6 releases (stable)
3.0.0-rc2 | Jan 29, 2023 |
---|---|
3.0.0-rc1 | Nov 16, 2022 |
2.0.0 | Nov 28, 2021 |
1.2.0 |
|
1.0.0 | Feb 24, 2020 |
#242 in Rust patterns
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Used in 4,093 crates
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SLoC
Prior to 1.0
, Rust had traits for the numeric primitive types to permit code
to generalize over which specific type it accepted. This was never stabilized,
and eventually removed.
This library provides a set of traits that abstract over common API surfaces of the primitive types, so that properties such as numeric behavior, register width, or signedness can be represented in the trait system.
Pointer Unification
*const T
and *mut T
are unified under the Pointer<T, Shared | Unique>
type. The Permission
trait allows code to be generic over write permissions,
and manages propagating, downgrading, and upgrading permissions correctly
without risking violations of Rust’s provenance tracking rules.
In particular, Pointer
uses the associated-type system to internally wrap
either *const T
or *mut T
according to the Permission
type parameter it is
given, so user code is never able to (safely) improperly upgrade write
permissions on a pointer that is derived from a read-only provenance history.
See the ptr
module for more details.
Functionality Traits
All primitive types (bool
, char
, {i,u}{8,16,32,64,128,size}
, and
f{32,64}
) implement the Fundamental
trait. This trait defines the basic
concepts available to primitives: they are plain-old-data values, and can be
as
-casted to each other. Fundamental
has no functionality other than
providing the basic set of traits and allowing conversion.
The numeric primitives (everything except bool
and char
) implement the
following trait hierarchy:
Numeric
exports all the trait implementations and methods found on all numeric primitives.Integral
exports the trait implementations and methods found on all integers.Signed
unifies all signed integersiN
.Unsigned
unifies all unsigned integersuN
.
Floating
unifies both floating-point numbers.
Width Traits
There are three trait families for type width. For Width
values of 8
, 16
,
32
, 64
, and 128
:
IsWidth
is implemented by the numbers that are exactly this width.AtLeastWidth
is implemented by all numbers that are this width or wider.AtMostWidth
is implemented by all numbers that are this width or narrower.
Usage
Type use funty::*;
, then declare the traits you need as generic bounds.
Examples
Perform bit arithmetic on some unsigned integer:
use funty::Unsigned;
fn invert_middle_bits<T: Unsigned>(num: T) -> T {
let mask = (!T::ZERO).wrapping_shl(2).wrapping_shr(4).wrapping_shl(2);
num ^ mask
}
#![no_std]
Compatibility
The floating-point numbers offer many functions which are implemented in the
target system’s libm
. This library is present only in std
-targets. If you
are compiling to a #![no_std]
target, depend on this library with
[dependencies.funty]
version = "3"
default-features = false