Removed an unused function.

    fprintf(mapping_output_file_, "%s", line.data());

  }

  inline std::string Seed2Sequence(uint64_t seed, uint32_t seed_length) const {

    std::string sequence;

    sequence.reserve(seed_length);

    uint64_t mask = 3;

    for (uint32_t i = 0; i < seed_length; ++i) {

      sequence.push_back(SequenceBatch::Uint8ToChar(

          (seed >> ((seed_length - 1 - i) * 2)) & mask));

    }

    return sequence;

  }

  const std::string mapping_output_file_path_;

  // TODO(Haowen): use this variable to decide output in BED or TagAlign. It

  // should be removed later.