csprng.h

#pragma once
 
#include <cstddef>
#include <cstdint>
#include <limits>
#include <mutex>
 
namespace xrpl {

class CsprngEngine
{
private:
    std::mutex mutex_;
 
public:
    using result_type = std::uint64_t;
 
    CsprngEngine(CsprngEngine const&) = delete;
    CsprngEngine&
    operator=(CsprngEngine const&) = delete;
 
    CsprngEngine(CsprngEngine&&) = delete;
    CsprngEngine&
    operator=(CsprngEngine&&) = delete;
 
    CsprngEngine();
    ~CsprngEngine();

    void
    mixEntropy(void* buffer = nullptr, std::size_t count = 0);

    result_type
    operator()();

    void
    operator()(void* ptr, std::size_t count);
 
    /* The smallest possible value that can be returned */
    static constexpr result_type
    min()
    {
        return std::numeric_limits<result_type>::min();
    }
 
    /* The largest possible value that can be returned */
    static constexpr result_type
    max()
    {
        return std::numeric_limits<result_type>::max();
    }
};

CsprngEngine&
cryptoPrng();
 
}  // namespace xrpl