com.github.pemapmodder.pocketminegui.utils.Ring.java Source code

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Here is the source code for com.github.pemapmodder.pocketminegui.utils.Ring.java

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package com.github.pemapmodder.pocketminegui.utils;

/*
 * This file is part of PocketMine-GUI.
 *
 * PocketMine-GUI 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.
 *
 * PocketMine-GUI 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 PocketMine-GUI.  If not, see <http://www.gnu.org/licenses/>.
 */

import org.apache.commons.lang3.ArrayUtils;

import java.util.Iterator;

public class Ring<T> implements Iterable<T> {
    private T[] array;
    /**
     * This is an array offset
     */
    private int start = 0;
    /**
     * This is an internal offset
     */
    private int size = 0;

    public Ring(T[] buffer) {
        array = buffer.clone();
    }

    public void add(T t) {
        if (size < array.length) {
            array[size++] = t;
        } else {
            array[start++] = t;
        }
    }

    public T get(int offset) {
        if (offset >= size) {
            throw new IndexOutOfBoundsException();
        }
        return array[internalOffset(offset)];
    }

    private int internalOffset(int offset) {
        return (offset + start) % array.length;
    }

    @Override
    public Iterator<T> iterator() {
        return new RingIterator();
    }

    private class RingIterator implements Iterator<T> {
        private T[] backup;
        private int start;
        private int next = 0;

        public RingIterator() {
            assert start == 0 || size == array.length;
            backup = ArrayUtils.subarray(array, 0, size);
            start = Ring.this.start;
        }

        @Override
        public boolean hasNext() {
            return next < backup.length;
        }

        @Override
        public T next() {
            T ret = backup[(next + start) % backup.length];
            next++; // I really want to put it in the same assigument, but then it would become next+++start...
            return ret;
        }
    }
}