Method AllocArrayData

cpp/src/gandiva/projector.cc:188–230

TODO : handle complex vectors (list/map/..)

// TODO : handle complex vectors (list/map/..)
Status Projector::AllocArrayData(const DataTypePtr& type, int64_t num_records,
                                 arrow::MemoryPool* pool,
                                 ArrayDataPtr* array_data) const {
  arrow::Status astatus;
  std::vector<std::shared_ptr<arrow::Buffer>> buffers;

  // The output vector always has a null bitmap.
  int64_t size = arrow::bit_util::BytesForBits(num_records);
  ARROW_ASSIGN_OR_RAISE(auto bitmap_buffer, arrow::AllocateBuffer(size, pool));
  buffers.push_back(std::move(bitmap_buffer));

  // String/Binary vectors have an offsets array.
  auto type_id = type->id();
  if (arrow::is_binary_like(type_id)) {
    auto offsets_len = arrow::bit_util::BytesForBits((num_records + 1) * 32);

    ARROW_ASSIGN_OR_RAISE(auto offsets_buffer, arrow::AllocateBuffer(offsets_len, pool));
    buffers.push_back(std::move(offsets_buffer));
  }

  // The output vector always has a data array.
  int64_t data_len;
  if (arrow::is_primitive(type_id) || type_id == arrow::Type::DECIMAL) {
    const auto& fw_type = static_cast<const arrow::FixedWidthType&>(*type);
    data_len = arrow::bit_util::BytesForBits(num_records * fw_type.bit_width());
  } else if (arrow::is_binary_like(type_id)) {
    // we don't know the expected size for varlen output vectors.
    data_len = 0;
  } else {
    return Status::Invalid("Unsupported output data type " + type->ToString());
  }
  ARROW_ASSIGN_OR_RAISE(auto data_buffer, arrow::AllocateResizableBuffer(data_len, pool));

  // This is not strictly required but valgrind gets confused and detects this
  // as uninitialized memory access. See arrow::util::SetBitTo().
  if (type->id() == arrow::Type::BOOL) {
    memset(data_buffer->mutable_data(), 0, data_len);
  }
  buffers.push_back(std::move(data_buffer));

  *array_data = arrow::ArrayData::Make(type, num_records, std::move(buffers));
  return Status::OK();
}

Status Projector::ValidateEvaluateArgsCommon(const arrow::RecordBatch& batch) const {
  ARROW_RETURN_IF(!batch.schema()->Equals(*schema_),