commit	b243aed6e736f66d2f1a2cfbbff883ed29a41fe6	[log] [tgz]
author	Android Build Coastguard Worker <[email protected]>	Mon Aug 05 23:11:55 2024 +0000
committer	Android Build Coastguard Worker <[email protected]>	Mon Aug 05 23:11:55 2024 +0000
tree	b14ef1c95a589cd848cbce5e8c2309d551fa04b8
parent	59a396a811ab56726ffbb6734c294ad03583206d [diff]
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tree: b14ef1c95a589cd848cbce5e8c2309d551fa04b8

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.