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.extractor.ogg;
  
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.ParserException;
  import com.google.android.exoplayer2.extractor.Extractor;
  import com.google.android.exoplayer2.extractor.ExtractorInput;
  import com.google.android.exoplayer2.extractor.ExtractorOutput;
  import com.google.android.exoplayer2.extractor.ExtractorsFactory;
  import com.google.android.exoplayer2.extractor.PositionHolder;
  import com.google.android.exoplayer2.extractor.TrackOutput;
  import com.google.android.exoplayer2.util.ParsableByteArray;
  import java.io.IOException;
  
  /**
   * Extracts data from the Ogg container format.
   */
  public class OggExtractor implements Extractor {
  
    /**
     * Factory for {@link OggExtractor} instances.
     */
    public static final ExtractorsFactory FACTORY = new ExtractorsFactory() {
  
      @Override
      public Extractor[] createExtractors() {
        return new Extractor[] {new OggExtractor()};
      }
  
    };
  
    private static final int MAX_VERIFICATION_BYTES = 8;
  
    private ExtractorOutput output;
    private StreamReader streamReader;
    private boolean streamReaderInitialized;
  
    @Override
    public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
      try {
        return sniffInternal(input);
      } catch (ParserException e) {
        return false;
      }
    }
  
    @Override
    public void init(ExtractorOutput output) {
      this.output = output;
    }
  
    @Override
    public void seek(long position, long timeUs) {
      if (streamReader != null) {
        streamReader.seek(position, timeUs);
      }
    }
  
    @Override
    public void release() {
      // Do nothing
    }
  
    @Override
    public int read(ExtractorInput input, PositionHolder seekPosition)
        throws IOException, InterruptedException {
      if (streamReader == null) {
        if (!sniffInternal(input)) {
          throw new ParserException("Failed to determine bitstream type");
        }
        input.resetPeekPosition();
      }
      if (!streamReaderInitialized) {
        TrackOutput trackOutput = output.track(0, C.TRACK_TYPE_AUDIO);
        output.endTracks();
        streamReader.init(output, trackOutput);
        streamReaderInitialized = true;
      }
      return streamReader.read(input, seekPosition);
    }
  
    private boolean sniffInternal(ExtractorInput input) throws IOException, InterruptedException {
      OggPageHeader header = new OggPageHeader();
      if (!header.populate(input, true) || (header.type & 0x02) != 0x02) {
        return false;
      }
  
      int length = Math.min(header.bodySize, MAX_VERIFICATION_BYTES);
      ParsableByteArray scratch = new ParsableByteArray(length);
      input.peekFully(scratch.data, 0, length);
  
      if (FlacReader.verifyBitstreamType(resetPosition(scratch))) {
        streamReader = new FlacReader();
      } else if (VorbisReader.verifyBitstreamType(resetPosition(scratch))) {
        streamReader = new VorbisReader();
      } else if (OpusReader.verifyBitstreamType(resetPosition(scratch))) {
        streamReader = new OpusReader();
      } else {
        return false;
      }
      return true;
    }
  
    private static ParsableByteArray resetPosition(ParsableByteArray scratch) {
      scratch.setPosition(0);
      return scratch;
    }
  
  }
  