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/* $Id$ */

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/** @file road_func.h Functions related to roads. */

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#ifndef ROAD_FUNC_H

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#define ROAD_FUNC_H

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#include "core/bitmath_func.hpp"

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#include "road_type.h"

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#include "direction_func.h"

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/**

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 * Whether the given roadtype is valid.

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 * @param rt the roadtype to check for validness

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 * @return true if and only if valid

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 */

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static inline bool IsValidRoadType(RoadType rt)

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{

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	return rt == ROADTYPE_ROAD || rt == ROADTYPE_TRAM;

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}

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/**

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 * Are the given bits pointing to valid roadtypes?

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 * @param rts the roadtypes to check for validness

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 * @return true if and only if valid

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 */

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static inline bool AreValidRoadTypes(RoadTypes rts)

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{

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	return HasBit(rts, ROADTYPE_ROAD) || HasBit(rts, ROADTYPE_TRAM);

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}

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/**

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 * Maps a RoadType to the corresponding RoadTypes value

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 *

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 * @param rt the roadtype to get the roadtypes from

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 * @return the roadtypes with the given roadtype

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 */

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static inline RoadTypes RoadTypeToRoadTypes(RoadType rt)

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{

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	return (RoadTypes)(1 << rt);

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}

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/**

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 * Returns the RoadTypes which are not present in the given RoadTypes

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 *

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 * This function returns the complement of a given RoadTypes.

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 *

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 * @param r The given RoadTypes

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 * @return The complement of the given RoadTypes

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 * @note The unused value ROADTYPES_HWAY will be used, too.

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 */

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static inline RoadTypes ComplementRoadTypes(RoadTypes r)

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{

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	return (RoadTypes)(ROADTYPES_ALL ^ r);

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}

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/**

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 * Calculate the complement of a RoadBits value

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 *

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 * Simply flips all bits in the RoadBits value to get the complement

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 * of the RoadBits.

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 *

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 * @param r The given RoadBits value

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 * @return the complement

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 */

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static inline RoadBits ComplementRoadBits(RoadBits r)

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{

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	return (RoadBits)(ROAD_ALL ^ r);

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}

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/**

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 * Calculate the mirrored RoadBits

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 *

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 * Simply move the bits to their new position.

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 *

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 * @param r The given RoadBits value

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 * @return the mirrored

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 */

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static inline RoadBits MirrorRoadBits(RoadBits r)

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{

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	return (RoadBits)(GB(r, 0, 2) << 2 | GB(r, 2, 2));

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}

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/**

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 * Calculate rotated RoadBits

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 *

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 * Move the Roadbits clockwise til they are in their final position.

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 *

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 * @param r The given RoadBits value

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 * @param rot The given Rotation angle

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 * @return the rotated

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 */

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static inline RoadBits RotateRoadBits(RoadBits r, DiagDirDiff rot)

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{

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	for (; rot > (DiagDirDiff)0; rot--){

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		r = (RoadBits)(GB(r, 0, 1) << 3 | GB(r, 1, 3));

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	}

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	return r;

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}

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/**

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 * Create the road-part which belongs to the given DiagDirection

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 *

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 * This function returns a RoadBits value which belongs to

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 * the given DiagDirection.

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 *

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 * @param d The DiagDirection

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 * @return The result RoadBits which the selected road-part set

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 */

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static inline RoadBits DiagDirToRoadBits(DiagDirection d)

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{

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	return (RoadBits)(ROAD_NW << (3 ^ d));

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}

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#endif /* ROAD_FUNC_H */