[](https://crates.io/crates/bitbag)
[](https://docs.rs/bitbag)
[](https://github.com/aatifsyed/bitbag)
This crate provides [`BitBag`], a type intended for tracking bitflags defined in a [field-less enum](https://doc.rust-lang.org/rust-by-example/custom_types/enum/c_like.html).
Get started like this:
```rust
#[derive(bitbag::Flags)]
#[repr(u8)]
enum MyFlags {
A = 0b0001,
B = 0b0010,
C = 0b0100,
}
```
Basic functionality is provided by [`Flags`]
```rust
let mut bag = bitbag::BitBag::::new_unchecked(0b0011);
assert!(bag.is_set(MyFlags::A));
assert!(bag.is_set(MyFlags::B));
assert!(!bag.is_set(MyFlags::C));
bag.set(MyFlags::C);
assert_eq!(bag.repr(), 0b0111);
```
Deriving [`BitOr`] will also give you very ergonomic constructors
```rust
#[derive(bitbag::BitOr)]
enum MyFlags { ... }
use MyFlags::*;
let bag = A | B | C;
assert!(bag.is_set(MyFlags::A));
assert!(bag.is_set(MyFlags::B));
assert!(bag.is_set(MyFlags::C));
```
You can also choose to reject unrecognised bits, and iterate over the set flags.
```rust
let e = bitbag::BitBag::::new_checked(0b1000).unwrap_err();
assert_eq!(e.to_string(), "The bits 0b1000 are not accounted for in MyFlags");
let bag = bitbag::BitBag::::new_checked(0b0110).unwrap();
for flag in bag {
match flag {
MyFlags::A => println!("Flag A was set"),
MyFlags::B => println!("Flag B was set"),
MyFlags::C => println!("Flag C was set"),
}
};
```