LiteLoaderBDS-1.16.40/LiteLoader/Header/Utils/RNG.h

/**
 * @file   RNG.h
 * @author OEOTYAN (https://github.com/OEOTYAN)
 * @brief  Random Number Generator
 *
 * @copyright Created by OEOTYAN on 2022/09/03.
 *
 */
#pragma once
#include "Global.h"
#include <pcg/pcg_random.hpp>
namespace RNG {

    template <class T>
    inline T rand() {
        static pcg64 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return static_cast<T>(rng());
    }

    template <class T>
    inline T rand(T min, T max) {
        static pcg64 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return min + static_cast<T>(rng(max - min + 1));
    }

    template <>
    inline bool rand() {
        static pcg32 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return static_cast<bool>(rng(2));
    }

    template <>
    inline uint32_t rand() {
        static pcg32 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return rng();
    }

    template <>
    inline uint32_t rand(uint32_t min, uint32_t max) {
        static pcg32 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return min + rng(max - min + 1);
    }

    template <>
    inline int32_t rand() {
        static pcg32 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return static_cast<int32_t>(rng());
    }

    template <>
    inline int32_t rand(int32_t min, int32_t max) {
        static pcg32 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return (static_cast<int64_t>(min) + rng(static_cast<uint32_t>(static_cast<int64_t>(max) - min + 1)));
    }

    template <>
    inline int64_t rand() {
        static pcg64 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return static_cast<int64_t>(rng());
    }

    template <>
    inline int64_t rand(int64_t min, int64_t max) {
        static pcg64 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return min + static_cast<int64_t>(rng(static_cast<uint64_t>(max - min + 1)));
    }

    template <>
    inline uint64_t rand() {
        static pcg64 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return rng();
    }

    template <>
    inline uint64_t rand(uint64_t min, uint64_t max) {
        static pcg64 rng(pcg_extras::seed_seq_from<std::random_device>{});
        return min + rng(max - min + 1);
    }

    template <>
    inline float rand() {
        union {
            uint32_t u;
            float f;
        } x;
        x.u = (rand<uint32_t>() >> 9u) | 0x3f800000u;
        /* Trick from MTGP: generate an uniformly distributed
        single precision number in [1,2) and subtract 1. */
        return x.f - 1.0f;
    }

    template <>
    inline float rand(float min, float max) {
        return min + rand<float>() * (max - min);
    }

    template <>
    inline double rand() {
        union {
            uint64_t u;
            double f;
        } x;
        x.u = (rand<uint64_t>() >> 12ull) | 0x3ff0000000000000ull;
        /* Trick from MTGP: generate an uniformly distributed
        single precision number in [1,2) and subtract 1. */
        return x.f - 1.0;
    }

    template <>
    inline double rand(double min, double max) {
        return min + rand<double>() * (max - min);
    }

    template <class T>
    inline T openIntervalRand(T min = 0, T max = 1) {
        return rand<T>(std::nexttoward(min, LDBL_MAX), max);
    }

    template <class T>
    inline T closeIntervalRand(T min = 0, T max = 1) {
        return rand<T>(min, std::nexttoward(max, LDBL_MAX));
    }

    template <class T>
    inline T rightCloseIntervalRand(T min = 0, T max = 1) {
        return rand<T>(std::nexttoward(min, LDBL_MAX), std::nexttoward(max, LDBL_MAX));
    }

    template <class T>
    inline T leftCloseIntervalRand(T min = 0, T max = 1) {
        return rand<T>(min, max);
    }

} // namespace RNG