content: /*
   * Copyright 2020 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.extractor;
  
  import static com.google.android.exoplayer2.util.Assertions.checkArgument;
  
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.util.Util;
  
  /**
   * A {@link SeekMap} implementation based on a mapping between times and positions in the input
   * stream.
   */
  public final class IndexSeekMap implements SeekMap {
  
    private final long[] positions;
    private final long[] timesUs;
    private final long durationUs;
    private final boolean isSeekable;
  
    /**
     * Creates an instance.
     *
     * @param positions The positions in the stream corresponding to {@code timesUs}, in bytes.
     * @param timesUs The times corresponding to {@code positions}, in microseconds.
     * @param durationUs The duration of the input stream, or {@link C#TIME_UNSET} if it is unknown.
     */
    public IndexSeekMap(long[] positions, long[] timesUs, long durationUs) {
      checkArgument(positions.length == timesUs.length);
      int length = timesUs.length;
      isSeekable = length > 0;
      if (isSeekable && timesUs[0] > 0) {
        // Add (position = 0, timeUs = 0) as first entry.
        this.positions = new long[length + 1];
        this.timesUs = new long[length + 1];
        System.arraycopy(positions, 0, this.positions, 1, length);
        System.arraycopy(timesUs, 0, this.timesUs, 1, length);
      } else {
        this.positions = positions;
        this.timesUs = timesUs;
      }
      this.durationUs = durationUs;
    }
  
    @Override
    public boolean isSeekable() {
      return isSeekable;
    }
  
    @Override
    public long getDurationUs() {
      return durationUs;
    }
  
    @Override
    public SeekMap.SeekPoints getSeekPoints(long timeUs) {
      if (!isSeekable) {
        return new SeekMap.SeekPoints(SeekPoint.START);
      }
      int targetIndex =
          Util.binarySearchFloor(timesUs, timeUs, /* inclusive= */ true, /* stayInBounds= */ true);
      SeekPoint leftSeekPoint = new SeekPoint(timesUs[targetIndex], positions[targetIndex]);
      if (leftSeekPoint.timeUs == timeUs || targetIndex == timesUs.length - 1) {
        return new SeekMap.SeekPoints(leftSeekPoint);
      } else {
        SeekPoint rightSeekPoint =
            new SeekPoint(timesUs[targetIndex + 1], positions[targetIndex + 1]);
        return new SeekMap.SeekPoints(leftSeekPoint, rightSeekPoint);
      }
    }
  }
  