(svn r9425) -Codechange/Fix (FS#689): Housekeeping in the convert rail functions: Changed the order of error checks to generate more meaningful error messages, added some doxygen comments and replaced bitshifting by proper mathematical operations

1 files changed, 12 insertions, 2 deletions

diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index aa2279d7d..e386da262 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -696,6 +696,16 @@ static int32 ClearTile_TunnelBridge(TileIndex tile, byte flags)
 	return CMD_ERROR;
 }
 
+/**
+ * Switches the rail type for a tunnel or a bridgehead. As the railtype
+ * on the bridge are determined by the one of the bridgehead, this
+ * functions converts the railtype on the entire bridge.
+ * @param tile        The tile on which the railtype is to be convert.
+ * @param totype      The railtype we want to convert to
+ * @param exec        Switches between test and execute mode
+ * @return            The cost and state of the operation
+ * @retval CMD_ERROR  An error occured during the operation.
+ */
 int32 DoConvertTunnelBridgeRail(TileIndex tile, RailType totype, bool exec)
 {
 	TileIndex endtile;
@@ -724,7 +734,7 @@ int32 DoConvertTunnelBridgeRail(TileIndex tile, RailType totype, bool exec)
 			YapfNotifyTrackLayoutChange(tile, track);
 			YapfNotifyTrackLayoutChange(endtile, track);
 		}
-		return (length + 1) * (_price.build_rail >> 1);
+		return (length + 1) * (_price.build_rail / 2);
 	} else if (IsBridge(tile) && GetBridgeTransportType(tile) == TRANSPORT_RAIL) {
 
 		if (!CheckTileOwnership(tile)) return CMD_ERROR;
@@ -758,7 +768,7 @@ int32 DoConvertTunnelBridgeRail(TileIndex tile, RailType totype, bool exec)
 			}
 		}
 
-		return (DistanceManhattan(tile, endtile) + 1) * (_price.build_rail >> 1);
+		return (DistanceManhattan(tile, endtile) + 1) * (_price.build_rail / 2);
 	} else {
 		return CMD_ERROR;
 	}