diff options
| -rw-r--r-- | station_cmd.c | 36 |
1 files changed, 26 insertions, 10 deletions
diff --git a/station_cmd.c b/station_cmd.c index 61d5d79a8..e7fcb9ca2 100644 --- a/station_cmd.c +++ b/station_cmd.c @@ -1307,15 +1307,31 @@ int32 DoConvertStationRail(TileIndex tile, RailType totype, bool exec) return _price.build_rail >> 1; } -static void FindRoadStationSpot(bool truck_station, Station* st, RoadStop*** currstop, RoadStop** prev) +/** Heavy wizardry used to add a roadstop to a station. + * To understand the function, lets first look at what is passed around, + * especially the last two parameters. CmdBuildRoadStop allocates a road + * stop and needs to put that stop into the linked list of road stops. + * It (CmdBuildRoadStop) has a **currstop pointer which points to element + * in the linked list of stops (each element in this list being a pointer + * in itself, hence the double pointer). We (FindRoadStopSpot) need to + * modify this pointer (**currstop) thus we need to pass by reference, + * obtaining a triple pointer (***currstop). When finished, **currstop + * in CmdBuildRoadStop will contain the address of the pointer which will + * then point into the global roadstop array. *prev (in CmdBuildRoadStop) + * is the pointer tino the global roadstop array which has *currstop in + * its ->next element. + * @param[in] truck_station Determines whether a stop is RS_BUS or RS_TRUCK + * @param[in] station The station to do the whole procedure for + * @param[out] currstop See the detailed function description + * @param prev See the detailed function description + */ +static void FindRoadStopSpot(bool truck_station, Station* st, RoadStop*** currstop, RoadStop** prev) { - RoadStop **primary_stop; - - primary_stop = (truck_station) ? &st->truck_stops : &st->bus_stops; + RoadStop **primary_stop = (truck_station) ? &st->truck_stops : &st->bus_stops; + assert(*prev == NULL); if (*primary_stop == NULL) { - //we have no station of the type yet, so write a "primary station" - //(the one at st->foo_stops) + //we have no roadstop of the type yet, so write a "primary stop" *currstop = primary_stop; } else { //there are stops already, so append to the end of the list @@ -1328,8 +1344,8 @@ static void FindRoadStationSpot(bool truck_station, Station* st, RoadStop*** cur } } -/** Build a bus station - * @param tile tile to build bus station at +/** Build a bus or truck stop + * @param tile tile to build the stop at * @param p1 entrance direction (DiagDirection) * @param p2 0 for Bus stops, 1 for truck stops */ @@ -1382,7 +1398,7 @@ int32 CmdBuildRoadStop(TileIndex tile, uint32 flags, uint32 p1, uint32 p2) if (!CheckStationSpreadOut(st, tile, 1, 1)) return CMD_ERROR; - FindRoadStationSpot(type, st, &currstop, &prev); + FindRoadStopSpot(type, st, &currstop, &prev); } else { Town *t; @@ -1391,7 +1407,7 @@ int32 CmdBuildRoadStop(TileIndex tile, uint32 flags, uint32 p1, uint32 p2) st->town = t = ClosestTownFromTile(tile, (uint)-1); - FindRoadStationSpot(type, st, &currstop, &prev); + FindRoadStopSpot(type, st, &currstop, &prev); if (_current_player < MAX_PLAYERS && flags & DC_EXEC) { SETBIT(t->have_ratings, _current_player); |