Function GetRailTypeTranslation

src/newgrf_railtype.cpp:151–165

* Translate an index to the GRF-local railtype-translation table into a RailType. * @param railtype Index into GRF-local translation table. * @param grffile Originating GRF file. * @return RailType or INVALID_RAILTYPE if the railtype is unknown. */

 * @return RailType or INVALID_RAILTYPE if the railtype is unknown.
 */
RailType GetRailTypeTranslation(uint8_t railtype, const GRFFile *grffile)
{
	if (grffile == nullptr || grffile->railtype_list.empty()) {
		/* No railtype table present. Return railtype as-is (if valid), so it works for original railtypes. */
		if (railtype >= RAILTYPE_END || GetRailTypeInfo(static_cast<RailType>(railtype))->label == 0) return INVALID_RAILTYPE;

		return static_cast<RailType>(railtype);
	} else {
		/* Railtype table present, but invalid index, return invalid type. */
		if (railtype >= grffile->railtype_list.size()) return INVALID_RAILTYPE;

		/* Look up railtype including alternate labels. */
		return GetRailTypeByLabel(grffile->railtype_list[railtype]);
	}
}

/**
 * Perform a reverse railtype lookup to get the GRF internal ID.