void deserializeFromWritable(DataInput input) throws IOException {
    fileInfoOffset = input.readLong();
    loadOnOpenDataOffset = input.readLong();
    dataIndexCount = input.readInt();
    uncompressedDataIndexSize = input.readLong();
    metaIndexCount = input.readInt();

    totalUncompressedBytes = input.readLong();
    entryCount = input.readLong();
    compressionCodec = Compression.Algorithm.values()[input.readInt()];
    numDataIndexLevels = input.readInt();
    firstDataBlockOffset = input.readLong();
    lastDataBlockOffset = input.readLong();
    // TODO this is a classname encoded into an HFile's trailer. We are going to need to have
    // some compat code here.
    setComparatorClass(
      getComparatorClass(Bytes.readStringFixedSize(input, MAX_COMPARATOR_NAME_LENGTH)));
  }
Deserialize the file trailer as writable data
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/FixedFileTrailer.java