org.apache.hadoop.io.compress.CompressionInputStream#resetState ( )源码实例Demo

/** Read a compressed buffer */
private synchronized void readBuffer(DataInputBuffer buffer, 
                                     CompressionInputStream filter) throws IOException {
  // Read data into a temporary buffer
  DataOutputBuffer dataBuffer = new DataOutputBuffer();

  try {
    int dataBufferLength = WritableUtils.readVInt(in);
    dataBuffer.write(in, dataBufferLength);
  
    // Set up 'buffer' connected to the input-stream
    buffer.reset(dataBuffer.getData(), 0, dataBuffer.getLength());
  } finally {
    dataBuffer.close();
  }

  // Reset the codec
  filter.resetState();
}
 

/** Read a compressed buffer */
private synchronized void readBuffer(DataInputBuffer buffer, 
                                     CompressionInputStream filter) throws IOException {
  // Read data into a temporary buffer
  DataOutputBuffer dataBuffer = new DataOutputBuffer();

  try {
    int dataBufferLength = WritableUtils.readVInt(in);
    dataBuffer.write(in, dataBufferLength);
  
    // Set up 'buffer' connected to the input-stream
    buffer.reset(dataBuffer.getData(), 0, dataBuffer.getLength());
  } finally {
    dataBuffer.close();
  }

  // Reset the codec
  filter.resetState();
}
 

/** Read a compressed buffer */
private synchronized void readBuffer(DataInputBuffer buffer, 
                                     CompressionInputStream filter) throws IOException {
  // Read data into a temporary buffer
  DataOutputBuffer dataBuffer = new DataOutputBuffer();

  try {
    int dataBufferLength = WritableUtils.readVInt(in);
    dataBuffer.write(in, dataBufferLength);
  
    // Set up 'buffer' connected to the input-stream
    buffer.reset(dataBuffer.getData(), 0, dataBuffer.getLength());
  } finally {
    dataBuffer.close();
  }

  // Reset the codec
  filter.resetState();
}
 

/** Read a compressed buffer */
private synchronized void readBuffer(DataInputBuffer buffer, 
                                     CompressionInputStream filter) throws IOException {
  // Read data into a temporary buffer
  DataOutputBuffer dataBuffer = new DataOutputBuffer();

  try {
    int dataBufferLength = WritableUtils.readVInt(in);
    dataBuffer.write(in, dataBufferLength);
  
    // Set up 'buffer' connected to the input-stream
    buffer.reset(dataBuffer.getData(), 0, dataBuffer.getLength());
  } finally {
    dataBuffer.close();
  }

  // Reset the codec
  filter.resetState();
}
 

/** Read a compressed buffer */
private synchronized void readBuffer(DataInputBuffer buffer, 
                                     CompressionInputStream filter) throws IOException {
  // Read data into a temporary buffer
  DataOutputBuffer dataBuffer = new DataOutputBuffer();

  try {
    int dataBufferLength = WritableUtils.readVInt(in);
    dataBuffer.write(in, dataBufferLength);
  
    // Set up 'buffer' connected to the input-stream
    buffer.reset(dataBuffer.getData(), 0, dataBuffer.getLength());
  } finally {
    dataBuffer.close();
  }

  // Reset the codec
  filter.resetState();
}
 

/** Read a compressed buffer */
private synchronized void readBuffer(DataInputBuffer buffer, 
                                     CompressionInputStream filter) throws IOException {
  // Read data into a temporary buffer
  DataOutputBuffer dataBuffer = new DataOutputBuffer();

  try {
    int dataBufferLength = WritableUtils.readVInt(in);
    dataBuffer.write(in, dataBufferLength);
  
    // Set up 'buffer' connected to the input-stream
    buffer.reset(dataBuffer.getData(), 0, dataBuffer.getLength());
  } finally {
    dataBuffer.close();
  }

  // Reset the codec
  filter.resetState();
}
 

@Override
public SplitCompressionInputStream createInputStream(InputStream seekableIn, Decompressor decompressor, long start, long end, READ_MODE readMode) throws IOException {
  if (!(seekableIn instanceof Seekable)) {
    throw new IOException("seekableIn must be an instance of " +
        Seekable.class.getName());
  }
  if (!BlockCompressedInputStream.isValidFile(new BufferedInputStream(seekableIn))) {
    // data is regular gzip, not BGZF
    ((Seekable)seekableIn).seek(0);
    final CompressionInputStream compressionInputStream = createInputStream(seekableIn,
        decompressor);
    return new SplitCompressionInputStream(compressionInputStream, start, end) {
      @Override
      public int read(byte[] b, int off, int len) throws IOException {
        return compressionInputStream.read(b, off, len);
      }
      @Override
      public void resetState() throws IOException {
        compressionInputStream.resetState();
      }
      @Override
      public int read() throws IOException {
        return compressionInputStream.read();
      }
    };
  }
  BGZFSplitGuesser splitGuesser = new BGZFSplitGuesser(seekableIn);
  long adjustedStart = splitGuesser.guessNextBGZFBlockStart(start, end);
  ((Seekable)seekableIn).seek(adjustedStart);
  return new BGZFSplitCompressionInputStream(seekableIn, adjustedStart, end);
}