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-rw-r--r--rand/rand_xoshiro/src/xoroshiro128starstar.rs127
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diff --git a/rand/rand_xoshiro/src/xoroshiro128starstar.rs b/rand/rand_xoshiro/src/xoroshiro128starstar.rs
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--- a/rand/rand_xoshiro/src/xoroshiro128starstar.rs
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-// 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_u64_into;
-use rand_core::impls::fill_bytes_via_next;
-use rand_core::{RngCore, SeedableRng};
-
-/// A xoroshiro128** random number generator.
-///
-/// The xoroshiro128** algorithm is not suitable for cryptographic purposes, but
-/// is very fast and has excellent statistical properties.
-///
-/// The algorithm used here is translated from [the `xoroshiro128starstar.c`
-/// reference source code](http://xoshiro.di.unimi.it/xoroshiro128starstar.c) by
-/// David Blackman and Sebastiano Vigna.
-#[allow(missing_copy_implementations)]
-#[derive(Debug, Clone)]
-#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))]
-pub struct Xoroshiro128StarStar {
- s0: u64,
- s1: u64,
-}
-
-impl Xoroshiro128StarStar {
- /// Jump forward, equivalently to 2^64 calls to `next_u64()`.
- ///
- /// This can be used to generate 2^64 non-overlapping subsequences for
- /// parallel computations.
- ///
- /// ```
- /// use rand_xoshiro::rand_core::SeedableRng;
- /// use rand_xoshiro::Xoroshiro128StarStar;
- ///
- /// let rng1 = Xoroshiro128StarStar::seed_from_u64(0);
- /// let mut rng2 = rng1.clone();
- /// rng2.jump();
- /// let mut rng3 = rng2.clone();
- /// rng3.jump();
- /// ```
- pub fn jump(&mut self) {
- impl_jump!(u64, self, [0xdf900294d8f554a5, 0x170865df4b3201fc]);
- }
-
- /// Jump forward, equivalently to 2^96 calls to `next_u64()`.
- ///
- /// This can be used to generate 2^32 starting points, from each of which
- /// `jump()` will generate 2^32 non-overlapping subsequences for parallel
- /// distributed computations.
- pub fn long_jump(&mut self) {
- impl_jump!(u64, self, [0xd2a98b26625eee7b, 0xdddf9b1090aa7ac1]);
- }
-}
-
-impl RngCore for Xoroshiro128StarStar {
- #[inline]
- fn next_u32(&mut self) -> u32 {
- self.next_u64() as u32
- }
-
- #[inline]
- fn next_u64(&mut self) -> u64 {
- let r = starstar_u64!(self.s0);
- impl_xoroshiro_u64!(self);
- r
- }
-
- #[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 Xoroshiro128StarStar {
- type Seed = [u8; 16];
-
- /// Create a new `Xoroshiro128StarStar`. If `seed` is entirely 0, it will be
- /// mapped to a different seed.
- fn from_seed(seed: [u8; 16]) -> Xoroshiro128StarStar {
- deal_with_zero_seed!(seed, Self);
- let mut s = [0; 2];
- read_u64_into(&seed, &mut s);
-
- Xoroshiro128StarStar {
- s0: s[0],
- s1: s[1],
- }
- }
-
- /// Seed a `Xoroshiro128StarStar` from a `u64` using `SplitMix64`.
- fn seed_from_u64(seed: u64) -> Xoroshiro128StarStar {
- from_splitmix!(seed)
- }
-}
-
-#[cfg(test)]
-mod tests {
- use super::*;
-
- #[test]
- fn reference() {
- let mut rng = Xoroshiro128StarStar::from_seed(
- [1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0]);
- // These values were produced with the reference implementation:
- // http://xoshiro.di.unimi.it/xoshiro128starstar.c
- let expected = [
- 5760, 97769243520, 9706862127477703552, 9223447511460779954,
- 8358291023205304566, 15695619998649302768, 8517900938696309774,
- 16586480348202605369, 6959129367028440372, 16822147227405758281,
- ];
- for &e in &expected {
- assert_eq!(rng.next_u64(), e);
- }
- }
-}