cpp/openttd-patchpack/source Files · src/cmd_helper.h

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Location: cpp/openttd-patchpack/source/src/cmd_helper.h

r8154:7eaecf565a0f 716 B text/x-c Show Annotation Show as Raw Download as Raw

glx

(svn r11716) -Fix [FS#1561]: don't put more than one Random() in function calls because parameter evaluation order is not guaranteed in the c++ standard (can lead to desyncs)

/* $Id$ */

#ifndef CMD_HELPER_H
#define CMD_HELPER_H

#include "direction_type.h"
#include "road_type.h"


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