Random Class Reference

Pseudo-random number generator wrapping std::mt19937_64. More...

#include <random.h>

Public Member Functions
	Random ()
	Constructs a Random seeded from std::random_device.
	Random (uint64_t seed)
	Constructs a Random with a specific seed.
void	seed (uint64_t seed)
	Reseeds the engine.
int	randomInt (int min, int max)
	Returns a uniformly distributed random integer in [min, max].
int64_t	randomInt64 (int64_t min, int64_t max)
	Returns a uniformly distributed random 64-bit integer in [min, max].
double	randomDouble (double min, double max)
	Returns a uniformly distributed random double in [min, max).
float	randomFloat (float min, float max)
	Returns a uniformly distributed random float in [min, max).
Buffer	randomBytes (size_t count)
	Returns a Buffer filled with random bytes.
bool	randomBool ()
	Returns a random boolean with 50/50 probability.

Static Public Member Functions
static Error	trueRandom (uint8_t *buf, size_t bytes)
	Fills a buffer with true random bytes from the OS entropy source.
static Random &	global ()
	Returns a thread-local global Random instance.

Detailed Description

Pseudo-random number generator wrapping std::mt19937_64.

Random provides two distinct categories of random data:

Pseudo-random (PRNG): All instance methods use a deterministic Mersenne Twister engine (std::mt19937_64). Given the same seed, the sequence is perfectly reproducible — useful for simulations, testing, and any case where repeatability matters. The default constructor seeds from std::random_device, so unseeded instances produce non-reproducible sequences that are statistically uniform but not cryptographically secure. A thread-local global instance is available via global() for convenience.

True random: The static trueRandom() method reads directly from the platform's hardware/OS entropy source (std::random_device) on every call. This is suitable for cryptographic seeds, UUIDs, nonces, and key generation. It is slower than PRNG output and should not be used for bulk data generation.

Constructor & Destructor Documentation

Random()

Random::Random ( uint64_t  seed )

explicit

Constructs a Random with a specific seed.

Parameters

seed	The seed value for the engine.

Member Function Documentation

global()

static Random & Random::global ( )

static

Returns a thread-local global Random instance.

Returns

Reference to the thread-local instance.

randomBool()

bool Random::randomBool

(

)

Returns a random boolean with 50/50 probability.

Returns

true or false with equal probability.

randomBytes()

Buffer Random::randomBytes

(

size_t

count

)

Returns a Buffer filled with random bytes.

Parameters

count

Number of random bytes.

Returns

A Buffer of the given size filled with random data.

randomDouble()

double Random::randomDouble	(	double	min,
		double	max
	)

Returns a uniformly distributed random double in [min, max).

Parameters

min	Lower bound (inclusive).
max	Upper bound (exclusive).

Returns

A random double.

randomFloat()

float Random::randomFloat	(	float	min,
		float	max
	)

Returns a uniformly distributed random float in [min, max).

Parameters

min	Lower bound (inclusive).
max	Upper bound (exclusive).

Returns

A random float.

randomInt()

int Random::randomInt	(	int	min,
		int	max
	)

Returns a uniformly distributed random integer in [min, max].

Parameters

min	Lower bound (inclusive).
max	Upper bound (inclusive).

Returns

A random integer.

randomInt64()

int64_t Random::randomInt64	(	int64_t	min,
		int64_t	max
	)

Returns a uniformly distributed random 64-bit integer in [min, max].

Parameters

min	Lower bound (inclusive).
max	Upper bound (inclusive).

Returns

A random 64-bit integer.

seed()

void Random::seed

(

uint64_t

seed

)

Reseeds the engine.

Parameters

seed	The new seed value.

trueRandom()

static Error Random::trueRandom ( uint8_t *  buf, size_t  bytes  )

static

Fills a buffer with true random bytes from the OS entropy source.

Reads directly from std::random_device on every call. Unlike the instance methods, this does not use a deterministic PRNG — each byte is drawn from the platform's entropy pool. Suitable for cryptographic seeding, UUID generation, and nonce creation.

Parameters

buf	Pointer to the destination buffer.
bytes	Number of bytes to generate.

Returns

Error::Ok on success.

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The documentation for this class was generated from the following file:

• include/promeki/core/random.h