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author | Daniel Mueller <deso@posteo.net> | 2019-01-16 17:26:30 -0800 |
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committer | Daniel Mueller <deso@posteo.net> | 2019-01-16 17:26:30 -0800 |
commit | 8350ac6afb2d678b74581000a6aafe1994b72231 (patch) | |
tree | 2330da01a806921b3849c9e64d2b9f506495e2c0 /rand/rand_xoshiro/src/splitmix64.rs | |
parent | d6652b913b33e432a748187f9f5623cec1e9926e (diff) | |
download | nitrocli-8350ac6afb2d678b74581000a6aafe1994b72231.tar.gz nitrocli-8350ac6afb2d678b74581000a6aafe1994b72231.tar.bz2 |
Update nitrokey crate to 0.3.3
This change updates the nitrokey crate to version 0.3.3. Along with that
change we update rand to 0.6.4 because rand 0.6.1 does not yet contain a
publicly accessible rand_os. Note that we no longer require all
crates in rand's workspace, but only rand_os and rand_core, which is a
significant reduction in the number of lines of code compiled.
Import subrepo nitrokey/:nitrokey at 7cf747d56ddc0b7eeedc3caf36dcc909907a171c
Import subrepo rand/:rand at 4336232dda03323634b10ec72ddf27914aebc3a2
Diffstat (limited to 'rand/rand_xoshiro/src/splitmix64.rs')
-rw-r--r-- | rand/rand_xoshiro/src/splitmix64.rs | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/rand/rand_xoshiro/src/splitmix64.rs b/rand/rand_xoshiro/src/splitmix64.rs new file mode 100644 index 0000000..a7cac9f --- /dev/null +++ b/rand/rand_xoshiro/src/splitmix64.rs @@ -0,0 +1,150 @@ +// 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. + +use byteorder::{ByteOrder, LittleEndian}; +use rand_core::le::read_u64_into; +use rand_core::impls::fill_bytes_via_next; +use rand_core::{RngCore, SeedableRng, Error}; + +/// A splitmix64 random number generator. +/// +/// The splitmix algorithm is not suitable for cryptographic purposes, but is +/// very fast and has a 64 bit state. +/// +/// The algorithm used here is translated from [the `splitmix64.c` +/// reference source code](http://xoshiro.di.unimi.it/splitmix64.c) by +/// Sebastiano Vigna. For `next_u32`, a more efficient mixing function taken +/// from [`dsiutils`](http://dsiutils.di.unimi.it/) is used. +#[allow(missing_copy_implementations)] +#[derive(Debug, Clone)] +pub struct SplitMix64 { + x: u64, +} + +const PHI: u64 = 0x9e3779b97f4a7c15; + +impl RngCore for SplitMix64 { + #[inline] + fn next_u32(&mut self) -> u32 { + self.x = self.x.wrapping_add(PHI); + let mut z = self.x; + // David Stafford's + // (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html) + // "Mix4" variant of the 64-bit finalizer in Austin Appleby's + // MurmurHash3 algorithm. + z = (z ^ (z >> 33)).wrapping_mul(0x62A9D9ED799705F5); + z = (z ^ (z >> 28)).wrapping_mul(0xCB24D0A5C88C35B3); + (z >> 32) as u32 + } + + #[inline] + fn next_u64(&mut self) -> u64 { + self.x = self.x.wrapping_add(PHI); + let mut z = self.x; + z = (z ^ (z >> 30)).wrapping_mul(0xbf58476d1ce4e5b9); + z = (z ^ (z >> 27)).wrapping_mul(0x94d049bb133111eb); + z ^ (z >> 31) + } + + #[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<(), Error> { + self.fill_bytes(dest); + Ok(()) + } +} + +impl SeedableRng for SplitMix64 { + type Seed = [u8; 8]; + + /// Create a new `SplitMix64`. + fn from_seed(seed: [u8; 8]) -> SplitMix64 { + let mut state = [0; 1]; + read_u64_into(&seed, &mut state); + SplitMix64 { + x: state[0], + } + } + + /// Seed a `SplitMix64` from a `u64`. + fn seed_from_u64(seed: u64) -> SplitMix64 { + let mut x = [0; 8]; + LittleEndian::write_u64(&mut x, seed); + SplitMix64::from_seed(x) + } +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn reference() { + let mut rng = SplitMix64::seed_from_u64(1477776061723855037); + // These values were produced with the reference implementation: + // http://xoshiro.di.unimi.it/splitmix64.c + let expected : [u64 ; 50]= [ + 1985237415132408290, 2979275885539914483, 13511426838097143398, + 8488337342461049707, 15141737807933549159, 17093170987380407015, + 16389528042912955399, 13177319091862933652, 10841969400225389492, + 17094824097954834098, 3336622647361835228, 9678412372263018368, + 11111587619974030187, 7882215801036322410, 5709234165213761869, + 7799681907651786826, 4616320717312661886, 4251077652075509767, + 7836757050122171900, 5054003328188417616, 12919285918354108358, + 16477564761813870717, 5124667218451240549, 18099554314556827626, + 7603784838804469118, 6358551455431362471, 3037176434532249502, + 3217550417701719149, 9958699920490216947, 5965803675992506258, + 12000828378049868312, 12720568162811471118, 245696019213873792, + 8351371993958923852, 14378754021282935786, 5655432093647472106, + 5508031680350692005, 8515198786865082103, 6287793597487164412, + 14963046237722101617, 3630795823534910476, 8422285279403485710, + 10554287778700714153, 10871906555720704584, 8659066966120258468, + 9420238805069527062, 10338115333623340156, 13514802760105037173, + 14635952304031724449, 15419692541594102413, + ]; + for &e in expected.iter() { + assert_eq!(rng.next_u64(), e); + } + } + + #[test] + fn next_u32() { + let mut rng = SplitMix64::seed_from_u64(10); + // These values were produced with the reference implementation: + // http://dsiutils.di.unimi.it/dsiutils-2.5.1-src.tar.gz + let expected : [u32 ; 100]= [ + 3930361779, 4016923089, 4113052479, 925926767, 1755287528, + 802865554, 954171070, 3724185978, 173676273, 1414488795, 12664133, + 1784889697, 1303817078, 261610523, 941280008, 2571813643, + 2954453492, 378291111, 2546873158, 3923319175, 645257028, + 3881821278, 2681538690, 3037029984, 1999958137, 1853970361, + 2989951788, 2126166628, 839962987, 3989679659, 3656977858, + 684284364, 1673258011, 170979192, 3037622326, 1600748179, + 1780764218, 1141430714, 4139736875, 3336905707, 2262051600, + 3830850262, 2430765325, 1073032139, 1668888979, 2716938970, + 4102420032, 40305196, 386350562, 2754480591, 622869439, 2129598760, + 2306038241, 4218338739, 412298926, 3453855056, 3061469690, + 4284292697, 994843708, 1591016681, 414726151, 1238182607, 18073498, + 1237631493, 351884714, 2347486264, 2488990876, 802846256, 645670443, + 957607012, 3126589776, 1966356370, 3036485766, 868696717, + 2808613630, 2070968151, 1025536863, 1743949425, 466212687, + 2994327271, 209776458, 1246125124, 3344380309, 2203947859, + 968313105, 2805485302, 197484837, 3472483632, 3931823935, + 3288490351, 4165666529, 3671080416, 689542830, 1272555356, + 1039141475, 3984640460, 4142959054, 2252788890, 2459379590, + 991872507, + ]; + for &e in expected.iter() { + assert_eq!(rng.next_u32(), e); + } + } +} |