(svn r23461) -Fix: handle a missing airport newgrf as graceful as possible by not crashing when loading such savegame or when an airport is removed

1 files changed, 30 insertions, 32 deletions

diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
index 49711f2e6..27b0c0934 100644
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -2019,24 +2019,17 @@ CommandCost CmdRemoveRoadStop(TileIndex tile, DoCommandFlag flags, uint32 p1, ui
 
 /**
  * Computes the minimal distance from town's xy to any airport's tile.
- * @param as airport's description
+ * @param it An iterator over all airport tiles.
  * @param town_tile town's tile (t->xy)
- * @param airport_tile st->airport.tile
  * @return minimal manhattan distance from town_tile to any airport's tile
  */
-static uint GetMinimalAirportDistanceToTile(const AirportSpec *as, byte layout, TileIndex town_tile, TileIndex airport_tile)
+static uint GetMinimalAirportDistanceToTile(TileIterator &it, TileIndex town_tile)
 {
 	uint mindist = UINT_MAX;
 
-	const AirportTileTable *it = as->table[layout];
-	do {
-		TileIndex cur_tile = airport_tile + ToTileIndexDiff(it->ti);
-
-		uint dist = DistanceManhattan(town_tile, cur_tile);
-		if (dist < mindist) {
-			mindist = dist;
-		}
-	} while ((++it)->ti.x != -0x80);
+	for (TileIndex cur_tile = it; cur_tile != INVALID_TILE; cur_tile = ++it) {
+		mindist = min(mindist, DistanceManhattan(town_tile, cur_tile));
+	}
 
 	return mindist;
 }
@@ -2046,18 +2039,17 @@ static uint GetMinimalAirportDistanceToTile(const AirportSpec *as, byte layout,
  * The further you get, the less noise you generate.
  * So all those folks at city council can now happily slee...  work in their offices
  * @param as airport information
+ * @param it An iterator over all airport tiles.
  * @param town_tile TileIndex of town's center, the one who will receive the airport's candidature
- * @param tile TileIndex of northern tile of an airport (present or to-be-built), NOT the station tile
  * @return the noise that will be generated, according to distance
  */
-uint8 GetAirportNoiseLevelForTown(const AirportSpec *as, byte layout, TileIndex town_tile, TileIndex tile)
+uint8 GetAirportNoiseLevelForTown(const AirportSpec *as, TileIterator &it, TileIndex town_tile)
 {
 	/* 0 cannot be accounted, and 1 is the lowest that can be reduced from town.
 	 * So no need to go any further*/
 	if (as->noise_level < 2) return as->noise_level;
 
-	assert(layout < as->num_table);
-	uint distance = GetMinimalAirportDistanceToTile(as, layout, town_tile, tile);
+	uint distance = GetMinimalAirportDistanceToTile(it, town_tile);
 
 	/* The steps for measuring noise reduction are based on the "magical" (and arbitrary) 8 base distance
 	 * adding the town_council_tolerance 4 times, as a way to graduate, depending of the tolerance.
@@ -2078,19 +2070,19 @@ uint8 GetAirportNoiseLevelForTown(const AirportSpec *as, byte layout, TileIndex
  * Finds the town nearest to given airport. Based on minimal manhattan distance to any airport's tile.
  * If two towns have the same distance, town with lower index is returned.
  * @param as airport's description
- * @param airport_tile st->airport.tile
+ * @param it An iterator over all airport tiles
  * @return nearest town to airport
  */
-Town *AirportGetNearestTown(const AirportSpec *as, byte layout, TileIndex airport_tile)
+Town *AirportGetNearestTown(const AirportSpec *as, const TileIterator &it)
 {
-	assert(layout < as->num_table);
-
 	Town *t, *nearest = NULL;
 	uint add = as->size_x + as->size_y - 2; // GetMinimalAirportDistanceToTile can differ from DistanceManhattan by this much
 	uint mindist = UINT_MAX - add; // prevent overflow
 	FOR_ALL_TOWNS(t) {
-		if (DistanceManhattan(t->xy, airport_tile) < mindist + add) { // avoid calling GetMinimalAirportDistanceToTile too often
-			uint dist = GetMinimalAirportDistanceToTile(as, layout, t->xy, airport_tile);
+		if (DistanceManhattan(t->xy, it) < mindist + add) { // avoid calling GetMinimalAirportDistanceToTile too often
+			TileIterator *copy = it.Clone();
+			uint dist = GetMinimalAirportDistanceToTile(*copy, t->xy);
+			delete copy;
 			if (dist < mindist) {
 				nearest = t;
 				mindist = dist;
@@ -2113,8 +2105,9 @@ void UpdateAirportsNoise()
 	FOR_ALL_STATIONS(st) {
 		if (st->airport.tile != INVALID_TILE && st->airport.type != AT_OILRIG) {
 			const AirportSpec *as = st->airport.GetSpec();
-			Town *nearest = AirportGetNearestTown(as, st->airport.layout, st->airport.tile);
-			nearest->noise_reached += GetAirportNoiseLevelForTown(as, st->airport.layout, nearest->xy, st->airport.tile);
+			AirportTileIterator it(st);
+			Town *nearest = AirportGetNearestTown(as, it);
+			nearest->noise_reached += GetAirportNoiseLevelForTown(as, it, nearest->xy);
 		}
 	}
 }
@@ -2166,8 +2159,9 @@ CommandCost CmdBuildAirport(TileIndex tile, DoCommandFlag flags, uint32 p1, uint
 	if (cost.Failed()) return cost;
 
 	/* The noise level is the noise from the airport and reduce it to account for the distance to the town center. */
-	Town *nearest = AirportGetNearestTown(as, layout, tile);
-	uint newnoise_level = GetAirportNoiseLevelForTown(as, layout, nearest->xy, tile);
+	AirportTileTableIterator iter(as->table[layout], tile);
+	Town *nearest = AirportGetNearestTown(as, iter);
+	uint newnoise_level = GetAirportNoiseLevelForTown(as, iter, nearest->xy);
 
 	/* Check if local auth would allow a new airport */
 	StringID authority_refuse_message = STR_NULL;
@@ -2309,6 +2303,16 @@ static CommandCost RemoveAirport(TileIndex tile, DoCommandFlag flags)
 		if (a->targetairport == st->index && a->state != FLYING) return CMD_ERROR;
 	}
 
+	if (flags & DC_EXEC) {
+		const AirportSpec *as = st->airport.GetSpec();
+		/* The noise level is the noise from the airport and reduce it to account for the distance to the town center.
+		 * And as for construction, always remove it, even if the setting is not set, in order to avoid the
+		 * need of recalculation */
+		AirportTileIterator it(st);
+		Town *nearest = AirportGetNearestTown(as, it);
+		nearest->noise_reached -= GetAirportNoiseLevelForTown(as, it, nearest->xy);
+	}
+
 	TILE_AREA_LOOP(tile_cur, st->airport) {
 		if (!st->TileBelongsToAirport(tile_cur)) continue;
 
@@ -2336,12 +2340,6 @@ static CommandCost RemoveAirport(TileIndex tile, DoCommandFlag flags)
 			);
 		}
 
-		/* The noise level is the noise from the airport and reduce it to account for the distance to the town center.
-		 * And as for construction, always remove it, even if the setting is not set, in order to avoid the
-		 * need of recalculation */
-		Town *nearest = AirportGetNearestTown(as, st->airport.layout, tile);
-		nearest->noise_reached -= GetAirportNoiseLevelForTown(as, st->airport.layout, nearest->xy, tile);
-
 		st->rect.AfterRemoveRect(st, st->airport);
 
 		st->airport.Clear();