Struct heapless::spsc::Queue

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pub struct Queue<T, const N: usize> { /* private fields */ }
Available on crate feature portable-atomic or target_has_atomic="ptr" or has_atomic_load_store only.
Expand description

A statically allocated single producer single consumer queue with a capacity of N - 1 elements

IMPORTANT: To get better performance use a value for N that is a power of 2 (e.g. 16, 32, etc.).

Implementations§

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impl<T, const N: usize> Queue<T, N>

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pub const fn new() -> Self

Creates an empty queue with a fixed capacity of N - 1

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pub const fn capacity(&self) -> usize

Returns the maximum number of elements the queue can hold

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pub fn len(&self) -> usize

Returns the number of elements in the queue

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pub fn is_empty(&self) -> bool

Returns true if the queue is empty

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pub fn is_full(&self) -> bool

Returns true if the queue is full

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pub fn iter(&self) -> Iter<'_, T, N>

Iterates from the front of the queue to the back

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pub fn iter_mut(&mut self) -> IterMut<'_, T, N>

Returns an iterator that allows modifying each value

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pub fn enqueue(&mut self, val: T) -> Result<(), T>

Adds an item to the end of the queue

Returns back the item if the queue is full

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pub fn dequeue(&mut self) -> Option<T>

Returns the item in the front of the queue, or None if the queue is empty

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pub fn peek(&self) -> Option<&T>

Returns a reference to the item in the front of the queue without dequeuing, or None if the queue is empty.

Examples
use heapless::spsc::Queue;

let mut queue: Queue<u8, 235> = Queue::new();
let (mut producer, mut consumer) = queue.split();
assert_eq!(None, consumer.peek());
producer.enqueue(1);
assert_eq!(Some(&1), consumer.peek());
assert_eq!(Some(1), consumer.dequeue());
assert_eq!(None, consumer.peek());
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pub unsafe fn enqueue_unchecked(&mut self, val: T)

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.

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pub unsafe fn dequeue_unchecked(&mut self) -> T

Returns the item in the front of the queue, without checking if there is something in the queue

Unsafety

If the queue is empty this operation will return uninitialized memory.

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pub fn split(&mut self) -> (Producer<'_, T, N>, Consumer<'_, T, N>)

Splits a queue into producer and consumer endpoints

Trait Implementations§

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impl<T, const N: usize> Clone for Queue<T, N>
where T: Clone,

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fn clone(&self) -> Self

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<T, const N: usize> Debug for Queue<T, N>
where T: Debug,

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<T, const N: usize> Default for Queue<T, N>

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fn default() -> Self

Returns the “default value” for a type. Read more
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impl<T, const N: usize> Drop for Queue<T, N>

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fn drop(&mut self)

Executes the destructor for this type. Read more
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impl<T, const N: usize> Hash for Queue<T, N>
where T: Hash,

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fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'a, T, const N: usize> IntoIterator for &'a Queue<T, N>

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type Item = &'a T

The type of the elements being iterated over.
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type IntoIter = Iter<'a, T, N>

Which kind of iterator are we turning this into?
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fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value. Read more
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impl<'a, T, const N: usize> IntoIterator for &'a mut Queue<T, N>

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type Item = &'a mut T

The type of the elements being iterated over.
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type IntoIter = IterMut<'a, T, N>

Which kind of iterator are we turning this into?
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fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value. Read more
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impl<T, const N: usize, const N2: usize> PartialEq<Queue<T, N2>> for Queue<T, N>
where T: PartialEq,

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fn eq(&self, other: &Queue<T, N2>) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<T, const N: usize> Eq for Queue<T, N>
where T: Eq,

Auto Trait Implementations§

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impl<T, const N: usize> !RefUnwindSafe for Queue<T, N>

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impl<T, const N: usize> Send for Queue<T, N>
where T: Send,

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impl<T, const N: usize> !Sync for Queue<T, N>

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impl<T, const N: usize> Unpin for Queue<T, N>
where T: Unpin,

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impl<T, const N: usize> UnwindSafe for Queue<T, N>
where T: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.