Trait Flags
pub trait Flags: Sized + 'static {
type Bits: Bits;
const FLAGS: &'static [Flag<Self>];
Show 25 methods
// Required methods
fn bits(&self) -> Self::Bits;
fn from_bits_retain(bits: Self::Bits) -> Self;
// Provided methods
fn empty() -> Self { ... }
fn all() -> Self { ... }
fn contains_unknown_bits(&self) -> bool { ... }
fn from_bits(bits: Self::Bits) -> Option<Self> { ... }
fn from_bits_truncate(bits: Self::Bits) -> Self { ... }
fn from_name(name: &str) -> Option<Self> { ... }
fn iter(&self) -> Iter<Self> ⓘ { ... }
fn iter_names(&self) -> IterNames<Self> ⓘ { ... }
fn is_empty(&self) -> bool { ... }
fn is_all(&self) -> bool { ... }
fn intersects(&self, other: Self) -> bool
where Self: Sized { ... }
fn contains(&self, other: Self) -> bool
where Self: Sized { ... }
fn truncate(&mut self)
where Self: Sized { ... }
fn insert(&mut self, other: Self)
where Self: Sized { ... }
fn remove(&mut self, other: Self)
where Self: Sized { ... }
fn toggle(&mut self, other: Self)
where Self: Sized { ... }
fn set(&mut self, other: Self, value: bool)
where Self: Sized { ... }
fn clear(&mut self)
where Self: Sized { ... }
fn intersection(self, other: Self) -> Self { ... }
fn union(self, other: Self) -> Self { ... }
fn difference(self, other: Self) -> Self { ... }
fn symmetric_difference(self, other: Self) -> Self { ... }
fn complement(self) -> Self { ... }
}Expand description
A set of defined flags using a bits type as storage.
§Implementing Flags
This trait is implemented by the bitflags macro:
use bitflags::bitflags;
bitflags! {
struct MyFlags: u8 {
const A = 1;
const B = 1 << 1;
}
}It can also be implemented manually:
use bitflags::{Flag, Flags};
struct MyFlags(u8);
impl Flags for MyFlags {
const FLAGS: &'static [Flag<Self>] = &[
Flag::new("A", MyFlags(1)),
Flag::new("B", MyFlags(1 << 1)),
];
type Bits = u8;
fn from_bits_retain(bits: Self::Bits) -> Self {
MyFlags(bits)
}
fn bits(&self) -> Self::Bits {
self.0
}
}§Using Flags
The Flags trait can be used generically to work with any flags types. In this example,
we can count the number of defined named flags:
fn defined_flags<F: Flags>() -> usize {
F::FLAGS.iter().filter(|f| f.is_named()).count()
}
bitflags! {
struct MyFlags: u8 {
const A = 1;
const B = 1 << 1;
const C = 1 << 2;
const _ = !0;
}
}
assert_eq!(3, defined_flags::<MyFlags>());Required Associated Constants§
Required Associated Types§
Required Methods§
fn bits(&self) -> Self::Bits
fn bits(&self) -> Self::Bits
Get the underlying bits value.
The returned value is exactly the bits set in this flags value.
fn from_bits_retain(bits: Self::Bits) -> Self
fn from_bits_retain(bits: Self::Bits) -> Self
Convert from a bits value exactly.
Provided Methods§
fn empty() -> Self
fn empty() -> Self
Get a flags value with all bits unset.
fn all() -> Self
fn all() -> Self
Get a flags value with all known bits set.
fn contains_unknown_bits(&self) -> bool
fn contains_unknown_bits(&self) -> bool
This method will return true if any unknown bits are set.
fn from_bits(bits: Self::Bits) -> Option<Self>
fn from_bits(bits: Self::Bits) -> Option<Self>
Convert from a bits value.
This method will return None if any unknown bits are set.
fn from_bits_truncate(bits: Self::Bits) -> Self
fn from_bits_truncate(bits: Self::Bits) -> Self
Convert from a bits value, unsetting any unknown bits.
fn from_name(name: &str) -> Option<Self>
fn from_name(name: &str) -> Option<Self>
Get a flags value with the bits of a flag with the given name set.
This method will return None if name is empty or doesn’t
correspond to any named flag.
fn iter(&self) -> Iter<Self> ⓘ
fn iter(&self) -> Iter<Self> ⓘ
Yield a set of contained flags values.
Each yielded flags value will correspond to a defined named flag. Any unknown bits will be yielded together as a final flags value.
fn iter_names(&self) -> IterNames<Self> ⓘ
fn iter_names(&self) -> IterNames<Self> ⓘ
Yield a set of contained named flags values.
This method is like Flags::iter, except only yields bits in contained named flags.
Any unknown bits, or bits not corresponding to a contained flag will not be yielded.
fn intersects(&self, other: Self) -> boolwhere
Self: Sized,
fn intersects(&self, other: Self) -> boolwhere
Self: Sized,
Whether any set bits in a source flags value are also set in a target flags value.
fn contains(&self, other: Self) -> boolwhere
Self: Sized,
fn contains(&self, other: Self) -> boolwhere
Self: Sized,
Whether all set bits in a source flags value are also set in a target flags value.
fn insert(&mut self, other: Self)where
Self: Sized,
fn insert(&mut self, other: Self)where
Self: Sized,
The bitwise or (|) of the bits in two flags values.
fn remove(&mut self, other: Self)where
Self: Sized,
fn remove(&mut self, other: Self)where
Self: Sized,
The intersection of a source flags value with the complement of a target flags value (&!).
This method is not equivalent to self & !other when other has unknown bits set.
remove won’t truncate other, but the ! operator will.
fn toggle(&mut self, other: Self)where
Self: Sized,
fn toggle(&mut self, other: Self)where
Self: Sized,
The bitwise exclusive-or (^) of the bits in two flags values.
fn set(&mut self, other: Self, value: bool)where
Self: Sized,
fn set(&mut self, other: Self, value: bool)where
Self: Sized,
Call Flags::insert when value is true or Flags::remove when value is false.
fn intersection(self, other: Self) -> Self
fn intersection(self, other: Self) -> Self
The bitwise and (&) of the bits in two flags values.
fn union(self, other: Self) -> Self
fn union(self, other: Self) -> Self
The bitwise or (|) of the bits in two flags values.
fn difference(self, other: Self) -> Self
fn difference(self, other: Self) -> Self
The intersection of a source flags value with the complement of a target flags value (&!).
This method is not equivalent to self & !other when other has unknown bits set.
difference won’t truncate other, but the ! operator will.
fn symmetric_difference(self, other: Self) -> Self
fn symmetric_difference(self, other: Self) -> Self
The bitwise exclusive-or (^) of the bits in two flags values.
fn complement(self) -> Self
fn complement(self) -> Self
The bitwise negation (!) of the bits in a flags value, truncating the result.
Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.