commit	f4b286ce15c35d1d9c27494f549f449fb13894fc	[log] [tgz]
author	James Farrell <[email protected]>	Wed Oct 23 17:26:38 2024 +0000
committer	James Farrell <[email protected]>	Wed Oct 23 17:26:38 2024 +0000
tree	430ea32a16bdb36849b6f5a66f3b4d297e28fc33
parent	b9cc27d90bc1f4ecbd08dd207ed0e990287d2654 [diff]

tree: 430ea32a16bdb36849b6f5a66f3b4d297e28fc33

README.md

bitflags

License

bitflags generates flags enums with well-defined semantics and ergonomic end-user APIs.

You can use bitflags to:

provide more user-friendly bindings to C APIs where flags may or may not be fully known in advance.
generate efficient options types with string parsing and formatting support.

You can't use bitflags to:

guarantee only bits corresponding to defined flags will ever be set. bitflags allows access to the underlying bits type so arbitrary bits may be set.
define bitfields. bitflags only generates types where set bits denote the presence of some combination of flags.
Documentation
Specification
Release notes

Usage

Add this to your Cargo.toml:

[dependencies]
bitflags = "2.5.0"

and this to your source code:

use bitflags::bitflags;

Example

Generate a flags structure:

use bitflags::bitflags;

// The `bitflags!` macro generates `struct`s that manage a set of flags.
bitflags! {
    /// Represents a set of flags.
    #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
    struct Flags: u32 {
        /// The value `A`, at bit position `0`.
        const A = 0b00000001;
        /// The value `B`, at bit position `1`.
        const B = 0b00000010;
        /// The value `C`, at bit position `2`.
        const C = 0b00000100;

        /// The combination of `A`, `B`, and `C`.
        const ABC = Self::A.bits() | Self::B.bits() | Self::C.bits();
    }
}

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
}

Rust Version Support

The minimum supported Rust version is documented in the Cargo.toml file. This may be bumped in minor releases as necessary.