/ray/src/lib/numerics/rng/libc.h

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/*
 * lib/numerics/rng/libc.h
 * 
 * Interface header for LIBC random() PRNG. 
 * 
 * Copyright (c) 2004 by Wolfgang Wieser ] wwieser (a) gmx <*> de [ 
 * 
 * This file may be distributed and/or modified under the terms of the 
 * GNU General Public License version 2 as published by the Free Software 
 * Foundation. (See COPYING.GPL for details.)
 * 
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 * 
 */

#ifndef _LIB_NUMERICS_RNG_LibCRandom_H_
#define _LIB_NUMERICS_RNG_LibCRandom_H_ 1

#include <lib/numerics/rng/rng.h>
#include <lib/salloc.h>


namespace NUM  // numerics
{

class RandomNumberGenerator_LibCRandom : public RandomNumberGenerator_Base
{
    private:
        random_data rdata;
        char *statebuf;
        
        inline int32 _rand31()
            {  int32 res;  random_r(&rdata,&res);  return(res);  }
        
        RandomNumberGenerator_LibCRandom(
            const RandomNumberGenerator_LibCRandom &);
        void operator=(const RandomNumberGenerator_LibCRandom &);
    public:
        RandomNumberGenerator_LibCRandom(uint32 s) : 
            RandomNumberGenerator_Base()
            {  statebuf=NULL;  seed(s);  }
        ~RandomNumberGenerator_LibCRandom()
            {  FREE(statebuf);  }
        
        void seed(uint32 seed)
            {  srandom_r(seed,&rdata);  }
        
        void seed(uint seed,int statelen);
        
        uint32 rand_uint32()  // not inline (overriding virtual)
            {  return( uint32(_rand31()<<2) ^ uint32(_rand31()) );  }
        
        int32 rand_int32()  // not inline (overriding virtual)
            {  return(_rand31());  }
        
        dbl rand_dbl32o()  // not inline (overriding virtual)
            {  return(_rand31()*FPConst<dbl>::div_1_pow_2_31);  }
        
        dbl rand_dbl32()  // not inline (overriding virtual)
            {  return(_rand31()*FPConst<dbl>::div_1_pow_2_31m1);  }
        
        dbl rand_dbl53o()  // not inline (overriding virtual)
        {
            int32 a=_rand31()>>4, b=_rand31()>>5; 
            return( (a*67108864.0+b)*FPConst<dbl>::div_1_pow_2_53 );
        }
        
        dbl rand_dbl53()  // not inline (overriding virtual)
        {
            int32 a=_rand31()>>4, b=_rand31()>>5; 
            return( (a*67108864.0+b)*FPConst<dbl>::div_1_pow_2_53m1 );
        }
};

}  // end of namespace NUM

#endif  /* _LIB_NUMERICS_RNG_LibCRandom_H_ */

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