OpenTTD-patches/src/cmd_helper.h
tron d3b29bcacb (svn r8876) -Fix
Replace tests with magic numbers by a simple extraction template for command parameters
2007-02-24 09:42:39 +00:00

29 lines
733 B
C++

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