Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog and this project adheres to Semantic Versioning.

A separate changelog is kept for rand_core.

You may also find the Upgrade Guide useful.

[0.8.5] - 2021-08-20

Fixes

• Fix build on non-32/64-bit architectures (#1144)
• Fix “min_const_gen” feature for no_std (#1173)
• Check libc::pthread_atfork return value with panic on error (#1178)
• More robust reseeding in case ReseedingRng is used from a fork handler (#1178)
• Fix nightly: remove unused slice_partition_at_index feature (#1215)
• Fix nightly + simd_support: update packed_simd (#1216)

Rngs

• StdRng: Switch from HC128 to ChaCha12 on emscripten (#1142). We now use ChaCha12 on all platforms.

Documentation

• Added docs about rand's use of const generics (#1150)
• Better random chars example (#1157)

[0.8.4] - 2021-06-15

Additions

• Use const-generics to support arrays of all sizes (#1104)
• Implement Clone and Copy for Alphanumeric (#1126)
• Add Distribution::map to derive a distribution using a closure (#1129)
• Add Slice distribution (#1107)
• Add DistString trait with impls for Standard and Alphanumeric (#1133)

Other

• Reorder asserts in Uniform float distributions for easier debugging of non-finite arguments (#1094, #1108)
• Add range overflow check in Uniform float distributions (#1108)
• Deprecate rngs::adapter::ReadRng (#1130)

[0.8.3] - 2021-01-25

Fixes

• Fix no-std + alloc build by gating choose_multiple_weighted on std (#1088)

[0.8.2] - 2021-01-12

Fixes

• Fix panic in UniformInt::sample_single_inclusive and Rng::gen_range when providing a full integer range (eg 0..=MAX) (#1087)

[0.8.1] - 2020-12-31

Other

• Enable all stable features in the playground (#1081)

[0.8.0] - 2020-12-18

Platform support

• The minimum supported Rust version is now 1.36 (#1011)
• getrandom updated to v0.2 (#1041)
• Remove wasm-bindgen and stdweb feature flags. For details of WASM support, see the getrandom documentation. (#948)
• ReadRng::next_u32 and next_u64 now use little-Endian conversion instead of native-Endian, affecting results on Big-Endian platforms (#1061)
• The nightly feature no longer implies the simd_support feature (#1048)
• Fix simd_support feature to work on current nightlies (#1056)

Rngs

• ThreadRng is no longer Copy to enable safe usage within thread-local destructors (#1035)
• gen_range(a, b) was replaced with gen_range(a..b). gen_range(a..=b) is also supported. Note that a and b can no longer be references or SIMD types. (#744, #1003)
• Replace AsByteSliceMut with Fill and add support for [bool], [char], [f32], [f64] (#940)
• Restrict rand::rngs::adapter to std (#1027; see also #928)
• StdRng: add new std_rng feature flag (enabled by default, but might need to be used if disabling default crate features) (#948)
• StdRng: Switch from ChaCha20 to ChaCha12 for better performance (#1028)
• SmallRng: Replace PCG algorithm with xoshiro{128,256}++ (#1038)

Sequences

• Add IteratorRandom::choose_stable as an alternative to choose which does not depend on size hints (#1057)
• Improve accuracy and performance of IteratorRandom::choose (#1059)
• Implement IntoIterator for IndexVec, replacing the into_iter method (#1007)
• Add value stability tests for seq module (#933)

Misc

• Support PartialEq and Eq for StdRng, SmallRng and StepRng (#979)
• Added a serde1 feature and added Serialize/Deserialize to UniformInt and WeightedIndex (#974)
• Drop some unsafe code (#962, #963, #1011)
• Reduce packaged crate size (#983)
• Migrate to GitHub Actions from Travis+AppVeyor (#1073)

Distributions

• Alphanumeric samples bytes instead of chars (#935)
• Uniform now supports char, enabling rng.gen_range('A'..='Z') (#1068)
• Add UniformSampler::sample_single_inclusive (#1003)

Weighted sampling

• Implement weighted sampling without replacement (#976, #1013)
• rand::distributions::alias_method::WeightedIndex was moved to rand_distr::WeightedAliasIndex. The simpler alternative rand::distribution::WeightedIndex remains. (#945)
• Improve treatment of rounding errors in WeightedIndex::update_weights (#956)
• WeightedIndex: return error on NaN instead of panic (#1005)

Documentation

• Document types supported by random (#994)
• Document notes on password generation (#995)
• Note that SmallRng may not be the best choice for performance and in some other cases (#1038)
• Use doc(cfg) to annotate feature-gated items (#1019)
• Adjust README (#1065)

[0.7.3] - 2020-01-10

Fixes

• The Bernoulli distribution constructors now reports an error on NaN and on denominator == 0. (#925)
• Use std::sync::Once to register fork handler, avoiding possible atomicity violation (#928)
• Fix documentation on the precision of generated floating-point values

Changes

• Unix: make libc dependency optional; only use fork protection with std feature (#928)

Additions

• Implement std::error::Error for BernoulliError (#919)

[0.7.2] - 2019-09-16

Fixes

• Fix dependency on rand_core 0.5.1 (#890)

Additions

• Unit tests for value stability of distributions added (#888)

[0.7.1] - 2019-09-13

Yanked

This release was yanked since it depends on rand_core::OsRng added in 0.5.1 but specifies a dependency on version 0.5.0 (#890), causing a broken builds when updating from rand 0.7.0 without also updating rand_core.

Fixes

• Fix no_std behaviour, appropriately enable c2-chacha's std feature (#844)
• alloc feature in no_std is available since Rust 1.36 (#856)
• Fix or squelch issues from Clippy lints (#840)

Additions

• Add a no_std target to CI to continuously evaluate no_std status (#844)
• WeightedIndex: allow adjusting a sub-set of weights (#866)

[0.7.0] - 2019-06-28

Fixes

• Fix incorrect pointer usages revealed by Miri testing (#780, #781)
• Fix (tiny!) bias in Uniform for 8- and 16-bit ints (#809)

Crate

• Bumped MSRV (min supported Rust version) to 1.32.0
• Updated to Rust Edition 2018 (#823, #824)
• Removed dependence on rand_xorshift, rand_isaac, rand_jitter crates (#759, #765)
• Remove dependency on winapi (#724)
• Removed all build.rs files (#824)
• Removed code already deprecated in version 0.6 (#757)
• Removed the serde1 feature (It's still available for backwards compatibility, but it does not do anything. #830)
• Many documentation changes

rand_core

• Updated to rand_core 0.5.0
• Error type redesigned with new API (#800)
• Move from_entropy method to SeedableRng and remove FromEntropy (#800)
• SeedableRng::from_rng is now expected to be value-stable (#815)

Standard RNGs

• OS interface moved from rand_os to new getrandom crate (#765, getrandom)
• Use ChaCha for StdRng and ThreadRng (#792)
• Feature-gate SmallRng (#792)
• ThreadRng now supports Copy (#758)
• Deprecated EntropyRng (#765)
• Enable fork protection of ReseedingRng without std (#724)

Distributions

• Many distributions have been moved to rand_distr (#761)
• Bernoulli::new constructor now returns a Result (#803)
• Distribution::sample_iter adjusted for more flexibility (#758)
• Added distributions::weighted::alias_method::WeightedIndex for O(1) sampling (#692)
• Support sampling NonZeroU* types with the Standard distribution (#728)
• Optimised Binomial distribution sampling (#735, #740, #752)
• Optimised SIMD float sampling (#739)

Sequences

• Make results portable across 32- and 64-bit by using u32 samples for usize where possible (#809)

[0.6.5] - 2019-01-28

Crates

• Update rand_core to 0.4 (#703)
• Move JitterRng to its own crate (#685)
• Add a wasm-bindgen test crate (#696)

Platforms

• Fuchsia: Replaced fuchsia-zircon with fuchsia-cprng

Doc

• Use RFC 1946 for doc links (#691)
• Fix some doc links and notes (#711)

[0.6.4] - 2019-01-08

Fixes

• Move wasm-bindgen shims to correct crate (#686)
• Make wasm32-unknown-unknown compile but fail at run-time if missing bindingsg (#686)

[0.6.3] - 2019-01-04

Fixes

• Make the std feature require the optional rand_os dependency (#675)
• Re-export the optional WASM dependencies of rand_os from rand to avoid breakage (#674)

[0.6.2] - 2019-01-04

Additions

• Add Default for ThreadRng (#657)
• Move rngs::OsRng to rand_os sub-crate; clean up code; use as dependency (#643) ##BLOCKER##
• Add rand_xoshiro sub-crate, plus benchmarks (#642, #668)

Fixes

• Fix bias in UniformInt::sample_single (#662)
• Use autocfg instead of rustc_version for rustc version detection (#664)
• Disable i128 and u128 if the target_os is emscripten (#671: work-around Emscripten limitation)
• CI fixes (#660, #671)

Optimisations

• Optimise memory usage of UnitCircle and UnitSphereSurface distributions (no PR)

[0.6.1] - 2018-11-22

• Support sampling Duration also for no_std (only since Rust 1.25) (#649)
• Disable default features of libc (#647)

[0.6.0] - 2018-11-14

Project organisation

• Rand has moved from rust-lang-nursery to rust-random! (#578)
• Created The Rust Random Book (source)
• Update copyright and licence notices (#591, #611)
• Migrate policy documentation from the wiki (#544)

Platforms

• Add fork protection on Unix (#466)
• Added support for wasm-bindgen. (#541, #559, #562, #600)
• Enable OsRng for powerpc64, sparc and sparc64 (#609)
• Use syscall from libc on Linux instead of redefining it (#629)

RNGs

• Switch SmallRng to use PCG (#623)
• Implement Pcg32 and Pcg64Mcg generators (#632)
• Move ISAAC RNGs to a dedicated crate (#551)
• Move Xorshift RNG to its own crate (#557)
• Move ChaCha and HC128 RNGs to dedicated crates (#607, #636)
• Remove usage of Rc from ThreadRng (#615)

Sampling and distributions

• Implement Rng.gen_ratio() and Bernoulli::new_ratio() (#491)
• Make Uniform strictly respect f32 / f64 high/low bounds (#477)
• Allow gen_range and Uniform to work on non-Copy types (#506)
• Uniform supports inclusive ranges: Uniform::from(a..=b). This is automatically enabled for Rust >= 1.27. (#566)
• Implement TrustedLen and FusedIterator for DistIter (#620)

New distributions

• Add the Dirichlet distribution (#485)
• Added sampling from the unit sphere and circle. (#567)
• Implement the triangular distribution (#575)
• Implement the Weibull distribution (#576)
• Implement the Beta distribution (#574)

Optimisations

• Optimise Bernoulli::new (#500)
• Optimise char sampling (#519)
• Optimise sampling of std::time::Duration (#583)

Sequences

• Redesign the seq module (#483, #515)
• Add WeightedIndex and choose_weighted (#518, #547)
• Optimised and changed return type of the sample_indices function. (#479)
• Use Iterator::size_hint() to speed up IteratorRandom::choose (#593)

SIMD

• Support for generating SIMD types (#523, #542, #561, #630)

Other

• Revise CI scripts (#632, #635)
• Remove functionality already deprecated in 0.5 (#499)
• Support for i128 and u128 is automatically enabled for Rust >= 1.26. This renders the i128_support feature obsolete. It still exists for backwards compatibility but does not have any effect. This breaks programs using Rand with i128_support on nightlies older than Rust 1.26. (#571)

[0.5.5] - 2018-08-07

Documentation

• Fix links in documentation (#582)

[0.5.4] - 2018-07-11

Platform support

• Make OsRng work via WASM/stdweb for WebWorkers

[0.5.3] - 2018-06-26

Platform support

• OpenBSD, Bitrig: fix compilation (broken in 0.5.1) (#530)

[0.5.2] - 2018-06-18

Platform support

• Hide OsRng and JitterRng on unsupported platforms (#512; fixes #503).

[0.5.1] - 2018-06-08

New distributions

• Added Cauchy distribution. (#474, #486)
• Added Pareto distribution. (#495)

Platform support and OsRng

• Remove blanket Unix implementation. (#484)
• Remove Wasm unimplemented stub. (#484)
• Dragonfly BSD: read from /dev/random. (#484)
• Bitrig: use getentropy like OpenBSD. (#484)
• Solaris: (untested) use getrandom if available, otherwise /dev/random. (#484)
• Emscripten, stdweb: split the read up in chunks. (#484)
• Emscripten, Haiku: don't do an extra blocking read from /dev/random. (#484)
• Linux, NetBSD, Solaris: read in blocking mode on first use in fill_bytes. (#484)
• Fuchsia, CloudABI: fix compilation (broken in Rand 0.5). (#484)

[0.5.0] - 2018-05-21

Crate features and organisation

• Minimum Rust version update: 1.22.0. (#239)
• Create a separate rand_core crate. (#288)
• Deprecate rand_derive. (#256)
• Add prelude (and module reorganisation). (#435)
• Add log feature. Logging is now available in JitterRng, OsRng, EntropyRng and ReseedingRng. (#246)
• Add serde1 feature for some PRNGs. (#189)
• stdweb feature for OsRng support on WASM via stdweb. (#272, #336)

Rng trait

• Split Rng in RngCore and Rng extension trait. next_u32, next_u64 and fill_bytes are now part of RngCore. (#265)
• Add Rng::sample. (#256)
• Deprecate Rng::gen_weighted_bool. (#308)
• Add Rng::gen_bool. (#308)
• Remove Rng::next_f32 and Rng::next_f64. (#273)
• Add optimized Rng::fill and Rng::try_fill methods. (#247)
• Deprecate Rng::gen_iter. (#286)
• Deprecate Rng::gen_ascii_chars. (#279)

rand_core crate

• rand now depends on new rand_core crate (#288)
• RngCore and SeedableRng are now part of rand_core. (#288)
• Add modules to help implementing RNGs impl and le. (#209, #228)
• Add Error and ErrorKind. (#225)
• Add CryptoRng marker trait. (#273)
• Add BlockRngCore trait. (#281)
• Add BlockRng and BlockRng64 wrappers to help implementations. (#281, #325)
• Revise the SeedableRng trait. (#233)
• Remove default implementations for RngCore::next_u64 and RngCore::fill_bytes. (#288)
• Add RngCore::try_fill_bytes. (#225)

Other traits and types

• Add FromEntropy trait. (#233, #375)
• Add SmallRng wrapper. (#296)
• Rewrite ReseedingRng to only work with BlockRngCore (substantial performance improvement). (#281)
• Deprecate weak_rng. Use SmallRng instead. (#296)
• Deprecate AsciiGenerator. (#279)

Random number generators

• Switch StdRng and thread_rng to HC-128. (#277)
• StdRng must now be created with from_entropy instead of new
• Change thread_rng reseeding threshold to 32 MiB. (#277)
• PRNGs no longer implement Copy. (#209)
• Debug implementations no longer show internals. (#209)
• Implement Clone for ReseedingRng, JitterRng, OsRng`. (#383, #384)
• Implement serialization for XorShiftRng, IsaacRng and Isaac64Rng under the serde1 feature. (#189)
• Implement BlockRngCore for ChaChaCore and Hc128Core. (#281)
• All PRNGs are now portable across big- and little-endian architectures. (#209)
• Isaac64Rng::next_u32 no longer throws away half the results. (#209)
• Add IsaacRng::new_from_u64 and Isaac64Rng::new_from_u64. (#209)
• Add the HC-128 CSPRNG Hc128Rng. (#210)
• Change ChaCha20 to have 64-bit counter and 64-bit stream. (#349)
• Changes to JitterRng to get its size down from 2112 to 24 bytes. (#251)
• Various performance improvements to all PRNGs.

Platform support and OsRng

• Add support for CloudABI. (#224)
• Remove support for NaCl. (#225)
• WASM support for OsRng via stdweb, behind the stdweb feature. (#272, #336)
• Use getrandom on more platforms for Linux, and on Android. (#338)
• Use the SecRandomCopyBytes interface on macOS. (#322)
• On systems that do not have a syscall interface, only keep a single file descriptor open for OsRng. (#239)
• On Unix, first try a single read from /dev/random, then /dev/urandom. (#338)
• Better error handling and reporting in OsRng (using new error type). (#225)
• OsRng now uses non-blocking when available. (#225)
• Add EntropyRng, which provides OsRng, but has JitterRng as a fallback. (#235)

Distributions

• New Distribution trait. (#256)
• Add Distribution::sample_iter and Rng::::sample_iter. (#361)
• Deprecate Rand, Sample and IndependentSample traits. (#256)
• Add a Standard distribution (replaces most Rand implementations). (#256)
• Add Binomial and Poisson distributions. (#96)
• Add Bernoulli dsitribution. (#411)
• Add Alphanumeric distribution. (#279)
• Remove Closed01 distribution, add OpenClosed01. (#274, #420)
• Rework Range type, making it possible to implement it for user types. (#274)
• Rename Range to Uniform. (#395)
• Add Uniform::new_inclusive for inclusive ranges. (#274)
• Use widening multiply method for much faster integer range reduction. (#274)
• Standard distribution for char uses Uniform internally. (#274)
• Standard distribution for bool uses sign test. (#274)
• Implement Standard distribution for Wrapping<T>. (#436)
• Implement Uniform distribution for Duration. (#427)

[0.4.3] - 2018-08-16

Fixed

• Use correct syscall number for PowerPC (#589)

[0.4.2] - 2018-01-06

Changed

• Use winapi on Windows
• Update for Fuchsia OS
• Remove dev-dependency on log

[0.4.1] - 2017-12-17

Added

• no_std support

[0.4.0-pre.0] - 2017-12-11

Added

• JitterRng added as a high-quality alternative entropy source using the system timer
• new seq module with sample_iter, sample_slice, etc.
• WASM support via dummy implementations (fail at run-time)
• Additional benchmarks, covering generators and new seq code

Changed

• thread_rng uses JitterRng if seeding from system time fails (slower but more secure than previous method)

Deprecated

• sample function deprecated (replaced by sample_iter)

[0.3.20] - 2018-01-06

Changed

• Remove dev-dependency on log
• Update fuchsia-zircon dependency to 0.3.2

[0.3.19] - 2017-12-27

Changed

• Require log <= 0.3.8 for dev builds
• Update fuchsia-zircon dependency to 0.3
• Fix broken links in docs (to unblock compiler docs testing CI)

[0.3.18] - 2017-11-06

Changed

• thread_rng is seeded from the system time if OsRng fails
• weak_rng now uses thread_rng internally

[0.3.17] - 2017-10-07

Changed

• Fuchsia: Magenta was renamed Zircon

[0.3.16] - 2017-07-27

Added

• Implement Debug for mote non-public types
• implement Rand for (i|u)i128
• Support for Fuchsia

Changed

• Add inline attribute to SampleRange::construct_range. This improves the benchmark for sample in 11% and for shuffle in 16%.
• Use RtlGenRandom instead of CryptGenRandom

[0.3.15] - 2016-11-26

Added

• Add Rng trait method choose_mut
• Redox support

Changed

• Use arc4rand for OsRng on FreeBSD.
• Use arc4random(3) for OsRng on OpenBSD.

Fixed

• Fix filling buffers 4 GiB or larger with OsRng::fill_bytes on Windows

[0.3.14] - 2016-02-13

Fixed

• Inline definitions from winapi/advapi32, which decreases build times

[0.3.13] - 2016-01-09

Fixed

• Compatible with Rust 1.7.0-nightly (needed some extra type annotations)

[0.3.12] - 2015-11-09

Changed

• Replaced the methods in next_f32 and next_f64 with the technique described Saito & Matsumoto at MCQMC'08. The new method should exhibit a slightly more uniform distribution.
• Depend on libc 0.2

Fixed

• Fix iterator protocol issue in rand::sample

[0.3.11] - 2015-08-31

Added

• Implement Rand for arrays with n <= 32

[0.3.10] - 2015-08-17

Added

• Support for NaCl platforms

Changed

• Allow Rng to be ?Sized, impl for &mut R and Box<R> where R: ?Sized + Rng

[0.3.9] - 2015-06-18

Changed

• Use winapi for Windows API things

Fixed

• Fixed test on stable/nightly
• Fix getrandom syscall number for aarch64-unknown-linux-gnu

[0.3.8] - 2015-04-23

Changed

• log is a dev dependency

Fixed

• Fix race condition of atomics in is_getrandom_available

[0.3.7] - 2015-04-03

Fixed

• Derive Copy/Clone changes

[0.3.6] - 2015-04-02

Changed

• Move to stable Rust!

[0.3.5] - 2015-04-01

Fixed

• Compatible with Rust master

[0.3.4] - 2015-03-31

Added

• Implement Clone for Weighted

Fixed

• Compatible with Rust master

[0.3.3] - 2015-03-26

Fixed

• Fix compile on Windows

[0.3.2] - 2015-03-26

[0.3.1] - 2015-03-26

Fixed

• Fix compile on Windows

[0.3.0] - 2015-03-25

Changed

• Update to use log version 0.3.x

[0.2.1] - 2015-03-22

Fixed

• Compatible with Rust master
• Fixed iOS compilation

[0.2.0] - 2015-03-06

Fixed

• Compatible with Rust master (move from old_io to std::io)

[0.1.4] - 2015-03-04

Fixed

• Compatible with Rust master (use wrapping ops)

[0.1.3] - 2015-02-20

Fixed

• Compatible with Rust master

Removed

• Removed Copy implementations from RNGs

[0.1.2] - 2015-02-03

Added

• Imported functionality from std::rand, including:
  • StdRng, SeedableRng, TreadRng, weak_rng()
  • ReaderRng: A wrapper around any Reader to treat it as an RNG.
• Imported documentation from std::rand
• Imported tests from std::rand

[0.1.1] - 2015-02-03

Added

• Migrate to a cargo-compatible directory structure.

Fixed

• Do not use entropy during gen_weighted_bool(1)

[Rust 0.12.0] - 2014-10-09

Added

• Impl Rand for tuples of arity 11 and 12
• Include ChaCha pseudorandom generator
• Add next_f64 and next_f32 to Rng
• Implement Clone for PRNGs

Changed

• Rename TaskRng to ThreadRng and task_rng to thread_rng (since a runtime is removed from Rust).

Fixed

• Improved performance of ISAAC and ISAAC64 by 30% and 12 % respectively, by informing the optimiser that indexing is never out-of-bounds.

Removed

• Removed the Deprecated choose_option

[Rust 0.11.0] - 2014-07-02

Added

• document when to use OSRng in cryptographic context, and explain why we use /dev/urandom instead of /dev/random
• Rng::gen_iter() which will return an infinite stream of random values
• Rng::gen_ascii_chars() which will return an infinite stream of random ascii characters

Changed

• Now only depends on libcore!
• Remove Rng.choose(), rename Rng.choose_option() to .choose()
• Rename OSRng to OsRng
• The WeightedChoice structure is no longer built with a Vec<Weighted<T>>, but rather a &mut [Weighted<T>]. This means that the WeightedChoice structure now has a lifetime associated with it.
• The sample method on Rng has been moved to a top-level function in the rand module due to its dependence on Vec.

Removed

• Rng::gen_vec() was removed. Previous behavior can be regained with rng.gen_iter().take(n).collect()
• Rng::gen_ascii_str() was removed. Previous behavior can be regained with rng.gen_ascii_chars().take(n).collect()
• {IsaacRng, Isaac64Rng, XorShiftRng}::new() have all been removed. These all relied on being able to use an OSRng for seeding, but this is no longer available in librand (where these types are defined). To retain the same functionality, these types now implement the Rand trait so they can be generated with a random seed from another random number generator. This allows the stdlib to use an OSRng to create seeded instances of these RNGs.
• Rand implementations for Box<T> and @T were removed. These seemed to be pretty rare in the codebase, and it allows for librand to not depend on liballoc. Additionally, other pointer types like Rc and Arc were not supported.
• Remove a slew of old deprecated functions

[Rust 0.10] - 2014-04-03

Changed

• replace Rng.shuffle's functionality with .shuffle_mut
• bubble up IO errors when creating an OSRng

Fixed

• Use fill() instead of read()
• Rewrite OsRng in Rust for windows

[0.10-pre] - 2014-03-02

Added

• Separate rand out of the standard library