diff options
Diffstat (limited to 'vendor/rand/src/rngs')
| -rw-r--r-- | vendor/rand/src/rngs/adapter/mod.rs | 16 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/adapter/read.rs | 150 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/adapter/reseeding.rs | 386 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/mock.rs | 87 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/mod.rs | 119 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/small.rs | 117 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/std.rs | 98 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/thread.rs | 143 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/xoshiro128plusplus.rs | 118 | ||||
| -rw-r--r-- | vendor/rand/src/rngs/xoshiro256plusplus.rs | 122 |
10 files changed, 1356 insertions, 0 deletions
diff --git a/vendor/rand/src/rngs/adapter/mod.rs b/vendor/rand/src/rngs/adapter/mod.rs new file mode 100644 index 000000000..bd1d29432 --- /dev/null +++ b/vendor/rand/src/rngs/adapter/mod.rs @@ -0,0 +1,16 @@ +// 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. + +//! Wrappers / adapters forming RNGs + +mod read; +mod reseeding; + +#[allow(deprecated)] +pub use self::read::{ReadError, ReadRng}; +pub use self::reseeding::ReseedingRng; diff --git a/vendor/rand/src/rngs/adapter/read.rs b/vendor/rand/src/rngs/adapter/read.rs new file mode 100644 index 000000000..25a9ca7fc --- /dev/null +++ b/vendor/rand/src/rngs/adapter/read.rs @@ -0,0 +1,150 @@ +// Copyright 2018 Developers of the Rand project. +// Copyright 2013 The Rust Project Developers. +// +// 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. + +//! A wrapper around any Read to treat it as an RNG. + +#![allow(deprecated)] + +use std::fmt; +use std::io::Read; + +use rand_core::{impls, Error, RngCore}; + + +/// An RNG that reads random bytes straight from any type supporting +/// [`std::io::Read`], for example files. +/// +/// This will work best with an infinite reader, but that is not required. +/// +/// This can be used with `/dev/urandom` on Unix but it is recommended to use +/// [`OsRng`] instead. +/// +/// # Panics +/// +/// `ReadRng` uses [`std::io::Read::read_exact`], which retries on interrupts. +/// All other errors from the underlying reader, including when it does not +/// have enough data, will only be reported through [`try_fill_bytes`]. +/// The other [`RngCore`] methods will panic in case of an error. +/// +/// [`OsRng`]: crate::rngs::OsRng +/// [`try_fill_bytes`]: RngCore::try_fill_bytes +#[derive(Debug)] +#[deprecated(since="0.8.4", note="removal due to lack of usage")] +pub struct ReadRng<R> { + reader: R, +} + +impl<R: Read> ReadRng<R> { + /// Create a new `ReadRng` from a `Read`. + pub fn new(r: R) -> ReadRng<R> { + ReadRng { reader: r } + } +} + +impl<R: Read> RngCore for ReadRng<R> { + fn next_u32(&mut self) -> u32 { + impls::next_u32_via_fill(self) + } + + fn next_u64(&mut self) -> u64 { + impls::next_u64_via_fill(self) + } + + fn fill_bytes(&mut self, dest: &mut [u8]) { + self.try_fill_bytes(dest).unwrap_or_else(|err| { + panic!( + "reading random bytes from Read implementation failed; error: {}", + err + ) + }); + } + + fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { + if dest.is_empty() { + return Ok(()); + } + // Use `std::io::read_exact`, which retries on `ErrorKind::Interrupted`. + self.reader + .read_exact(dest) + .map_err(|e| Error::new(ReadError(e))) + } +} + +/// `ReadRng` error type +#[derive(Debug)] +#[deprecated(since="0.8.4")] +pub struct ReadError(std::io::Error); + +impl fmt::Display for ReadError { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + write!(f, "ReadError: {}", self.0) + } +} + +impl std::error::Error for ReadError { + fn source(&self) -> Option<&(dyn std::error::Error + 'static)> { + Some(&self.0) + } +} + + +#[cfg(test)] +mod test { + use std::println; + + use super::ReadRng; + use crate::RngCore; + + #[test] + fn test_reader_rng_u64() { + // transmute from the target to avoid endianness concerns. + #[rustfmt::skip] + let v = [0u8, 0, 0, 0, 0, 0, 0, 1, + 0, 4, 0, 0, 3, 0, 0, 2, + 5, 0, 0, 0, 0, 0, 0, 0]; + let mut rng = ReadRng::new(&v[..]); + + assert_eq!(rng.next_u64(), 1 << 56); + assert_eq!(rng.next_u64(), (2 << 56) + (3 << 32) + (4 << 8)); + assert_eq!(rng.next_u64(), 5); + } + + #[test] + fn test_reader_rng_u32() { + let v = [0u8, 0, 0, 1, 0, 0, 2, 0, 3, 0, 0, 0]; + let mut rng = ReadRng::new(&v[..]); + + assert_eq!(rng.next_u32(), 1 << 24); + assert_eq!(rng.next_u32(), 2 << 16); + assert_eq!(rng.next_u32(), 3); + } + + #[test] + fn test_reader_rng_fill_bytes() { + let v = [1u8, 2, 3, 4, 5, 6, 7, 8]; + let mut w = [0u8; 8]; + + let mut rng = ReadRng::new(&v[..]); + rng.fill_bytes(&mut w); + + assert!(v == w); + } + + #[test] + fn test_reader_rng_insufficient_bytes() { + let v = [1u8, 2, 3, 4, 5, 6, 7, 8]; + let mut w = [0u8; 9]; + + let mut rng = ReadRng::new(&v[..]); + + let result = rng.try_fill_bytes(&mut w); + assert!(result.is_err()); + println!("Error: {}", result.unwrap_err()); + } +} diff --git a/vendor/rand/src/rngs/adapter/reseeding.rs b/vendor/rand/src/rngs/adapter/reseeding.rs new file mode 100644 index 000000000..ae3fcbb2f --- /dev/null +++ b/vendor/rand/src/rngs/adapter/reseeding.rs @@ -0,0 +1,386 @@ +// Copyright 2018 Developers of the Rand project. +// Copyright 2013 The Rust Project Developers. +// +// 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. + +//! A wrapper around another PRNG that reseeds it after it +//! generates a certain number of random bytes. + +use core::mem::size_of; + +use rand_core::block::{BlockRng, BlockRngCore}; +use rand_core::{CryptoRng, Error, RngCore, SeedableRng}; + +/// A wrapper around any PRNG that implements [`BlockRngCore`], that adds the +/// ability to reseed it. +/// +/// `ReseedingRng` reseeds the underlying PRNG in the following cases: +/// +/// - On a manual call to [`reseed()`]. +/// - After `clone()`, the clone will be reseeded on first use. +/// - When a process is forked on UNIX, the RNGs in both the parent and child +/// processes will be reseeded just before the next call to +/// [`BlockRngCore::generate`], i.e. "soon". For ChaCha and Hc128 this is a +/// maximum of fifteen `u32` values before reseeding. +/// - After the PRNG has generated a configurable number of random bytes. +/// +/// # When should reseeding after a fixed number of generated bytes be used? +/// +/// Reseeding after a fixed number of generated bytes is never strictly +/// *necessary*. Cryptographic PRNGs don't have a limited number of bytes they +/// can output, or at least not a limit reachable in any practical way. There is +/// no such thing as 'running out of entropy'. +/// +/// Occasionally reseeding can be seen as some form of 'security in depth'. Even +/// if in the future a cryptographic weakness is found in the CSPRNG being used, +/// or a flaw in the implementation, occasionally reseeding should make +/// exploiting it much more difficult or even impossible. +/// +/// Use [`ReseedingRng::new`] with a `threshold` of `0` to disable reseeding +/// after a fixed number of generated bytes. +/// +/// # Limitations +/// +/// It is recommended that a `ReseedingRng` (including `ThreadRng`) not be used +/// from a fork handler. +/// Use `OsRng` or `getrandom`, or defer your use of the RNG until later. +/// +/// # Error handling +/// +/// Although unlikely, reseeding the wrapped PRNG can fail. `ReseedingRng` will +/// never panic but try to handle the error intelligently through some +/// combination of retrying and delaying reseeding until later. +/// If handling the source error fails `ReseedingRng` will continue generating +/// data from the wrapped PRNG without reseeding. +/// +/// Manually calling [`reseed()`] will not have this retry or delay logic, but +/// reports the error. +/// +/// # Example +/// +/// ``` +/// use rand::prelude::*; +/// use rand_chacha::ChaCha20Core; // Internal part of ChaChaRng that +/// // implements BlockRngCore +/// use rand::rngs::OsRng; +/// use rand::rngs::adapter::ReseedingRng; +/// +/// let prng = ChaCha20Core::from_entropy(); +/// let mut reseeding_rng = ReseedingRng::new(prng, 0, OsRng); +/// +/// println!("{}", reseeding_rng.gen::<u64>()); +/// +/// let mut cloned_rng = reseeding_rng.clone(); +/// assert!(reseeding_rng.gen::<u64>() != cloned_rng.gen::<u64>()); +/// ``` +/// +/// [`BlockRngCore`]: rand_core::block::BlockRngCore +/// [`ReseedingRng::new`]: ReseedingRng::new +/// [`reseed()`]: ReseedingRng::reseed +#[derive(Debug)] +pub struct ReseedingRng<R, Rsdr>(BlockRng<ReseedingCore<R, Rsdr>>) +where + R: BlockRngCore + SeedableRng, + Rsdr: RngCore; + +impl<R, Rsdr> ReseedingRng<R, Rsdr> +where + R: BlockRngCore + SeedableRng, + Rsdr: RngCore, +{ + /// Create a new `ReseedingRng` from an existing PRNG, combined with a RNG + /// to use as reseeder. + /// + /// `threshold` sets the number of generated bytes after which to reseed the + /// PRNG. Set it to zero to never reseed based on the number of generated + /// values. + pub fn new(rng: R, threshold: u64, reseeder: Rsdr) -> Self { + ReseedingRng(BlockRng::new(ReseedingCore::new(rng, threshold, reseeder))) + } + + /// Reseed the internal PRNG. + pub fn reseed(&mut self) -> Result<(), Error> { + self.0.core.reseed() + } +} + +// TODO: this should be implemented for any type where the inner type +// implements RngCore, but we can't specify that because ReseedingCore is private +impl<R, Rsdr: RngCore> RngCore for ReseedingRng<R, Rsdr> +where + R: BlockRngCore<Item = u32> + SeedableRng, + <R as BlockRngCore>::Results: AsRef<[u32]> + AsMut<[u32]>, +{ + #[inline(always)] + fn next_u32(&mut self) -> u32 { + self.0.next_u32() + } + + #[inline(always)] + fn next_u64(&mut self) -> u64 { + self.0.next_u64() + } + + fn fill_bytes(&mut self, dest: &mut [u8]) { + self.0.fill_bytes(dest) + } + + fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { + self.0.try_fill_bytes(dest) + } +} + +impl<R, Rsdr> Clone for ReseedingRng<R, Rsdr> +where + R: BlockRngCore + SeedableRng + Clone, + Rsdr: RngCore + Clone, +{ + fn clone(&self) -> ReseedingRng<R, Rsdr> { + // Recreating `BlockRng` seems easier than cloning it and resetting + // the index. + ReseedingRng(BlockRng::new(self.0.core.clone())) + } +} + +impl<R, Rsdr> CryptoRng for ReseedingRng<R, Rsdr> +where + R: BlockRngCore + SeedableRng + CryptoRng, + Rsdr: RngCore + CryptoRng, +{ +} + +#[derive(Debug)] +struct ReseedingCore<R, Rsdr> { + inner: R, + reseeder: Rsdr, + threshold: i64, + bytes_until_reseed: i64, + fork_counter: usize, +} + +impl<R, Rsdr> BlockRngCore for ReseedingCore<R, Rsdr> +where + R: BlockRngCore + SeedableRng, + Rsdr: RngCore, +{ + type Item = <R as BlockRngCore>::Item; + type Results = <R as BlockRngCore>::Results; + + fn generate(&mut self, results: &mut Self::Results) { + let global_fork_counter = fork::get_fork_counter(); + if self.bytes_until_reseed <= 0 || self.is_forked(global_fork_counter) { + // We get better performance by not calling only `reseed` here + // and continuing with the rest of the function, but by directly + // returning from a non-inlined function. + return self.reseed_and_generate(results, global_fork_counter); + } + let num_bytes = results.as_ref().len() * size_of::<Self::Item>(); + self.bytes_until_reseed -= num_bytes as i64; + self.inner.generate(results); + } +} + +impl<R, Rsdr> ReseedingCore<R, Rsdr> +where + R: BlockRngCore + SeedableRng, + Rsdr: RngCore, +{ + /// Create a new `ReseedingCore`. + fn new(rng: R, threshold: u64, reseeder: Rsdr) -> Self { + use ::core::i64::MAX; + fork::register_fork_handler(); + + // Because generating more values than `i64::MAX` takes centuries on + // current hardware, we just clamp to that value. + // Also we set a threshold of 0, which indicates no limit, to that + // value. + let threshold = if threshold == 0 { + MAX + } else if threshold <= MAX as u64 { + threshold as i64 + } else { + MAX + }; + + ReseedingCore { + inner: rng, + reseeder, + threshold: threshold as i64, + bytes_until_reseed: threshold as i64, + fork_counter: 0, + } + } + + /// Reseed the internal PRNG. + fn reseed(&mut self) -> Result<(), Error> { + R::from_rng(&mut self.reseeder).map(|result| { + self.bytes_until_reseed = self.threshold; + self.inner = result + }) + } + + fn is_forked(&self, global_fork_counter: usize) -> bool { + // In theory, on 32-bit platforms, it is possible for + // `global_fork_counter` to wrap around after ~4e9 forks. + // + // This check will detect a fork in the normal case where + // `fork_counter < global_fork_counter`, and also when the difference + // between both is greater than `isize::MAX` (wrapped around). + // + // It will still fail to detect a fork if there have been more than + // `isize::MAX` forks, without any reseed in between. Seems unlikely + // enough. + (self.fork_counter.wrapping_sub(global_fork_counter) as isize) < 0 + } + + #[inline(never)] + fn reseed_and_generate( + &mut self, results: &mut <Self as BlockRngCore>::Results, global_fork_counter: usize, + ) { + #![allow(clippy::if_same_then_else)] // false positive + if self.is_forked(global_fork_counter) { + info!("Fork detected, reseeding RNG"); + } else { + trace!("Reseeding RNG (periodic reseed)"); + } + + let num_bytes = results.as_ref().len() * size_of::<<R as BlockRngCore>::Item>(); + + if let Err(e) = self.reseed() { + warn!("Reseeding RNG failed: {}", e); + let _ = e; + } + self.fork_counter = global_fork_counter; + + self.bytes_until_reseed = self.threshold - num_bytes as i64; + self.inner.generate(results); + } +} + +impl<R, Rsdr> Clone for ReseedingCore<R, Rsdr> +where + R: BlockRngCore + SeedableRng + Clone, + Rsdr: RngCore + Clone, +{ + fn clone(&self) -> ReseedingCore<R, Rsdr> { + ReseedingCore { + inner: self.inner.clone(), + reseeder: self.reseeder.clone(), + threshold: self.threshold, + bytes_until_reseed: 0, // reseed clone on first use + fork_counter: self.fork_counter, + } + } +} + +impl<R, Rsdr> CryptoRng for ReseedingCore<R, Rsdr> +where + R: BlockRngCore + SeedableRng + CryptoRng, + Rsdr: RngCore + CryptoRng, +{ +} + + +#[cfg(all(unix, not(target_os = "emscripten")))] +mod fork { + use core::sync::atomic::{AtomicUsize, Ordering}; + use std::sync::Once; + + // Fork protection + // + // We implement fork protection on Unix using `pthread_atfork`. + // When the process is forked, we increment `RESEEDING_RNG_FORK_COUNTER`. + // Every `ReseedingRng` stores the last known value of the static in + // `fork_counter`. If the cached `fork_counter` is less than + // `RESEEDING_RNG_FORK_COUNTER`, it is time to reseed this RNG. + // + // If reseeding fails, we don't deal with this by setting a delay, but just + // don't update `fork_counter`, so a reseed is attempted as soon as + // possible. + + static RESEEDING_RNG_FORK_COUNTER: AtomicUsize = AtomicUsize::new(0); + + pub fn get_fork_counter() -> usize { + RESEEDING_RNG_FORK_COUNTER.load(Ordering::Relaxed) + } + + extern "C" fn fork_handler() { + // Note: fetch_add is defined to wrap on overflow + // (which is what we want). + RESEEDING_RNG_FORK_COUNTER.fetch_add(1, Ordering::Relaxed); + } + + pub fn register_fork_handler() { + static REGISTER: Once = Once::new(); + REGISTER.call_once(|| { + // Bump the counter before and after forking (see #1169): + let ret = unsafe { libc::pthread_atfork( + Some(fork_handler), + Some(fork_handler), + Some(fork_handler), + ) }; + if ret != 0 { + panic!("libc::pthread_atfork failed with code {}", ret); + } + }); + } +} + +#[cfg(not(all(unix, not(target_os = "emscripten"))))] +mod fork { + pub fn get_fork_counter() -> usize { + 0 + } + pub fn register_fork_handler() {} +} + + +#[cfg(feature = "std_rng")] +#[cfg(test)] +mod test { + use super::ReseedingRng; + use crate::rngs::mock::StepRng; + use crate::rngs::std::Core; + use crate::{Rng, SeedableRng}; + + #[test] + fn test_reseeding() { + let mut zero = StepRng::new(0, 0); + let rng = Core::from_rng(&mut zero).unwrap(); + let thresh = 1; // reseed every time the buffer is exhausted + let mut reseeding = ReseedingRng::new(rng, thresh, zero); + + // RNG buffer size is [u32; 64] + // Debug is only implemented up to length 32 so use two arrays + let mut buf = ([0u32; 32], [0u32; 32]); + reseeding.fill(&mut buf.0); + reseeding.fill(&mut buf.1); + let seq = buf; + for _ in 0..10 { + reseeding.fill(&mut buf.0); + reseeding.fill(&mut buf.1); + assert_eq!(buf, seq); + } + } + + #[test] + fn test_clone_reseeding() { + #![allow(clippy::redundant_clone)] + + let mut zero = StepRng::new(0, 0); + let rng = Core::from_rng(&mut zero).unwrap(); + let mut rng1 = ReseedingRng::new(rng, 32 * 4, zero); + + let first: u32 = rng1.gen(); + for _ in 0..10 { + let _ = rng1.gen::<u32>(); + } + + let mut rng2 = rng1.clone(); + assert_eq!(first, rng2.gen::<u32>()); + } +} diff --git a/vendor/rand/src/rngs/mock.rs b/vendor/rand/src/rngs/mock.rs new file mode 100644 index 000000000..a1745a490 --- /dev/null +++ b/vendor/rand/src/rngs/mock.rs @@ -0,0 +1,87 @@ +// 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. + +//! Mock random number generator + +use rand_core::{impls, Error, RngCore}; + +#[cfg(feature = "serde1")] +use serde::{Serialize, Deserialize}; + +/// A simple implementation of `RngCore` for testing purposes. +/// +/// This generates an arithmetic sequence (i.e. adds a constant each step) +/// over a `u64` number, using wrapping arithmetic. If the increment is 0 +/// the generator yields a constant. +/// +/// ``` +/// use rand::Rng; +/// use rand::rngs::mock::StepRng; +/// +/// let mut my_rng = StepRng::new(2, 1); +/// let sample: [u64; 3] = my_rng.gen(); +/// assert_eq!(sample, [2, 3, 4]); +/// ``` +#[derive(Debug, Clone, PartialEq, Eq)] +#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))] +pub struct StepRng { + v: u64, + a: u64, +} + +impl StepRng { + /// Create a `StepRng`, yielding an arithmetic sequence starting with + /// `initial` and incremented by `increment` each time. + pub fn new(initial: u64, increment: u64) -> Self { + StepRng { + v: initial, + a: increment, + } + } +} + +impl RngCore for StepRng { + #[inline] + fn next_u32(&mut self) -> u32 { + self.next_u64() as u32 + } + + #[inline] + fn next_u64(&mut self) -> u64 { + let result = self.v; + self.v = self.v.wrapping_add(self.a); + result + } + + #[inline] + fn fill_bytes(&mut self, dest: &mut [u8]) { + impls::fill_bytes_via_next(self, dest); + } + + #[inline] + fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { + self.fill_bytes(dest); + Ok(()) + } +} + +#[cfg(test)] +mod tests { + #[test] + #[cfg(feature = "serde1")] + fn test_serialization_step_rng() { + use super::StepRng; + + let some_rng = StepRng::new(42, 7); + let de_some_rng: StepRng = + bincode::deserialize(&bincode::serialize(&some_rng).unwrap()).unwrap(); + assert_eq!(some_rng.v, de_some_rng.v); + assert_eq!(some_rng.a, de_some_rng.a); + + } +} diff --git a/vendor/rand/src/rngs/mod.rs b/vendor/rand/src/rngs/mod.rs new file mode 100644 index 000000000..ac3c2c595 --- /dev/null +++ b/vendor/rand/src/rngs/mod.rs @@ -0,0 +1,119 @@ +// 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. + +//! Random number generators and adapters +//! +//! ## Background: Random number generators (RNGs) +//! +//! Computers cannot produce random numbers from nowhere. We classify +//! random number generators as follows: +//! +//! - "True" random number generators (TRNGs) use hard-to-predict data sources +//! (e.g. the high-resolution parts of event timings and sensor jitter) to +//! harvest random bit-sequences, apply algorithms to remove bias and +//! estimate available entropy, then combine these bits into a byte-sequence +//! or an entropy pool. This job is usually done by the operating system or +//! a hardware generator (HRNG). +//! - "Pseudo"-random number generators (PRNGs) use algorithms to transform a +//! seed into a sequence of pseudo-random numbers. These generators can be +//! fast and produce well-distributed unpredictable random numbers (or not). +//! They are usually deterministic: given algorithm and seed, the output +//! sequence can be reproduced. They have finite period and eventually loop; +//! with many algorithms this period is fixed and can be proven sufficiently +//! long, while others are chaotic and the period depends on the seed. +//! - "Cryptographically secure" pseudo-random number generators (CSPRNGs) +//! are the sub-set of PRNGs which are secure. Security of the generator +//! relies both on hiding the internal state and using a strong algorithm. +//! +//! ## Traits and functionality +//! +//! All RNGs implement the [`RngCore`] trait, as a consequence of which the +//! [`Rng`] extension trait is automatically implemented. Secure RNGs may +//! additionally implement the [`CryptoRng`] trait. +//! +//! All PRNGs require a seed to produce their random number sequence. The +//! [`SeedableRng`] trait provides three ways of constructing PRNGs: +//! +//! - `from_seed` accepts a type specific to the PRNG +//! - `from_rng` allows a PRNG to be seeded from any other RNG +//! - `seed_from_u64` allows any PRNG to be seeded from a `u64` insecurely +//! - `from_entropy` securely seeds a PRNG from fresh entropy +//! +//! Use the [`rand_core`] crate when implementing your own RNGs. +//! +//! ## Our generators +//! +//! This crate provides several random number generators: +//! +//! - [`OsRng`] is an interface to the operating system's random number +//! source. Typically the operating system uses a CSPRNG with entropy +//! provided by a TRNG and some type of on-going re-seeding. +//! - [`ThreadRng`], provided by the [`thread_rng`] function, is a handle to a +//! thread-local CSPRNG with periodic seeding from [`OsRng`]. Because this +//! is local, it is typically much faster than [`OsRng`]. It should be +//! secure, though the paranoid may prefer [`OsRng`]. +//! - [`StdRng`] is a CSPRNG chosen for good performance and trust of security +//! (based on reviews, maturity and usage). The current algorithm is ChaCha12, +//! which is well established and rigorously analysed. +//! [`StdRng`] provides the algorithm used by [`ThreadRng`] but without +//! periodic reseeding. +//! - [`SmallRng`] is an **insecure** PRNG designed to be fast, simple, require +//! little memory, and have good output quality. +//! +//! The algorithms selected for [`StdRng`] and [`SmallRng`] may change in any +//! release and may be platform-dependent, therefore they should be considered +//! **not reproducible**. +//! +//! ## Additional generators +//! +//! **TRNGs**: The [`rdrand`] crate provides an interface to the RDRAND and +//! RDSEED instructions available in modern Intel and AMD CPUs. +//! The [`rand_jitter`] crate provides a user-space implementation of +//! entropy harvesting from CPU timer jitter, but is very slow and has +//! [security issues](https://github.com/rust-random/rand/issues/699). +//! +//! **PRNGs**: Several companion crates are available, providing individual or +//! families of PRNG algorithms. These provide the implementations behind +//! [`StdRng`] and [`SmallRng`] but can also be used directly, indeed *should* +//! be used directly when **reproducibility** matters. +//! Some suggestions are: [`rand_chacha`], [`rand_pcg`], [`rand_xoshiro`]. +//! A full list can be found by searching for crates with the [`rng` tag]. +//! +//! [`Rng`]: crate::Rng +//! [`RngCore`]: crate::RngCore +//! [`CryptoRng`]: crate::CryptoRng +//! [`SeedableRng`]: crate::SeedableRng +//! [`thread_rng`]: crate::thread_rng +//! [`rdrand`]: https://crates.io/crates/rdrand +//! [`rand_jitter`]: https://crates.io/crates/rand_jitter +//! [`rand_chacha`]: https://crates.io/crates/rand_chacha +//! [`rand_pcg`]: https://crates.io/crates/rand_pcg +//! [`rand_xoshiro`]: https://crates.io/crates/rand_xoshiro +//! [`rng` tag]: https://crates.io/keywords/rng + +#[cfg_attr(doc_cfg, doc(cfg(feature = "std")))] +#[cfg(feature = "std")] pub mod adapter; + +pub mod mock; // Public so we don't export `StepRng` directly, making it a bit + // more clear it is intended for testing. + +#[cfg(all(feature = "small_rng", target_pointer_width = "64"))] +mod xoshiro256plusplus; +#[cfg(all(feature = "small_rng", not(target_pointer_width = "64")))] +mod xoshiro128plusplus; +#[cfg(feature = "small_rng")] mod small; + +#[cfg(feature = "std_rng")] mod std; +#[cfg(all(feature = "std", feature = "std_rng"))] pub(crate) mod thread; + +#[cfg(feature = "small_rng")] pub use self::small::SmallRng; +#[cfg(feature = "std_rng")] pub use self::std::StdRng; +#[cfg(all(feature = "std", feature = "std_rng"))] pub use self::thread::ThreadRng; + +#[cfg_attr(doc_cfg, doc(cfg(feature = "getrandom")))] +#[cfg(feature = "getrandom")] pub use rand_core::OsRng; diff --git a/vendor/rand/src/rngs/small.rs b/vendor/rand/src/rngs/small.rs new file mode 100644 index 000000000..fb0e0d119 --- /dev/null +++ b/vendor/rand/src/rngs/small.rs @@ -0,0 +1,117 @@ +// 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. + +//! A small fast RNG + +use rand_core::{Error, RngCore, SeedableRng}; + +#[cfg(target_pointer_width = "64")] +type Rng = super::xoshiro256plusplus::Xoshiro256PlusPlus; +#[cfg(not(target_pointer_width = "64"))] +type Rng = super::xoshiro128plusplus::Xoshiro128PlusPlus; + +/// A small-state, fast non-crypto PRNG +/// +/// `SmallRng` may be a good choice when a PRNG with small state, cheap +/// initialization, good statistical quality and good performance are required. +/// Note that depending on the application, [`StdRng`] may be faster on many +/// modern platforms while providing higher-quality randomness. Furthermore, +/// `SmallRng` is **not** a good choice when: +/// - Security against prediction is important. Use [`StdRng`] instead. +/// - Seeds with many zeros are provided. In such cases, it takes `SmallRng` +/// about 10 samples to produce 0 and 1 bits with equal probability. Either +/// provide seeds with an approximately equal number of 0 and 1 (for example +/// by using [`SeedableRng::from_entropy`] or [`SeedableRng::seed_from_u64`]), +/// or use [`StdRng`] instead. +/// +/// The algorithm is deterministic but should not be considered reproducible +/// due to dependence on platform and possible replacement in future +/// library versions. For a reproducible generator, use a named PRNG from an +/// external crate, e.g. [rand_xoshiro] or [rand_chacha]. +/// Refer also to [The Book](https://rust-random.github.io/book/guide-rngs.html). +/// +/// The PRNG algorithm in `SmallRng` is chosen to be efficient on the current +/// platform, without consideration for cryptography or security. The size of +/// its state is much smaller than [`StdRng`]. The current algorithm is +/// `Xoshiro256PlusPlus` on 64-bit platforms and `Xoshiro128PlusPlus` on 32-bit +/// platforms. Both are also implemented by the [rand_xoshiro] crate. +/// +/// # Examples +/// +/// Initializing `SmallRng` with a random seed can be done using [`SeedableRng::from_entropy`]: +/// +/// ``` +/// use rand::{Rng, SeedableRng}; +/// use rand::rngs::SmallRng; +/// +/// // Create small, cheap to initialize and fast RNG with a random seed. +/// // The randomness is supplied by the operating system. +/// let mut small_rng = SmallRng::from_entropy(); +/// # let v: u32 = small_rng.gen(); +/// ``` +/// +/// When initializing a lot of `SmallRng`'s, using [`thread_rng`] can be more +/// efficient: +/// +/// ``` +/// use rand::{SeedableRng, thread_rng}; +/// use rand::rngs::SmallRng; +/// +/// // Create a big, expensive to initialize and slower, but unpredictable RNG. +/// // This is cached and done only once per thread. +/// let mut thread_rng = thread_rng(); +/// // Create small, cheap to initialize and fast RNGs with random seeds. +/// // One can generally assume this won't fail. +/// let rngs: Vec<SmallRng> = (0..10) +/// .map(|_| SmallRng::from_rng(&mut thread_rng).unwrap()) +/// .collect(); +/// ``` +/// +/// [`StdRng`]: crate::rngs::StdRng +/// [`thread_rng`]: crate::thread_rng +/// [rand_chacha]: https://crates.io/crates/rand_chacha +/// [rand_xoshiro]: https://crates.io/crates/rand_xoshiro +#[cfg_attr(doc_cfg, doc(cfg(feature = "small_rng")))] +#[derive(Clone, Debug, PartialEq, Eq)] +pub struct SmallRng(Rng); + +impl RngCore for SmallRng { + #[inline(always)] + fn next_u32(&mut self) -> u32 { + self.0.next_u32() + } + + #[inline(always)] + fn next_u64(&mut self) -> u64 { + self.0.next_u64() + } + + #[inline(always)] + fn fill_bytes(&mut self, dest: &mut [u8]) { + self.0.fill_bytes(dest); + } + + #[inline(always)] + fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { + self.0.try_fill_bytes(dest) + } +} + +impl SeedableRng for SmallRng { + type Seed = <Rng as SeedableRng>::Seed; + + #[inline(always)] + fn from_seed(seed: Self::Seed) -> Self { + SmallRng(Rng::from_seed(seed)) + } + + #[inline(always)] + fn from_rng<R: RngCore>(rng: R) -> Result<Self, Error> { + Rng::from_rng(rng).map(SmallRng) + } +} diff --git a/vendor/rand/src/rngs/std.rs b/vendor/rand/src/rngs/std.rs new file mode 100644 index 000000000..cdae8fab0 --- /dev/null +++ b/vendor/rand/src/rngs/std.rs @@ -0,0 +1,98 @@ +// 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 standard RNG + +use crate::{CryptoRng, Error, RngCore, SeedableRng}; + +pub(crate) use rand_chacha::ChaCha12Core as Core; + +use rand_chacha::ChaCha12Rng as Rng; + +/// The standard RNG. The PRNG algorithm in `StdRng` is chosen to be efficient +/// on the current platform, to be statistically strong and unpredictable +/// (meaning a cryptographically secure PRNG). +/// +/// The current algorithm used is the ChaCha block cipher with 12 rounds. Please +/// see this relevant [rand issue] for the discussion. This may change as new +/// evidence of cipher security and performance becomes available. +/// +/// The algorithm is deterministic but should not be considered reproducible +/// due to dependence on configuration and possible replacement in future +/// library versions. For a secure reproducible generator, we recommend use of +/// the [rand_chacha] crate directly. +/// +/// [rand_chacha]: https://crates.io/crates/rand_chacha +/// [rand issue]: https://github.com/rust-random/rand/issues/932 +#[cfg_attr(doc_cfg, doc(cfg(feature = "std_rng")))] +#[derive(Clone, Debug, PartialEq, Eq)] +pub struct StdRng(Rng); + +impl RngCore for StdRng { + #[inline(always)] + fn next_u32(&mut self) -> u32 { + self.0.next_u32() + } + + #[inline(always)] + fn next_u64(&mut self) -> u64 { + self.0.next_u64() + } + + #[inline(always)] + fn fill_bytes(&mut self, dest: &mut [u8]) { + self.0.fill_bytes(dest); + } + + #[inline(always)] + fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { + self.0.try_fill_bytes(dest) + } +} + +impl SeedableRng for StdRng { + type Seed = <Rng as SeedableRng>::Seed; + + #[inline(always)] + fn from_seed(seed: Self::Seed) -> Self { + StdRng(Rng::from_seed(seed)) + } + + #[inline(always)] + fn from_rng<R: RngCore>(rng: R) -> Result<Self, Error> { + Rng::from_rng(rng).map(StdRng) + } +} + +impl CryptoRng for StdRng {} + + +#[cfg(test)] +mod test { + use crate::rngs::StdRng; + use crate::{RngCore, SeedableRng}; + + #[test] + fn test_stdrng_construction() { + // Test value-stability of StdRng. This is expected to break any time + // the algorithm is changed. + #[rustfmt::skip] + let seed = [1,0,0,0, 23,0,0,0, 200,1,0,0, 210,30,0,0, + 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0]; + + let target = [10719222850664546238, 14064965282130556830]; + + let mut rng0 = StdRng::from_seed(seed); + let x0 = rng0.next_u64(); + + let mut rng1 = StdRng::from_rng(rng0).unwrap(); + let x1 = rng1.next_u64(); + + assert_eq!([x0, x1], target); + } +} diff --git a/vendor/rand/src/rngs/thread.rs b/vendor/rand/src/rngs/thread.rs new file mode 100644 index 000000000..baebb1d99 --- /dev/null +++ b/vendor/rand/src/rngs/thread.rs @@ -0,0 +1,143 @@ +// 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. + +//! Thread-local random number generator + +use core::cell::UnsafeCell; +use std::rc::Rc; +use std::thread_local; + +use super::std::Core; +use crate::rngs::adapter::ReseedingRng; +use crate::rngs::OsRng; +use crate::{CryptoRng, Error, RngCore, SeedableRng}; + +// Rationale for using `UnsafeCell` in `ThreadRng`: +// +// Previously we used a `RefCell`, with an overhead of ~15%. There will only +// ever be one mutable reference to the interior of the `UnsafeCell`, because +// we only have such a reference inside `next_u32`, `next_u64`, etc. Within a +// single thread (which is the definition of `ThreadRng`), there will only ever +// be one of these methods active at a time. +// +// A possible scenario where there could be multiple mutable references is if +// `ThreadRng` is used inside `next_u32` and co. But the implementation is +// completely under our control. We just have to ensure none of them use +// `ThreadRng` internally, which is nonsensical anyway. We should also never run +// `ThreadRng` in destructors of its implementation, which is also nonsensical. + + +// Number of generated bytes after which to reseed `ThreadRng`. +// According to benchmarks, reseeding has a noticeable impact with thresholds +// of 32 kB and less. We choose 64 kB to avoid significant overhead. +const THREAD_RNG_RESEED_THRESHOLD: u64 = 1024 * 64; + +/// A reference to the thread-local generator +/// +/// An instance can be obtained via [`thread_rng`] or via `ThreadRng::default()`. +/// This handle is safe to use everywhere (including thread-local destructors), +/// though it is recommended not to use inside a fork handler. +/// The handle cannot be passed between threads (is not `Send` or `Sync`). +/// +/// `ThreadRng` uses the same PRNG as [`StdRng`] for security and performance +/// and is automatically seeded from [`OsRng`]. +/// +/// Unlike `StdRng`, `ThreadRng` uses the [`ReseedingRng`] wrapper to reseed +/// the PRNG from fresh entropy every 64 kiB of random data as well as after a +/// fork on Unix (though not quite immediately; see documentation of +/// [`ReseedingRng`]). +/// Note that the reseeding is done as an extra precaution against side-channel +/// attacks and mis-use (e.g. if somehow weak entropy were supplied initially). +/// The PRNG algorithms used are assumed to be secure. +/// +/// [`ReseedingRng`]: crate::rngs::adapter::ReseedingRng +/// [`StdRng`]: crate::rngs::StdRng +#[cfg_attr(doc_cfg, doc(cfg(all(feature = "std", feature = "std_rng"))))] +#[derive(Clone, Debug)] +pub struct ThreadRng { + // Rc is explicitly !Send and !Sync + rng: Rc<UnsafeCell<ReseedingRng<Core, OsRng>>>, +} + +thread_local!( + // We require Rc<..> to avoid premature freeing when thread_rng is used + // within thread-local destructors. See #968. + static THREAD_RNG_KEY: Rc<UnsafeCell<ReseedingRng<Core, OsRng>>> = { + let r = Core::from_rng(OsRng).unwrap_or_else(|err| + panic!("could not initialize thread_rng: {}", err)); + let rng = ReseedingRng::new(r, + THREAD_RNG_RESEED_THRESHOLD, + OsRng); + Rc::new(UnsafeCell::new(rng)) + } +); + +/// Retrieve the lazily-initialized thread-local random number generator, +/// seeded by the system. Intended to be used in method chaining style, +/// e.g. `thread_rng().gen::<i32>()`, or cached locally, e.g. +/// `let mut rng = thread_rng();`. Invoked by the `Default` trait, making +/// `ThreadRng::default()` equivalent. +/// +/// For more information see [`ThreadRng`]. +#[cfg_attr(doc_cfg, doc(cfg(all(feature = "std", feature = "std_rng"))))] +pub fn thread_rng() -> ThreadRng { + let rng = THREAD_RNG_KEY.with(|t| t.clone()); + ThreadRng { rng } +} + +impl Default for ThreadRng { + fn default() -> ThreadRng { + crate::prelude::thread_rng() + } +} + +impl RngCore for ThreadRng { + #[inline(always)] + fn next_u32(&mut self) -> u32 { + // SAFETY: We must make sure to stop using `rng` before anyone else + // creates another mutable reference + let rng = unsafe { &mut *self.rng.get() }; + rng.next_u32() + } + + #[inline(always)] + fn next_u64(&mut self) -> u64 { + // SAFETY: We must make sure to stop using `rng` before anyone else + // creates another mutable reference + let rng = unsafe { &mut *self.rng.get() }; + rng.next_u64() + } + + fn fill_bytes(&mut self, dest: &mut [u8]) { + // SAFETY: We must make sure to stop using `rng` before anyone else + // creates another mutable reference + let rng = unsafe { &mut *self.rng.get() }; + rng.fill_bytes(dest) + } + + fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { + // SAFETY: We must make sure to stop using `rng` before anyone else + // creates another mutable reference + let rng = unsafe { &mut *self.rng.get() }; + rng.try_fill_bytes(dest) + } +} + +impl CryptoRng for ThreadRng {} + + +#[cfg(test)] +mod test { + #[test] + fn test_thread_rng() { + use crate::Rng; + let mut r = crate::thread_rng(); + r.gen::<i32>(); + assert_eq!(r.gen_range(0..1), 0); + } +} diff --git a/vendor/rand/src/rngs/xoshiro128plusplus.rs b/vendor/rand/src/rngs/xoshiro128plusplus.rs new file mode 100644 index 000000000..ece98fafd --- /dev/null +++ b/vendor/rand/src/rngs/xoshiro128plusplus.rs @@ -0,0 +1,118 @@ +// 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::impls::{next_u64_via_u32, fill_bytes_via_next}; +use rand_core::le::read_u32_into; +use rand_core::{SeedableRng, RngCore, Error}; + +/// A xoshiro128++ random number generator. +/// +/// The xoshiro128++ algorithm is not suitable for cryptographic purposes, but +/// is very fast and has excellent statistical properties. +/// +/// The algorithm used here is translated from [the `xoshiro128plusplus.c` +/// reference source code](http://xoshiro.di.unimi.it/xoshiro128plusplus.c) by +/// David Blackman and Sebastiano Vigna. +#[derive(Debug, Clone, PartialEq, Eq)] +#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))] +pub struct Xoshiro128PlusPlus { + s: [u32; 4], +} + +impl SeedableRng for Xoshiro128PlusPlus { + type Seed = [u8; 16]; + + /// Create a new `Xoshiro128PlusPlus`. If `seed` is entirely 0, it will be + /// mapped to a different seed. + #[inline] + fn from_seed(seed: [u8; 16]) -> Xoshiro128PlusPlus { + if seed.iter().all(|&x| x == 0) { + return Self::seed_from_u64(0); + } + let mut state = [0; 4]; + read_u32_into(&seed, &mut state); + Xoshiro128PlusPlus { s: state } + } + + /// Create a new `Xoshiro128PlusPlus` from a `u64` seed. + /// + /// This uses the SplitMix64 generator internally. + fn seed_from_u64(mut state: u64) -> Self { + const PHI: u64 = 0x9e3779b97f4a7c15; + let mut seed = Self::Seed::default(); + for chunk in seed.as_mut().chunks_mut(8) { + state = state.wrapping_add(PHI); + let mut z = state; + z = (z ^ (z >> 30)).wrapping_mul(0xbf58476d1ce4e5b9); + z = (z ^ (z >> 27)).wrapping_mul(0x94d049bb133111eb); + z = z ^ (z >> 31); + chunk.copy_from_slice(&z.to_le_bytes()); + } + Self::from_seed(seed) + } +} + +impl RngCore for Xoshiro128PlusPlus { + #[inline] + fn next_u32(&mut self) -> u32 { + let result_starstar = self.s[0] + .wrapping_add(self.s[3]) + .rotate_left(7) + .wrapping_add(self.s[0]); + + let t = self.s[1] << 9; + + self.s[2] ^= self.s[0]; + self.s[3] ^= self.s[1]; + self.s[1] ^= self.s[2]; + self.s[0] ^= self.s[3]; + + self.s[2] ^= t; + + self.s[3] = self.s[3].rotate_left(11); + + result_starstar + } + + #[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<(), Error> { + self.fill_bytes(dest); + Ok(()) + } +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn reference() { + let mut rng = Xoshiro128PlusPlus::from_seed( + [1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0]); + // These values were produced with the reference implementation: + // http://xoshiro.di.unimi.it/xoshiro128plusplus.c + let expected = [ + 641, 1573767, 3222811527, 3517856514, 836907274, 4247214768, + 3867114732, 1355841295, 495546011, 621204420, + ]; + for &e in &expected { + assert_eq!(rng.next_u32(), e); + } + } +} diff --git a/vendor/rand/src/rngs/xoshiro256plusplus.rs b/vendor/rand/src/rngs/xoshiro256plusplus.rs new file mode 100644 index 000000000..8ffb18b80 --- /dev/null +++ b/vendor/rand/src/rngs/xoshiro256plusplus.rs @@ -0,0 +1,122 @@ +// 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::impls::fill_bytes_via_next; +use rand_core::le::read_u64_into; +use rand_core::{SeedableRng, RngCore, Error}; + +/// A xoshiro256++ random number generator. +/// +/// The xoshiro256++ algorithm is not suitable for cryptographic purposes, but +/// is very fast and has excellent statistical properties. +/// +/// The algorithm used here is translated from [the `xoshiro256plusplus.c` +/// reference source code](http://xoshiro.di.unimi.it/xoshiro256plusplus.c) by +/// David Blackman and Sebastiano Vigna. +#[derive(Debug, Clone, PartialEq, Eq)] +#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))] +pub struct Xoshiro256PlusPlus { + s: [u64; 4], +} + +impl SeedableRng for Xoshiro256PlusPlus { + type Seed = [u8; 32]; + + /// Create a new `Xoshiro256PlusPlus`. If `seed` is entirely 0, it will be + /// mapped to a different seed. + #[inline] + fn from_seed(seed: [u8; 32]) -> Xoshiro256PlusPlus { + if seed.iter().all(|&x| x == 0) { + return Self::seed_from_u64(0); + } + let mut state = [0; 4]; + read_u64_into(&seed, &mut state); + Xoshiro256PlusPlus { s: state } + } + + /// Create a new `Xoshiro256PlusPlus` from a `u64` seed. + /// + /// This uses the SplitMix64 generator internally. + fn seed_from_u64(mut state: u64) -> Self { + const PHI: u64 = 0x9e3779b97f4a7c15; + let mut seed = Self::Seed::default(); + for chunk in seed.as_mut().chunks_mut(8) { + state = state.wrapping_add(PHI); + let mut z = state; + z = (z ^ (z >> 30)).wrapping_mul(0xbf58476d1ce4e5b9); + z = (z ^ (z >> 27)).wrapping_mul(0x94d049bb133111eb); + z = z ^ (z >> 31); + chunk.copy_from_slice(&z.to_le_bytes()); + } + Self::from_seed(seed) + } +} + +impl RngCore for Xoshiro256PlusPlus { + #[inline] + fn next_u32(&mut self) -> u32 { + // The lowest bits have some linear dependencies, so we use the + // upper bits instead. + (self.next_u64() >> 32) as u32 + } + + #[inline] + fn next_u64(&mut self) -> u64 { + let result_plusplus = self.s[0] + .wrapping_add(self.s[3]) + .rotate_left(23) + .wrapping_add(self.s[0]); + + let t = self.s[1] << 17; + + self.s[2] ^= self.s[0]; + self.s[3] ^= self.s[1]; + self.s[1] ^= self.s[2]; + self.s[0] ^= self.s[3]; + + self.s[2] ^= t; + + self.s[3] = self.s[3].rotate_left(45); + + result_plusplus + } + + #[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(()) + } +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn reference() { + let mut rng = Xoshiro256PlusPlus::from_seed( + [1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, + 3, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0]); + // These values were produced with the reference implementation: + // http://xoshiro.di.unimi.it/xoshiro256plusplus.c + let expected = [ + 41943041, 58720359, 3588806011781223, 3591011842654386, + 9228616714210784205, 9973669472204895162, 14011001112246962877, + 12406186145184390807, 15849039046786891736, 10450023813501588000, + ]; + for &e in &expected { + assert_eq!(rng.next_u64(), e); + } + } +} |