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Diffstat (limited to 'rand/rand_xoshiro/src/xoroshiro64star.rs')
-rw-r--r-- | rand/rand_xoshiro/src/xoroshiro64star.rs | 102 |
1 files changed, 0 insertions, 102 deletions
diff --git a/rand/rand_xoshiro/src/xoroshiro64star.rs b/rand/rand_xoshiro/src/xoroshiro64star.rs deleted file mode 100644 index 6bb708a..0000000 --- a/rand/rand_xoshiro/src/xoroshiro64star.rs +++ /dev/null @@ -1,102 +0,0 @@ -// Copyright 2018 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. - -#[cfg(feature="serde1")] use serde::{Serialize, Deserialize}; -use rand_core; -use rand_core::le::read_u32_into; -use rand_core::impls::{fill_bytes_via_next, next_u64_via_u32}; -use rand_core::{RngCore, SeedableRng}; - -/// A xoroshiro64* random number generator. -/// -/// The xoroshiro64* algorithm is not suitable for cryptographic purposes, but -/// is very fast and has good statistical properties, besides a low linear -/// complexity in the lowest bits. -/// -/// The algorithm used here is translated from [the `xoroshiro64star.c` -/// reference source code](http://xoshiro.di.unimi.it/xoroshiro64star.c) by -/// David Blackman and Sebastiano Vigna. -#[allow(missing_copy_implementations)] -#[derive(Debug, Clone)] -#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))] -pub struct Xoroshiro64Star { - s0: u32, - s1: u32, -} - -impl RngCore for Xoroshiro64Star { - #[inline] - fn next_u32(&mut self) -> u32 { - let r = self.s0.wrapping_mul(0x9E3779BB); - impl_xoroshiro_u32!(self); - r - } - - #[inline] - fn next_u64(&mut self) -> u64 { - next_u64_via_u32(self) - } - - #[inline] - fn fill_bytes(&mut self, dest: &mut [u8]) { - fill_bytes_via_next(self, dest); - } - - #[inline] - fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand_core::Error> { - self.fill_bytes(dest); - Ok(()) - } -} - -impl SeedableRng for Xoroshiro64Star { - type Seed = [u8; 8]; - - /// Create a new `Xoroshiro64Star`. If `seed` is entirely 0, it will be - /// mapped to a different seed. - fn from_seed(seed: [u8; 8]) -> Xoroshiro64Star { - deal_with_zero_seed!(seed, Self); - let mut s = [0; 2]; - read_u32_into(&seed, &mut s); - - Xoroshiro64Star { - s0: s[0], - s1: s[1], - } - } - - /// Seed a `Xoroshiro64Star` from a `u64` using `SplitMix64`. - fn seed_from_u64(seed: u64) -> Xoroshiro64Star { - from_splitmix!(seed) - } -} - -#[cfg(test)] -mod tests { - use super::*; - - #[test] - fn reference() { - let mut rng = Xoroshiro64Star::from_seed([1, 0, 0, 0, 2, 0, 0, 0]); - // These values were produced with the reference implementation: - // http://xoshiro.di.unimi.it/xoshiro64star.c - let expected = [ - 2654435771, 327208753, 4063491769, 4259754937, 261922412, 168123673, - 552743735, 1672597395, 1031040050, 2755315674, - ]; - for &e in &expected { - assert_eq!(rng.next_u32(), e); - } - } - - #[test] - fn zero_seed() { - let mut rng = Xoroshiro64Star::seed_from_u64(0); - assert_ne!(rng.next_u64(), 0); - } -} |