[][src]Struct alloc_wg::boxed::Box

pub struct Box<T: ?Sized, A: AllocRef = Global> { /* fields omitted */ }

A pointer type for heap allocation.

See the module-level documentation for more.

Implementations

impl<T> Box<T>[src]

#[must_use]pub fn new(x: T) -> Self[src]

Allocates memory on the heap and then places x into it.

This doesn't actually allocate if T is zero-sized.

Example

use alloc_wg::boxed::Box;

let five = Box::new(5);

#[must_use]pub fn new_uninit() -> Box<MaybeUninit<T>>

Important traits for Box<I, A>

impl<I: Iterator + ?Sized, A: AllocRef> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: AllocRef> Future for Box<F, A> type Output = F::Output;
[src]

Constructs a new box with uninitialized contents.

Example

use alloc_wg::boxed::Box;

let mut five = Box::<u32>::new_uninit();

let five = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5)

pub fn pin(x: T) -> Pin<Self>[src]

Constructs a new Pin<Box<T>>. If T does not implement Unpin, then x will be pinned in memory and unable to be moved.

impl<T, A: AllocRef> Box<T, A>[src]

pub fn new_in(x: T, a: A) -> Self[src]

Allocates memory with the given allocator and then places x into it.

This doesn't actually allocate if T is zero-sized.

Example

#![feature(allocator_api)]
use alloc_wg::{alloc::Global, boxed::Box};

let five = Box::new_in(5, Global);

pub fn try_new_in(x: T, alloc: A) -> Result<Self, AllocErr>[src]

Tries to allocate memory with the given allocator and then places x into it.

This doesn't actually allocate if T is zero-sized.

Example

#![feature(allocator_api)]
use alloc_wg::{alloc::Global, boxed::Box};

let five = Box::try_new_in(5, Global)?;

pub fn new_uninit_in(a: A) -> Box<MaybeUninit<T>, A>

Important traits for Box<I, A>

impl<I: Iterator + ?Sized, A: AllocRef> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: AllocRef> Future for Box<F, A> type Output = F::Output;
[src]

Constructs a new box with uninitialized contents in a specified allocator.

Example

#![feature(allocator_api)]
use alloc_wg::{alloc::Global, boxed::Box};

let mut five = Box::<u32, _>::new_uninit_in(Global);

let five = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5)

pub fn try_new_uninit_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocErr>[src]

Tries to construct a new box with uninitialized contents in a specified allocator.

Example

#![feature(allocator_api)]
use alloc_wg::{alloc::Global, boxed::Box};

let mut five = Box::<u32, Global>::try_new_uninit_in(Global)?;

let five = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5);

pub fn pin_in(x: T, a: A) -> Pin<Self>[src]

Constructs a new Pin<Box<T, A>> with the specified allocator. If T does not implement Unpin, then x will be pinned in memory and unable to be moved.

pub fn try_pin_in(x: T, a: A) -> Result<Pin<Self>, AllocErr>[src]

Constructs a new Pin<Box<T, A>> with the specified allocator. If T does not implement Unpin, then x will be pinned in memory and unable to be moved.

impl<T> Box<[T]>[src]

#[must_use]pub fn new_uninit_slice(len: usize) -> Box<[MaybeUninit<T>]>

Important traits for Box<I, A>

impl<I: Iterator + ?Sized, A: AllocRef> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: AllocRef> Future for Box<F, A> type Output = F::Output;
[src]

Construct a new boxed slice with uninitialized contents.

Example

use alloc_wg::boxed::Box;

let mut values = Box::<[u32]>::new_uninit_slice(3);

let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);

    values.assume_init()
};

assert_eq!(*values, [1, 2, 3]);

impl<T, A: AllocRef> Box<[T], A>[src]

pub fn new_uninit_slice_in(len: usize, a: A) -> Box<[MaybeUninit<T>], A>

Important traits for Box<I, A>

impl<I: Iterator + ?Sized, A: AllocRef> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: AllocRef> Future for Box<F, A> type Output = F::Output;
[src]

Construct a new boxed slice with uninitialized contents with the spoecified allocator.

Example

#![feature(allocator_api)]
use alloc_wg::{alloc::Global, boxed::Box};

let mut values = Box::<[u32], _>::new_uninit_slice_in(3, Global);

let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);

    values.assume_init()
};

assert_eq!(*values, [1, 2, 3]);

pub fn try_new_uninit_slice_in(
    len: usize,
    a: A
) -> Result<Box<[MaybeUninit<T>], A>, TryReserveError>
[src]

Tries to construct a new boxed slice with uninitialized contents with the spoecified allocator.

Example

#![feature(allocator_api)]
use alloc_wg::{alloc::Global, boxed::Box};

let mut values = Box::<[u32], Global>::try_new_uninit_slice_in(3, Global)?;

let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);

    values.assume_init()
};

assert_eq!(*values, [1, 2, 3]);

impl<T, A: AllocRef> Box<MaybeUninit<T>, A>[src]

pub unsafe fn assume_init(self) -> Box<T, A>

Important traits for Box<I, A>

impl<I: Iterator + ?Sized, A: AllocRef> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: AllocRef> Future for Box<F, A> type Output = F::Output;
[src]

Converts to Box<T, A>.

Safety

As with MaybeUninit::assume_init, it is up to the caller to guarantee that the value really is in an initialized state. Calling this when the content is not yet fully initialized causes immediate undefined behavior.

Example

use alloc_wg::boxed::Box;

let mut five = Box::<u32>::new_uninit();

let five = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5)

impl<T, A: AllocRef> Box<[MaybeUninit<T>], A>[src]

pub unsafe fn assume_init(self) -> Box<[T], A>

Important traits for Box<I, A>

impl<I: Iterator + ?Sized, A: AllocRef> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: AllocRef> Future for Box<F, A> type Output = F::Output;
[src]

Converts to Box<[T], B>.

Safety

As with MaybeUninit::assume_init, it is up to the caller to guarantee that the values really are in an initialized state. Calling this when the content is not yet fully initialized causes immediate undefined behavior.

Example

use alloc_wg::boxed::Box;

let mut values = Box::<[u32]>::new_uninit_slice(3);

let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);

    values.assume_init()
};

assert_eq!(*values, [1, 2, 3])

impl<T: ?Sized> Box<T>[src]

pub unsafe fn from_raw(raw: *mut T) -> Self[src]

Constructs a box from a raw pointer.

After calling this function, the raw pointer is owned by the resulting Box.2 Specifically, the Box destructor will call the destructor of T and free the allocated memory. For this to be safe, the memory must have been allocated in accordance with the memory layout used by Box .

Safety

This function is unsafe because improper use may lead to memory problems. For example, a double-free may occur if the function is called twice on the same raw pointer.

Examples

Recreate a Box which was previously converted to a raw pointer using Box::into_raw:

use alloc_wg::boxed::Box;

let x = Box::new(5);
let ptr = Box::into_raw(x);
let x = unsafe { Box::from_raw(ptr) };

Manually create a Box from scratch by using the global allocator:

use alloc_wg::{alloc::alloc, boxed::Box};
use core::alloc::Layout;

unsafe {
    let ptr = alloc(Layout::new::<i32>()) as *mut i32;
    *ptr = 5;
    let x = Box::from_raw(ptr);
}

impl<T: ?Sized, A: AllocRef> Box<T, A>[src]

pub unsafe fn from_raw_in(raw: *mut T, alloc: A) -> Self[src]

Constructs a box from a raw pointer.

After calling this function, the raw pointer is owned by the resulting Box. Specifically, the Box destructor will call the destructor of T and free the allocated memory. For this to be safe, the memory must have been allocated in accordance with the [memory layout] used by Box .

Safety

This function is unsafe because improper use may lead to memory problems. For example, a double-free may occur if the function is called twice on the same raw pointer.

Example

Manually create a Box from scratch by using the global allocator:

#![feature(allocator_api)]
use alloc_wg::{
    alloc::{alloc, Global},
    boxed::Box,
};
use core::alloc::Layout;

unsafe {
    let ptr = alloc(Layout::new::<i32>()) as *mut i32;
    *ptr = 5;
    let x: Box<_, Global> = Box::from_raw_in(ptr, Global);
}

pub fn build_alloc(&self) -> &A[src]

Returns a shared reference to the associated BuildAlloc

pub fn build_alloc_mut(&mut self) -> &mut A[src]

Returns a mutable reference to the associated BuildAlloc

pub fn alloc_ref(&self) -> &A[src]

Returns a shared reference to the allocator.

pub fn alloc_ref_mut(&mut self) -> &mut A[src]

Returns a mutable reference to the allocator.

pub fn into_raw(b: Self) -> *mut T[src]

Consumes the Box, returning a wrapped raw pointer.

The pointer will be properly aligned and non-null.

After calling this function, the caller is responsible for the memory previously managed by the Box. In particular, the caller should properly destroy T and release the memory, taking into account the memory layout used by Box. The easiest way to do this is to convert the raw pointer back into a Box with the Box::from_raw function, allowing the Box destructor to perform the cleanup.

Note: this is an associated function, which means that you have to call it as Box::into_raw(b) instead of b.into_raw(). This is so that there is no conflict with a method on the inner type.

Examples

Converting the raw pointer back into a Box with Box::from_raw for automatic cleanup:

use alloc_wg::boxed::Box;

let x = Box::new(String::from("Hello"));
let ptr = Box::into_raw(x);
let x = unsafe { Box::from_raw(ptr) };

Manual cleanup by explicitly running the destructor and deallocating the memory:

use alloc_wg::{alloc::dealloc, boxed::Box};
use core::{alloc::Layout, ptr};

let x = Box::new(String::from("Hello"));
let p = Box::into_raw(x);
unsafe {
    ptr::drop_in_place(p);
    dealloc(p as *mut u8, Layout::new::<String>());
}

pub fn into_raw_alloc(b: Self) -> (*mut T, A)[src]

pub fn into_raw_non_null(b: Self) -> NonNull<T>[src]

Consumes the Box, returning the wrapped pointer as NonNull<T>.

After calling this function, the caller is responsible for the memory previously managed by the Box. In particular, the caller should properly destroy T and release the memory. The easiest way to do so is to convert the NonNull<T> pointer into a raw pointer and back into a Box with the Box::from_raw function.

Note: this is an associated function, which means that you have to call it as Box::into_raw_non_null(b) instead of b.into_raw_non_null(). This is so that there is no conflict with a method on the inner type.

Examples

use alloc_wg::boxed::Box;

let x = Box::new(5);
let ptr = Box::into_raw_non_null(x);

// Clean up the memory by converting the NonNull pointer back
// into a Box and letting the Box be dropped.
let x = unsafe { Box::from_raw(ptr.as_ptr()) };

pub fn into_raw_non_null_alloc(b: Self) -> (NonNull<T>, A)[src]

pub fn leak<'a>(b: Self) -> &'a mut T where
    T: 'a, 
[src]

Consumes and leaks the Box, returning a mutable reference, &'a mut T. Note that the type T must outlive the chosen lifetime 'a. If the type has only static references, or none at all, then this may be chosen to be 'static.

This function is mainly useful for data that lives for the remainder of the program's life. Dropping the returned reference will cause a memory leak. If this is not acceptable, the reference should first be wrapped with the Box::from_raw function producing a Box. This Box can then be dropped which will properly destroy T and release the allocated memory.

Note: this is an associated function, which means that you have to call it as Box::leak(b) instead of b.leak(). This is so that there is no conflict with a method on the inner type.

Examples

Simple usage:

use alloc_wg::boxed::Box;

let x = Box::new(41);
let static_ref: &'static mut usize = Box::leak(x);
*static_ref += 1;
assert_eq!(*static_ref, 42);

pub fn into_pin(boxed: Self) -> Pin<Self>[src]

Converts a Box<T, A> into a Pin<Box<T, A>>

This conversion does not allocate and happens in place.

This is also available via From.

impl<A: AllocRef> Box<dyn Any, A>[src]

pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Box<dyn Any, A>>[src]

Attempt to downcast the box to a concrete type.

Examples

use std::any::Any;

fn print_if_string(value: Box<dyn Any>) {
    if let Ok(string) = value.downcast::<String>() {
        println!("String ({}): {}", string.len(), string);
    }
}

let my_string = "Hello World".to_string();
print_if_string(Box::new(my_string));
print_if_string(Box::new(0i8));

impl<A: AllocRef> Box<dyn Any + Send, A>[src]

pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Box<dyn Any + Send, A>>[src]

Attempt to downcast the box to a concrete type.

Examples

use std::any::Any;

fn print_if_string(value: Box<dyn Any + Send>) {
    if let Ok(string) = value.downcast::<String>() {
        println!("String ({}): {}", string.len(), string);
    }
}

let my_string = "Hello World".to_string();
print_if_string(Box::new(my_string));
print_if_string(Box::new(0i8));

Trait Implementations

impl<T: ?Sized, A: AllocRef> AsMut<T> for Box<T, A>[src]

impl<T: ?Sized, A: AllocRef> AsRef<T> for Box<T, A>[src]

impl<T: ?Sized, A: AllocRef> Borrow<T> for Box<T, A>[src]

impl<T: ?Sized, A: AllocRef> BorrowMut<T> for Box<T, A>[src]

impl<T: Clone, A: AllocRef + Clone> Clone for Box<T, A>[src]

fn clone(&self) -> Self[src]

Returns a new box with a clone() of this box's contents.

Examples

use alloc_wg::boxed::Box;

let x = Box::new(5);
let y = x.clone();

// The value is the same
assert_eq!(x, y);

// But they are unique objects
assert_ne!(&*x as *const i32, &*y as *const i32);

fn clone_from(&mut self, source: &Self)[src]

Copies source's contents into self without creating a new allocation.

Examples

use alloc_wg::boxed::Box;

let x = Box::new(5);
let mut y = Box::new(10);
let yp: *const i32 = &*y;

y.clone_from(&x);

// The value is the same
assert_eq!(x, y);

// And no allocation occurred
assert_eq!(yp, &*y);

impl<T: Clone, A: Clone> Clone for Box<[T], A> where
    A: AllocRef
[src]

impl<T: Clone, A: AllocRef, B: AllocRef> CloneIn<B> for Box<T, A>[src]

type Cloned = Box<T, B>

impl<T: ?Sized + Unsize<U>, U: ?Sized, A: AllocRef> CoerceUnsized<Box<U, A>> for Box<T, A>[src]

impl<T: Debug + ?Sized, A: AllocRef> Debug for Box<T, A>[src]

impl<T, A> Default for Box<T, A> where
    T: Default,
    A: Default + AllocRef
[src]

impl<T, A: AllocRef> Default for Box<[T], A> where
    A: Default
[src]

impl<A> Default for Box<str, A> where
    A: Default + AllocRef
[src]

impl<T: ?Sized, A: AllocRef> Deref for Box<T, A>[src]

type Target = T

The resulting type after dereferencing.

impl<T: ?Sized, A: AllocRef> DerefMut for Box<T, A>[src]

impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Box<U, Global>> for Box<T, Global>[src]

impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Box<U, System>> for Box<T, System>[src]

impl<T: Display + ?Sized, A: AllocRef> Display for Box<T, A>[src]

impl<I: DoubleEndedIterator + ?Sized, A: AllocRef> DoubleEndedIterator for Box<I, A>[src]

impl<T: ?Sized, A: AllocRef> Drop for Box<T, A>[src]

impl<T: ?Sized + Eq, A: AllocRef> Eq for Box<T, A>[src]

impl<I: ExactSizeIterator + ?Sized, A: AllocRef> ExactSizeIterator for Box<I, A>[src]

impl<Args, F: Fn<Args> + Copy + ?Sized, A: AllocRef> Fn<Args> for Box<F, A>[src]

impl<Args, F: FnMut<Args> + Copy + ?Sized, A: AllocRef> FnMut<Args> for Box<F, A>[src]

impl<Args, F: FnOnce<Args> + Copy + ?Sized, A: AllocRef> FnOnce<Args> for Box<F, A>[src]

type Output = <F as FnOnce<Args>>::Output

The returned type after the call operator is used.

impl<T: Copy, A: AllocRef, '_> From<&'_ [T]> for Box<[T], A> where
    A: Default
[src]

fn from(slice: &[T]) -> Self[src]

Converts a &[T] into a Box<[T], B>

This conversion allocates and performs a copy of slice.

Examples

use alloc_wg::boxed::Box;

// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice: Box<[u8]> = Box::from(slice);

println!("{:?}", boxed_slice);

impl<A: AllocRef, '_> From<&'_ str> for Box<str, A> where
    A: Default
[src]

#[must_use]fn from(s: &str) -> Self[src]

Converts a &str into a Box<str>

This conversion allocates on the heap and performs a copy of s.

Examples

use alloc_wg::boxed::Box;

let boxed: Box<str> = Box::from("hello");
println!("{}", boxed);

impl<T: ?Sized, A: AllocRef> From<Box<T, A>> for Pin<Box<T, A>>[src]

fn from(boxed: Box<T, A>) -> Self[src]

Converts a Box<T, A> into a Pin<Box<T, A>>

This conversion does not allocate on the heap and happens in place.

impl<A: AllocRef> From<Box<str, A>> for Box<[u8], A>[src]

fn from(s: Box<str, A>) -> Self[src]

Converts a Box<str>> into a Box<[u8]>

This conversion does not allocate on the heap and happens in place.

Examples

// create a Box<str> which will be used to create a Box<[u8]>
let boxed: Box<str> = Box::from("hello");
let boxed_str: Box<[u8]> = Box::from(boxed);

// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice = Box::from(slice);

assert_eq!(boxed_slice, boxed_str);

impl From<Box<str, Global>> for String[src]

#[must_use]fn from(s: Box<str>) -> Self[src]

Converts the given boxed str slice to a String. It is notable that the str slice is owned.

Examples

Basic usage:

let s1: String = String::from("hello world");
let s2 = s1.into_boxed_str();
let s3: String = String::from(s2);

assert_eq!("hello world", s3)

impl<A> From<String<A>> for Box<str, A> where
    A: AllocRef
[src]

fn from(s: String<A>) -> Self[src]

Converts the given String to a boxed str slice that is owned.

Examples

Basic usage:

let s1: String = String::from("hello world");
let s2: Box<str> = Box::from(s1);
let s3: String = String::from(s2);

assert_eq!("hello world", s3)

impl<T, A> From<T> for Box<T, A> where
    A: Default + AllocRef
[src]

fn from(t: T) -> Self[src]

Converts a generic type T into a Box<T>

The conversion allocates on the heap and moves t from the stack into it.

Examples

use alloc_wg::boxed::Box;

let x = 5;
let boxed = Box::new(5);

assert_eq!(Box::from(x), boxed);

impl<T> From<Vec<T, Global>> for Box<[T]>[src]

impl<I: FusedIterator + ?Sized, A: AllocRef> FusedIterator for Box<I, A>[src]

impl<F: ?Sized + Future + Unpin, A: AllocRef> Future for Box<F, A>[src]

type Output = F::Output

The type of value produced on completion.

impl<T: ?Sized + Hash, A: AllocRef> Hash for Box<T, A>[src]

impl<T: ?Sized + Hasher, A: AllocRef> Hasher for Box<T, A>[src]

impl<I: Iterator + ?Sized, A: AllocRef> Iterator for Box<I, A>[src]

type Item = I::Item

The type of the elements being iterated over.

impl<T: ?Sized + Ord, A: AllocRef> Ord for Box<T, A>[src]

impl<T: ?Sized + PartialEq, A: AllocRef> PartialEq<Box<T, A>> for Box<T, A>[src]

impl<T: ?Sized + PartialOrd, A: AllocRef> PartialOrd<Box<T, A>> for Box<T, A>[src]

impl<T: ?Sized, A: AllocRef> Pointer for Box<T, A>[src]

impl<T: ?Sized, A: AllocRef> Receiver for Box<T, A>[src]

impl<T, const N: usize> TryFrom<Box<[T], Global>> for Box<[T; N]>[src]

type Error = Box<[T]>

The type returned in the event of a conversion error.

impl<T: ?Sized, A: AllocRef> Unpin for Box<T, A>[src]

Auto Trait Implementations

impl<T: ?Sized, A> RefUnwindSafe for Box<T, A> where
    A: RefUnwindSafe,
    T: RefUnwindSafe

impl<T: ?Sized, A> Send for Box<T, A> where
    A: Send,
    T: Send

impl<T: ?Sized, A> Sync for Box<T, A> where
    A: Sync,
    T: Sync

impl<T: ?Sized, A> UnwindSafe for Box<T, A> where
    A: UnwindSafe,
    T: RefUnwindSafe + UnwindSafe

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> From<!> for T[src]

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<I> IntoIterator for I where
    I: Iterator
[src]

type Item = <I as Iterator>::Item

The type of the elements being iterated over.

type IntoIter = I

Which kind of iterator are we turning this into?

impl<T> IteratorExt for T where
    T: Iterator
[src]

impl<T> ToOwned for T where
    T: Clone
[src]

type Owned = T

The resulting type after obtaining ownership.

impl<T> ToString for T where
    T: Display + ?Sized
[src]

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

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

The type returned in the event of a conversion error.