LobFile.java 文件源码

public void readFields(DataInput in) throws IOException {
  // After the RecordStartMark, we expect to get a SEGMENT_HEADER_ID (-1).
  long segmentId = WritableUtils.readVLong(in);
  if (SEGMENT_HEADER_ID != segmentId) {
    throw new IOException("Expected segment header id " + SEGMENT_HEADER_ID
        + "; got " + segmentId);
  }

  // Get the length of the rest of the segment, in bytes.
  long length = WritableUtils.readVLong(in);

  // Now read the actual main byte array.
  if (length > Integer.MAX_VALUE) {
    throw new IOException("Unexpected oversize data array length: "
        + length);
  } else if (length < 0) {
    throw new IOException("Unexpected undersize data array length: "
        + length);
  }
  byte [] segmentData = new byte[(int) length];
  in.readFully(segmentData);
  recordLenBytes = new BytesWritable(segmentData);

  reset(); // Reset the iterator allowing the user to yield offset/lengths.
}