Struct RngBuffer

pub(crate) struct RngBuffer<'a, T: RngCore> {
    inner: &'a mut T,
    u8_vec: ArrayVec<u8, 7>,
    u32_opt: Option<u32>,
}

Wrap a RngCore implementation for fast u8 and u32 output.

This maintains small queues for each data type: up to one u32 and up to 7 bytes. The queueing behavior matches convenions required by HashX: The underlying u64 values are always generated lazily, and component values are extracted in big endian order.

Fields

inner: &'a mut T

Inner RngCore implementation

u8_vec: ArrayVec<u8, 7>

Buffer of remaining u8 values from breaking up a u64

u32_opt: Option<u32>

Up to one buffered u32 value

Implementations

impl<'a, T: RngCore> RngBuffer<'a, T>

pub(crate) fn new(rng: &'a mut T) -> Self

Construct a new empty buffer around a RngCore implementation.

No actual random numbers will be generated until the first call to Self::next_u8 or Self::next_u32.

pub(crate) fn next_u32(&mut self) -> u32

Request 32 bits from the buffered random number generator.

If we have buffered data stored, returns that. If not, requests 64 bits from the RngCore and saves half for later.

pub(crate) fn next_u8(&mut self) -> u8

Request 8 bits from the buffered random number generator.

If we have buffered data stored, returns that. If not, requests 64 bits from the RngCore and saves 7 bytes for later.

Trait Implementations

impl<'a, T: Debug + RngCore> Debug for RngBuffer<'a, T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.