[−][src]Struct heapless::spsc::Queue
A statically allocated single producer single consumer queue with a capacity of N
elements
IMPORTANT: To get better performance use a capacity that is a power of 2 (e.g. U16
, U32
,
etc.).
By default spsc::Queue
will use usize
integers to hold the indices to its head and tail. For
small queues usize
indices may be overkill. However, spsc::Queue
's index type is generic and
can be changed to u8
or u16
to reduce its footprint. The easiest to construct a
spsc::Queue
with a smaller index type is to use the u8
and u16
constructors.
IMPORTANT: spsc::Queue<_, _, u8>
has a maximum capacity of 255 elements; spsc::Queue<_, _, u16>
has a maximum capacity of 65535 elements.
spsc::Queue
also comes in a single core variant. This variant can be created using the
following constructors: u8_sc
, u16_sc
, usize_sc
and new_sc
. This variant is unsafe
to
create because the programmer must make sure that the queue's consumer and producer endpoints
(if split) are kept on a single core for their entire lifetime.
Examples
use heapless::spsc::Queue; use heapless::consts::*; let mut rb: Queue<u8, U4> = Queue::new(); assert!(rb.enqueue(0).is_ok()); assert!(rb.enqueue(1).is_ok()); assert!(rb.enqueue(2).is_ok()); assert!(rb.enqueue(3).is_ok()); assert!(rb.enqueue(4).is_err()); // full assert_eq!(rb.dequeue(), Some(0));
Single producer single consumer mode
use heapless::spsc::Queue; use heapless::consts::*; static mut RB: Queue<Event, U4> = Queue(heapless::i::Queue::new()); enum Event { A, B } fn main() { // NOTE(unsafe) beware of aliasing the `consumer` end point let mut consumer = unsafe { RB.split().1 }; loop { // `dequeue` is a lockless operation match consumer.dequeue() { Some(Event::A) => { /* .. */ }, Some(Event::B) => { /* .. */ }, None => { /* sleep */}, } } } // this is a different execution context that can preempt `main` fn interrupt_handler() { // NOTE(unsafe) beware of aliasing the `producer` end point let mut producer = unsafe { RB.split().0 }; // .. if condition { producer.enqueue(Event::A).ok().unwrap(); } else { producer.enqueue(Event::B).ok().unwrap(); } // .. }
Methods
impl<T, N, U, C> Queue<T, N, U, C> where
N: ArrayLength<T>,
U: Uxx,
C: XCore,
[src]
N: ArrayLength<T>,
U: Uxx,
C: XCore,
pub fn split<'rb>(
&'rb mut self
) -> (Producer<'rb, T, N, U, C>, Consumer<'rb, T, N, U, C>)
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&'rb mut self
) -> (Producer<'rb, T, N, U, C>, Consumer<'rb, T, N, U, C>)
Splits a statically allocated queue into producer and consumer end points
impl<T, N, U, C> Queue<T, N, U, C> where
N: ArrayLength<T>,
U: Uxx,
C: XCore,
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N: ArrayLength<T>,
U: Uxx,
C: XCore,
pub fn capacity(&self) -> U
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Returns the maximum number of elements the queue can hold
pub fn is_empty(&self) -> bool
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Returns true
if the queue has a length of 0
ⓘImportant traits for Iter<'a, T, N, U, C>pub fn iter(&self) -> Iter<T, N, U, C>
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Iterates from the front of the queue to the back
ⓘImportant traits for IterMut<'a, T, N, U, C>pub fn iter_mut(&mut self) -> IterMut<T, N, U, C>
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Returns an iterator that allows modifying each value.
impl<T, N> Queue<T, N, usize, MultiCore> where
N: ArrayLength<T>,
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N: ArrayLength<T>,
pub fn new() -> Self
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Alias for spsc::Queue::usize
impl<T, N> Queue<T, N, usize, SingleCore> where
N: ArrayLength<T>,
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N: ArrayLength<T>,
pub unsafe fn new_sc() -> Self
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Alias for spsc::Queue::usize_sc
impl<T, N> Queue<T, N, u8, MultiCore> where
N: ArrayLength<T>,
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N: ArrayLength<T>,
impl<T, N> Queue<T, N, u8, SingleCore> where
N: ArrayLength<T>,
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N: ArrayLength<T>,
pub unsafe fn u8_sc() -> Self
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Creates an empty queue with a fixed capacity of N
(single core variant)
impl<T, N, C> Queue<T, N, u8, C> where
N: ArrayLength<T>,
C: XCore,
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N: ArrayLength<T>,
C: XCore,
pub fn dequeue(&mut self) -> Option<T>
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Returns the item in the front of the queue, or None
if the queue is empty
pub fn enqueue(&mut self, item: T) -> Result<(), T>
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Adds an item
to the end of the queue
Returns back the item
if the queue is full
pub unsafe fn enqueue_unchecked(&mut self, item: T)
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Adds an item
to the end of the queue, without checking if it's full
Unsafety
If the queue is full this operation will leak a value (T's destructor won't run on
the value that got overwritten by item
), and will allow the dequeue
operation
to create a copy of item
, which could result in T
's destructor running on item
twice.
pub fn len(&self) -> u8
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Returns the number of elements in the queue
impl<T, N> Queue<T, N, u16, MultiCore> where
N: ArrayLength<T>,
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N: ArrayLength<T>,
impl<T, N> Queue<T, N, u16, SingleCore> where
N: ArrayLength<T>,
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N: ArrayLength<T>,
pub unsafe fn u16_sc() -> Self
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Creates an empty queue with a fixed capacity of N
(single core variant)
impl<T, N, C> Queue<T, N, u16, C> where
N: ArrayLength<T>,
C: XCore,
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N: ArrayLength<T>,
C: XCore,
pub fn dequeue(&mut self) -> Option<T>
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Returns the item in the front of the queue, or None
if the queue is empty
pub fn enqueue(&mut self, item: T) -> Result<(), T>
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Adds an item
to the end of the queue
Returns back the item
if the queue is full
pub unsafe fn enqueue_unchecked(&mut self, item: T)
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Adds an item
to the end of the queue, without checking if it's full
Unsafety
If the queue is full this operation will leak a value (T's destructor won't run on
the value that got overwritten by item
), and will allow the dequeue
operation
to create a copy of item
, which could result in T
's destructor running on item
twice.
pub fn len(&self) -> u16
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Returns the number of elements in the queue
impl<T, N> Queue<T, N, usize, MultiCore> where
N: ArrayLength<T>,
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N: ArrayLength<T>,
impl<T, N> Queue<T, N, usize, SingleCore> where
N: ArrayLength<T>,
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N: ArrayLength<T>,
pub unsafe fn usize_sc() -> Self
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Creates an empty queue with a fixed capacity of N
(single core variant)
impl<T, N, C> Queue<T, N, usize, C> where
N: ArrayLength<T>,
C: XCore,
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N: ArrayLength<T>,
C: XCore,
pub fn dequeue(&mut self) -> Option<T>
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Returns the item in the front of the queue, or None
if the queue is empty
pub fn enqueue(&mut self, item: T) -> Result<(), T>
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Adds an item
to the end of the queue
Returns back the item
if the queue is full
pub unsafe fn enqueue_unchecked(&mut self, item: T)
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Adds an item
to the end of the queue, without checking if it's full
Unsafety
If the queue is full this operation will leak a value (T's destructor won't run on
the value that got overwritten by item
), and will allow the dequeue
operation
to create a copy of item
, which could result in T
's destructor running on item
twice.
pub fn len(&self) -> usize
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Returns the number of elements in the queue
Trait Implementations
impl<T, N, U, C, N2, U2, C2> PartialEq<Queue<T, N2, U2, C2>> for Queue<T, N, U, C> where
T: PartialEq,
N: ArrayLength<T>,
U: Uxx,
C: XCore,
N2: ArrayLength<T>,
U2: Uxx,
C2: XCore,
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T: PartialEq,
N: ArrayLength<T>,
U: Uxx,
C: XCore,
N2: ArrayLength<T>,
U2: Uxx,
C2: XCore,
fn eq(&self, other: &Queue<T, N2, U2, C2>) -> bool
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#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0[src]
This method tests for !=
.
impl<T, N, U, C> Eq for Queue<T, N, U, C> where
T: Eq,
N: ArrayLength<T>,
U: Uxx,
C: XCore,
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T: Eq,
N: ArrayLength<T>,
U: Uxx,
C: XCore,
impl<T, N, U, C> Debug for Queue<T, N, U, C> where
N: ArrayLength<T>,
T: Debug,
U: Uxx,
C: XCore,
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N: ArrayLength<T>,
T: Debug,
U: Uxx,
C: XCore,
impl<T, N, U, C> Drop for Queue<T, N, U, C> where
N: ArrayLength<T>,
U: Uxx,
C: XCore,
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N: ArrayLength<T>,
U: Uxx,
C: XCore,
impl<T, N, U, C> Hash for Queue<T, N, U, C> where
N: ArrayLength<T>,
T: Hash,
U: Uxx,
C: XCore,
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N: ArrayLength<T>,
T: Hash,
U: Uxx,
C: XCore,
fn hash<H: Hasher>(&self, state: &mut H)
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fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
Feeds a slice of this type into the given [Hasher
]. Read more
impl<'a, T, N, U, C> IntoIterator for &'a Queue<T, N, U, C> where
N: ArrayLength<T>,
U: Uxx,
C: XCore,
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N: ArrayLength<T>,
U: Uxx,
C: XCore,
type Item = &'a T
The type of the elements being iterated over.
type IntoIter = Iter<'a, T, N, U, C>
Which kind of iterator are we turning this into?
fn into_iter(self) -> Self::IntoIter
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impl<'a, T, N, U, C> IntoIterator for &'a mut Queue<T, N, U, C> where
N: ArrayLength<T>,
U: Uxx,
C: XCore,
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N: ArrayLength<T>,
U: Uxx,
C: XCore,
type Item = &'a mut T
The type of the elements being iterated over.
type IntoIter = IterMut<'a, T, N, U, C>
Which kind of iterator are we turning this into?
fn into_iter(self) -> Self::IntoIter
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impl<T, N, C> Clone for Queue<T, N, u8, C> where
T: Clone,
N: ArrayLength<T>,
C: XCore,
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T: Clone,
N: ArrayLength<T>,
C: XCore,
fn clone(&self) -> Self
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fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
impl<T, N, C> Clone for Queue<T, N, u16, C> where
T: Clone,
N: ArrayLength<T>,
C: XCore,
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T: Clone,
N: ArrayLength<T>,
C: XCore,
fn clone(&self) -> Self
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fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
impl<T, N, C> Clone for Queue<T, N, usize, C> where
T: Clone,
N: ArrayLength<T>,
C: XCore,
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T: Clone,
N: ArrayLength<T>,
C: XCore,
fn clone(&self) -> Self
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fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
impl<T, N, U, C> Hash for Queue<T, N, U, C> where
N: ArrayLength<T>,
T: Hash,
U: Uxx,
C: XCore,
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N: ArrayLength<T>,
T: Hash,
U: Uxx,
C: XCore,
Auto Trait Implementations
impl<T, N, U, C> Send for Queue<T, N, U, C> where
C: Send,
T: Send,
C: Send,
T: Send,
impl<T, N, U = usize, C = MultiCore> !Sync for Queue<T, N, U, C>
Blanket Implementations
impl<T> From<T> for T
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Same<T> for T
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type Output = T
Should always be Self