Java Util.getIntegerCodeForString方法代碼示例

import com.google.android.exoplayer2.util.Util; //導入方法依賴的package包/類
/**
 * Skips to the data in the given WAV input stream and returns its data size. After calling, the
 * input stream's position will point to the start of sample data in the WAV.
 * <p>
 * If an exception is thrown, the input position will be left pointing to a chunk header.
 *
 * @param input Input stream to skip to the data chunk in. Its peek position must be pointing to
 *     a valid chunk header.
 * @param wavHeader WAV header to populate with data bounds.
 * @throws ParserException If an error occurs parsing chunks.
 * @throws IOException If reading from the input fails.
 * @throws InterruptedException If interrupted while reading from input.
 */
public static void skipToData(ExtractorInput input, WavHeader wavHeader)
    throws IOException, InterruptedException {
  Assertions.checkNotNull(input);
  Assertions.checkNotNull(wavHeader);

  // Make sure the peek position is set to the read position before we peek the first header.
  input.resetPeekPosition();

  ParsableByteArray scratch = new ParsableByteArray(ChunkHeader.SIZE_IN_BYTES);
  // Skip all chunks until we hit the data header.
  ChunkHeader chunkHeader = ChunkHeader.peek(input, scratch);
  while (chunkHeader.id != Util.getIntegerCodeForString("data")) {
    Log.w(TAG, "Ignoring unknown WAV chunk: " + chunkHeader.id);
    long bytesToSkip = ChunkHeader.SIZE_IN_BYTES + chunkHeader.size;
    // Override size of RIFF chunk, since it describes its size as the entire file.
    if (chunkHeader.id == Util.getIntegerCodeForString("RIFF")) {
      bytesToSkip = ChunkHeader.SIZE_IN_BYTES + 4;
    }
    if (bytesToSkip > Integer.MAX_VALUE) {
      throw new ParserException("Chunk is too large (~2GB+) to skip; id: " + chunkHeader.id);
    }
    input.skipFully((int) bytesToSkip);
    chunkHeader = ChunkHeader.peek(input, scratch);
  }
  // Skip past the "data" header.
  input.skipFully(ChunkHeader.SIZE_IN_BYTES);

  wavHeader.setDataBounds(input.getPosition(), chunkHeader.size);
}
 

import com.google.android.exoplayer2.util.Util; //導入方法依賴的package包/類
/**
 * Returns whether {@code brand} is an ftyp atom brand that is compatible with the MP4 extractors.
 */
private static boolean isCompatibleBrand(int brand) {
  // Accept all brands starting '3gp'.
  if (brand >>> 8 == Util.getIntegerCodeForString("3gp")) {
    return true;
  }
  for (int compatibleBrand : COMPATIBLE_BRANDS) {
    if (compatibleBrand == brand) {
      return true;
    }
  }
  return false;
}
 

import com.google.android.exoplayer2.util.Util; //導入方法依賴的package包/類
/**
 * Peeks and returns a {@code WavHeader}.
 *
 * @param input Input stream to peek the WAV header from.
 * @throws ParserException If the input file is an incorrect RIFF WAV.
 * @throws IOException If peeking from the input fails.
 * @throws InterruptedException If interrupted while peeking from input.
 * @return A new {@code WavHeader} peeked from {@code input}, or null if the input is not a
 *     supported WAV format.
 */
public static WavHeader peek(ExtractorInput input) throws IOException, InterruptedException {
  Assertions.checkNotNull(input);

  // Allocate a scratch buffer large enough to store the format chunk.
  ParsableByteArray scratch = new ParsableByteArray(16);

  // Attempt to read the RIFF chunk.
  ChunkHeader chunkHeader = ChunkHeader.peek(input, scratch);
  if (chunkHeader.id != Util.getIntegerCodeForString("RIFF")) {
    return null;
  }

  input.peekFully(scratch.data, 0, 4);
  scratch.setPosition(0);
  int riffFormat = scratch.readInt();
  if (riffFormat != Util.getIntegerCodeForString("WAVE")) {
    Log.e(TAG, "Unsupported RIFF format: " + riffFormat);
    return null;
  }

  // Skip chunks until we find the format chunk.
  chunkHeader = ChunkHeader.peek(input, scratch);
  while (chunkHeader.id != Util.getIntegerCodeForString("fmt ")) {
    input.advancePeekPosition((int) chunkHeader.size);
    chunkHeader = ChunkHeader.peek(input, scratch);
  }

  Assertions.checkState(chunkHeader.size >= 16);
  input.peekFully(scratch.data, 0, 16);
  scratch.setPosition(0);
  int type = scratch.readLittleEndianUnsignedShort();
  int numChannels = scratch.readLittleEndianUnsignedShort();
  int sampleRateHz = scratch.readLittleEndianUnsignedIntToInt();
  int averageBytesPerSecond = scratch.readLittleEndianUnsignedIntToInt();
  int blockAlignment = scratch.readLittleEndianUnsignedShort();
  int bitsPerSample = scratch.readLittleEndianUnsignedShort();

  int expectedBlockAlignment = numChannels * bitsPerSample / 8;
  if (blockAlignment != expectedBlockAlignment) {
    throw new ParserException("Expected block alignment: " + expectedBlockAlignment + "; got: "
        + blockAlignment);
  }

  @C.PcmEncoding int encoding = Util.getPcmEncoding(bitsPerSample);
  if (encoding == C.ENCODING_INVALID) {
    Log.e(TAG, "Unsupported WAV bit depth: " + bitsPerSample);
    return null;
  }

  if (type != TYPE_PCM && type != TYPE_WAVE_FORMAT_EXTENSIBLE) {
    Log.e(TAG, "Unsupported WAV format type: " + type);
    return null;
  }

  // If present, skip extensionSize, validBitsPerSample, channelMask, subFormatGuid, ...
  input.advancePeekPosition((int) chunkHeader.size - 16);

  return new WavHeader(numChannels, sampleRateHz, averageBytesPerSecond, blockAlignment,
      bitsPerSample, encoding);
}