blob: 8a51fb289d8f30367798410eb29cb5725c445a16 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
//! Random value generation.
use crate::range::RangeFull;
/// A source of randomness.
#[unstable(feature = "random", issue = "130703")]
pub trait RandomSource {
/// Fills `bytes` with random bytes.
///
/// Note that calling `fill_bytes` multiple times is not equivalent to calling `fill_bytes` once
/// with a larger buffer. A `RandomSource` is allowed to return different bytes for those two
/// cases. For instance, this allows a `RandomSource` to generate a word at a time and throw
/// part of it away if not needed.
fn fill_bytes(&mut self, bytes: &mut [u8]);
}
/// A trait representing a distribution of random values for a type.
#[unstable(feature = "random", issue = "130703")]
pub trait Distribution<T> {
/// Samples a random value from the distribution, using the specified random source.
fn sample(&self, source: &mut (impl RandomSource + ?Sized)) -> T;
}
impl<T, DT: Distribution<T>> Distribution<T> for &DT {
fn sample(&self, source: &mut (impl RandomSource + ?Sized)) -> T {
(*self).sample(source)
}
}
impl Distribution<bool> for RangeFull {
fn sample(&self, source: &mut (impl RandomSource + ?Sized)) -> bool {
let byte: u8 = RangeFull.sample(source);
byte & 1 == 1
}
}
macro_rules! impl_primitive {
($t:ty) => {
impl Distribution<$t> for RangeFull {
fn sample(&self, source: &mut (impl RandomSource + ?Sized)) -> $t {
let mut bytes = (0 as $t).to_ne_bytes();
source.fill_bytes(&mut bytes);
<$t>::from_ne_bytes(bytes)
}
}
};
}
impl_primitive!(u8);
impl_primitive!(i8);
impl_primitive!(u16);
impl_primitive!(i16);
impl_primitive!(u32);
impl_primitive!(i32);
impl_primitive!(u64);
impl_primitive!(i64);
impl_primitive!(u128);
impl_primitive!(i128);
impl_primitive!(usize);
impl_primitive!(isize);
|
