# HG changeset patch
# User adf88@interia.pl
# Date 1503167716 -7200
#      Sat Aug 19 20:35:16 2017 +0200
# Branch trunk
# Node ID 1549869412e37381c1d259752997479faee6482d
# Parent  584e1cc2ffb25cb095e7ffa701d23530d5d10ea5
When placing an airport, check for flat land and clear tiles that belong to the airport tile table only rather then iterating whole airport rectangle.

diff -r 584e1cc2ffb2 -r 1549869412e3 src/station_cmd.cpp
--- a/src/station_cmd.cpp	Sun Aug 13 18:38:42 2017 +0000
+++ b/src/station_cmd.cpp	Sat Aug 19 20:35:16 2017 +0200
@@ -771,22 +771,22 @@
 }
 
 /**
- * Tries to clear the given area.
- * @param tile_area Area to check.
+ * Checks if an airport can be built at the given location and clear the area.
+ * @param tile_iter Airport tile iterator.
  * @param flags Operation to perform.
  * @return The cost in case of success, or an error code if it failed.
  */
-CommandCost CheckFlatLand(TileArea tile_area, DoCommandFlag flags)
+static CommandCost CheckFlatLandAirport(AirportTileTableIterator tile_iter, DoCommandFlag flags)
 {
 	CommandCost cost(EXPENSES_CONSTRUCTION);
 	int allowed_z = -1;
 
-	TILE_AREA_LOOP(tile_cur, tile_area) {
-		CommandCost ret = CheckBuildableTile(tile_cur, 0, allowed_z, true);
+	for (; tile_iter != INVALID_TILE; ++tile_iter) {
+		CommandCost ret = CheckBuildableTile(tile_iter, 0, allowed_z, true);
 		if (ret.Failed()) return ret;
 		cost.AddCost(ret);
 
-		ret = DoCommand(tile_cur, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+		ret = DoCommand(tile_iter, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 		if (ret.Failed()) return ret;
 		cost.AddCost(ret);
 	}
@@ -2216,11 +2216,11 @@
 		return_cmd_error(STR_ERROR_STATION_TOO_SPREAD_OUT);
 	}
 
-	CommandCost cost = CheckFlatLand(airport_area, flags);
+	AirportTileTableIterator iter(as->table[layout], tile);
+	CommandCost cost = CheckFlatLandAirport(iter, flags);
 	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. */
-	AirportTileTableIterator iter(as->table[layout], tile);
 	Town *nearest = AirportGetNearestTown(as, iter);
 	uint newnoise_level = GetAirportNoiseLevelForTown(as, iter, nearest->xy);