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.dash;
  
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.source.dash.manifest.RangedUri;
  
  /**
   * Indexes the segments within a media stream.
   */
  public interface DashSegmentIndex {
  
    int INDEX_UNBOUNDED = -1;
  
    /**
     * Returns {@code getFirstSegmentNum()} if the index has no segments or if the given media time is
     * earlier than the start of the first segment. Returns {@code getFirstSegmentNum() +
     * getSegmentCount() - 1} if the given media time is later than the end of the last segment.
     * Otherwise, returns the segment number of the segment containing the given media time.
     *
     * @param timeUs The time in microseconds.
     * @param periodDurationUs The duration of the enclosing period in microseconds, or {@link
     *     C#TIME_UNSET} if the period's duration is not yet known.
     * @return The segment number of the corresponding segment.
     */
    long getSegmentNum(long timeUs, long periodDurationUs);
  
    /**
     * Returns the start time of a segment.
     *
     * @param segmentNum The segment number.
     * @return The corresponding start time in microseconds.
     */
    long getTimeUs(long segmentNum);
  
    /**
     * Returns the duration of a segment.
     *
     * @param segmentNum The segment number.
     * @param periodDurationUs The duration of the enclosing period in microseconds, or {@link
     *     C#TIME_UNSET} if the period's duration is not yet known.
     * @return The duration of the segment, in microseconds.
     */
    long getDurationUs(long segmentNum, long periodDurationUs);
  
    /**
     * Returns a {@link RangedUri} defining the location of a segment.
     *
     * @param segmentNum The segment number.
     * @return The {@link RangedUri} defining the location of the data.
     */
    RangedUri getSegmentUrl(long segmentNum);
  
    /**
     * Returns the segment number of the first segment.
     *
     * @return The segment number of the first segment.
     */
    long getFirstSegmentNum();
  
    /**
     * Returns the number of segments in the index, or {@link #INDEX_UNBOUNDED}.
     * <p>
     * An unbounded index occurs if a dynamic manifest uses SegmentTemplate elements without a
     * SegmentTimeline element, and if the period duration is not yet known. In this case the caller
     * must manually determine the window of currently available segments.
     *
     * @param periodDurationUs The duration of the enclosing period in microseconds, or
     *     {@link C#TIME_UNSET} if the period's duration is not yet known.
     * @return The number of segments in the index, or {@link #INDEX_UNBOUNDED}.
     */
    int getSegmentCount(long periodDurationUs);
  
    /**
     * Returns true if segments are defined explicitly by the index.
     * <p>
     * If true is returned, each segment is defined explicitly by the index data, and all of the
     * listed segments are guaranteed to be available at the time when the index was obtained.
     * <p>
     * If false is returned then segment information was derived from properties such as a fixed
     * segment duration. If the presentation is dynamic, it's possible that only a subset of the
     * segments are available.
     *
     * @return Whether segments are defined explicitly by the index.
     */
    boolean isExplicit();
  
  }
  