLength == m_currentLength)
        {
            throw new NoMoreElementException();
        }
        m_chosenLength++;
        return m_picker.pick();
    }
 
    @Override
    public Bound<T> duplicate(boolean with_state)
    {
        Bound<T> b = new Bound<T>(m_picker.duplicate(with_state), m_length.duplicate(with_state));
        if (with_state)
        {
            b.m_chosenLength = m_chosenLength;
            b.m_currentLength = m_currentLength;
        }
        return b;
    }
 
    @Override
    public boolean isDone()
    {
        return m_chosenLength == m_currentLength;
    }
    
    @SuppressWarnings("unchecked")
    @Override
    public Shrinkable<T> shrink(T o, Picker<Float> decision, float m)
    {
        if (!(m_picker instanceof Shrinkable))
        {
            throw new CannotShrinkException(m_picker);
        }
        return new Bound<T>(((Shrinkable<T>) m_picker).shrink(o, decision, 1), m_length);
    }
 
    @Override
    public Shrinkable<T> shrink(T o)
    {
        return shrink(o, RandomFloat.instance, 1);
    }
}