/*
* Link front and rear multiheaded engines to each other
* This is done when loading a savegame
*/
void ConnectMultiheadedTrains()
{
Train *v;
FOR_ALL_TRAINS(v) {
v->other_multiheaded_part = NULL;
}
FOR_ALL_TRAINS(v) {
if (v->IsFrontEngine() || v->IsFreeWagon()) {
/* Two ways to associate multiheaded parts to each other:
* sequential-matching: Trains shall be arranged to look like <..>..<..>..<..>..
* bracket-matching: Free vehicle chains shall be arranged to look like ..<..<..>..<..>..>..
*
* Note: Old savegames might contain chains which do not comply with these rules, e.g.
* - the front and read parts have invalid orders
* - different engine types might be combined
* - there might be different amounts of front and rear parts.
*
* Note: The multiheaded parts need to be matched exactly like they are matched on the server, else desyncs will occur.
* This is why two matching strategies are needed.
*/
bool sequential_matching = v->IsFrontEngine();
for (Train *u = v; u != NULL; u = u->GetNextVehicle()) {
if (u->other_multiheaded_part != NULL) continue; // we already linked this one
if (u->IsMultiheaded()) {
if (!u->IsEngine()) {
/* we got a rear car without a front car. We will convert it to a front one */
u->SetEngine();
u->spritenum--;
}
/* Find a matching back part */
EngineID eid = u->engine_type;
Train *w;
if (sequential_matching) {
for (w = u->GetNextVehicle(); w != NULL; w = w->GetNextVehicle()) {
if (w->engine_type != eid || w->other_multiheaded_part != NULL || !w->IsMultiheaded()) continue;
/* we found a car to partner with this engine. Now we will make sure it face the right way */
if (w->IsEngine()) {
w->ClearEngine();
w->spritenum++;
}
break;
}
} else {
uint stack_pos = 0;
for (w = u->GetNextVehicle(); w != NULL; w = w->GetNextVehicle()) {
if (w->engine_type != eid || w->other_multiheaded_part != NULL || !w->IsMultiheaded()) continue;
if (w->IsEngine()) {
stack_pos++;
} else {
if (stack_pos == 0) break;
stack_pos--;
}
}
}
if (w != NULL) {
w->other_multiheaded_part = u;
u->other_multiheaded_part = w;
} else {
/* we got a front car and no rear cars. We will fake this one for forget that it should have been multiheaded */
u->ClearMultiheaded();
}
}
}
}
}
}
/**
* Autoreplaces a vehicle
* Trains are replaced as a whole chain, free wagons in depot are replaced on their own
* @param tile not used
* @param flags type of operation
* @param p1 Index of vehicle
* @param p2 not used
* @param text unused
* @return the cost of this operation or an error
*/
CommandCost CmdAutoreplaceVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
{
Vehicle *v = Vehicle::GetIfValid(p1);
if (v == NULL) return CMD_ERROR;
CommandCost ret = CheckOwnership(v->owner);
if (ret.Failed()) return ret;
if (!v->IsInDepot()) return CMD_ERROR;
if (v->vehstatus & VS_CRASHED) return CMD_ERROR;
bool free_wagon = false;
if (v->type == VEH_TRAIN) {
Train *t = Train::From(v);
if (t->IsArticulatedPart() || t->IsRearDualheaded()) return CMD_ERROR;
free_wagon = !t->IsFrontEngine();
if (free_wagon && t->First()->IsFrontEngine()) return CMD_ERROR;
} else {
if (!v->IsPrimaryVehicle()) return CMD_ERROR;
}
const Company *c = Company::Get(_current_company);
bool wagon_removal = c->settings.renew_keep_length;
/* Test whether any replacement is set, before issuing a whole lot of commands that would end in nothing changed */
Vehicle *w = v;
bool any_replacements = false;
while (w != NULL) {
EngineID e;
CommandCost cost = GetNewEngineType(w, c, e);
if (cost.Failed()) return cost;
any_replacements |= (e != INVALID_ENGINE);
w = (!free_wagon && w->type == VEH_TRAIN ? Train::From(w)->GetNextUnit() : NULL);
}
CommandCost cost = CommandCost(EXPENSES_NEW_VEHICLES, 0);
bool nothing_to_do = true;
if (any_replacements) {
bool was_stopped = free_wagon || ((v->vehstatus & VS_STOPPED) != 0);
/* Stop the vehicle */
if (!was_stopped) cost.AddCost(CmdStartStopVehicle(v, true));
if (cost.Failed()) return cost;
assert(v->IsStoppedInDepot());
/* We have to construct the new vehicle chain to test whether it is valid.
* Vehicle construction needs random bits, so we have to save the random seeds
* to prevent desyncs and to replay newgrf callbacks during DC_EXEC */
SavedRandomSeeds saved_seeds;
SaveRandomSeeds(&saved_seeds);
if (free_wagon) {
cost.AddCost(ReplaceFreeUnit(&v, flags & ~DC_EXEC, ¬hing_to_do));
} else {
cost.AddCost(ReplaceChain(&v, flags & ~DC_EXEC, wagon_removal, ¬hing_to_do));
}
RestoreRandomSeeds(saved_seeds);
if (cost.Succeeded() && (flags & DC_EXEC) != 0) {
CommandCost ret;
if (free_wagon) {
ret = ReplaceFreeUnit(&v, flags, ¬hing_to_do);
} else {
ret = ReplaceChain(&v, flags, wagon_removal, ¬hing_to_do);
}
assert(ret.Succeeded() && ret.GetCost() == cost.GetCost());
}
/* Restart the vehicle */
if (!was_stopped) cost.AddCost(CmdStartStopVehicle(v, false));
}
if (cost.Succeeded() && nothing_to_do) cost = CommandCost(STR_ERROR_AUTOREPLACE_NOTHING_TO_DO);
return cost;
}