khanat-code-old/code/nel/include/nel/misc/random.h
2010-05-06 02:08:41 +02:00

108 lines
3 KiB
C++

// NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
// Copyright (C) 2010 Winch Gate Property Limited
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#ifndef NL_RANDOM_H
#define NL_RANDOM_H
#include "types_nl.h"
namespace NLMISC
{
/** A simple, os-independant random generator.
* \author Nicolas Vizerie
* \author Nevrax France
* \date 2002
*/
class CRandom
{
public:
// The max value that can be returned by the random generator
enum { RandMax = 0x7fff };
public:
// ctor
inline CRandom();
// generate a random value in [0, RandMax]
inline sint32 rand();
// generate a random value in [0, mod]
inline sint32 rand(uint16 mod);
// generate a floating point random value in [0, mod]
inline float frand(double mod=1.0f);
// generate a random value in [-mod, mod]
inline sint32 randPlusMinus(uint16 mod);
// generate a random value in [-mod, mod]
inline float frandPlusMinus(double mod=1.0);
// set a new seed for the random generator
inline void srand(sint32 seed);
private:
sint32 _Seed;
};
//===========================================================================
inline CRandom::CRandom() : _Seed(1)
{
}
//===========================================================================
// NB : In fact this random generator has the same behaviour than the VC6 one
inline sint32 CRandom::rand()
{
return ((_Seed = _Seed * 214013L + 2531011L) >> 16) & RandMax;
}
//===========================================================================
inline sint32 CRandom::rand(uint16 mod)
{
sint32 m=mod;
return rand()*(m+1)/(sint32(RandMax)+1);
}
//===========================================================================
inline sint32 CRandom::randPlusMinus(uint16 mod)
{
sint32 m=mod;
return m - rand()*(2*m+1)/(sint32(RandMax)+1);
}
//===========================================================================
inline float CRandom::frand(double mod)
{
double r = (double) rand();
r /= (double) RandMax;
return (float)(r * mod);
}
//===========================================================================
inline float CRandom::frandPlusMinus(double mod)
{
return frand(2*mod)-(float)mod;
}
//===========================================================================
inline void CRandom::srand(sint32 seed)
{
_Seed = seed;
}
}
#endif