content: /*
   * Copyright (C) 2016 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.source;
  
  import com.google.android.exoplayer2.C;
  import java.util.Arrays;
  
  /**
   * An array of {@link TrackGroup}s exposed by a {@link MediaPeriod}.
   */
  public final class TrackGroupArray {
  
    /**
     * The empty array.
     */
    public static final TrackGroupArray EMPTY = new TrackGroupArray();
  
    /**
     * The number of groups in the array. Greater than or equal to zero.
     */
    public final int length;
  
    private final TrackGroup[] trackGroups;
  
    // Lazily initialized hashcode.
    private int hashCode;
  
    /**
     * @param trackGroups The groups. Must not be null or contain null elements, but may be empty.
     */
    public TrackGroupArray(TrackGroup... trackGroups) {
      this.trackGroups = trackGroups;
      this.length = trackGroups.length;
    }
  
    /**
     * Returns the group at a given index.
     *
     * @param index The index of the group.
     * @return The group.
     */
    public TrackGroup get(int index) {
      return trackGroups[index];
    }
  
    /**
     * Returns the index of a group within the array.
     *
     * @param group The group.
     * @return The index of the group, or {@link C#INDEX_UNSET} if no such group exists.
     */
    @SuppressWarnings("ReferenceEquality")
    public int indexOf(TrackGroup group) {
      for (int i = 0; i < length; i++) {
        // Suppressed reference equality warning because this is looking for the index of a specific
        // TrackGroup object, not the index of a potential equal TrackGroup.
        if (trackGroups[i] == group) {
          return i;
        }
      }
      return C.INDEX_UNSET;
    }
  
    /**
     * Returns whether this track group array is empty.
     */
    public boolean isEmpty() {
      return length == 0;
    }
  
    @Override
    public int hashCode() {
      if (hashCode == 0) {
        hashCode = Arrays.hashCode(trackGroups);
      }
      return hashCode;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }
      if (obj == null || getClass() != obj.getClass()) {
        return false;
      }
      TrackGroupArray other = (TrackGroupArray) obj;
      return length == other.length && Arrays.equals(trackGroups, other.trackGroups);
    }
  
  }
  