78 lines
2.4 KiB
Markdown
78 lines
2.4 KiB
Markdown
bitflags
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========
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[](https://github.com/bitflags/bitflags/actions)
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[](https://crates.io/crates/bitflags)
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[](https://docs.rs/bitflags)
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`bitflags` generates flags enums with well-defined semantics and ergonomic end-user APIs.
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You can use `bitflags` to:
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- provide more user-friendly bindings to C APIs where flags may or may not be fully known in advance.
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- generate efficient options types with string parsing and formatting support.
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You can't use `bitflags` to:
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- 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.
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- define bitfields. `bitflags` only generates types where set bits denote the presence of some combination of flags.
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- [Documentation](https://docs.rs/bitflags)
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- [Specification](https://github.com/bitflags/bitflags/blob/main/spec.md)
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- [Release notes](https://github.com/bitflags/bitflags/releases)
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## Usage
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Add this to your `Cargo.toml`:
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```toml
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[dependencies]
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bitflags = "2.4.1"
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```
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and this to your source code:
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```rust
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use bitflags::bitflags;
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```
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## Example
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Generate a flags structure:
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```rust
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use bitflags::bitflags;
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// The `bitflags!` macro generates `struct`s that manage a set of flags.
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bitflags! {
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/// Represents a set of flags.
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#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
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struct Flags: u32 {
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/// The value `A`, at bit position `0`.
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const A = 0b00000001;
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/// The value `B`, at bit position `1`.
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const B = 0b00000010;
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/// The value `C`, at bit position `2`.
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const C = 0b00000100;
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/// The combination of `A`, `B`, and `C`.
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const ABC = Self::A.bits() | Self::B.bits() | Self::C.bits();
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}
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}
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fn main() {
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let e1 = Flags::A | Flags::C;
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let e2 = Flags::B | Flags::C;
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assert_eq!((e1 | e2), Flags::ABC); // union
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assert_eq!((e1 & e2), Flags::C); // intersection
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assert_eq!((e1 - e2), Flags::A); // set difference
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assert_eq!(!e2, Flags::A); // set complement
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}
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```
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## Rust Version Support
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The minimum supported Rust version is documented in the `Cargo.toml` file.
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This may be bumped in minor releases as necessary.
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