org.vesalainen.math.sliding.AbstractSlidingBound Maven / Gradle / Ivy

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/*
 * Copyright (C) 2016 tkv
 *
 * 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 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */
package org.vesalainen.math.sliding;

import java.util.Arrays;
import java.util.function.DoubleConsumer;
import java.util.stream.DoubleStream;

/**
 * Base class for sliding bound calculation
 * @author tkv
 */
public abstract class AbstractSlidingBound extends AbstractSliding implements DoubleConsumer, ValueArray
{
    protected double[] ring;
    /**
     * 
     * @param size Initial size of the ringbuffer
     */
    public AbstractSlidingBound(int size)
    {
        super(size);
        ring = new double[size];
    }
    /**
     * Returns the calculated bound
     * @return 
     */
    public double getBound()
    {
        return ring[begin % size];
    }
    /**
     * Add new value
     * @param value 
     */
    @Override
    public void accept(double value)
    {
        eliminate();
        assign(end % size, value);
        int e = end;
        while (e > begin && exceedsBounds(e, value))
        {
            e--;
            assign(e % size, value);
        }
        end++;
    }
    /**
     * Assign value for inner storage.
     * @param index Mod size
     * @param value 
     */
    @Override
    protected void assign(int index, double value)
    {
        ring[index] = value;
    }
    /**
     * Removes value from calculation
     * @param index Mod size
     */
    @Override
    protected void remove(int index)
    {
    }
    /**
     * return true if value at index is no longer needed.
     * @param index Mod size
     * @return 
     */
    @Override
    protected boolean isRemovable(int index)
    {
        return end-begin >= size;
    }
    /**
     * Grows ring buffer
     */
    @Override
    protected void grow()
    {
        int newSize = newSize();
        ring = (double[]) newArray(ring, size, new double[newSize]);
        size = newSize;
    }
    /**
     * Returns true if value exceeds value[index-1]
     * @param index Mod size
     * @param value
     * @return 
     */
    protected abstract boolean exceedsBounds(int index, double value);
    
    /**
     * Returns values as stream in the same order as entered
     * @return 
     */
    @Override
    public DoubleStream stream()
    {
        if (begin == end)
        {
            return DoubleStream.empty();
        }
        else
        {
            int b = begin % size;
            int e = end % size;
            if (b < e)
            {
                return Arrays.stream(ring, b, e);
            }
            else
            {
                return DoubleStream.concat(Arrays.stream(ring, e, size), Arrays.stream(ring, 0, b));
            }
        }
    }

    @Override
    public double count()
    {
        return end-begin;
    }

    @Override
    public double last()
    {
        if (count() < 1)
        {
            throw new IllegalStateException("count() < 1");
        }
        return ring[(end+size-1) % size];
    }

    @Override
    public double previous()
    {
        if (count() < 2)
        {
            throw new IllegalStateException("count() < 2");
        }
        return ring[(end+size-2) % size];
    }
    
}