Random.h

#ifndef RANDOM_H_INCLUDED
#define RANDOM_H_INCLUDED

#include "config.h"
#include <limits>

/*
    Random number generator xoroshiro128+
*/
class Random {
public:
    Random(int seed = -1);
    void seedrandom(uint32 s);

    // random numbers from 0 to max
    template<int MAX>
    uint32 randfix() {
        static_assert(0 < MAX && MAX < std::numeric_limits<uint32>::max(),
                     "randfix out of range");
        // Last bit isn't random, so don't use it in isolation. We specialize
        // this case.
        static_assert(MAX != 2, "don't isolate the LSB with xoroshiro128+");
        return random() % MAX;
    }

    uint16 randuint16(const uint16 max);
    uint32 randuint32(const uint32 max);
    uint32 randuint32();

    // random float from 0 to 1
    float randflt(void);

    // return the thread local RNG
    static Random* get_Rng(void);

private:
    uint64 random(void);
    uint64 m_s[2];
};

// Specialization for last bit: use sign test
template<>
inline uint32 Random::randfix<2>() {
    return (random() > (std::numeric_limits<uint64>::max() / 2));
}

#endif