Struct crossbeam::queue::ArrayQueue

pub struct ArrayQueue<T> { /* private fields */ }

A bounded multi-producer multi-consumer queue.

This queue allocates a fixed-capacity buffer on construction, which is used to store pushed elements. The queue cannot hold more elements than the buffer allows. Attempting to push an element into a full queue will fail. Alternatively, force_push makes it possible for this queue to be used as a ring-buffer. Having a buffer allocated upfront makes this queue a bit faster than SegQueue.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::new(2);

assert_eq!(q.push('a'), Ok(()));
assert_eq!(q.push('b'), Ok(()));
assert_eq!(q.push('c'), Err('c'));
assert_eq!(q.pop(), Some('a'));

Implementations

impl<T> ArrayQueue<T>

pub fn new(cap: usize) -> ArrayQueue<T>

Creates a new bounded queue with the given capacity.

Panics

Panics if the capacity is zero.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::<i32>::new(100);

pub fn push(&self, value: T) -> Result<(), T>

Attempts to push an element into the queue.

If the queue is full, the element is returned back as an error.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::new(1);

assert_eq!(q.push(10), Ok(()));
assert_eq!(q.push(20), Err(20));

pub fn force_push(&self, value: T) -> Option<T>

Pushes an element into the queue, replacing the oldest element if necessary.

If the queue is full, the oldest element is replaced and returned, otherwise None is returned.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::new(2);

assert_eq!(q.force_push(10), None);
assert_eq!(q.force_push(20), None);
assert_eq!(q.force_push(30), Some(10));
assert_eq!(q.pop(), Some(20));

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

Attempts to pop an element from the queue.

If the queue is empty, None is returned.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::new(1);
assert_eq!(q.push(10), Ok(()));

assert_eq!(q.pop(), Some(10));
assert!(q.pop().is_none());

pub fn capacity(&self) -> usize

Returns the capacity of the queue.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::<i32>::new(100);

assert_eq!(q.capacity(), 100);

pub fn is_empty(&self) -> bool

Returns true if the queue is empty.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::new(100);

assert!(q.is_empty());
q.push(1).unwrap();
assert!(!q.is_empty());

pub fn is_full(&self) -> bool

Returns true if the queue is full.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::new(1);

assert!(!q.is_full());
q.push(1).unwrap();
assert!(q.is_full());

pub fn len(&self) -> usize

Returns the number of elements in the queue.

Examples

use crossbeam_queue::ArrayQueue;

let q = ArrayQueue::new(100);
assert_eq!(q.len(), 0);

q.push(10).unwrap();
assert_eq!(q.len(), 1);

q.push(20).unwrap();
assert_eq!(q.len(), 2);

Trait Implementations

impl<T> Debug for ArrayQueue<T>

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

Formats the value using the given formatter.

impl<T> Drop for ArrayQueue<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T> IntoIterator for ArrayQueue<T>

type Item = T

The type of the elements being iterated over.

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> <ArrayQueue<T> as IntoIterator>::IntoIter

Creates an iterator from a value.

impl<T> Send for ArrayQueue<T> where
    T: Send, 

impl<T> Sync for ArrayQueue<T> where
    T: Send,