Enum smallbox::SmallBox

pub enum SmallBox<T: ?Sized, Space = S2> {
    Stack(StackBox<T, Space>),
    Box(Box<T>),
}

Stack allocation with heap fallback

Examples

use smallbox::SmallBox;

let val: SmallBox<PartialEq<usize>> = SmallBox::new(5usize);

assert!(*val == 5)

Variants

Stack(StackBox<T, Space>)Box(Box<T>)

Methods

impl<T: ?Sized, Space> SmallBox<T, Space>

fn new<U>(val: U) -> SmallBox<T, Space> where
    U: Unsize<T>, 

Box val on stack or heap depending on its size

Example

use smallbox::SmallBox;
use smallbox::space::*;

let tiny: SmallBox<[u64], S4> = SmallBox::new([0; 2]);
let big: SmallBox<[u64], S4> = SmallBox::new([1; 8]);

assert_eq!(tiny.len(), 2);
assert_eq!(big[7], 1);

match tiny {
    SmallBox::Stack(val) => assert_eq!(*val, [0; 2]),
    _ => unreachable!()
}

match big {
    SmallBox::Box(val) => assert_eq!(*val, [1; 8]),
    _ => unreachable!()
}

fn resize<ToSpace>(self) -> Result<SmallBox<T, ToSpace>, Self>

Try to transforms to the SmallBox<T> of bigger capacity, and return Err when target capacity is smaller. Note that this method will always success when the allocation is on heap.

Example

use smallbox::SmallBox;
use smallbox::space::*;

let s = SmallBox::<[usize], S8>::new([0usize; 4]);
assert!(s.resize::<S16>().is_ok());

let s = SmallBox::<[usize], S8>::new([0usize; 4]);
assert!(s.resize::<S4>().is_err());

Trait Implementations

impl<T: ?Sized, Space> Deref for SmallBox<T, Space>

type Target = T

The resulting type after dereferencing

fn deref(&self) -> &T

The method called to dereference a value

impl<T: ?Sized, Space> DerefMut for SmallBox<T, Space>

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

The method called to mutably dereference a value

impl<T: Display + ?Sized, Space> Display for SmallBox<T, Space>

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

Formats the value using the given formatter.

impl<T: Debug + ?Sized, Space> Debug for SmallBox<T, Space>

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

Formats the value using the given formatter.

impl<T: ?Sized, Space> Pointer for SmallBox<T, Space>

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

Formats the value using the given formatter.

impl<T: ?Sized + PartialEq, Space> PartialEq for SmallBox<T, Space>

fn eq(&self, other: &SmallBox<T, Space>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &SmallBox<T, Space>) -> bool

This method tests for !=.

impl<T: ?Sized + PartialOrd, Space> PartialOrd for SmallBox<T, Space>

fn partial_cmp(&self, other: &SmallBox<T, Space>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &SmallBox<T, Space>) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &SmallBox<T, Space>) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn ge(&self, other: &SmallBox<T, Space>) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

fn gt(&self, other: &SmallBox<T, Space>) -> bool

This method tests greater than (for self and other) and is used by the > operator.

impl<T: ?Sized + Ord, Space> Ord for SmallBox<T, Space>

fn cmp(&self, other: &SmallBox<T, Space>) -> Ordering

This method returns an Ordering between self and other.

impl<T: ?Sized + Eq, Space> Eq for SmallBox<T, Space>

impl<T: ?Sized + Hash, Space> Hash for SmallBox<T, Space>

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

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].