/**
* Retrieve the engine replacement in a given renewlist for an original engine type.
* @param erl The renewlist to search in.
* @param engine Engine type to be replaced.
* @param group The group related to this replacement.
* @return The engine type to replace with, or INVALID_ENGINE if no
* replacement is in the list.
*/
EngineID EngineReplacement(EngineRenewList erl, EngineID engine, GroupID group)
{
const EngineRenew *er = GetEngineReplacement(erl, engine, group);
if (er == NULL && (group == DEFAULT_GROUP || (Group::IsValidID(group) && !Group::Get(group)->replace_protection))) {
/* We didn't find anything useful in the vehicle's own group so we will try ALL_GROUP */
er = GetEngineReplacement(erl, engine, ALL_GROUP);
}
return er == NULL ? INVALID_ENGINE : er->to;
}
/**
* Add an engine replacement to the given renewlist.
* @param erl The renewlist to add to.
* @param old_engine The original engine type.
* @param new_engine The replacement engine type.
* @param group The group related to this replacement.
* @param replace_when_old Replace when old or always?
* @param flags The calling command flags.
* @return 0 on success, CMD_ERROR on failure.
*/
CommandCost AddEngineReplacement(EngineRenewList *erl, EngineID old_engine, EngineID new_engine, GroupID group, bool replace_when_old, DoCommandFlag flags)
{
/* Check if the old vehicle is already in the list */
EngineRenew *er = GetEngineReplacement(*erl, old_engine, group);
if (er != NULL) {
if (flags & DC_EXEC) {
er->to = new_engine;
er->replace_when_old = replace_when_old;
}
return CommandCost();
}
if (!EngineRenew::CanAllocateItem()) return CMD_ERROR;
if (flags & DC_EXEC) {
er = new EngineRenew(old_engine, new_engine);
er->group_id = group;
er->replace_when_old = replace_when_old;
/* Insert before the first element */
er->next = (EngineRenew *)(*erl);
*erl = (EngineRenewList)er;
}
return CommandCost();
}
