random/
lib.rs

1#![no_std]
2
3use core::marker::PhantomData;
4use core::ptr;
5
6pub trait Random: Sized {
7    fn random<G: ?Sized + RandomGen>(g: &mut G) -> Self;
8}
9
10pub trait RandomGen {
11    #[inline]
12    fn gen_u32(&mut self) -> u32 { self.gen_u64() as u32 }
13    #[inline]
14    fn gen_u64(&mut self) -> u64 { (self.gen_u32() as u64) << 32 | (self.gen_u32() as u64) }
15    #[inline]
16    fn gen_f32(&mut self) -> f32 { (self.gen_u32() >>  8) as f32 / (1u64 << 24) as f32 }
17    #[inline]
18    fn gen_f64(&mut self) -> f64 { (self.gen_u64() >> 11) as f64 / (1u64 << 53) as f64 }
19    #[inline]
20    fn fill_bytes(&mut self, bs: &mut [u8]) {
21        let mut p = bs.as_mut_ptr();
22        let mut l = bs.len();
23        loop { unsafe {
24            if l >= 8 {
25                let n = self.gen_u64();
26                ptr::copy_nonoverlapping(&n as *const _ as *const u8, p, 8);
27                p = p.offset(8);
28                l -= 8;
29            } else {
30                let n = self.gen_u32();
31                ptr::copy_nonoverlapping(&n as *const _ as *const u8, p, usize::min(4, l));
32                if 4 >= l { return; }
33                p = p.offset(4);
34                l -= 4;
35            }
36        } }
37    }
38    #[inline]
39    fn gen<A: Random>(&mut self) -> A { A::random(self) }
40}
41
42impl<'a, G: RandomGen> RandomGen for &'a mut G {
43    #[inline] fn gen_u32(&mut self) -> u32 { G::gen_u32(self) }
44    #[inline] fn gen_u64(&mut self) -> u64 { G::gen_u64(self) }
45    #[inline] fn gen_f32(&mut self) -> f32 { G::gen_f32(self) }
46    #[inline] fn gen_f64(&mut self) -> f64 { G::gen_f64(self) }
47    #[inline] fn fill_bytes(&mut self, bs: &mut [u8]) { G::fill_bytes(self, bs) }
48}
49
50#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
51pub struct Stream<G, A>(G, PhantomData<A>);
52
53impl<G, A> Stream<G, A> {
54    #[inline]
55    pub fn new(g: G) -> Self { Stream(g, PhantomData) }
56}
57
58impl<G: RandomGen, A: Random> Iterator for Stream<G, A> {
59    type Item = A;
60    #[inline]
61    fn next(&mut self) -> Option<A> { Some(self.0.gen()) }
62}
63
64impl Random for u32 {
65    #[inline]
66    fn random<G: ?Sized + RandomGen>(g: &mut G) -> u32 { g.gen_u32() }
67}
68
69impl Random for u64 {
70    #[inline]
71    fn random<G: ?Sized + RandomGen>(g: &mut G) -> u64 { g.gen_u64() }
72}
73
74impl Random for i32 {
75    #[inline]
76    fn random<G: ?Sized + RandomGen>(g: &mut G) -> i32 { g.gen_u32() as _ }
77}
78
79impl Random for i64 {
80    #[inline]
81    fn random<G: ?Sized + RandomGen>(g: &mut G) -> i64 { g.gen_u64() as _ }
82}
83
84impl Random for f32 {
85    #[inline]
86    fn random<G: ?Sized + RandomGen>(g: &mut G) -> f32 { g.gen_f32() }
87}
88
89impl Random for f64 {
90    #[inline]
91    fn random<G: ?Sized + RandomGen>(g: &mut G) -> f64 { g.gen_f64() }
92}
93
94pub trait Seedable<Seed>: RandomGen {
95    fn reseed(&mut self, _: Seed);
96    fn from_seed(_: Seed) -> Self;
97}
random/lib.rs

random/
lib.rs
