content: /*
   * Copyright (C) 2019 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.google.android.exoplayer2.mediacodec;
  
  import java.util.NoSuchElementException;
  
  /**
   * Array-based unbounded queue for int primitives with amortized O(1) add and remove.
   *
   * <p>Use this class instead of a {@link java.util.Deque} to avoid boxing int primitives to {@link
   * Integer} instances.
   */
  /* package */ final class IntArrayQueue {
  
    /** Default capacity needs to be a power of 2. */
    private static final int DEFAULT_INITIAL_CAPACITY = 16;
  
    private int headIndex;
    private int tailIndex;
    private int size;
    private int[] data;
    private int wrapAroundMask;
  
    public IntArrayQueue() {
      headIndex = 0;
      tailIndex = -1;
      size = 0;
      data = new int[DEFAULT_INITIAL_CAPACITY];
      wrapAroundMask = data.length - 1;
    }
  
    /** Add a new item to the queue. */
    public void add(int value) {
      if (size == data.length) {
        doubleArraySize();
      }
  
      tailIndex = (tailIndex + 1) & wrapAroundMask;
      data[tailIndex] = value;
      size++;
    }
  
    /**
     * Remove an item from the queue.
     *
     * @throws NoSuchElementException if the queue is empty.
     */
    public int remove() {
      if (size == 0) {
        throw new NoSuchElementException();
      }
  
      int value = data[headIndex];
      headIndex = (headIndex + 1) & wrapAroundMask;
      size--;
  
      return value;
    }
  
    /** Returns the number of items in the queue. */
    public int size() {
      return size;
    }
  
    /** Returns whether the queue is empty. */
    public boolean isEmpty() {
      return size == 0;
    }
  
    /** Clears the queue. */
    public void clear() {
      headIndex = 0;
      tailIndex = -1;
      size = 0;
    }
  
    /** Returns the length of the backing array. */
    public int capacity() {
      return data.length;
    }
  
    private void doubleArraySize() {
      int newCapacity = data.length << 1;
      if (newCapacity < 0) {
        throw new IllegalStateException();
      }
  
      int[] newData = new int[newCapacity];
      int itemsToRight = data.length - headIndex;
      int itemsToLeft = headIndex;
      System.arraycopy(data, headIndex, newData, 0, itemsToRight);
      System.arraycopy(data, 0, newData, itemsToRight, itemsToLeft);
  
      headIndex = 0;
      tailIndex = size - 1;
      data = newData;
      wrapAroundMask = data.length - 1;
    }
  }
  