TUrbg32x2.h

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#pragma once
 
#include "Math/Random/TUniformRandomBitGenerator.h"
 
#include <Common/primitive_type.h>
 
#include <type_traits>
#include <utility>
 
namespace ph::math
{
 
template<CURBG URBG1, CURBG URBG2 = URBG1>
class TUrbg32x2 final : public TUniformRandomBitGenerator<TUrbg32x2<URBG1, URBG2>, uint64>
{
    static_assert(
        std::is_same_v<typename URBG1::BitsType, uint32> || 
        std::is_same_v<typename URBG1::BitsType, uint64>,
        "URBG1 must have `uint32` or `uint64` bits type.");
 
    static_assert(
        std::is_same_v<typename URBG2::BitsType, uint32> ||
        std::is_same_v<typename URBG2::BitsType, uint64>,
        "URBG2 must have `uint32` or `uint64` bits type.");
 
public:
    PH_DEFINE_INLINE_RULE_OF_5_MEMBERS(TUrbg32x2);
 
    TUrbg32x2(URBG1 urbg1, URBG2 urbg2);
 
    uint64 impl_generate();
    void impl_jumpAhead(uint64 distance);
 
private:
    URBG1 m_urbg1;
    URBG2 m_urbg2;
};
 
template<CURBG URBG1, CURBG URBG2>
inline TUrbg32x2<URBG1, URBG2>::TUrbg32x2(URBG1 urbg1, URBG2 urbg2)
    : m_urbg1(std::move(urbg1))
    , m_urbg2(std::move(urbg2))
{}
 
template<CURBG URBG1, CURBG URBG2>
inline uint64 TUrbg32x2<URBG1, URBG2>::impl_generate()
{
    // Generate 8-byte bits by combining two 4-byte bits
    // (prefer `URGB1` by placing it in the higher bits, since some algorithm consider higher bits
    // may be of better quality by default)
    const auto higher4B = uint64(m_urbg1.template generate<uint32>()) << 32;
    const auto lower4B = uint64(m_urbg2.template generate<uint32>());
    return higher4B | lower4B;
}
 
template<CURBG URBG1, CURBG URBG2>
inline void TUrbg32x2<URBG1, URBG2>::impl_jumpAhead(const uint64 distance)
{
    m_urbg1.jumpAhead(distance);
    m_urbg2.jumpAhead(distance);
}
 
}// end namespace ph::math