Method getFieldByIndex

matlab/src/cpp/arrow/matlab/tabular/proxy/schema.cc:61–89

std::shared_ptr<arrow::Schema> Schema::unwrap() { return schema; }

void Schema::getFieldByIndex(libmexclass::proxy::method::Context& context) {
  namespace mda = ::matlab::data;
  using namespace libmexclass::proxy;
  using FieldProxy = arrow::matlab::type::proxy::Field;
  mda::ArrayFactory factory;

  mda::StructArray args = context.inputs[0];
  const mda::TypedArray<int32_t> index_mda = args[0]["Index"];
  const auto matlab_index = int32_t(index_mda[0]);

  // Validate there is at least 1 field
  MATLAB_ERROR_IF_NOT_OK_WITH_CONTEXT(
      index::validateNonEmptyContainer(schema->num_fields()), context,
      error::INDEX_EMPTY_CONTAINER);

  // Validate the matlab index provided is within the range [1, num_fields]
  MATLAB_ERROR_IF_NOT_OK_WITH_CONTEXT(
      index::validateInRange(matlab_index, schema->num_fields()), context,
      error::INDEX_OUT_OF_RANGE);

  // Note: MATLAB uses 1-based indexing, so subtract 1.
  // arrow::Schema::field does not do any bounds checking.
  const int32_t index = matlab_index - 1;

  auto field = schema->field(index);
  auto field_proxy = std::make_shared<FieldProxy>(std::move(field));
  auto field_proxy_id = ProxyManager::manageProxy(field_proxy);
  context.outputs[0] = factory.createScalar(field_proxy_id);
}

void Schema::getFieldByName(libmexclass::proxy::method::Context& context) {
  namespace mda = ::matlab::data;