9 releases (breaking)
new 0.7.1 | Nov 20, 2024 |
---|---|
0.6.0 | Nov 18, 2024 |
0.3.0 | May 16, 2024 |
#55 in No standard library
556 downloads per month
31KB
669 lines
bitflag-attr
This is a proc-macro Rust crate that allows to turn a C-like enum into a bitflag structures with an API similar to bitfields
crate.
You can use this crate to:
- provide more user-friendly bindings to C APIs where flags may or may not be fully known in advance.
You can't use this crate to:
- guarantee only bits corresponding to defined flags will ever be set.
bitflag-attr
allows access to the underlying bits type so arbitrary bits may be set. - define bitfields.
bitflag-attr
only generates types where set bits denote the presence of some combination of flags.
Implemented traits
The macro will also implement some traits for bitwise operations and formatting.
- core::ops::Not
- core::ops::BitAnd
- core::ops::BitOr
- core::ops::BitXor
- core::ops::BitAndAssign
- core::ops::BitOrAssign
- core::ops::BitXorAssign
- core::ops::Sub
- core::ops::SubAssign
- core::fmt::Debug (This can be opt-out with the
no_auto_debug
) - core::fmt::Binary
- core::fmt::UpperHex
- core::fmt::LowerHex
- core::fmt::Octal
- From
- Clone
- Copy
Besides the Debug
, Clone
and Copy
traits, all other standard derivable traits can be used together with the type.
The macro also generate iterator types to iterate over the set flags, and for convenience also implement the following traits:
- core::iter::Extend
- core::iter::FromIterator
- core::iter::Iterator (for the type and reference)
There is a opt-in crate feature serde
that generate a parsing error type and implements the traits:
- core::str::FromStr
- serde::Serialize
- serde::Deserialize
Note: This crate does not import/re-export serde traits, your project MUST have serde
as dependency.
Example
Generate a flags structure:
use bitflag_attr::bitflag;
#[bitflag(u32)]
#[derive(PartialEq, PartialOrd, Eq, Ord, Hash)]
enum Flags {
/// The value `A`, at bit position `0`.
A = 0b00000001,
/// The value `B`, at bit position `1`.
B = 0b00000010,
/// The value `C`, at bit position `2`.
C = 0b00000100,
/// The combination of `A`, `B`, and `C`.
ABC = A | B | C,
}
fn main() {
let e1 = Flags::A | Flags::C;
let e2 = Flags::B | Flags::C;
assert_eq!((e1 | e2), Flags::ABC); // union
assert_eq!((e1 & e2), Flags::C); // intersection
assert_eq!((e1 - e2), Flags::A); // set difference
assert_eq!(!e2, Flags::A); // set complement
}
If you don't want Debug
trait to be generated, you can pass no_auto_debug
to the attribute.
use bitflag_attr::bitflag;
#[bitflag(u32, no_auto_debug)]
#[derive(PartialEq, PartialOrd, Eq, Ord, Hash)]
enum Flags {
/// The value `A`, at bit position `0`.
A = 0b00000001,
/// The value `B`, at bit position `1`.
B = 0b00000010,
/// The value `C`, at bit position `2`.
C = 0b00000100,
/// The combination of `A`, `B`, and `C`.
ABC = A | B | C,
}
Rust Version Support
The minimum supported Rust version is documented in the Cargo.toml
file.
This may be bumped in minor releases as necessary.
Dependencies
~215–660KB
~16K SLoC