Function AddEngineReplacement

src/autoreplace.cpp:96–116

* 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. */

 * @return 0 on success, CMD_ERROR on failure.
 */
CommandCost AddEngineReplacement(EngineRenewList *erl, EngineID old_engine, EngineID new_engine, GroupID group, bool replace_when_old, DoCommandFlags flags)
{
	/* Check if the old vehicle is already in the list */
	EngineRenew *er = GetEngineReplacement(*erl, old_engine, group);
	if (er != nullptr) {
		if (flags.Test(DoCommandFlag::Execute)) {
			er->to = new_engine;
			er->replace_when_old = replace_when_old;
		}
		return CommandCost();
	}

	if (!EngineRenew::CanAllocateItem()) return CMD_ERROR;

	if (flags.Test(DoCommandFlag::Execute)) {
		/* Insert before the first element */
		*erl = new EngineRenew(old_engine, new_engine, group, replace_when_old, *erl);
	}

	return CommandCost();
}

/**
 * Remove an engine replacement from a given renewlist.