Struct sp_std::boxed::Box

#[lang = "owned_box"]pub struct Box<T, A = Global>(_, _)
 where
    T: ?Sized,
    A: Allocator;

A pointer type for heap allocation.

See the module-level documentation for more.

Implementations

impl<T> Box<T, Global>

pub fn new(x: T) -> Box<T, Global>

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

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

Examples

let five = Box::new(5);

pub fn new_uninit() -> Box<MaybeUninit<T>, Global>

🔬 This is a nightly-only experimental API. (new_uninit)

Constructs a new box with uninitialized contents.

Examples

#![feature(new_uninit)]

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 new_zeroed() -> Box<MaybeUninit<T>, Global>

🔬 This is a nightly-only experimental API. (new_uninit)

Constructs a new Box with uninitialized contents, with the memory being filled with 0 bytes.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

Examples

#![feature(new_uninit)]

let zero = Box::<u32>::new_zeroed();
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0)

pub fn pin(x: T) -> Pin<Box<T, Global>>

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

pub fn try_new(x: T) -> Result<Box<T, Global>, AllocError>

🔬 This is a nightly-only experimental API. (allocator_api)

Allocates memory on the heap then places x into it, returning an error if the allocation fails

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

Examples

#![feature(allocator_api)]

let five = Box::try_new(5)?;

pub fn try_new_uninit() -> Result<Box<MaybeUninit<T>, Global>, AllocError>

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a new box with uninitialized contents on the heap, returning an error if the allocation fails

Examples

#![feature(allocator_api, new_uninit)]

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

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

    five.assume_init()
};

assert_eq!(*five, 5);

pub fn try_new_zeroed() -> Result<Box<MaybeUninit<T>, Global>, AllocError>

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a new Box with uninitialized contents, with the memory being filled with 0 bytes on the heap

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

Examples

#![feature(allocator_api, new_uninit)]

let zero = Box::<u32>::try_new_zeroed()?;
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0);

impl<T, A> Box<T, A> where
    A: Allocator, 

pub fn new_in(x: T, alloc: A) -> Box<T, A>

🔬 This is a nightly-only experimental API. (allocator_api)

Allocates memory in the given allocator then places x into it.

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

Examples

#![feature(allocator_api)]

use std::alloc::System;

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

pub fn try_new_in(x: T, alloc: A) -> Result<Box<T, A>, AllocError>

🔬 This is a nightly-only experimental API. (allocator_api)

Allocates memory in the given allocator then places x into it, returning an error if the allocation fails

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

Examples

#![feature(allocator_api)]

use std::alloc::System;

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

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

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a new box with uninitialized contents in the provided allocator.

Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

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

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>, AllocError>

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a new box with uninitialized contents in the provided allocator, returning an error if the allocation fails

Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

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

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

    five.assume_init()
};

assert_eq!(*five, 5);

pub fn new_zeroed_in(alloc: A) -> Box<MaybeUninit<T>, A>

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a new Box with uninitialized contents, with the memory being filled with 0 bytes in the provided allocator.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let zero = Box::<u32, _>::new_zeroed_in(System);
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0)

pub fn try_new_zeroed_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a new Box with uninitialized contents, with the memory being filled with 0 bytes in the provided allocator, returning an error if the allocation fails,

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let zero = Box::<u32, _>::try_new_zeroed_in(System)?;
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0);

pub fn pin_in(x: T, alloc: A) -> Pin<Box<T, A>> where
    A: 'static, 

🔬 This is a nightly-only experimental API. (allocator_api)

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

pub fn into_boxed_slice(boxed: Box<T, A>) -> Box<[T], A>

🔬 This is a nightly-only experimental API. (box_into_boxed_slice)

Converts a Box<T> into a Box<[T]>

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

impl<T> Box<[T], Global>

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

🔬 This is a nightly-only experimental API. (new_uninit)

Constructs a new boxed slice with uninitialized contents.

Examples

#![feature(new_uninit)]

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])

pub fn new_zeroed_slice(len: usize) -> Box<[MaybeUninit<T>], Global>

🔬 This is a nightly-only experimental API. (new_uninit)

Constructs a new boxed slice with uninitialized contents, with the memory being filled with 0 bytes.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

Examples

#![feature(new_uninit)]

let values = Box::<[u32]>::new_zeroed_slice(3);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0])

impl<T, A> Box<[T], A> where
    A: Allocator, 

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

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a new boxed slice with uninitialized contents in the provided allocator.

Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

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

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 new_zeroed_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a new boxed slice with uninitialized contents in the provided allocator, with the memory being filled with 0 bytes.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let values = Box::<[u32], _>::new_zeroed_slice_in(3, System);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0])

impl<T, A> Box<MaybeUninit<T>, A> where
    A: Allocator, 

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

🔬 This is a nightly-only experimental API. (new_uninit)

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.

Examples

#![feature(new_uninit)]

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

let five: Box<u32> = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5)

impl<T, A> Box<[MaybeUninit<T>], A> where
    A: Allocator, 

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

🔬 This is a nightly-only experimental API. (new_uninit)

Converts to Box<[T], A>.

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.

Examples

#![feature(new_uninit)]

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> Box<T, Global> where
    T: ?Sized, 

pub unsafe fn from_raw(raw: *mut T) -> Box<T, Global>

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.

The safety conditions are described in the memory layout section.

Examples

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

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 std::alloc::{alloc, Layout};

unsafe {
    let ptr = alloc(Layout::new::<i32>()) as *mut i32;
    // In general .write is required to avoid attempting to destruct
    // the (uninitialized) previous contents of `ptr`, though for this
    // simple example `*ptr = 5` would have worked as well.
    ptr.write(5);
    let x = Box::from_raw(ptr);
}

impl<T, A> Box<T, A> where
    T: ?Sized,
    A: Allocator, 

pub unsafe fn from_raw_in(raw: *mut T, alloc: A) -> Box<T, A>

🔬 This is a nightly-only experimental API. (allocator_api)

Constructs a box from a raw pointer in the given allocator.

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.

Examples

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

#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(5, System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
let x = unsafe { Box::from_raw_in(ptr, alloc) };

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

#![feature(allocator_api, slice_ptr_get)]

use std::alloc::{Allocator, Layout, System};

unsafe {
    let ptr = System.allocate(Layout::new::<i32>())?.as_mut_ptr();
    // In general .write is required to avoid attempting to destruct
    // the (uninitialized) previous contents of `ptr`, though for this
    // simple example `*ptr = 5` would have worked as well.
    ptr.write(5);
    let x = Box::from_raw_in(ptr, System);
}

pub fn into_raw(b: Box<T, A>) -> *mut T

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:

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 std::alloc::{dealloc, Layout};
use std::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_with_allocator(b: Box<T, A>) -> (*mut T, A)

🔬 This is a nightly-only experimental API. (allocator_api)

Consumes the Box, returning a wrapped raw pointer and the allocator.

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_in 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_with_allocator(b) instead of b.into_raw_with_allocator(). 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_in for automatic cleanup:

#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(String::from("Hello"), System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
let x = unsafe { Box::from_raw_in(ptr, alloc) };

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

#![feature(allocator_api)]

use std::alloc::{Allocator, Layout, System};
use std::ptr::{self, NonNull};

let x = Box::new_in(String::from("Hello"), System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
unsafe {
    ptr::drop_in_place(ptr);
    let non_null = NonNull::new_unchecked(ptr);
    alloc.deallocate(non_null.cast(), Layout::new::<String>());
}

pub fn allocator(b: &Box<T, A>) -> &A

🔬 This is a nightly-only experimental API. (allocator_api)

Returns a reference to the underlying allocator.

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

pub fn leak<'a>(b: Box<T, A>) -> &'a mut T where
    A: 'a, 

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:

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

Unsized data:

let x = vec![1, 2, 3].into_boxed_slice();
let static_ref = Box::leak(x);
static_ref[0] = 4;
assert_eq!(*static_ref, [4, 2, 3]);

pub fn into_pin(boxed: Box<T, A>) -> Pin<Box<T, A>> where
    A: 'static, 

🔬 This is a nightly-only experimental API. (box_into_pin)

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

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

This is also available via From.

impl<A> Box<dyn Any + 'static, A> where
    A: Allocator, 

pub fn downcast<T>(self) -> Result<Box<T, A>, Box<dyn Any + 'static, A>> where
    T: Any, 

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> Box<dyn Any + 'static + Send, A> where
    A: Allocator, 

pub fn downcast<T>(self) -> Result<Box<T, A>, Box<dyn Any + 'static + Send, A>> where
    T: Any, 

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, A> AsMut<T> for Box<T, A> where
    T: ?Sized,
    A: Allocator, 

pub fn as_mut(&mut self) -> &mut T

Performs the conversion.

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

pub fn as_ref(&self) -> &T

Performs the conversion.

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

pub fn borrow(&self) -> &T

Immutably borrows from an owned value.

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

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

Mutably borrows from an owned value.

impl<B> BufRead for Box<B, Global> where
    B: BufRead + ?Sized, 

pub fn fill_buf(&mut self) -> Result<&[u8], Error>

Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty.

pub fn consume(&mut self, amt: usize)

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to read.

pub fn read_until(
    &mut self,
    byte: u8,
    buf: &mut Vec<u8, Global>
) -> Result<usize, Error>

Read all bytes into buf until the delimiter byte or EOF is reached.

pub fn read_line(&mut self, buf: &mut String) -> Result<usize, Error>

Read all bytes until a newline (the 0xA byte) is reached, and append them to the provided buffer.

pub fn split(self, byte: u8) -> Split<Self>

Returns an iterator over the contents of this reader split on the byte byte.

pub fn lines(self) -> Lines<Self>

Returns an iterator over the lines of this reader.

impl Clone for Box<Path, Global>

pub fn clone(&self) -> Box<Path, Global>

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Clone for Box<CStr, Global>

pub fn clone(&self) -> Box<CStr, Global>

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Clone for Box<OsStr, Global>

pub fn clone(&self) -> Box<OsStr, Global>

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Clone for Box<str, Global>

pub fn clone(&self) -> Box<str, Global>

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T, A> Clone for Box<[T], A> where
    T: Clone,
    A: Clone + Allocator, 

pub fn clone(&self) -> Box<[T], A>

Returns a copy of the value.

pub fn clone_from(&mut self, other: &Box<[T], A>)

Performs copy-assignment from source.

impl<T, A> Clone for Box<T, A> where
    T: Clone,
    A: Clone + Allocator, 

pub fn clone(&self) -> Box<T, A>

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

Examples

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);

pub fn clone_from(&mut self, source: &Box<T, A>)

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

Examples

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, U, A> CoerceUnsized<Box<U, A>> for Box<T, A> where
    T: Unsize<U> + ?Sized,
    A: Allocator,
    U: ?Sized, 

impl<T, A> Debug for Box<T, A> where
    T: Debug + ?Sized,
    A: Allocator, 

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

Formats the value using the given formatter.

impl Default for Box<CStr, Global>

pub fn default() -> Box<CStr, Global>

Returns the "default value" for a type.

impl Default for Box<OsStr, Global>

pub fn default() -> Box<OsStr, Global>

Returns the "default value" for a type.

impl Default for Box<str, Global>

pub fn default() -> Box<str, Global>

Returns the "default value" for a type.

impl<T> Default for Box<T, Global> where
    T: Default, 

pub fn default() -> Box<T, Global>

Creates a Box<T>, with the Default value for T.

impl<T> Default for Box<[T], Global>

pub fn default() -> Box<[T], Global>

Returns the "default value" for a type.

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

type Target = T

The resulting type after dereferencing.

pub fn deref(&self) -> &T

Dereferences the value.

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

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

Mutably dereferences the value.

impl<T, U> DispatchFromDyn<Box<U, Global>> for Box<T, Global> where
    T: Unsize<U> + ?Sized,
    U: ?Sized, 

impl<T, A> Display for Box<T, A> where
    T: Display + ?Sized,
    A: Allocator, 

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

Formats the value using the given formatter.

impl<I, A> DoubleEndedIterator for Box<I, A> where
    A: Allocator,
    I: DoubleEndedIterator + ?Sized, 

pub fn next_back(&mut self) -> Option<<I as Iterator>::Item>

Removes and returns an element from the end of the iterator.

pub fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item>

Returns the nth element from the end of the iterator.

pub fn advance_back_by(&mut self, n: usize) -> Result<(), usize>

🔬 This is a nightly-only experimental API. (iter_advance_by)

recently added

Advances the iterator from the back by n elements.

pub fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R where
    R: Try<Ok = B>,
    F: FnMut(B, Self::Item) -> R, 

This is the reverse version of Iterator::try_fold(): it takes elements starting from the back of the iterator.

pub fn rfold<B, F>(self, init: B, f: F) -> B where
    F: FnMut(B, Self::Item) -> B, 

An iterator method that reduces the iterator's elements to a single, final value, starting from the back.

pub fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item> where
    P: FnMut(&Self::Item) -> bool, 

Searches for an element of an iterator from the back that satisfies a predicate.

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

pub fn drop(&mut self)

Executes the destructor for this type.

impl<T, A> Eq for Box<T, A> where
    T: Eq + ?Sized,
    A: Allocator, 

impl<T> Error for Box<T, Global> where
    T: Error, 

pub fn description(&self) -> &str

👎 Deprecated since 1.42.0:

use the Display impl or to_string()

pub fn cause(&self) -> Option<&dyn Error>

👎 Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

pub fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any.

pub fn backtrace(&self) -> Option<&Backtrace>

🔬 This is a nightly-only experimental API. (backtrace)

Returns a stack backtrace, if available, of where this error occurred.

impl<I, A> ExactSizeIterator for Box<I, A> where
    A: Allocator,
    I: ExactSizeIterator + ?Sized, 

pub fn len(&self) -> usize

Returns the exact length of the iterator.

pub fn is_empty(&self) -> bool

🔬 This is a nightly-only experimental API. (exact_size_is_empty)

Returns true if the iterator is empty.

impl Extend<Box<str, Global>> for String

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = Box<str, Global>>, 

Extends a collection with the contents of an iterator.

pub fn extend_one(&mut self, item: A)

🔬 This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<Args, F, A> Fn<Args> for Box<F, A> where
    A: Allocator,
    F: Fn<Args> + ?Sized, 

pub extern "rust-call" fn call(
    &self,
    args: Args
) -> <Box<F, A> as FnOnce<Args>>::Output

🔬 This is a nightly-only experimental API. (fn_traits)

Performs the call operation.

impl<Args, F, A> FnMut<Args> for Box<F, A> where
    A: Allocator,
    F: FnMut<Args> + ?Sized, 

pub extern "rust-call" fn call_mut(
    &mut self,
    args: Args
) -> <Box<F, A> as FnOnce<Args>>::Output

🔬 This is a nightly-only experimental API. (fn_traits)

Performs the call operation.

impl<Args, F, A> FnOnce<Args> for Box<F, A> where
    A: Allocator,
    F: FnOnce<Args> + ?Sized, 

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

The returned type after the call operator is used.

pub extern "rust-call" fn call_once(
    self,
    args: Args
) -> <Box<F, A> as FnOnce<Args>>::Output

🔬 This is a nightly-only experimental API. (fn_traits)

Performs the call operation.

impl<'_, T> From<&'_ [T]> for Box<[T], Global> where
    T: Copy, 

pub fn from(slice: &[T]) -> Box<[T], Global>

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

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

Examples

// 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<'_> From<&'_ CStr> for Box<CStr, Global>

pub fn from(s: &CStr) -> Box<CStr, Global>

Performs the conversion.

impl<'_> From<&'_ OsStr> for Box<OsStr, Global>

pub fn from(s: &OsStr) -> Box<OsStr, Global>

Performs the conversion.

impl<'_> From<&'_ Path> for Box<Path, Global>

pub fn from(path: &Path) -> Box<Path, Global>

Performs the conversion.

impl<'a, '_> From<&'_ str> for Box<dyn Error + 'a + Send + Sync, Global>

pub fn from(err: &str) -> Box<dyn Error + 'a + Send + Sync, Global>

Converts a str into a box of dyn Error + Send + Sync.

Examples

use std::error::Error;
use std::mem;

let a_str_error = "a str error";
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

impl<'_> From<&'_ str> for Box<dyn Error + 'static, Global>

pub fn from(err: &str) -> Box<dyn Error + 'static, Global>

Converts a str into a box of dyn Error.

Examples

use std::error::Error;
use std::mem;

let a_str_error = "a str error";
let a_boxed_error = Box::<dyn Error>::from(a_str_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

impl<'_> From<&'_ str> for Box<str, Global>

pub fn from(s: &str) -> Box<str, Global>

Converts a &str into a Box<str>

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

Examples

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

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

pub fn from(array: [T; N]) -> Box<[T], Global>

Converts a [T; N] into a Box<[T]>

This conversion moves the array to newly heap-allocated memory.

Examples

let boxed: Box<[u8]> = Box::from([4, 2]);
println!("{:?}", boxed);

impl<T, A> From<Box<[T], A>> for Vec<T, A> where
    A: Allocator, 

pub fn from(s: Box<[T], A>) -> Vec<T, A>

Performs the conversion.

impl From<Box<CStr, Global>> for CString

pub fn from(s: Box<CStr, Global>) -> CString

Converts a Box<CStr> into a CString without copying or allocating.

impl From<Box<OsStr, Global>> for OsString

pub fn from(boxed: Box<OsStr, Global>) -> OsString

Converts a Box<OsStr> into a OsString without copying or allocating.

impl From<Box<Path, Global>> for PathBuf

pub fn from(boxed: Box<Path, Global>) -> PathBuf

Converts a Box<Path> into a PathBuf

This conversion does not allocate or copy memory.

impl<T, A> From<Box<T, A>> for Pin<Box<T, A>> where
    T: ?Sized,
    A: Allocator + 'static, 

pub fn from(boxed: Box<T, A>) -> Pin<Box<T, A>>

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

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

impl<T> From<Box<T, Global>> for Arc<T> where
    T: ?Sized, 

pub fn from(v: Box<T, Global>) -> Arc<T>

Performs the conversion.

impl<T> From<Box<T, Global>> for Rc<T> where
    T: ?Sized, 

pub fn from(v: Box<T, Global>) -> Rc<T>

Performs the conversion.

impl<A> From<Box<str, A>> for Box<[u8], A> where
    A: Allocator, 

pub fn from(s: Box<str, A>) -> Box<[u8], A>

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

pub fn from(s: Box<str, Global>) -> String

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: Box<str> = s1.into_boxed_str();
let s3: String = String::from(s2);

assert_eq!("hello world", s3)

impl From<CString> for Box<CStr, Global>

pub fn from(s: CString) -> Box<CStr, Global>

Converts a CString into a Box<CStr> without copying or allocating.

impl<'_, T> From<Cow<'_, [T]>> for Box<[T], Global> where
    T: Copy, 

pub fn from(cow: Cow<'_, [T]>) -> Box<[T], Global>

Performs the conversion.

impl<'_> From<Cow<'_, CStr>> for Box<CStr, Global>

pub fn from(cow: Cow<'_, CStr>) -> Box<CStr, Global>

Performs the conversion.

impl<'_> From<Cow<'_, OsStr>> for Box<OsStr, Global>

pub fn from(cow: Cow<'_, OsStr>) -> Box<OsStr, Global>

Performs the conversion.

impl<'_> From<Cow<'_, Path>> for Box<Path, Global>

pub fn from(cow: Cow<'_, Path>) -> Box<Path, Global>

Performs the conversion.

impl<'_> From<Cow<'_, str>> for Box<str, Global>

pub fn from(cow: Cow<'_, str>) -> Box<str, Global>

Performs the conversion.

impl<'a> From<Cow<'a, str>> for Box<dyn Error + 'static, Global>

pub fn from(err: Cow<'a, str>) -> Box<dyn Error + 'static, Global>

Converts a Cow into a box of dyn Error.

Examples

use std::error::Error;
use std::mem;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error>::from(a_cow_str_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + 'a + Send + Sync, Global>

pub fn from(err: Cow<'b, str>) -> Box<dyn Error + 'a + Send + Sync, Global>

Converts a Cow into a box of dyn Error + Send + Sync.

Examples

use std::error::Error;
use std::mem;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

impl<'a, E> From<E> for Box<dyn Error + 'a, Global> where
    E: 'a + Error, 

pub fn from(err: E) -> Box<dyn Error + 'a, Global>

Converts a type of Error into a box of dyn Error.

Examples

use std::error::Error;
use std::fmt;
use std::mem;

#[derive(Debug)]
struct AnError;

impl fmt::Display for AnError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f , "An error")
    }
}

impl Error for AnError {}

let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error>::from(an_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

impl<'a, E> From<E> for Box<dyn Error + 'a + Send + Sync, Global> where
    E: 'a + Error + Send + Sync, 

pub fn from(err: E) -> Box<dyn Error + 'a + Send + Sync, Global>

Converts a type of Error + Send + Sync into a box of dyn Error + Send + Sync.

Examples

use std::error::Error;
use std::fmt;
use std::mem;

#[derive(Debug)]
struct AnError;

impl fmt::Display for AnError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f , "An error")
    }
}

impl Error for AnError {}

unsafe impl Send for AnError {}

unsafe impl Sync for AnError {}

let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

impl From<OsString> for Box<OsStr, Global>

pub fn from(s: OsString) -> Box<OsStr, Global>

Converts a OsString into a Box<OsStr> without copying or allocating.

impl From<PathBuf> for Box<Path, Global>

pub fn from(p: PathBuf) -> Box<Path, Global>

Converts a PathBuf into a Box<Path>

This conversion currently should not allocate memory, but this behavior is not guaranteed on all platforms or in all future versions.

impl From<String> for Box<dyn Error + 'static, Global>

pub fn from(str_err: String) -> Box<dyn Error + 'static, Global>

Converts a String into a box of dyn Error.

Examples

use std::error::Error;
use std::mem;

let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<dyn Error>::from(a_string_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

impl From<String> for Box<dyn Error + 'static + Send + Sync, Global>

pub fn from(err: String) -> Box<dyn Error + 'static + Send + Sync, Global>

Converts a String into a box of dyn Error + Send + Sync.

Examples

use std::error::Error;
use std::mem;

let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

impl From<String> for Box<str, Global>

pub fn from(s: String) -> Box<str, Global>

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> From<T> for Box<T, Global>

pub fn from(t: T) -> Box<T, Global>

Converts a generic type T into a Box<T>

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

Examples

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

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

impl<T, A> From<Vec<T, A>> for Box<[T], A> where
    A: Allocator, 

pub fn from(v: Vec<T, A>) -> Box<[T], A>

Performs the conversion.

impl FromIterator<Box<str, Global>> for String

pub fn from_iter<I>(iter: I) -> String where
    I: IntoIterator<Item = Box<str, Global>>, 

Creates a value from an iterator.

impl<I> FromIterator<I> for Box<[I], Global>

pub fn from_iter<T>(iter: T) -> Box<[I], Global> where
    T: IntoIterator<Item = I>, 

Creates a value from an iterator.

impl<I, A> FusedIterator for Box<I, A> where
    A: Allocator,
    I: FusedIterator + ?Sized, 

impl<F, A> Future for Box<F, A> where
    A: Allocator + 'static,
    F: Unpin + Future + ?Sized, 

type Output = <F as Future>::Output

The type of value produced on completion.

pub fn poll(
    self: Pin<&mut Box<F, A>>,
    cx: &mut Context<'_>
) -> Poll<<Box<F, A> as Future>::Output>

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.

impl<G, R, A> Generator<R> for Box<G, A> where
    A: Allocator + 'static,
    G: Unpin + Generator<R> + ?Sized, 

type Yield = <G as Generator<R>>::Yield

🔬 This is a nightly-only experimental API. (generator_trait)

The type of value this generator yields.

type Return = <G as Generator<R>>::Return

🔬 This is a nightly-only experimental API. (generator_trait)

The type of value this generator returns.

pub fn resume(
    self: Pin<&mut Box<G, A>>,
    arg: R
) -> GeneratorState<<Box<G, A> as Generator<R>>::Yield, <Box<G, A> as Generator<R>>::Return>

🔬 This is a nightly-only experimental API. (generator_trait)

Resumes the execution of this generator.

impl<T, A> Hash for Box<T, A> where
    T: Hash + ?Sized,
    A: Allocator, 

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

Feeds this value into the given Hasher.

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

Feeds a slice of this type into the given Hasher.

impl<T, A> Hasher for Box<T, A> where
    T: Hasher + ?Sized,
    A: Allocator, 

pub fn finish(&self) -> u64

Returns the hash value for the values written so far.

pub fn write(&mut self, bytes: &[u8])

Writes some data into this Hasher.

pub fn write_u8(&mut self, i: u8)

Writes a single u8 into this hasher.

pub fn write_u16(&mut self, i: u16)

Writes a single u16 into this hasher.

pub fn write_u32(&mut self, i: u32)

Writes a single u32 into this hasher.

pub fn write_u64(&mut self, i: u64)

Writes a single u64 into this hasher.

pub fn write_u128(&mut self, i: u128)

Writes a single u128 into this hasher.

pub fn write_usize(&mut self, i: usize)

Writes a single usize into this hasher.

pub fn write_i8(&mut self, i: i8)

Writes a single i8 into this hasher.

pub fn write_i16(&mut self, i: i16)

Writes a single i16 into this hasher.

pub fn write_i32(&mut self, i: i32)

Writes a single i32 into this hasher.

pub fn write_i64(&mut self, i: i64)

Writes a single i64 into this hasher.

pub fn write_i128(&mut self, i: i128)

Writes a single i128 into this hasher.

pub fn write_isize(&mut self, i: isize)

Writes a single isize into this hasher.

impl<I, A> Iterator for Box<I, A> where
    A: Allocator,
    I: Iterator + ?Sized, 

type Item = <I as Iterator>::Item

The type of the elements being iterated over.

pub fn next(&mut self) -> Option<<I as Iterator>::Item>

Advances the iterator and returns the next value.

pub fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

pub fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>

Returns the nth element of the iterator.

pub fn last(self) -> Option<<I as Iterator>::Item>

Consumes the iterator, returning the last element.

pub fn count(self) -> usize

Consumes the iterator, counting the number of iterations and returning it.

pub fn advance_by(&mut self, n: usize) -> Result<(), usize>

🔬 This is a nightly-only experimental API. (iter_advance_by)

recently added

Advances the iterator by n elements.

pub fn step_by(self, step: usize) -> StepBy<Self>

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

pub fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where
    U: IntoIterator<Item = Self::Item>, 

Takes two iterators and creates a new iterator over both in sequence.

pub fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where
    U: IntoIterator, 

'Zips up' two iterators into a single iterator of pairs.

pub fn intersperse(self, separator: Self::Item) -> Intersperse<Self> where
    Self::Item: Clone, 

🔬 This is a nightly-only experimental API. (iter_intersperse)

recently added

Creates a new iterator which places a copy of separator between adjacent items of the original iterator.

pub fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G> where
    G: FnMut() -> Self::Item, 

🔬 This is a nightly-only experimental API. (iter_intersperse)

recently added

Creates a new iterator which places an item generated by separator between adjacent items of the original iterator.

pub fn map<B, F>(self, f: F) -> Map<Self, F> where
    F: FnMut(Self::Item) -> B, 

Takes a closure and creates an iterator which calls that closure on each element.

pub fn for_each<F>(self, f: F) where
    F: FnMut(Self::Item), 

Calls a closure on each element of an iterator.

pub fn filter<P>(self, predicate: P) -> Filter<Self, P> where
    P: FnMut(&Self::Item) -> bool, 

Creates an iterator which uses a closure to determine if an element should be yielded.

pub fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where
    F: FnMut(Self::Item) -> Option<B>, 

Creates an iterator that both filters and maps.

pub fn enumerate(self) -> Enumerate<Self>

Creates an iterator which gives the current iteration count as well as the next value.

pub fn peekable(self) -> Peekable<Self>

Creates an iterator which can use peek to look at the next element of the iterator without consuming it.

pub fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
    P: FnMut(&Self::Item) -> bool, 

Creates an iterator that skips elements based on a predicate.

pub fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
    P: FnMut(&Self::Item) -> bool, 

Creates an iterator that yields elements based on a predicate.

pub fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P> where
    P: FnMut(Self::Item) -> Option<B>, 

🔬 This is a nightly-only experimental API. (iter_map_while)

recently added

Creates an iterator that both yields elements based on a predicate and maps.

pub fn skip(self, n: usize) -> Skip<Self>

Creates an iterator that skips the first n elements.

pub fn take(self, n: usize) -> Take<Self>

Creates an iterator that yields its first n elements.

pub fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
    F: FnMut(&mut St, Self::Item) -> Option<B>, 

An iterator adaptor similar to fold that holds internal state and produces a new iterator.

pub fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where
    F: FnMut(Self::Item) -> U,
    U: IntoIterator, 

Creates an iterator that works like map, but flattens nested structure.

pub fn flatten(self) -> Flatten<Self> where
    Self::Item: IntoIterator, 

Creates an iterator that flattens nested structure.

pub fn fuse(self) -> Fuse<Self>

Creates an iterator which ends after the first None.

pub fn inspect<F>(self, f: F) -> Inspect<Self, F> where
    F: FnMut(&Self::Item), 

Does something with each element of an iterator, passing the value on.

pub fn by_ref(&mut self) -> &mut Self

Borrows an iterator, rather than consuming it.

#[must_use = "if you really need to exhaust the iterator, consider `.for_each(drop)` instead"]pub fn collect<B>(self) -> B where
    B: FromIterator<Self::Item>, 

Transforms an iterator into a collection.

pub fn partition<B, F>(self, f: F) -> (B, B) where
    F: FnMut(&Self::Item) -> bool,
    B: Default + Extend<Self::Item>, 

Consumes an iterator, creating two collections from it.

pub fn partition_in_place<'a, T, P>(self, predicate: P) -> usize where
    Self: DoubleEndedIterator<Item = &'a mut T>,
    T: 'a,
    P: FnMut(&T) -> bool, 

🔬 This is a nightly-only experimental API. (iter_partition_in_place)

new API

Reorders the elements of this iterator in-place according to the given predicate, such that all those that return true precede all those that return false. Returns the number of true elements found.

pub fn is_partitioned<P>(self, predicate: P) -> bool where
    P: FnMut(Self::Item) -> bool, 

🔬 This is a nightly-only experimental API. (iter_is_partitioned)

new API

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false.

pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
    R: Try<Ok = B>,
    F: FnMut(B, Self::Item) -> R, 

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

pub fn try_for_each<F, R>(&mut self, f: F) -> R where
    R: Try<Ok = ()>,
    F: FnMut(Self::Item) -> R, 

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

pub fn fold<B, F>(self, init: B, f: F) -> B where
    F: FnMut(B, Self::Item) -> B, 

An iterator method that applies a function, producing a single, final value.

pub fn fold_first<F>(self, f: F) -> Option<Self::Item> where
    F: FnMut(Self::Item, Self::Item) -> Self::Item, 

🔬 This is a nightly-only experimental API. (iterator_fold_self)

The same as fold(), but uses the first element in the iterator as the initial value, folding every subsequent element into it. If the iterator is empty, return None; otherwise, return the result of the fold.

pub fn all<F>(&mut self, f: F) -> bool where
    F: FnMut(Self::Item) -> bool, 

Tests if every element of the iterator matches a predicate.

pub fn any<F>(&mut self, f: F) -> bool where
    F: FnMut(Self::Item) -> bool, 

Tests if any element of the iterator matches a predicate.

pub fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where
    P: FnMut(&Self::Item) -> bool, 

Searches for an element of an iterator that satisfies a predicate.

pub fn find_map<B, F>(&mut self, f: F) -> Option<B> where
    F: FnMut(Self::Item) -> Option<B>, 

Applies function to the elements of iterator and returns the first non-none result.

pub fn try_find<F, R>(
    &mut self,
    f: F
) -> Result<Option<Self::Item>, <R as Try>::Error> where
    R: Try<Ok = bool>,
    F: FnMut(&Self::Item) -> R, 

🔬 This is a nightly-only experimental API. (try_find)

new API

Applies function to the elements of iterator and returns the first true result or the first error.

pub fn position<P>(&mut self, predicate: P) -> Option<usize> where
    P: FnMut(Self::Item) -> bool, 

Searches for an element in an iterator, returning its index.

pub fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
    Self: ExactSizeIterator + DoubleEndedIterator,
    P: FnMut(Self::Item) -> bool, 

Searches for an element in an iterator from the right, returning its index.

pub fn max(self) -> Option<Self::Item> where
    Self::Item: Ord, 

Returns the maximum element of an iterator.

pub fn min(self) -> Option<Self::Item> where
    Self::Item: Ord, 

Returns the minimum element of an iterator.

pub fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where
    F: FnMut(&Self::Item) -> B,
    B: Ord, 

Returns the element that gives the maximum value from the specified function.

pub fn max_by<F>(self, compare: F) -> Option<Self::Item> where
    F: FnMut(&Self::Item, &Self::Item) -> Ordering, 

Returns the element that gives the maximum value with respect to the specified comparison function.

pub fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where
    F: FnMut(&Self::Item) -> B,
    B: Ord, 

Returns the element that gives the minimum value from the specified function.

pub fn min_by<F>(self, compare: F) -> Option<Self::Item> where
    F: FnMut(&Self::Item, &Self::Item) -> Ordering, 

Returns the element that gives the minimum value with respect to the specified comparison function.

pub fn rev(self) -> Rev<Self> where
    Self: DoubleEndedIterator, 

Reverses an iterator's direction.

pub fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where
    Self: Iterator<Item = (A, B)>,
    FromA: Default + Extend<A>,
    FromB: Default + Extend<B>, 

Converts an iterator of pairs into a pair of containers.

pub fn copied<'a, T>(self) -> Copied<Self> where
    Self: Iterator<Item = &'a T>,
    T: 'a + Copy, 

Creates an iterator which copies all of its elements.

pub fn cloned<'a, T>(self) -> Cloned<Self> where
    Self: Iterator<Item = &'a T>,
    T: 'a + Clone, 

Creates an iterator which clones all of its elements.

pub fn cycle(self) -> Cycle<Self> where
    Self: Clone, 

Repeats an iterator endlessly.

pub fn sum<S>(self) -> S where
    S: Sum<Self::Item>, 

Sums the elements of an iterator.

pub fn product<P>(self) -> P where
    P: Product<Self::Item>, 

Iterates over the entire iterator, multiplying all the elements

pub fn cmp<I>(self, other: I) -> Ordering where
    I: IntoIterator<Item = Self::Item>,
    Self::Item: Ord, 

Lexicographically compares the elements of this Iterator with those of another.

pub fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering where
    F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
    I: IntoIterator, 

🔬 This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

pub fn partial_cmp<I>(self, other: I) -> Option<Ordering> where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Lexicographically compares the elements of this Iterator with those of another.

pub fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering> where
    F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
    I: IntoIterator, 

🔬 This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

pub fn eq<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialEq<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are equal to those of another.

pub fn eq_by<I, F>(self, other: I, eq: F) -> bool where
    F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
    I: IntoIterator, 

🔬 This is a nightly-only experimental API. (iter_order_by)

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

pub fn ne<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialEq<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are unequal to those of another.

pub fn lt<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are lexicographically less than those of another.

pub fn le<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

pub fn gt<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are lexicographically greater than those of another.

pub fn ge<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

pub fn is_sorted(self) -> bool where
    Self::Item: PartialOrd<Self::Item>, 

🔬 This is a nightly-only experimental API. (is_sorted)

new API

Checks if the elements of this iterator are sorted.

pub fn is_sorted_by<F>(self, compare: F) -> bool where
    F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>, 

🔬 This is a nightly-only experimental API. (is_sorted)

new API

Checks if the elements of this iterator are sorted using the given comparator function.

pub fn is_sorted_by_key<F, K>(self, f: F) -> bool where
    K: PartialOrd<K>,
    F: FnMut(Self::Item) -> K, 

🔬 This is a nightly-only experimental API. (is_sorted)

new API

Checks if the elements of this iterator are sorted using the given key extraction function.

impl<T, A> Ord for Box<T, A> where
    T: Ord + ?Sized,
    A: Allocator, 

pub fn cmp(&self, other: &Box<T, A>) -> Ordering

This method returns an Ordering between self and other.

#[must_use]pub fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]pub fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl<T, A> PartialEq<Box<T, A>> for Box<T, A> where
    T: PartialEq<T> + ?Sized,
    A: Allocator, 

pub fn eq(&self, other: &Box<T, A>) -> bool

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

pub fn ne(&self, other: &Box<T, A>) -> bool

This method tests for !=.

impl<T, A> PartialOrd<Box<T, A>> for Box<T, A> where
    T: PartialOrd<T> + ?Sized,
    A: Allocator, 

pub fn partial_cmp(&self, other: &Box<T, A>) -> Option<Ordering>

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

pub fn lt(&self, other: &Box<T, A>) -> bool

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

pub fn le(&self, other: &Box<T, A>) -> bool

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

pub fn ge(&self, other: &Box<T, A>) -> bool

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

pub fn gt(&self, other: &Box<T, A>) -> bool

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

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

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

Formats the value using the given formatter.

impl<R> Read for Box<R, Global> where
    R: Read + ?Sized, 

pub fn read(&mut self, buf: &mut [u8]) -> Result<usize, Error>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

pub fn read_vectored(
    &mut self,
    bufs: &mut [IoSliceMut<'_>]
) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

pub fn is_read_vectored(&self) -> bool

🔬 This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

pub unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer)

Determines if this Reader can work with buffers of uninitialized memory.

pub fn read_to_end(&mut self, buf: &mut Vec<u8, Global>) -> Result<usize, Error>

Read all bytes until EOF in this source, placing them into buf.

pub fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Read all bytes until EOF in this source, appending them to buf.

pub fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Read the exact number of bytes required to fill buf.

pub fn by_ref(&mut self) -> &mut Self

Creates a "by reference" adaptor for this instance of Read.

pub fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an Iterator over its bytes.

pub fn chain<R>(self, next: R) -> Chain<Self, R> where
    R: Read, 

Creates an adaptor which will chain this stream with another.

pub fn take(self, limit: u64) -> Take<Self>

Creates an adaptor which will read at most limit bytes from it.

impl<S> Seek for Box<S, Global> where
    S: Seek + ?Sized, 

pub fn seek(&mut self, pos: SeekFrom) -> Result<u64, Error>

Seek to an offset, in bytes, in a stream.

pub fn stream_len(&mut self) -> Result<u64, Error>

🔬 This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

pub fn stream_position(&mut self) -> Result<u64, Error>

Returns the current seek position from the start of the stream.

impl<S> Stream for Box<S, Global> where
    S: Unpin + Stream + ?Sized, 

type Item = <S as Stream>::Item

🔬 This is a nightly-only experimental API. (async_stream)

The type of items yielded by the stream.

pub fn poll_next(
    self: Pin<&mut Box<S, Global>>,
    cx: &mut Context<'_>
) -> Poll<Option<<Box<S, Global> as Stream>::Item>>

🔬 This is a nightly-only experimental API. (async_stream)

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

pub fn size_hint(&self) -> (usize, Option<usize>)

🔬 This is a nightly-only experimental API. (async_stream)

Returns the bounds on the remaining length of the stream.

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

type Error = Box<[T], Global>

The type returned in the event of a conversion error.

pub fn try_from(
    boxed_slice: Box<[T], Global>
) -> Result<Box<[T; N], Global>, <Box<[T; N], Global> as TryFrom<Box<[T], Global>>>::Error>

Performs the conversion.

impl<T, A> Unpin for Box<T, A> where
    T: ?Sized,
    A: Allocator + 'static, 

impl<W> Write for Box<W, Global> where
    W: Write + ?Sized, 

pub fn write(&mut self, buf: &[u8]) -> Result<usize, Error>

Write a buffer into this writer, returning how many bytes were written.

pub fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

pub fn is_write_vectored(&self) -> bool

🔬 This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

pub fn flush(&mut self) -> Result<(), Error>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

pub fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

pub fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

pub fn write_all_vectored(
    &mut self,
    bufs: &mut [IoSlice<'_>]
) -> Result<(), Error>

🔬 This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

pub fn by_ref(&mut self) -> &mut Self

Creates a "by reference" adaptor for this instance of Write.