public static HyperLogLog deserializeHLL(final byte[] buf, final int start, final int len) {
    InputStream is = new ByteArrayInputStream(buf, start, len); // TODO: use faster non-sync inputstream
    try {
      HyperLogLog result = deserializeHLL(is);
      is.close();
      return result;
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }
This function deserializes the serialized hyperloglogs from a byte array.
@param buf
@param start
@param len
@return
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/common/ndv/hll/HyperLogLogUtils.java