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.ts;
  
  import android.util.Log;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.extractor.ExtractorOutput;
  import com.google.android.exoplayer2.extractor.TrackOutput;
  import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
  import com.google.android.exoplayer2.util.MimeTypes;
  import com.google.android.exoplayer2.util.ParsableByteArray;
  
  /**
   * Parses ID3 data and extracts individual text information frames.
   */
  public final class Id3Reader implements ElementaryStreamReader {
  
    private static final String TAG = "Id3Reader";
  
    private static final int ID3_HEADER_SIZE = 10;
  
    private final ParsableByteArray id3Header;
  
    private TrackOutput output;
  
    // State that should be reset on seek.
    private boolean writingSample;
  
    // Per sample state that gets reset at the start of each sample.
    private long sampleTimeUs;
    private int sampleSize;
    private int sampleBytesRead;
  
    public Id3Reader() {
      id3Header = new ParsableByteArray(ID3_HEADER_SIZE);
    }
  
    @Override
    public void seek() {
      writingSample = false;
    }
  
    @Override
    public void createTracks(ExtractorOutput extractorOutput, TrackIdGenerator idGenerator) {
      idGenerator.generateNewId();
      output = extractorOutput.track(idGenerator.getTrackId(), C.TRACK_TYPE_METADATA);
      output.format(Format.createSampleFormat(idGenerator.getFormatId(), MimeTypes.APPLICATION_ID3,
          null, Format.NO_VALUE, null));
    }
  
    @Override
    public void packetStarted(long pesTimeUs, boolean dataAlignmentIndicator) {
      if (!dataAlignmentIndicator) {
        return;
      }
      writingSample = true;
      sampleTimeUs = pesTimeUs;
      sampleSize = 0;
      sampleBytesRead = 0;
    }
  
    @Override
    public void consume(ParsableByteArray data) {
      if (!writingSample) {
        return;
      }
      int bytesAvailable = data.bytesLeft();
      if (sampleBytesRead < ID3_HEADER_SIZE) {
        // We're still reading the ID3 header.
        int headerBytesAvailable = Math.min(bytesAvailable, ID3_HEADER_SIZE - sampleBytesRead);
        System.arraycopy(data.data, data.getPosition(), id3Header.data, sampleBytesRead,
            headerBytesAvailable);
        if (sampleBytesRead + headerBytesAvailable == ID3_HEADER_SIZE) {
          // We've finished reading the ID3 header. Extract the sample size.
          id3Header.setPosition(0);
          if ('I' != id3Header.readUnsignedByte() || 'D' != id3Header.readUnsignedByte()
              || '3' != id3Header.readUnsignedByte()) {
            Log.w(TAG, "Discarding invalid ID3 tag");
            writingSample = false;
            return;
          }
          id3Header.skipBytes(3); // version (2) + flags (1)
          sampleSize = ID3_HEADER_SIZE + id3Header.readSynchSafeInt();
        }
      }
      // Write data to the output.
      int bytesToWrite = Math.min(bytesAvailable, sampleSize - sampleBytesRead);
      output.sampleData(data, bytesToWrite);
      sampleBytesRead += bytesToWrite;
    }
  
    @Override
    public void packetFinished() {
      if (!writingSample || sampleSize == 0 || sampleBytesRead != sampleSize) {
        return;
      }
      output.sampleMetadata(sampleTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
      writingSample = false;
    }
  
  }
  