Core traits and error types of the rand library, plus tools for implementing RNGs.
This crate is intended for use when implementing the core trait, RngCore
; it defines the core traits to be implemented as well as several small functions to aid in their implementation and types required for error handling.
The main rand crate re-exports most items defined in this crate, along with tools to convert the integer samples generated by RngCore
to many different applications (including sampling from restricted ranges, conversion to floating point, list permutations and secure initialisation of RNGs). Most users should prefer to use the main rand crate.
Links:
The rand_core
crate provides:
The traits and error types are also available via rand
.
The current version is:
rand_core = "0.5.0"
Rand libs have inter-dependencies and make use of the semver trick in order to make traits compatible across crate versions. (This is especially important for RngCore
and SeedableRng
.) A few crate releases are thus compatibility shims, depending on the next lib version (e.g. rand_core
versions 0.2.2
and 0.3.1
). This means, for example, that rand_core_0_4_0::SeedableRng
and rand_core_0_3_0::SeedableRng
are distinct, incompatible traits, which can cause build errors. Usually, running cargo update
is enough to fix any issues.
rand_core
supports no_std
and alloc
-only configurations, as well as full std
functionality. The differences between no_std
and full std
are small, comprising RngCore
support for Box<R>
types where R: RngCore
, std::io::Read
support for types supporting RngCore
, and extensions to the Error
type's functionality.
The std
feature is not enabled by default. This is primarily to avoid build problems where one crate implicitly requires rand_core
with std
support and another crate requires rand
without std
support. However, the rand
crate continues to enable std
support by default, both for itself and rand_core
.
The serde1
feature can be used to derive Serialize
and Deserialize
for RNG implementations that use the BlockRng
or BlockRng64
wrappers.
rand_core
is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT, and COPYRIGHT for details.