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