pub trait Flags: Sized + 'static {
type Bits: Bits;
const FLAGS: &'static [Flag<Self>];
Show 22 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 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 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 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 Types§
Required Associated Constants§
Required Methods§
sourcefn 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.
sourcefn from_bits_retain(bits: Self::Bits) -> Self
fn from_bits_retain(bits: Self::Bits) -> Self
Convert from a bits value exactly.
Provided Methods§
sourcefn 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.
sourcefn from_bits_truncate(bits: Self::Bits) -> Self
fn from_bits_truncate(bits: Self::Bits) -> Self
Convert from a bits value, unsetting any unknown bits.
sourcefn 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.
sourcefn 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.
sourcefn 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.
sourcefn 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.
sourcefn 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.
sourcefn 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.
sourcefn 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.
sourcefn 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.
sourcefn 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
.
sourcefn intersection(self, other: Self) -> Self
fn intersection(self, other: Self) -> Self
The bitwise and (&
) of the bits in two flags values.
sourcefn 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.
sourcefn symmetric_difference(self, other: Self) -> Self
fn symmetric_difference(self, other: Self) -> Self
The bitwise exclusive-or (^
) of the bits in two flags values.
sourcefn complement(self) -> Self
fn complement(self) -> Self
The bitwise negation (!
) of the bits in a flags value, truncating the result.