code: private String makeOneLine(byte[] value, String filename) {
          StringBuilder sb = new StringBuilder();
          for (int i = 0; i < value.length; i++) {
              sb.append(value[i]).append('\t');
          }
          sb.append(filename);
          return sb.toString();
      }
docs: Concatenates the given range value and the file name to one string. It is used to write the hash function file.