tron@6460: /* $Id$ */
tron@6460: 
tron@6460: #ifndef CMD_HELPER_H
tron@6460: #define CMD_HELPER_H
tron@6460: 
rubidium@8596: #include "direction_type.h"
rubidium@8598: #include "road_type.h"
tron@6460: 
tron@6460: 
tron@6460: template<uint N> static inline void ExtractValid();
smatz@8624: template<> inline void ExtractValid<1>() {}
tron@6460: 
tron@6460: 
tron@6460: template<typename T> struct ExtractBits;
tron@6460: template<> struct ExtractBits<Axis>          { static const uint Count =  1; };
tron@6460: template<> struct ExtractBits<DiagDirection> { static const uint Count =  2; };
tron@6460: template<> struct ExtractBits<RoadBits>      { static const uint Count =  4; };
tron@6460: 
tron@6460: 
tron@6460: template<typename T, uint N, typename U> static inline T Extract(U v)
tron@6460: {
tron@6460: 	// Check if there are enough bits in v
tron@6460: 	ExtractValid<N + ExtractBits<T>::Count <= sizeof(U) * 8>();
tron@6460: 	return (T)GB(v, N, ExtractBits<T>::Count);
tron@6460: }
tron@6460: 
tron@6460: #endif