cc.redberry.transformation.NativeReccursionTransformation Maven / Gradle / Ivy

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/*
 * Redberry: symbolic tensor computations.
 *
 * Copyright (c) 2010-2012:
 *   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.transformation;

import cc.redberry.core.tensor.Tensor;
import cc.redberry.core.tensor.TensorIterator;
import cc.redberry.core.tensor.iterators.GuidePermit;
import cc.redberry.core.tensor.iterators.IterationGuide;

/**
 *
 * @author Dmitry Bolotin
 * @author Stanislav Poslavsky
 */
public abstract class NativeReccursionTransformation {
    private final IterationGuide guide;

    public NativeReccursionTransformation(IterationGuide guide) {
        this.guide = guide;
    }

    protected void innerTransform(Tensor tensor, T parameter) {
        TensorIterator it = tensor.iterator();
        Tensor t, newT;
        while (it.hasNext()) {
            t = it.next();
            //TODO diskuss
            if (guide.letInside(it, t) != GuidePermit.Enter)
                continue;
            newT = transform(t, preprocessParameter(parameter, it));
            if (newT == null) {
                it.remove();
                continue;
            }
            if (newT != t)
                it.set(newT);
        }
    }

    protected T preprocessParameter(T parameter, TensorIterator info) {
        return parameter;
    }

    protected abstract Tensor transform(Tensor tensor, T parameter);
}