[−][src]Struct rand::rngs::EntropyRng
An interface returning random data from external source(s), provided specifically for securely seeding algorithmic generators (PRNGs).
Where possible, EntropyRng retrieves random data from the operating
system's interface for random numbers (OsRng); if that fails it will
fall back to the JitterRng entropy collector. In the latter case it will
still try to use OsRng on the next usage.
If no secure source of entropy is available EntropyRng will panic on use;
i.e. it should never output predictable data.
This is either a little slow (OsRng requires a system call) or extremely
slow (JitterRng must use significant CPU time to generate sufficient
jitter); for better performance it is common to seed a local PRNG from
external entropy then primarily use the local PRNG (thread_rng is
provided as a convenient, local, automatically-seeded CSPRNG).
Panics
On most systems, like Windows, Linux, macOS and *BSD on common hardware, it
is highly unlikely for both OsRng and JitterRng to fail. But on
combinations like webassembly without Emscripten or stdweb both sources are
unavailable. If both sources fail, only try_fill_bytes is able to
report the error, and only the one from OsRng. The other RngCore
methods will panic in case of an error.
Methods
impl EntropyRng[src]
pub fn new() -> Self[src]
Create a new EntropyRng.
This method will do no system calls or other initialization routines,
those are done on first use. This is done to make new infallible,
and try_fill_bytes the only place to report errors.
Trait Implementations
impl Default for EntropyRng[src]
impl Debug for EntropyRng[src]
impl RngCore for EntropyRng[src]
fn next_u32(&mut self) -> u32[src]
fn next_u64(&mut self) -> u64[src]
fn fill_bytes(&mut self, dest: &mut [u8])[src]
fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>[src]
impl CryptoRng for EntropyRng[src]
Auto Trait Implementations
impl Send for EntropyRng
impl Sync for EntropyRng
Blanket Implementations
impl<R> Rng for R where
R: RngCore + ?Sized, [src]
R: RngCore + ?Sized,
fn gen<T>(&mut self) -> T where
Standard: Distribution<T>, [src]
Standard: Distribution<T>,
Return a random value supporting the [Standard] distribution. Read more
fn gen_range<T: SampleUniform, B1, B2>(&mut self, low: B1, high: B2) -> T where
B1: SampleBorrow<T> + Sized,
B2: SampleBorrow<T> + Sized, [src]
B1: SampleBorrow<T> + Sized,
B2: SampleBorrow<T> + Sized,
Generate a random value in the range [low, high), i.e. inclusive of low and exclusive of high. Read more
fn sample<T, D: Distribution<T>>(&mut self, distr: D) -> T[src]
Sample a new value, using the given distribution. Read more
ⓘImportant traits for DistIter<'a, D, R, T>fn sample_iter<'a, T, D: Distribution<T>>(
&'a mut self,
distr: &'a D
) -> DistIter<'a, D, Self, T> where
Self: Sized, [src]
&'a mut self,
distr: &'a D
) -> DistIter<'a, D, Self, T> where
Self: Sized,
Create an iterator that generates values using the given distribution. Read more
fn fill<T: AsByteSliceMut + ?Sized>(&mut self, dest: &mut T)[src]
Fill dest entirely with random bytes (uniform value distribution), where dest is any type supporting AsByteSliceMut, namely slices and arrays over primitive integer types (i8, i16, u32, etc.). Read more
fn try_fill<T: AsByteSliceMut + ?Sized>(
&mut self,
dest: &mut T
) -> Result<(), Error>[src]
&mut self,
dest: &mut T
) -> Result<(), Error>
Fill dest entirely with random bytes (uniform value distribution), where dest is any type supporting AsByteSliceMut, namely slices and arrays over primitive integer types (i8, i16, u32, etc.). Read more
fn gen_bool(&mut self, p: f64) -> bool[src]
Return a bool with a probability p of being true. Read more
fn gen_ratio(&mut self, numerator: u32, denominator: u32) -> bool[src]
Return a bool with a probability of numerator/denominator of being true. I.e. gen_ratio(2, 3) has chance of 2 in 3, or about 67%, of returning true. If numerator == denominator, then the returned value is guaranteed to be true. If numerator == 0, then the returned value is guaranteed to be false. Read more
fn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T>[src]
use SliceRandom::choose instead
Return a random element from values. Read more
fn choose_mut<'a, T>(&mut self, values: &'a mut [T]) -> Option<&'a mut T>[src]
use SliceRandom::choose_mut instead
Return a mutable pointer to a random element from values. Read more
fn shuffle<T>(&mut self, values: &mut [T])[src]
use SliceRandom::shuffle instead
Shuffle a mutable slice in place. Read more
impl<T> From for T[src]
impl<T, U> Into for T where
U: From<T>, [src]
U: From<T>,
impl<T, U> TryFrom for T where
U: Into<T>, [src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>[src]
impl<T> Borrow for T where
T: ?Sized, [src]
T: ?Sized,
impl<T> BorrowMut for T where
T: ?Sized, [src]
T: ?Sized,
fn borrow_mut(&mut self) -> &mut T[src]
impl<T, U> TryInto for T where
U: TryFrom<T>, [src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>[src]
impl<T> Any for T where
T: 'static + ?Sized, [src]
T: 'static + ?Sized,