Struct heapless::Deque

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pub struct Deque<T, const N: usize> { /* private fields */ }
Expand description

A fixed capacity double-ended queue.

§Examples

use heapless::Deque;

// A deque with a fixed capacity of 8 elements allocated on the stack
let mut deque = Deque::<_, 8>::new();

// You can use it as a good old FIFO queue.
deque.push_back(1);
deque.push_back(2);
assert_eq!(deque.len(), 2);

assert_eq!(deque.pop_front(), Some(1));
assert_eq!(deque.pop_front(), Some(2));
assert_eq!(deque.len(), 0);

// Deque is double-ended, you can push and pop from the front and back.
deque.push_back(1);
deque.push_front(2);
deque.push_back(3);
deque.push_front(4);
assert_eq!(deque.pop_front(), Some(4));
assert_eq!(deque.pop_front(), Some(2));
assert_eq!(deque.pop_front(), Some(1));
assert_eq!(deque.pop_front(), Some(3));

// You can iterate it, yielding all the elements front-to-back.
for x in &deque {
    println!("{}", x);
}

Implementations§

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

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pub const fn new() -> Self

Constructs a new, empty deque with a fixed capacity of N

§Examples
use heapless::Deque;

// allocate the deque on the stack
let mut x: Deque<u8, 16> = Deque::new();

// allocate the deque in a static variable
static mut X: Deque<u8, 16> = Deque::new();
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pub const fn capacity(&self) -> usize

Returns the maximum number of elements the deque can hold.

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pub const fn len(&self) -> usize

Returns the number of elements currently in the deque.

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pub fn clear(&mut self)

Clears the deque, removing all values.

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pub fn is_empty(&self) -> bool

Returns whether the deque is empty.

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pub fn is_full(&self) -> bool

Returns whether the deque is full (i.e. if len() == capacity().

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pub fn as_slices(&self) -> (&[T], &[T])

Returns a pair of slices which contain, in order, the contents of the Deque.

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pub fn as_mut_slices(&mut self) -> (&mut [T], &mut [T])

Returns a pair of mutable slices which contain, in order, the contents of the Deque.

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

Provides a reference to the front element, or None if the Deque is empty.

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

Provides a mutable reference to the front element, or None if the Deque is empty.

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

Provides a reference to the back element, or None if the Deque is empty.

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

Provides a mutable reference to the back element, or None if the Deque is empty.

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

Removes the item from the front of the deque and returns it, or None if it’s empty

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

Removes the item from the back of the deque and returns it, or None if it’s empty

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pub fn push_front(&mut self, item: T) -> Result<(), T>

Appends an item to the front of the deque

Returns back the item if the deque is full

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pub fn push_back(&mut self, item: T) -> Result<(), T>

Appends an item to the back of the deque

Returns back the item if the deque is full

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

Removes an item from the front of the deque and returns it, without checking that the deque is not empty

§Safety

It’s undefined behavior to call this on an empty deque

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

Removes an item from the back of the deque and returns it, without checking that the deque is not empty

§Safety

It’s undefined behavior to call this on an empty deque

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pub unsafe fn push_front_unchecked(&mut self, item: T)

Appends an item to the front of the deque

§Safety

This assumes the deque is not full.

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pub unsafe fn push_back_unchecked(&mut self, item: T)

Appends an item to the back of the deque

§Safety

This assumes the deque is not full.

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

Returns an iterator over the deque.

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

Returns an iterator that allows modifying each value.

Trait Implementations§

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impl<T, const N: usize> Clone for Deque<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: Debug, const N: usize> Debug for Deque<T, N>

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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 Deque<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 Deque<T, N>

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fn drop(&mut self)

Executes the destructor for this type. Read more
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impl<'a, T, const N: usize> IntoIterator for &'a Deque<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 Deque<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> IntoIterator for Deque<T, N>

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type Item = T

The type of the elements being iterated over.
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type IntoIter = IntoIter<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

Auto Trait Implementations§

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impl<T, const N: usize> Freeze for Deque<T, N>
where T: Freeze,

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impl<T, const N: usize> RefUnwindSafe for Deque<T, N>
where T: RefUnwindSafe,

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

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impl<T, const N: usize> Sync for Deque<T, N>
where T: Sync,

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

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impl<T, const N: usize> UnwindSafe for Deque<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> CloneToUninit for T
where T: Clone,

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default unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. 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> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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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.