/*
 * Redberry: symbolic tensor computations.
 *
 * Copyright (c) 2010-2015:
 *   Stanislav Poslavsky   
 *   Bolotin Dmitriy       
 *
 * This file is part of Redberry.
 *
 * Redberry 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 3 of the License, or
 * (at your option) any later version.
 *
 * Redberry 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with Redberry. If not, see .
 */
package cc.redberry.core.utils.stretces;

import java.util.Iterator;

/**
 *
 * @author Dmitry Bolotin
 * @author Stanislav Poslavsky
 */
public class StretchIterator implements Iterator {
    private final Object[] elements;
    private final IntObjectProvider provider;
    private int pointer = 0;

    public StretchIterator(Object[] elements, IntObjectProvider provider) {
        this.elements = elements;
        this.provider = provider;
    }

    @Override
    public boolean hasNext() {
        return pointer < elements.length;
    }

    @Override
    public Stretch next() {
        int i = pointer;
        final int value = provider.get(elements[i]);
        final int begin = i;
        while ((++i < elements.length) && provider.get(elements[i]) == value);
        pointer = i;
        return new Stretch(begin, i - begin);
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public static Iterable goHash(final Object[] elements) {
        return new Iterable() {
            @Override
            public Iterator iterator() {
                return new StretchIterator(elements, IntObjectProvider.HASH_POVIDER);
            }
        };
    }
}