--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/road.h	Wed Jan 03 08:49:36 2007 +0000
@@ -0,0 +1,26 @@
+/* $Id$ */
+
+#ifndef ROAD_H
+#define ROAD_H
+
+typedef enum RoadBits {
+	ROAD_NW  = 1U,
+	ROAD_SW  = 2U,
+	ROAD_SE  = 4U,
+	ROAD_NE  = 8U,
+	ROAD_X   = ROAD_SW | ROAD_NE,
+	ROAD_Y   = ROAD_NW | ROAD_SE,
+	ROAD_ALL = ROAD_X  | ROAD_Y
+} RoadBits;
+
+static inline RoadBits ComplementRoadBits(RoadBits r)
+{
+	return (RoadBits)(ROAD_ALL ^ r);
+}
+
+static inline RoadBits DiagDirToRoadBits(DiagDirection d)
+{
+	return (RoadBits)(1U << (3 ^ d));
+}
+
+#endif /* ROAD_H */