Function CalcEngineReliability

src/engine.cpp:646–689

* Update #Engine::reliability and (if needed) update the engine GUIs. * @param e %Engine to update. */

 * @param e %Engine to update.
 */
void CalcEngineReliability(Engine *e, bool new_month)
{
	/* Get source engine for reliability age. This is normally our engine unless variant reliability syncing is requested. */
	Engine *re = e;
	while (re->info.variant_id != EngineID::Invalid() && re->info.extra_flags.Test(ExtraEngineFlag::SyncReliability)) {
		re = Engine::Get(re->info.variant_id);
	}

	uint32_t age = re->age;
	if (new_month && re->index > e->index && age != INT32_MAX) age++; /* parent variant's age has not yet updated. */

	/* Check for early retirement */
	if (e->company_avail.Any() && !_settings_game.vehicle.never_expire_vehicles && e->info.base_life != 0xFF) {
		int retire_early = e->info.retire_early;
		uint retire_early_max_age = std::max(0, e->duration_phase_1 + e->duration_phase_2 - retire_early * 12);
		if (retire_early != 0 && age >= retire_early_max_age) {
			/* Early retirement is enabled and we're past the date... */
			e->company_avail = CompanyMask{};
			ClearLastVariant(e->index, e->type);
			AddRemoveEngineFromAutoreplaceAndBuildWindows(e->type);
		}
	}

	if (age < e->duration_phase_1) {
		uint start = e->reliability_start;
		e->reliability = age * (e->reliability_max - start) / e->duration_phase_1 + start;
	} else if ((age -= e->duration_phase_1) < e->duration_phase_2 || _settings_game.vehicle.never_expire_vehicles || e->info.base_life == 0xFF) {
		/* We are at the peak of this engines life. It will have max reliability.
		 * This is also true if the engines never expire. They will not go bad over time */
		e->reliability = e->reliability_max;
	} else if ((age -= e->duration_phase_2) < e->duration_phase_3) {
		uint max = e->reliability_max;
		e->reliability = (int)age * (int)(e->reliability_final - max) / e->duration_phase_3 + max;
	} else {
		/* time's up for this engine.
		 * We will now completely retire this design */
		e->company_avail = CompanyMask{};
		e->reliability = e->reliability_final;
		/* Kick this engine out of the lists */
		ClearLastVariant(e->index, e->type);
		AddRemoveEngineFromAutoreplaceAndBuildWindows(e->type);
	}

}

/** Compute the value for #_year_engine_aging_stops. */
void SetYearEngineAgingStops()