Files
addr2line
adler
adler32
ahash
aho_corasick
angle
approx
backtrace
bitflags
blender
bytemuck
byteorder
case
cast_trait
cfg_if
chrono
color
color_quant
const_fn
crc32fast
crossbeam
crossbeam_channel
crossbeam_deque
crossbeam_epoch
crossbeam_queue
crossbeam_skiplist
crossbeam_utils
darling
darling_core
darling_macro
dds
deflate
densevec
derive_builder
derive_builder_core
dot
downcast_rs
dual_quat
either
erased_serde
failure
failure_derive
fixedbitset
float_cmp
fnv
freeimage
freeimage_sys
freetype
freetype_gl_sys
freetype_sys
freetypegl
futures
futures_channel
futures_core
futures_executor
futures_io
futures_macro
futures_sink
futures_task
futures_util
async_await
future
io
lock
sink
stream
task
fxhash
generational_arena
generic_array
getrandom
gif
gimli
glfw
glfw_sys
glin
glin_derive
glsl
half
harfbuzz
harfbuzz_ft_sys
harfbuzz_sys
hashbrown
human_sort
ident_case
image
indexmap
instant
itertools
itoa
jpeg_decoder
lazy_static
libc
libm
lock_api
log
lut_parser
matrixmultiply
memchr
memoffset
meshopt
miniz_oxide
monotonic_clock
mopa
mutiny_derive
na
nalgebra
base
geometry
linalg
ncollide3d
bounding_volume
interpolation
partitioning
pipeline
procedural
query
algorithms
closest_points
contact
distance
nonlinear_time_of_impact
point
proximity
ray
time_of_impact
visitors
shape
transformation
utils
nom
num_complex
num_cpus
num_integer
num_iter
num_rational
num_traits
numext_constructor
numext_fixed_uint
numext_fixed_uint_core
numext_fixed_uint_hack
object
once_cell
parking_lot
parking_lot_core
pathfinding
pennereq
petgraph
pin_project_lite
pin_utils
png
polygon2
ppv_lite86
proc_macro2
proc_macro_crate
proc_macro_hack
proc_macro_nested
quote
rand
rand_chacha
rand_core
rand_distr
raw_window_handle
rawpointer
rayon
rayon_core
rect_packer
regex
regex_syntax
retain_mut
rin
rin_app
rin_blender
rin_core
rin_gl
rin_graphics
rin_gui
rin_material
rin_math
rin_postpo
rin_scene
rin_util
rin_window
rinblender
rinecs
rinecs_derive
rinecs_derive_utils
ringui_derive
rustc_demangle
rusty_pool
ryu
scopeguard
seitan
seitan_derive
semver
semver_parser
serde
serde_derive
serde_json
shaderdata_derive
simba
slab
slice_of_array
slotmap
smallvec
std140_data
streaming_iterator
strsim
syn
synstructure
thiserror
thiserror_impl
thread_local
tiff
time
toml
typenum
unchecked_unwrap
unicode_xid
vec2
vec3
weezl
x11
zlib_sys
 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
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
// Copyright 2019 Developers of the Rand project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Interface to the random number generator of the operating system.
// Note: keep this code in sync with the rand_os crate!

use getrandom::getrandom;
use crate::{CryptoRng, RngCore, Error, impls};

/// A random number generator that retrieves randomness from from the
/// operating system.
///
/// This is a zero-sized struct. It can be freely constructed with `OsRng`.
///
/// The implementation is provided by the [getrandom] crate. Refer to
/// [getrandom] documentation for details.
///
/// This struct is only available when specifying the crate feature `getrandom`
/// or `std`. When using the `rand` lib, it is also available as `rand::rngs::OsRng`.
///
/// # Blocking and error handling
///
/// It is possible that when used during early boot the first call to `OsRng`
/// will block until the system's RNG is initialised. It is also possible
/// (though highly unlikely) for `OsRng` to fail on some platforms, most
/// likely due to system mis-configuration.
///
/// After the first successful call, it is highly unlikely that failures or
/// significant delays will occur (although performance should be expected to
/// be much slower than a user-space PRNG).
///
/// # Usage example
/// ```
/// use rand_core::{RngCore, OsRng};
///
/// let mut key = [0u8; 16];
/// OsRng.fill_bytes(&mut key);
/// let random_u64 = OsRng.next_u64();
/// ```
///
/// [getrandom]: https://crates.io/crates/getrandom
#[derive(Clone, Copy, Debug, Default)]
pub struct OsRng;

impl CryptoRng for OsRng {}

impl RngCore for OsRng {
    fn next_u32(&mut self) -> u32 {
        impls::next_u32_via_fill(self)
    }

    fn next_u64(&mut self) -> u64 {
        impls::next_u64_via_fill(self)
    }

    fn fill_bytes(&mut self, dest: &mut [u8]) {
        if let Err(e) = self.try_fill_bytes(dest) {
            panic!("Error: {}", e);
        }
    }

    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
        getrandom(dest)?;
        Ok(())
    }
}

#[test]
fn test_os_rng() {
    let x = OsRng.next_u64();
    let y = OsRng.next_u64();
    assert!(x != 0);
    assert!(x != y);
}

#[test]
fn test_construction() {
    let mut rng = OsRng::default();
    assert!(rng.next_u64() != 0);
}