Differential D19043 Diff 56876 src/random.h

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src/random.h

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class FastRandomContext {		class FastRandomContext {
private:		private:
bool requires_seed;		bool requires_seed;
ChaCha20 rng;		ChaCha20 rng;

uint64_t bitbuf;		uint64_t bitbuf;
int bitbuf_size;		int bitbuf_size;

void RandomSeed();		void RandomSeed() noexcept;

void FillBitBuffer() {		void FillBitBuffer() noexcept {
bitbuf = rand64();		bitbuf = rand64();
bitbuf_size = 64;		bitbuf_size = 64;
}		}

public:		public:
explicit FastRandomContext(bool fDeterministic = false) noexcept;		explicit FastRandomContext(bool fDeterministic = false) noexcept;

/** Initialize with explicit seed (only for testing) */		/** Initialize with explicit seed (only for testing) */
▲ Show 20 Lines • Show All 50 Lines • ▼ Show 20 Lines	uint64_t randrange(uint64_t range) noexcept {
uint64_t ret = randbits(bits);		uint64_t ret = randbits(bits);
if (ret <= range) {		if (ret <= range) {
return ret;		return ret;
}		}
}		}
}		}

/** Generate random bytes. */		/** Generate random bytes. */
template <typename B = uint8_t> std::vector<B> randbytes(size_t len) {		template <typename B = uint8_t>
		std::vector<B> randbytes(size_t len) noexcept {
std::vector<B> ret(len);		std::vector<B> ret(len);
fillrand(MakeWritableByteSpan(ret));		fillrand(MakeWritableByteSpan(ret));
return ret;		return ret;
}		}

/** Fill a byte Span with random bytes. */		/** Fill a byte Span with random bytes. */
void fillrand(Span<std::byte> output);		void fillrand(Span<std::byte> output) noexcept;

/** Generate a random 32-bit integer. */		/** Generate a random 32-bit integer. */
uint32_t rand32() noexcept { return randbits(32); }		uint32_t rand32() noexcept { return randbits(32); }

/** generate a random uint160. */		/** generate a random uint160. */
uint160 rand160() noexcept {		uint160 rand160() noexcept {
uint160 ret;		uint160 ret;
fillrand(MakeWritableByteSpan(ret));		fillrand(MakeWritableByteSpan(ret));
return ret;		return ret;
}		}

/** generate a random uint256. */		/** generate a random uint256. */
uint256 rand256() noexcept {		uint256 rand256() noexcept {
uint256 ret;		uint256 ret;
fillrand(MakeWritableByteSpan(ret));		fillrand(MakeWritableByteSpan(ret));
return ret;		return ret;
}		}

/** Generate a random boolean. */		/** Generate a random boolean. */
bool randbool() noexcept { return randbits(1); }		bool randbool() noexcept { return randbits(1); }

/** Return the time point advanced by a uniform random duration. */		/** Return the time point advanced by a uniform random duration. */
template <typename Tp>		template <typename Tp>
Tp rand_uniform_delay(const Tp &time, typename Tp::duration range) {		Tp rand_uniform_delay(const Tp &time,
		typename Tp::duration range) noexcept {
using Dur = typename Tp::duration;		using Dur = typename Tp::duration;
Dur dur{range.count() > 0		Dur dur{range.count() > 0
? /* interval [0..range) */ Dur{randrange(range.count())}		? /* interval [0..range) */ Dur{randrange(range.count())}
: range.count() < 0		: range.count() < 0
? /* interval (range..0] */ -Dur{randrange(-range.count())}		? /* interval (range..0] */ -Dur{randrange(-range.count())}
:		:
/* interval [0..0] */ Dur{0}};		/* interval [0..0] */ Dur{0}};
return time + dur;		return time + dur;
}		}

// Compatibility with the C++11 UniformRandomBitGenerator concept		// Compatibility with the C++11 UniformRandomBitGenerator concept
typedef uint64_t result_type;		typedef uint64_t result_type;
static constexpr uint64_t min() { return 0; }		static constexpr uint64_t min() noexcept { return 0; }
static constexpr uint64_t max() {		static constexpr uint64_t max() noexcept {
return std::numeric_limits<uint64_t>::max();		return std::numeric_limits<uint64_t>::max();
}		}
inline uint64_t operator()() noexcept { return rand64(); }		inline uint64_t operator()() noexcept { return rand64(); }
};		};

/**		/**
* More efficient than using std::shuffle on a FastRandomContext.		* More efficient than using std::shuffle on a FastRandomContext.
*		*
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