org.jpedal.utils.repositories.Vector_Double Maven / Gradle / Ivy

/*
 * ===========================================
 * Java Pdf Extraction Decoding Access Library
 * ===========================================
 *
 * Project Info:  http://www.idrsolutions.com
 * Help section for developers at http://www.idrsolutions.com/support/
 *
 * (C) Copyright 1997-2017 IDRsolutions and Contributors.
 *
 * This file is part of JPedal/JPDF2HTML5
 *
     This library 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 2.1 of the License, or (at your option) any later version.

    This library 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 library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


 *
 * ---------------
 * Vector_Double.java
 * ---------------
 */
package org.jpedal.utils.repositories;

import java.io.Serializable;

/**
 * Provides the functionality/convenience of a Vector for Doubles
 * 
 * Much faster because not synchronized and no cast
 * Does not double in size each time
 */
public class Vector_Double implements Serializable {

    //how much we resize each time - will be doubled up to 160
    int increment_size = 1000;
    protected int current_item;

    //current max size
    int max_size = 250;

    //holds the data
    private double[] items = new double[max_size];

    private int checkPoint = -1;

    /**
     * used to store end of PDF components
     */
    public void resetToCheckpoint() {

        if (checkPoint != -1) {
            current_item = checkPoint;
        }

        checkPoint = -1;
    }

    /**
     * used to rollback array to point
     */
    public void setCheckpoint() {
        if (checkPoint == -1) {
            checkPoint = current_item;
        }
    }

    protected static int incrementSize(int increment_size) {

        if (increment_size < 8000) {
            increment_size *= 4;
        } else if (increment_size < 16000) {
            increment_size *= 2;
        } else {
            increment_size += 2000;
        }
        return increment_size;
    }

    //set size
    public Vector_Double(final int number) {
        max_size = number;
        items = new double[max_size];
    }

    /**
     * extract underlying data
     */
    public final double[] get() {
        return items;
    }

    /**
     * add an item
     */
    public final void addElement(final double value) {
        checkSize(current_item);
        items[current_item] = value;
        current_item++;
    }

    /**
     * remove element at
     */
    public final double elementAt(final int id) {
        if (id >= max_size) {
            return 0d;
        } else {
            return items[id];
        }
    }
    ///////////////////////////////////

    /**
     * clear the array
     */
    public final void clear() {
        checkPoint = -1;
        //items = null;
        //holds the data
        //items = new double[max_size];
        if (current_item > 0) {
            for (int i = 0; i < current_item; i++) {
                items[i] = 0d;
            }
        } else {
            for (int i = 0; i < max_size; i++) {
                items[i] = 0d;
            }
        }
        current_item = 0;
    }

    /////////////////////////////////////

    /**
     * pull item from top as in LIFO stack
     */
    @SuppressWarnings("UnusedReturnValue")
    public final double pull() {

        if (current_item > 0) {
            current_item--;
        }

        return (items[current_item]);
    }


    /**
     * check the size of the array and increase if needed
     */
    private void checkSize(final int i) {
        if (i >= max_size) {
            final int old_size = max_size;
            max_size += increment_size;

            //allow for it not creating space
            if (max_size <= i) {
                max_size = i + increment_size + 2;
            }
            final double[] temp = items;
            items = new double[max_size];
            System.arraycopy(temp, 0, items, 0, old_size);

            //increase size increase for next time
            increment_size = incrementSize(increment_size);
        }
    }

    public void trim() {

        final double[] newItems = new double[current_item];

        System.arraycopy(items, 0, newItems, 0, current_item);

        items = newItems;
        max_size = current_item;
    }
}