SEXP nanoarrow_c_buffer_info()

in r/src/buffer.c [131:188]

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

SEXP nanoarrow_c_buffer_info(SEXP buffer_xptr) {
  struct ArrowBuffer* buffer = buffer_from_xptr(buffer_xptr);

  SEXP buffer_types_sexp = R_ExternalPtrTag(buffer_xptr);

  SEXP buffer_type_sexp;
  SEXP buffer_data_type_sexp;
  int32_t element_size_bits;

  if (buffer_types_sexp == R_NilValue) {
    buffer_type_sexp = PROTECT(Rf_mkString("unknown"));
    buffer_data_type_sexp = PROTECT(Rf_mkString("unknown"));
    element_size_bits = 0;
  } else {
    enum ArrowBufferType buffer_type = INTEGER(buffer_types_sexp)[0];
    const char* buffer_type_string;
    switch (buffer_type) {
      case NANOARROW_BUFFER_TYPE_VALIDITY:
        buffer_type_string = "validity";
        break;
      case NANOARROW_BUFFER_TYPE_DATA_OFFSET:
        buffer_type_string = "data_offset";
        break;
      case NANOARROW_BUFFER_TYPE_DATA:
        buffer_type_string = "data";
        break;
      case NANOARROW_BUFFER_TYPE_TYPE_ID:
        buffer_type_string = "type_id";
        break;
      case NANOARROW_BUFFER_TYPE_UNION_OFFSET:
        buffer_type_string = "union_offset";
        break;
      default:
        buffer_type_string = "unknown";
        break;
    }

    enum ArrowType buffer_data_type = INTEGER(buffer_types_sexp)[1];
    const char* buffer_data_type_string = ArrowTypeString(buffer_data_type);

    buffer_type_sexp = PROTECT(Rf_mkString(buffer_type_string));
    buffer_data_type_sexp = PROTECT(Rf_mkString(buffer_data_type_string));
    element_size_bits = INTEGER(buffer_types_sexp)[2];
  }

  const char* names[] = {"data", "size_bytes", "capacity_bytes",
                         "type", "data_type",  "element_size_bits",
                         ""};
  SEXP info = PROTECT(Rf_mkNamed(VECSXP, names));
  SET_VECTOR_ELT(info, 0, R_MakeExternalPtr(buffer->data, NULL, buffer_xptr));
  SET_VECTOR_ELT(info, 1, Rf_ScalarReal(buffer->size_bytes));
  SET_VECTOR_ELT(info, 2, Rf_ScalarReal(buffer->capacity_bytes));
  SET_VECTOR_ELT(info, 3, buffer_type_sexp);
  SET_VECTOR_ELT(info, 4, buffer_data_type_sexp);
  SET_VECTOR_ELT(info, 5, Rf_ScalarInteger(element_size_bits));
  UNPROTECT(3);
  return info;
}