| commit | c5fd900ff30e416bc6c71fd5e46b6d044b2a394e | [log] [tgz] |
|---|---|---|
| author | James Farrell <[email protected]> | Tue Sep 05 23:33:19 2023 +0000 |
| committer | James Farrell <[email protected]> | Tue Sep 05 23:33:19 2023 +0000 |
| tree | f4ec7bf8a872174e4452a977a49e34bf2a1a6e87 | |
| parent | 0b57c89760e0ba65238da7255ecd4800dbd60cd4 [diff] |
Upgrade fastrand to 2.0.0 This project was upgraded with external_updater. Usage: tools/external_updater/updater.sh update rust/crates/fastrand For more info, check https://cs.android.com/android/platform/superproject/+/main:tools/external_updater/README.md Test: TreeHugger Change-Id: I46d2f7a42890e5ae04f07df79f8edd4d8fe69d95
A simple and fast random number generator.
The implementation uses Wyrand, a simple and fast generator but not cryptographically secure.
Flip a coin:
if fastrand::bool() { println!("heads"); } else { println!("tails"); }
Generate a random i32:
let num = fastrand::i32(..);
Choose a random element in an array:
let v = vec![1, 2, 3, 4, 5]; let i = fastrand::usize(..v.len()); let elem = v[i];
Sample values from an array with O(n) complexity (n is the length of array):
fastrand::choose_multiple(vec![1, 4, 5].iter(), 2); fastrand::choose_multiple(0..20, 12);
Shuffle an array:
let mut v = vec![1, 2, 3, 4, 5]; fastrand::shuffle(&mut v);
Generate a random Vec or String:
use std::iter::repeat_with; let v: Vec<i32> = repeat_with(|| fastrand::i32(..)).take(10).collect(); let s: String = repeat_with(fastrand::alphanumeric).take(10).collect();
To get reproducible results on every run, initialize the generator with a seed:
// Pick an arbitrary number as seed. fastrand::seed(7); // Now this prints the same number on every run: println!("{}", fastrand::u32(..));
To be more efficient, create a new Rng instance instead of using the thread-local generator:
use std::iter::repeat_with; let rng = fastrand::Rng::new(); let mut bytes: Vec<u8> = repeat_with(|| rng.u8(..)).take(10_000).collect();
std (enabled by default): Enables the std library. This is required for the global generator and global entropy. Without this feature, [Rng] can only be instantiated using the with_seed method.Licensed under either of
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.