SEXP nanoarrow_converter_from_type()

in r/src/convert.c [50:101]

• 46 lines of code
• 7 McCabe index (conditional complexity)

SEXP nanoarrow_converter_from_type(enum VectorType vector_type) {
  struct RConverter* converter =
      (struct RConverter*)ArrowMalloc(sizeof(struct RConverter));
  if (converter == NULL) {
    Rf_error("Failed to allocate RConverter");
  }

  // 0: ptype, 1: schema_xptr, 2: array_xptr, 3: children, 4: result
  SEXP converter_shelter = PROTECT(Rf_allocVector(VECSXP, 5));
  SEXP converter_xptr =
      PROTECT(R_MakeExternalPtr(converter, R_NilValue, converter_shelter));
  R_RegisterCFinalizer(converter_xptr, &finalize_converter);

  ArrowArrayViewInitFromType(&converter->array_view, NANOARROW_TYPE_UNINITIALIZED);
  converter->schema_view.type = NANOARROW_TYPE_UNINITIALIZED;
  converter->schema_view.storage_type = NANOARROW_TYPE_UNINITIALIZED;
  converter->src.array_view = &converter->array_view;
  converter->dst.vec_sexp = R_NilValue;
  converter->options = NULL;
  converter->error.message[0] = '\0';
  converter->size = 0;
  converter->capacity = 0;
  converter->n_children = 0;
  converter->children = NULL;

  converter->ptype_view.vector_type = vector_type;
  converter->ptype_view.ptype = R_NilValue;

  switch (vector_type) {
    case VECTOR_TYPE_NULL:
      converter->ptype_view.sexp_type = NILSXP;
      break;
    case VECTOR_TYPE_LGL:
      converter->ptype_view.sexp_type = LGLSXP;
      break;
    case VECTOR_TYPE_INT:
      converter->ptype_view.sexp_type = INTSXP;
      break;
    case VECTOR_TYPE_DBL:
      converter->ptype_view.sexp_type = REALSXP;
      break;
    case VECTOR_TYPE_CHR:
      converter->ptype_view.sexp_type = STRSXP;
      break;
    default:
      UNPROTECT(2);
      return R_NilValue;
  }

  UNPROTECT(2);
  return converter_xptr;
}