Crate wyhash

Source
Expand description

Rust implementation of the wyhash algorithm by Wang Yi.

The hashing algorithm passes SMHasher and the random number generator passes BigCrush and practrand. As of now it is the fastest algorithm in the SMHasher benchmark (faster than t1ha and XXH3). See here.

Furthermore, this algorithm is solid, simple, portable (does not need hardware support, can be used in no_std environments) and has no dependencies.

The generated hashes are equal (see tests) as of the version stated here although the speed varies (PRs are welcome).

§Usage (see also examples folder)

For the hashing function you can use either the free function or the Hasher trait.

§wyhash function usage

use wyhash::wyhash;

let data = [0, 1, 2];
let seed = 3;
let hash = wyhash(&data, seed);

assert_eq!(0xb0f9_4152_0b1a_d95d, hash);

§Hasher trait usage

You can also use std::hash::Hasher, it is the same.

use core::hash::Hasher;
use wyhash::WyHash;

let mut hasher = WyHash::with_seed(3);
hasher.write(&[0, 1, 2]);

assert_eq!(0xb0f9_4152_0b1a_d95d, hasher.finish());

§wyrng function usage

Note that the seed parameter is updated so that it is possible to generate a sequence of random numbers.

use wyhash::wyrng;

let mut seed = 3;
let random_number = wyrng(&mut seed);

assert_eq!(0x3e9_9a77_2750_dcbe, random_number);
assert_eq!(0xa0761d6478bd6432, seed);

§RngCore trait usage

You can also use rand::Rng, it is the same.

use rand_core::RngCore;
use wyhash::WyRng;

let mut rng = WyRng::default();
assert_eq!(0x111c_b3a7_8f59_a58e, rng.next_u64());

§SeedableRng trait usage

You can also use rand::SeedableRng, it is the same.

use rand_core::{SeedableRng, RngCore};
use wyhash::WyRng;

// Seeds are 8-byte long.
let seed = [0, 1, 2, 3, 4, 5, 6, 7];
let mut rng1 = WyRng::from_seed(seed);
assert_eq!(0xd730_1357_74c6_ae31, rng1.next_u64());

// Alternatively you can also use this convenience method:
let mut rng2 = WyRng::seed_from_u64(3);
assert_eq!(0x3e9_9a77_2750_dcbe, rng2.next_u64());

Structs§

Functions§

  • wyhash
    Generate a hash for the input data and seed
  • wyrng
    Pseudo-Random Number Generator (PRNG)