aboutsummaryrefslogtreecommitdiff
path: root/rand/rand_xorshift/src/lib.rs
diff options
context:
space:
mode:
Diffstat (limited to 'rand/rand_xorshift/src/lib.rs')
-rw-r--r--rand/rand_xorshift/src/lib.rs117
1 files changed, 0 insertions, 117 deletions
diff --git a/rand/rand_xorshift/src/lib.rs b/rand/rand_xorshift/src/lib.rs
deleted file mode 100644
index b9fef23..0000000
--- a/rand/rand_xorshift/src/lib.rs
+++ /dev/null
@@ -1,117 +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.
-
-//! The xorshift random number generator.
-
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk.png",
- html_favicon_url = "https://www.rust-lang.org/favicon.ico",
- html_root_url = "https://rust-random.github.io/rand/")]
-
-#![deny(missing_docs)]
-#![deny(missing_debug_implementations)]
-
-#![no_std]
-
-use core::num::Wrapping as w;
-use core::fmt;
-use rand_core::{RngCore, SeedableRng, Error, impls, le};
-#[cfg(feature="serde1")] use serde::{Serialize, Deserialize};
-
-/// An Xorshift random number generator.
-///
-/// The Xorshift[^1] algorithm is not suitable for cryptographic purposes
-/// but is very fast. If you do not know for sure that it fits your
-/// requirements, use a more secure one such as `StdRng` or `OsRng`.
-///
-/// [^1]: Marsaglia, George (July 2003).
-/// ["Xorshift RNGs"](https://www.jstatsoft.org/v08/i14/paper).
-/// *Journal of Statistical Software*. Vol. 8 (Issue 14).
-#[derive(Clone)]
-#[cfg_attr(feature="serde1", derive(Serialize,Deserialize))]
-pub struct XorShiftRng {
- x: w<u32>,
- y: w<u32>,
- z: w<u32>,
- w: w<u32>,
-}
-
-// Custom Debug implementation that does not expose the internal state
-impl fmt::Debug for XorShiftRng {
- fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
- write!(f, "XorShiftRng {{}}")
- }
-}
-
-impl RngCore for XorShiftRng {
- #[inline]
- fn next_u32(&mut self) -> u32 {
- let x = self.x;
- let t = x ^ (x << 11);
- self.x = self.y;
- self.y = self.z;
- self.z = self.w;
- let w_ = self.w;
- self.w = w_ ^ (w_ >> 19) ^ (t ^ (t >> 8));
- self.w.0
- }
-
- #[inline]
- fn next_u64(&mut self) -> u64 {
- impls::next_u64_via_u32(self)
- }
-
- #[inline]
- fn fill_bytes(&mut self, dest: &mut [u8]) {
- impls::fill_bytes_via_next(self, dest)
- }
-
- fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
- self.fill_bytes(dest);
- Ok(())
- }
-}
-
-impl SeedableRng for XorShiftRng {
- type Seed = [u8; 16];
-
- fn from_seed(seed: Self::Seed) -> Self {
- let mut seed_u32 = [0u32; 4];
- le::read_u32_into(&seed, &mut seed_u32);
-
- // Xorshift cannot be seeded with 0 and we cannot return an Error, but
- // also do not wish to panic (because a random seed can legitimately be
- // 0); our only option is therefore to use a preset value.
- if seed_u32.iter().all(|&x| x == 0) {
- seed_u32 = [0xBAD_5EED, 0xBAD_5EED, 0xBAD_5EED, 0xBAD_5EED];
- }
-
- XorShiftRng {
- x: w(seed_u32[0]),
- y: w(seed_u32[1]),
- z: w(seed_u32[2]),
- w: w(seed_u32[3]),
- }
- }
-
- fn from_rng<R: RngCore>(mut rng: R) -> Result<Self, Error> {
- let mut b = [0u8; 16];
- loop {
- rng.try_fill_bytes(&mut b[..])?;
- if !b.iter().all(|&x| x == 0) {
- break;
- }
- }
-
- Ok(XorShiftRng {
- x: w(u32::from_le_bytes([b[0], b[1], b[2], b[3]])),
- y: w(u32::from_le_bytes([b[4], b[5], b[6], b[7]])),
- z: w(u32::from_le_bytes([b[8], b[9], b[10], b[11]])),
- w: w(u32::from_le_bytes([b[12], b[13], b[14], b[15]])),
- })
- }
-}