_random.h

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/* === S T A R T =========================================================== */

#ifndef __ETL__RANDOM_H
#define __ETL__RANDOM_H

/* === H E A D E R S ======================================================= */

/* === M A C R O S ========================================================= */

/* === C L A S S E S & S T R U C T S ======================================= */

_ETL_BEGIN_NAMESPACE

/*
class rand_source_xor
{
public:
    typedef int seed_type;
    typedef short value_type;

private:
    short entropy_pool[256];
    int pool_index;

public:
    random()
    {
        seed(0);
        mod=offset=0;
    }

    void seed(const seed_type &x)
    { pool_index=0; }

    void add_entropy(value_type entropy)
    {
        int i;
        for(i=0;i<POOL_SIZE;i++)
            entropy^=(entropy_pool[i]^=entropy*i);
    }

    void add_entropy(const value_type *entropy, int size)
    {
    }

    short get_short()
    {
        if(pool_index>POOL_SIZE)
            pool_index=0;
        if(mod)
            return entropy_pool[pool_index++]%mod+offset;
        return entropy_pool[pool_index++];
    }
};
*/

template <class T,int POOL_SIZE=256>
class random
{
public:
    typedef T value_type;
    typedef int seed_type;

private:
    value_type entropy_pool[POOL_SIZE];
    int pool_index;

    value_type mod,offset;

public:
    random()
    {
        seed(0);
        mod=offset=0;
    }

    void seed(const seed_type &x __attribute__ ((unused)))
    { pool_index=0; }

    void set_range(const value_type &floor,const value_type &ceil)
    { mod=ceil-floor; offset=floor; }

    void set_range(const value_type &ceil)
    { mod=ceil; }

    void add_entropy(value_type entropy)
    {
        int i;
        for(i=0;i<POOL_SIZE;i++)
            entropy^=(entropy_pool[i]^=entropy*i);
    }

    void add_entropy(const char *entropy)
    {
    }

    value_type operator()(void)
    {
        if(pool_index>POOL_SIZE)
            pool_index=0;
        if(mod)
            return entropy_pool[pool_index++]%mod+offset;
        return entropy_pool[pool_index++];
    }
};

/* === T Y P E D E F S ===================================================== */

_ETL_END_NAMESPACE

/* === E N D =============================================================== */

#endif