Function AddDateIntroducedRailTypes

src/rail.cpp:102–127

* Add the rail types that are to be introduced at the given date. * @param current The currently available railtypes. * @param date The date for the introduction comparisons. * @return The rail types that should be available when date * introduced rail types are taken into account as well. */

 *         introduced rail types are taken into account as well.
 */
RailTypes AddDateIntroducedRailTypes(RailTypes current, TimerGameCalendar::Date date)
{
	RailTypes rts = current;

	for (RailType rt = RAILTYPE_BEGIN; rt != RAILTYPE_END; rt++) {
		const RailTypeInfo *rti = GetRailTypeInfo(rt);
		/* Unused rail type. */
		if (rti->label == 0) continue;

		/* Not date introduced. */
		if (!IsInsideMM(rti->introduction_date, 0, CalendarTime::MAX_DATE.base())) continue;

		/* Not yet introduced at this date. */
		if (rti->introduction_date > date) continue;

		/* Have we introduced all required railtypes? */
		RailTypes required = rti->introduction_required_railtypes;
		if (!rts.All(required)) continue;

		rts.Set(rti->introduces_railtypes);
	}

	/* When we added railtypes we need to run this method again; the added
	 * railtypes might enable more rail types to become introduced. */
	return rts == current ? rts : AddDateIntroducedRailTypes(rts, date);
}

/**
 * Get the rail types the given company can build.