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 com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.util.Assertions;
  import java.util.Arrays;
  
  // TODO: Add an allowMultipleStreams boolean to indicate where the one stream per group restriction
  // does not apply.
  /**
   * Defines a group of tracks exposed by a {@link MediaPeriod}.
   * <p>
   * A {@link MediaPeriod} is only able to provide one {@link SampleStream} corresponding to a group
   * at any given time, however this {@link SampleStream} may adapt between multiple tracks within the
   * group.
   */
  public final class TrackGroup {
  
    /**
     * The number of tracks in the group.
     */
    public final int length;
  
    private final Format[] formats;
  
    // Lazily initialized hashcode.
    private int hashCode;
  
    /**
     * @param formats The track formats. Must not be null, contain null elements or be of length 0.
     */
    public TrackGroup(Format... formats) {
      Assertions.checkState(formats.length > 0);
      this.formats = formats;
      this.length = formats.length;
    }
  
    /**
     * Returns the format of the track at a given index.
     *
     * @param index The index of the track.
     * @return The track's format.
     */
    public Format getFormat(int index) {
      return formats[index];
    }
  
    /**
     * Returns the index of the track with the given format in the group.
     *
     * @param format The format.
     * @return The index of the track, or {@link C#INDEX_UNSET} if no such track exists.
     */
    public int indexOf(Format format) {
      for (int i = 0; i < formats.length; i++) {
        if (format == formats[i]) {
          return i;
        }
      }
      return C.INDEX_UNSET;
    }
  
    @Override
    public int hashCode() {
      if (hashCode == 0) {
        int result = 17;
        result = 31 * result + Arrays.hashCode(formats);
        hashCode = result;
      }
      return hashCode;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }
      if (obj == null || getClass() != obj.getClass()) {
        return false;
      }
      TrackGroup other = (TrackGroup) obj;
      return length == other.length && Arrays.equals(formats, other.formats);
    }
  
  }
  