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/* $Id$ */

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/** @file cmd_helper.h Helper functions to extract data from command parameters. */

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#ifndef CMD_HELPER_H

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#define CMD_HELPER_H

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#include "direction_type.h"

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#include "road_type.h"

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template<uint N> static inline void ExtractValid();

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template<> inline void ExtractValid<1>() {}

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template<typename T> struct ExtractBits;

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template<> struct ExtractBits<Axis>          { static const uint Count =  1; };

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template<> struct ExtractBits<DiagDirection> { static const uint Count =  2; };

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template<> struct ExtractBits<RoadBits>      { static const uint Count =  4; };

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template<typename T, uint N, typename U> static inline T Extract(U v)

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{

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	// Check if there are enough bits in v

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	ExtractValid<N + ExtractBits<T>::Count <= sizeof(U) * 8>();

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	return (T)GB(v, N, ExtractBits<T>::Count);

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}

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#endif