--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/road_func.h	Wed Jan 09 18:11:12 2008 +0000
@@ -0,0 +1,116 @@
+/* $Id$ */
+
+/** @file road_func.h Functions related to roads. */
+
+#ifndef ROAD_FUNC_H
+#define ROAD_FUNC_H
+
+#include "core/bitmath_func.hpp"
+#include "road_type.h"
+#include "direction_func.h"
+
+/**
+ * Whether the given roadtype is valid.
+ * @param rt the roadtype to check for validness
+ * @return true if and only if valid
+ */
+static inline bool IsValidRoadType(RoadType rt)
+{
+	return rt == ROADTYPE_ROAD || rt == ROADTYPE_TRAM;
+}
+
+/**
+ * Are the given bits pointing to valid roadtypes?
+ * @param rts the roadtypes to check for validness
+ * @return true if and only if valid
+ */
+static inline bool AreValidRoadTypes(RoadTypes rts)
+{
+	return HasBit(rts, ROADTYPE_ROAD) || HasBit(rts, ROADTYPE_TRAM);
+}
+
+/**
+ * Maps a RoadType to the corresponding RoadTypes value
+ *
+ * @param rt the roadtype to get the roadtypes from
+ * @return the roadtypes with the given roadtype
+ */
+static inline RoadTypes RoadTypeToRoadTypes(RoadType rt)
+{
+	return (RoadTypes)(1 << rt);
+}
+
+/**
+ * Returns the RoadTypes which are not present in the given RoadTypes
+ *
+ * This function returns the complement of a given RoadTypes.
+ *
+ * @param r The given RoadTypes
+ * @return The complement of the given RoadTypes
+ * @note The unused value ROADTYPES_HWAY will be used, too.
+ */
+static inline RoadTypes ComplementRoadTypes(RoadTypes r)
+{
+	return (RoadTypes)(ROADTYPES_ALL ^ r);
+}
+
+
+/**
+ * Calculate the complement of a RoadBits value
+ *
+ * Simply flips all bits in the RoadBits value to get the complement
+ * of the RoadBits.
+ *
+ * @param r The given RoadBits value
+ * @return the complement
+ */
+static inline RoadBits ComplementRoadBits(RoadBits r)
+{
+	return (RoadBits)(ROAD_ALL ^ r);
+}
+
+/**
+ * Calculate the mirrored RoadBits
+ *
+ * Simply move the bits to their new position.
+ *
+ * @param r The given RoadBits value
+ * @return the mirrored
+ */
+static inline RoadBits MirrorRoadBits(RoadBits r)
+{
+	return (RoadBits)(GB(r, 0, 2) << 2 | GB(r, 2, 2));
+}
+
+/**
+ * Calculate rotated RoadBits
+ *
+ * Move the Roadbits clockwise til they are in their final position.
+ *
+ * @param r The given RoadBits value
+ * @param rot The given Rotation angle
+ * @return the rotated
+ */
+static inline RoadBits RotateRoadBits(RoadBits r, DiagDirDiff rot)
+{
+	for (; rot > (DiagDirDiff)0; rot--){
+		r = (RoadBits)(GB(r, 0, 1) << 3 | GB(r, 1, 3));
+	}
+	return r;
+}
+
+/**
+ * Create the road-part which belongs to the given DiagDirection
+ *
+ * This function returns a RoadBits value which belongs to
+ * the given DiagDirection.
+ *
+ * @param d The DiagDirection
+ * @return The result RoadBits which the selected road-part set
+ */
+static inline RoadBits DiagDirToRoadBits(DiagDirection d)
+{
+	return (RoadBits)(ROAD_NW << (3 ^ d));
+}
+
+#endif /* ROAD_FUNC_H */