Method index_into_array

cpp/src/arrow/util/ree_util.h:509–511

  /// pointing to the value of the current run
  template <size_t input_id>
  int64_t index_into_array() const {
    return std::get<input_id>(ree_iterators_).index_into_array();
  }

  int64_t index_into_left_array() const { return index_into_array<0>(); }
  int64_t index_into_right_array() const { return index_into_array<1>(); }