uint MoveGoodsToStation(CargoID type, uint amount, SourceType source_type, SourceID source_id, const StationList *all_stations)
{
/* Return if nothing to do. Also the rounding below fails for 0. */
if (amount == 0) return 0;
Station *st1 = NULL; // Station with best rating
Station *st2 = NULL; // Second best station
Station *st3 = NULL; // Third best station
uint best_rating1 = 0; // rating of st1
uint best_rating2 = 0; // rating of st2
uint best_rating3 = 0; // rating of st3
for (Station * const *st_iter = all_stations->Begin(); st_iter != all_stations->End(); ++st_iter) {
Station *st = *st_iter;
/* Is the station reserved exclusively for somebody else? */
if (st->town->exclusive_counter > 0 && st->town->exclusivity != st->owner) continue;
if (st->goods[type].rating == 0) continue; // Lowest possible rating, better not to give cargo anymore
if (_settings_game.order.selectgoods && !st->goods[type].HasVehicleEverTriedLoading()) continue; // Selectively servicing stations, and not this one
if (IsCargoInClass(type, CC_PASSENGERS)) {
if (st->facilities == FACIL_TRUCK_STOP) continue; // passengers are never served by just a truck stop
} else {
if (st->facilities == FACIL_BUS_STOP) continue; // non-passengers are never served by just a bus stop
}
/* This station can be used, add it to st1/st2/st3 */
if (st1 == NULL || st->goods[type].rating >= best_rating1) {
st3 = st2;
best_rating3 = best_rating2;
st2 = st1;
best_rating2 = best_rating1;
st1 = st;
best_rating1 = st->goods[type].rating;
} else if (st2 == NULL || st->goods[type].rating >= best_rating2) {
st3 = st2;
best_rating3 = best_rating2;
st2 = st;
best_rating2 = st->goods[type].rating;
} else if (st3 == NULL || st->goods[type].rating >= best_rating3) {
st3 = st;
best_rating3 = st->goods[type].rating;
}
}
/* no stations around at all? */
if (st1 == NULL) return 0;
/* From now we'll calculate with fractal cargo amounts.
* First determine how much cargo we really have. */
amount *= best_rating1 + 1;
if (st2 == NULL) {
/* only one station around */
return UpdateStationWaiting(st1, type, amount, source_type, source_id);
}
if (st3 == NULL) {
/* two stations around, the best two (highest rating) are in st1 and st2 */
assert(st1 != NULL);
assert(st2 != NULL);
assert(best_rating1 != 0 || best_rating2 != 0);
/* Then determine the amount the worst station gets. We do it this way as the
* best should get a bonus, which in this case is the rounding difference from
* this calculation. In reality that will mean the bonus will be pretty low.
* Nevertheless, the best station should always get the most cargo regardless
* of rounding issues. */
uint worst_cargo = amount * best_rating2 / (best_rating1 + best_rating2);
assert(worst_cargo <= (amount - worst_cargo));
/* And then send the cargo to the stations! */
uint moved = UpdateStationWaiting(st1, type, amount - worst_cargo, source_type, source_id);
/* These two UpdateStationWaiting's can't be in the statement as then the order
* of execution would be undefined and that could cause desyncs with callbacks. */
return moved + UpdateStationWaiting(st2, type, worst_cargo, source_type, source_id);
}
/* three stations around, the best three (highest rating) are in st1, st2 and st3 */
assert(st1 != NULL);
assert(st2 != NULL);
assert(st3 != NULL);
assert(best_rating1 != 0 || best_rating2 != 0 || best_rating3 !=0);
/* Then determine the amount the worst station gets. We do it this way as the
* best should get a bonus, which in this case is the rounding difference from
* this calculation. In reality that will mean the bonus will be pretty low.
* Nevertheless, the best station should always get the most cargo regardless
* of rounding issues. */
uint worst_cargo_st3 = amount * best_rating3 / (best_rating1 + best_rating2 + best_rating3);
assert(worst_cargo_st3 <= (amount - worst_cargo_st3));
uint remaining_amount = amount - worst_cargo_st3;
uint worst_cargo_st2 = remaining_amount * best_rating2 / (best_rating1 + best_rating2);
assert(worst_cargo_st2 <= (remaining_amount - worst_cargo_st2));
/* And then send the cargo to the stations! */
uint moved = UpdateStationWaiting(st1, type, remaining_amount - worst_cargo_st2, source_type, source_id);
/* HALP - I GOT 3 UpdateStationWaitings now! */
moved += UpdateStationWaiting(st2, type, worst_cargo_st2, source_type, source_id);
return moved + UpdateStationWaiting(st3, type, worst_cargo_st3, source_type, source_id);
}