Method Merge

cpp/src/arrow/compute/kernels/hash_aggregate.cc:1592–1611

  }

  Status Merge(GroupedAggregator&& raw_other,
               const ArrayData& group_id_mapping) override {
    auto other = checked_cast<GroupedOneImpl*>(&raw_other);

    auto raw_ones = ones_.mutable_data();
    auto other_raw_ones = other->ones_.mutable_data();

    auto g = group_id_mapping.GetValues<uint32_t>(1);
    for (uint32_t other_g = 0; static_cast<int64_t>(other_g) < group_id_mapping.length;
         ++other_g, ++g) {
      if (!bit_util::GetBit(has_one_.data(), *g)) {
        if (bit_util::GetBit(other->has_one_.data(), other_g)) {
          GetSet::Set(raw_ones, *g, GetSet::Get(other_raw_ones, other_g));
          bit_util::SetBit(has_one_.mutable_data(), *g);
        }
      }
    }

    return Status::OK();
  }

  Result<Datum> Finalize() override {
    ARROW_ASSIGN_OR_RAISE(auto null_bitmap, has_one_.Finish());