Function ConvertColumnsToTensor

cpp/src/arrow/tensor.cc:306–341

template <typename DataType, typename Container>
inline void ConvertColumnsToTensor(const Container& container, uint8_t* out,
                                   bool row_major) {
  using CType = typename arrow::TypeTraits<DataType>::CType;
  auto* out_values = reinterpret_cast<CType*>(out);

  const int num_columns = container.num_columns();

  for (int col_idx = 0; col_idx < num_columns; ++col_idx) {
    if constexpr (std::is_same_v<Container, Table>) {
      int64_t chunk_idx = 0;

      for (const auto& chunk : container.columns()[col_idx]->chunks()) {
        if (row_major) {
          ConvertArrayToTensorRowMajorVisitor<CType> visitor{
              out_values, *chunk->data(), num_columns, col_idx, chunk_idx};
          DCHECK_OK(VisitTypeInline(*chunk->type(), &visitor));
          chunk_idx += chunk->length();
        } else {
          ConvertArrayToTensorVisitor<CType> visitor{out_values, *chunk->data()};
          DCHECK_OK(VisitTypeInline(*chunk->type(), &visitor));
        }
      }
    } else if constexpr (std::is_same_v<Container, RecordBatch>) {
      const auto& array_data = container.column_data()[col_idx];

      if (row_major) {
        ConvertArrayToTensorRowMajorVisitor<CType> visitor{out_values, *array_data,
                                                           num_columns, col_idx, 0};
        DCHECK_OK(VisitTypeInline(*array_data->type, &visitor));
      } else {
        ConvertArrayToTensorVisitor<CType> visitor{out_values, *array_data};
        DCHECK_OK(VisitTypeInline(*array_data->type, &visitor));
      }
    }
  }
}

template <typename Container>
Status ToTensorImpl(const Container& container, bool null_to_nan, bool row_major,