Function ReferenceToInt

src/saveload/saveload.cpp:1226–1246

* Pointers cannot be saved to a savegame, so this functions gets * the index of the item, and if not available, it hussles with * pointers (looks really bad :() * Remember that a nullptr item has value 0, and all * indices have +1, so vehicle 0 is saved as index 1. * @param obj The object that we want to get the index of * @param rt SLRefType type of the object the index is being sought of

 * @return Return the pointer converted to an index of the type pointed to
 */
static size_t ReferenceToInt(const void *obj, SLRefType rt)
{
	assert(_sl.action == SLA_SAVE);

	if (obj == nullptr) return 0;

	switch (rt) {
		case REF_VEHICLE_OLD: // Old vehicles we save as new ones
		case REF_VEHICLE:   return ((const  Vehicle*)obj)->index + 1;
		case REF_STATION:   return ((const  Station*)obj)->index + 1;
		case REF_TOWN:      return ((const     Town*)obj)->index + 1;
		case REF_ROADSTOPS: return ((const RoadStop*)obj)->index + 1;
		case REF_ENGINE_RENEWS:  return ((const       EngineRenew*)obj)->index + 1;
		case REF_CARGO_PACKET:   return ((const       CargoPacket*)obj)->index + 1;
		case REF_ORDERLIST:      return ((const         OrderList*)obj)->index + 1;
		case REF_STORAGE:        return ((const PersistentStorage*)obj)->index + 1;
		case REF_LINK_GRAPH:     return ((const         LinkGraph*)obj)->index + 1;
		case REF_LINK_GRAPH_JOB: return ((const      LinkGraphJob*)obj)->index + 1;
		default: NOT_REACHED();
	}
}

/**
 * Pointers cannot be loaded from a savegame, so this function