Method Allocate

r/src/array_to_vector.cpp:756–777

  }

  SEXP Allocate(R_xlen_t n) const {
    // allocate a data frame column to host each array
    // If possible, a column is dealt with directly with altrep
    auto type =
        checked_cast<const arrow::StructType*>(this->chunked_array_->type().get());
    auto out =
        arrow::r::to_r_list(converters, [n](const std::shared_ptr<Converter>& converter) {
          SEXP out = converter->MaybeAltrep();
          if (Rf_isNull(out)) {
            out = converter->Allocate(n);
          }
          return out;
        });
    auto colnames = arrow::r::to_r_strings(
        type->fields(),
        [](const std::shared_ptr<Field>& field) { return field->name(); });
    out.attr(symbols::row_names) = arrow::r::short_row_names(static_cast<int>(n));
    out.attr(R_NamesSymbol) = colnames;
    out.attr(R_ClassSymbol) = arrow::r::data::classes_tbl_df;

    return out;
  }

  Status Ingest_all_nulls(SEXP data, R_xlen_t start, R_xlen_t n) const {
    int nf = static_cast<int>(converters.size());