Struct multiversx_chain_vm::Box

1.0.0 · source · 
pub struct Box<T, A = Global>(_, _)
where
    A: Allocator,
    T: ?Sized;
Expand description

A pointer type that uniquely owns a heap allocation of type T.

See the module-level documentation for more.

Implementations§

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);
🔬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)
🔬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)

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

Constructing and pinning of the Box can also be done in two steps: Box::pin(x) does the same as Box::into_pin(Box::new(x)). Consider using into_pin if you already have a Box<T>, or if you want to construct a (pinned) Box in a different way than with Box::new.

🔬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)?;
🔬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);
🔬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);
🔬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);
🔬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)?;
🔬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)
🔬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);
🔬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)
🔬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);
🔬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.

Constructing and pinning of the Box can also be done in two steps: Box::pin_in(x, alloc) does the same as Box::into_pin(Box::new_in(x, alloc)). Consider using into_pin if you already have a Box<T, A>, or if you want to construct a (pinned) Box in a different way than with Box::new_in.

🔬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.

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

Consumes the Box, returning the wrapped value.

Examples
#![feature(box_into_inner)]

let c = Box::new(5);

assert_eq!(Box::into_inner(c), 5);
🔬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])
🔬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])
🔬This is a nightly-only experimental API. (allocator_api)

Constructs a new boxed slice with uninitialized contents. Returns an error if the allocation fails

Examples
#![feature(allocator_api, new_uninit)]

let mut values = Box::<[u32]>::try_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]);
🔬This is a nightly-only experimental API. (allocator_api)

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

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

assert_eq!(*values, [0, 0, 0]);
🔬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])
🔬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])
🔬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)
🔬This is a nightly-only experimental API. (new_uninit)

Writes the value and converts to Box<T, A>.

This method converts the box similarly to Box::assume_init but writes value into it before conversion thus guaranteeing safety. In some scenarios use of this method may improve performance because the compiler may be able to optimize copying from stack.

Examples
#![feature(new_uninit)]

let big_box = Box::<[usize; 1024]>::new_uninit();

let mut array = [0; 1024];
for (i, place) in array.iter_mut().enumerate() {
    *place = i;
}

// The optimizer may be able to elide this copy, so previous code writes
// to heap directly.
let big_box = Box::write(big_box, array);

for (i, x) in big_box.iter().enumerate() {
    assert_eq!(*x, i);
}
🔬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])

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);
}
🔬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() 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_in(ptr, System);
}

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>());
}
🔬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>());
}
🔬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.

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]);

Converts a Box<T> into a Pin<Box<T>>. If T does not implement Unpin, then *boxed will be pinned in memory and unable to be moved.

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

This is also available via From.

Constructing and pinning a Box with Box::into_pin(Box::new(x)) can also be written more concisely using Box::pin(x). This into_pin method is useful if you already have a Box<T>, or you are constructing a (pinned) Box in a different way than with Box::new.

Notes

It’s not recommended that crates add an impl like From<Box<T>> for Pin<T>, as it’ll introduce an ambiguity when calling Pin::from. A demonstration of such a poor impl is shown below.

ⓘ
struct Foo; // A type defined in this crate.
impl From<Box<()>> for Pin<Foo> {
    fn from(_: Box<()>) -> Pin<Foo> {
        Pin::new(Foo)
    }
}

let foo = Box::new(());
let bar = Pin::from(foo);

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

Downcasts the box to a concrete type.

For a safe alternative see downcast.

Examples
#![feature(downcast_unchecked)]

use std::any::Any;

let x: Box<dyn Any> = Box::new(1_usize);

unsafe {
    assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}
Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

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

Downcasts the box to a concrete type.

For a safe alternative see downcast.

Examples
#![feature(downcast_unchecked)]

use std::any::Any;

let x: Box<dyn Any + Send> = Box::new(1_usize);

unsafe {
    assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}
Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

Attempt to downcast the box to a concrete type.

Examples
use std::any::Any;

fn print_if_string(value: Box<dyn Any + Send + Sync>) {
    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));
🔬This is a nightly-only experimental API. (downcast_unchecked)

Downcasts the box to a concrete type.

For a safe alternative see downcast.

Examples
#![feature(downcast_unchecked)]

use std::any::Any;

let x: Box<dyn Any + Send + Sync> = Box::new(1_usize);

unsafe {
    assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}
Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

Trait Implementations§

Append to [Command] so it can instantiate Self. Read more
Append to [Command] so it can update self. Read more
Report the [ArgGroup::id][crate::ArgGroup::id] for this set of arguments
Borrows the file descriptor. Read more
Converts this type into a mutable reference of the (usually inferred) input type.
Extracts the raw file descriptor. Read more
Converts this type into a shared reference of the (usually inferred) input type.
🔬This is a nightly-only experimental API. (async_iterator)
The type of items yielded by the async iterator.
🔬This is a nightly-only experimental API. (async_iterator)
Attempt to pull out the next value of this async iterator, registering the current task for wakeup if the value is not yet available, and returning None if the async iterator is exhausted. Read more
🔬This is a nightly-only experimental API. (async_iterator)
Returns the bounds on the remaining length of the async iterator. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more
Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to read. Read more
Read all bytes into buf until the delimiter byte or EOF is reached. Read more
Read all bytes until a newline (the 0xA byte) is reached, and append them to the provided String buffer. Read more
🔬This is a nightly-only experimental API. (buf_read_has_data_left)
Check if the underlying Read has any data left to be read. Read more
Returns an iterator over the contents of this reader split on the byte byte. Read more
Returns an iterator over the lines of this reader. Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more

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);

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);
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Build a [Command] that can instantiate Self. Read more
Build a [Command] that can update self. Read more
Formats the value using the given formatter. Read more
Returns the “default value” for a type. Read more
Returns the “default value” for a type. Read more
Returns the “default value” for a type. Read more

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

Returns the “default value” for a type. Read more
The resulting type after dereferencing.
Dereferences the value.
Mutably dereferences the value.
Deserialize this value from the given Serde deserializer. Read more
Deserialize this value from the given Serde deserializer. Read more
Deserialize this value from the given Serde deserializer. Read more
Deserialize this value from the given Serde deserializer. Read more
Deserialize this value from the given Serde deserializer. Read more
Formats the value using the given formatter. Read more
Removes and returns an element from the end of the iterator. Read more
Returns the nth element from the end of the iterator. Read more
🔬This is a nightly-only experimental API. (iter_advance_by)
Advances the iterator from the back by n elements. Read more
This is the reverse version of Iterator::try_fold(): it takes elements starting from the back of the iterator. Read more
An iterator method that reduces the iterator’s elements to a single, final value, starting from the back. Read more
Searches for an element of an iterator from the back that satisfies a predicate. Read more
Executes the destructor for this type. Read more
👎Deprecated since 1.42.0: use the Display impl or to_string()
Read more
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
The lower-level source of this error, if any. Read more
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type based access to context intended for error reports. Read more
Returns the exact remaining length of the iterator. Read more
🔬This is a nightly-only experimental API. (exact_size_is_empty)
Returns true if the iterator is empty. Read more
🔬This is a nightly-only experimental API. (fn_traits)
Performs the call operation.
🔬This is a nightly-only experimental API. (fn_traits)
Performs the call operation.
The returned type after the call operator is used.
🔬This is a nightly-only experimental API. (fn_traits)
Performs the call operation.

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

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

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:?}");

Converts a &CStr into a Box<CStr>, by copying the contents into a newly allocated Box.

Copies the string into a newly allocated Box<OsStr>.

Creates a boxed Path from a reference.

This will allocate and clone path to it.

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))

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))

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}");

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:?}");

Convert a boxed slice into a vector by transferring ownership of the existing heap allocation.

Examples
let b: Box<[i32]> = vec![1, 2, 3].into_boxed_slice();
assert_eq!(Vec::from(b), vec![1, 2, 3]);
Converts to this type from the input type.
Converts to this type from the input type.

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);
Converts to this type from the input type.

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

Converts a Cow<'_, [T]> into a Box<[T]>

When cow is the Cow::Borrowed variant, this conversion allocates on the heap and copies the underlying slice. Otherwise, it will try to reuse the owned Vec’s allocation.

Converts a Cow<'a, CStr> into a Box<CStr>, by copying the contents if they are borrowed.

Converts a Cow<'a, OsStr> into a Box<OsStr>, by copying the contents if they are borrowed.

Creates a boxed Path from a clone-on-write pointer.

Converting from a Cow::Owned does not clone or allocate.

Converts a Cow<'_, str> into a Box<str>

When cow is the Cow::Borrowed variant, this conversion allocates on the heap and copies the underlying str. Otherwise, it will try to reuse the owned String’s allocation.

Examples
use std::borrow::Cow;

let unboxed = Cow::Borrowed("hello");
let boxed: Box<str> = Box::from(unboxed);
println!("{boxed}");
let unboxed = Cow::Owned("hello".to_string());
let boxed: Box<str> = Box::from(unboxed);
println!("{boxed}");

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))

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))

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))

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))
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.

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

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.

Converts to this type from the input type.

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))

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))

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)

Converts a 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);

Convert a vector into a boxed slice.

If v has excess capacity, its items will be moved into a newly-allocated buffer with exactly the right capacity.

Examples
assert_eq!(Box::from(vec![1, 2, 3]), vec![1, 2, 3].into_boxed_slice());

Any excess capacity is removed:

let mut vec = Vec::with_capacity(10);
vec.extend([1, 2, 3]);

assert_eq!(Box::from(vec), vec![1, 2, 3].into_boxed_slice());
Instantiate Self from [ArgMatches], parsing the arguments as needed. Read more
Instantiate Self from [ArgMatches], parsing the arguments as needed. Read more
Assign values from ArgMatches to self.
Assign values from ArgMatches to self.
Creates a value from an iterator. Read more
The type of value produced on completion.
Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available. Read more
🔬This is a nightly-only experimental API. (generator_trait)
The type of value this generator yields. Read more
🔬This is a nightly-only experimental API. (generator_trait)
The type of value this generator returns. Read more
🔬This is a nightly-only experimental API. (generator_trait)
Resumes the execution of this generator. Read more
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
Returns the hash value for the values written so far. Read more
Writes some data into this Hasher. Read more
Writes a single u8 into this hasher.
Writes a single u16 into this hasher.
Writes a single u32 into this hasher.
Writes a single u64 into this hasher.
Writes a single u128 into this hasher.
Writes a single usize into this hasher.
Writes a single i8 into this hasher.
Writes a single i16 into this hasher.
Writes a single i32 into this hasher.
Writes a single i64 into this hasher.
Writes a single i128 into this hasher.
Writes a single isize into this hasher.
🔬This is a nightly-only experimental API. (hasher_prefixfree_extras)
Writes a length prefix into this hasher, as part of being prefix-free. Read more
🔬This is a nightly-only experimental API. (hasher_prefixfree_extras)
Writes a single str into this hasher. Read more
The type of the elements being iterated over.
Advances the iterator and returns the next value. Read more
Returns the bounds on the remaining length of the iterator. Read more
Returns the nth element of the iterator. Read more
Consumes the iterator, returning the last element. Read more
🔬This is a nightly-only experimental API. (iter_next_chunk)
Advances the iterator and returns an array containing the next N values. Read more
Consumes the iterator, counting the number of iterations and returning it. Read more
🔬This is a nightly-only experimental API. (iter_advance_by)
Advances the iterator by n elements. Read more
Creates an iterator starting at the same point, but stepping by the given amount at each iteration. Read more
Takes two iterators and creates a new iterator over both in sequence. Read more
‘Zips up’ two iterators into a single iterator of pairs. Read more
🔬This is a nightly-only experimental API. (iter_intersperse)
Creates a new iterator which places an item generated by separator between adjacent items of the original iterator. Read more
Takes a closure and creates an iterator which calls that closure on each element. Read more
Calls a closure on each element of an iterator. Read more
Creates an iterator which uses a closure to determine if an element should be yielded. Read more
Creates an iterator that both filters and maps. Read more
Creates an iterator which gives the current iteration count as well as the next value. Read more
Creates an iterator which can use the peek and peek_mut methods to look at the next element of the iterator without consuming it. See their documentation for more information. Read more
Creates an iterator that skips elements based on a predicate. Read more
Creates an iterator that yields elements based on a predicate. Read more
Creates an iterator that both yields elements based on a predicate and maps. Read more
Creates an iterator that skips the first n elements. Read more
Creates an iterator that yields the first n elements, or fewer if the underlying iterator ends sooner. Read more
An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator. Read more
Creates an iterator that works like map, but flattens nested structure. Read more
Creates an iterator which ends after the first None. Read more
Does something with each element of an iterator, passing the value on. Read more
Borrows an iterator, rather than consuming it. Read more
Transforms an iterator into a collection. Read more
🔬This is a nightly-only experimental API. (iter_collect_into)
Collects all the items from an iterator into a collection. Read more
Consumes an iterator, creating two collections from it. Read more
🔬This is a nightly-only experimental API. (iter_is_partitioned)
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. Read more
An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more
An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error. Read more
Folds every element into an accumulator by applying an operation, returning the final result. Read more
Reduces the elements to a single one, by repeatedly applying a reducing operation. Read more
🔬This is a nightly-only experimental API. (iterator_try_reduce)
Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately. Read more
Tests if every element of the iterator matches a predicate. Read more
Tests if any element of the iterator matches a predicate. Read more
Searches for an element of an iterator that satisfies a predicate. Read more
Applies function to the elements of iterator and returns the first non-none result. Read more
🔬This is a nightly-only experimental API. (try_find)
Applies function to the elements of iterator and returns the first true result or the first error. Read more
Searches for an element in an iterator, returning its index. Read more
Returns the element that gives the maximum value from the specified function. Read more
Returns the element that gives the maximum value with respect to the specified comparison function. Read more
Returns the element that gives the minimum value from the specified function. Read more
Returns the element that gives the minimum value with respect to the specified comparison function. Read more
Converts an iterator of pairs into a pair of containers. Read more
Creates an iterator which copies all of its elements. Read more
Creates an iterator which clones all of its elements. Read more
🔬This is a nightly-only experimental API. (iter_array_chunks)
Returns an iterator over N elements of the iterator at a time. Read more
Sums the elements of an iterator. Read more
Iterates over the entire iterator, multiplying all the elements Read more
🔬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. Read more
Lexicographically compares the elements of this Iterator with those of another. Read more
🔬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. Read more
Determines if the elements of this Iterator are equal to those of another. Read more
🔬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. Read more
Determines if the elements of this Iterator are unequal to those of another. Read more
Determines if the elements of this Iterator are lexicographically less than those of another. Read more
Determines if the elements of this Iterator are lexicographically less or equal to those of another. Read more
Determines if the elements of this Iterator are lexicographically greater than those of another. Read more
Determines if the elements of this Iterator are lexicographically greater than or equal to those of another. Read more
🔬This is a nightly-only experimental API. (is_sorted)
Checks if the elements of this iterator are sorted using the given comparator function. Read more
🔬This is a nightly-only experimental API. (is_sorted)
Checks if the elements of this iterator are sorted using the given key extraction function. Read more
Version of dep_decode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to deserialise the value from input, using the format of an object nested inside another structure. In case of success returns the deserialized value and the number of bytes consumed during the operation.
Version of dep_decode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to deserialise the value from input, using the format of an object nested inside another structure. In case of success returns the deserialized value and the number of bytes consumed during the operation.
Version of dep_encode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
NestedEncode to output, using the format of an object nested inside another structure. Does not provide compact version.
Version of dep_encode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
NestedEncode to output, using the format of an object nested inside another structure. Does not provide compact version.
Version of dep_encode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
NestedEncode to output, using the format of an object nested inside another structure. Does not provide compact version.
This method returns an Ordering between self and other. Read more
Compares and returns the maximum of two values. Read more
Compares and returns the minimum of two values. Read more
Restrict a value to a certain interval. Read more
Parse from std::env::args_os(), exit on error
Parse from std::env::args_os(), return Err on error.
Parse from iterator, exit on error
Parse from iterator, return Err on error.
Update from iterator, exit on error
Update from iterator, return Err on error.
This method tests for self and other values to be equal, and is used by ==.
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
Formats the value using the given formatter.
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
🔬This is a nightly-only experimental API. (read_buf)
Pull some bytes from this source into the specified buffer. Read more
Like read, except that it reads into a slice of buffers. Read more
🔬This is a nightly-only experimental API. (can_vector)
Determines if this Reader has an efficient read_vectored implementation. Read more
Read all bytes until EOF in this source, placing them into buf. Read more
Read all bytes until EOF in this source, appending them to buf. Read more
Read the exact number of bytes required to fill buf. Read more
🔬This is a nightly-only experimental API. (read_buf)
Read the exact number of bytes required to fill cursor. Read more
Creates a “by reference” adaptor for this instance of Read. Read more
Transforms this Read instance to an Iterator over its bytes. Read more
Creates an adapter which will chain this stream with another. Read more
Creates an adapter which will read at most limit bytes from it. Read more
Return the next random u32. Read more
Return the next random u64. Read more
Fill dest with random data. Read more
Fill dest entirely with random data. Read more
Return the next random u32. Read more
Return the next random u64. Read more
Fill dest with random data. Read more
Fill dest entirely with random data. Read more
Seek to an offset, in bytes, in a stream. Read more
Returns the current seek position from the start of the stream. Read more
Rewind to the beginning of a stream. Read more
🔬This is a nightly-only experimental API. (seek_stream_len)
Returns the length of this stream (in bytes). Read more
Serialize this value into the given Serde serializer. Read more
Append to [Command] so it can instantiate Self. Read more
Append to [Command] so it can update self. Read more
Test whether Self can parse a specific subcommand
Version of top_decode that can handle errors as soon as they occur. For instance it can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to deserialize the value from input.
Version of top_decode that can handle errors as soon as they occur. For instance it can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to deserialize the value from input.
Version of top_decode that can handle errors as soon as they occur. For instance it can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to deserialize the value from input.
Length of the underlying data, in bytes.
Provides the underlying data as an owned byte slice box. Consumes the input object in the process.
Puts the underlying data into a fixed size byte buffer and returns the populated data slice from this buffer. Read more
Retrieves the underlying data as a pre-parsed u64. Expected to panic if the conversion is not possible. Read more
Retrieves the underlying data as a pre-parsed i64. Expected to panic if the conversion is not possible. Read more
Version of top_encode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to serialize the value to ouput.
Version of top_encode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to serialize the value to ouput.
Version of top_encode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to serialize the value to ouput.

Attempts to convert a Box<[T]> into a Box<[T; N]>.

The conversion occurs in-place and does not require a new memory allocation.

Errors

Returns the old Box<[T]> in the Err variant if boxed_slice.len() does not equal N.

The type returned in the event of a conversion error.

Attempts to convert a Vec<T> into a Box<[T; N]>.

Like Vec::into_boxed_slice, this is in-place if vec.capacity() == N, but will require a reallocation otherwise.

Errors

Returns the original Vec<T> in the Err variant if boxed_slice.len() does not equal N.

Examples

This can be used with vec! to create an array on the heap:

let state: Box<[f32; 100]> = vec![1.0; 100].try_into().unwrap();
assert_eq!(state.len(), 100);
The type returned in the event of a conversion error.
A type can provide more than its own description. For instance, a struct can also provide the descriptions of the type of its fields. TypeAbi doesn’t care for the exact accumulator type, which is abstracted by the TypeDescriptionContainer trait.
A type can provide more than its own description. For instance, a struct can also provide the descriptions of the type of its fields. TypeAbi doesn’t care for the exact accumulator type, which is abstracted by the TypeDescriptionContainer trait.
A type can provide more than its own description. For instance, a struct can also provide the descriptions of the type of its fields. TypeAbi doesn’t care for the exact accumulator type, which is abstracted by the TypeDescriptionContainer trait.
Write a buffer into this writer, returning how many bytes were written. Read more
Like write, except that it writes from a slice of buffers. Read more
🔬This is a nightly-only experimental API. (can_vector)
Determines if this Writer has an efficient write_vectored implementation. Read more
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
Attempts to write an entire buffer into this writer. Read more
Writes a formatted string into this writer, returning any error encountered. Read more
🔬This is a nightly-only experimental API. (write_all_vectored)
Attempts to write multiple buffers into this writer. Read more
Creates a “by reference” adapter for this instance of Write. Read more
Returns true if and only if the underlying writer supports colors.
Set the color settings of the writer. Read more
Reset the current color settings to their original settings. Read more
Returns true if and only if the underlying writer must synchronously interact with an end user’s device in order to control colors. By default, this always returns false. Read more

Unlike Vec, Box<[Z]> cannot reallocate, so we can be sure that we are not leaving values on the heap.

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Borrows the reference. Read more
Return a borrowing view of a resource which dereferences to a &Target. Read more
Returns the raw value.
Returns the raw value.
Borrows the reference.
Return a borrowing view of a resource which dereferences to a &Target. Read more
Calculate the base32 serialized length
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
Returns an iterator over the lines of this reader, where each line is represented as a byte string. Read more
Returns an iterator over byte-terminated records of this reader, where each record is represented as a byte string. Read more
Executes the given closure on each line in the underlying reader. Read more
Executes the given closure on each byte-terminated record in the underlying reader. Read more
Executes the given closure on each line in the underlying reader. Read more
Executes the given closure on each byte-terminated record in the underlying reader. Read more
Error type if conversion fails
Check if all values are in range and return array-like struct of u5 values
Upcast to an RngCore trait object.
Checks if this value is equivalent to the given key. Read more
Compare self to key and return true if they are equal.
Converts to this type from the input type.

Returns the argument unchanged.

👎Deprecated since 1.0.0: FromFd::from_fd is replaced by From<OwnedFd>::from
Constructs a new instance of Self from the given file descriptor. Read more
Constructs a new instance of Self from the given file descriptor converted from into_owned. Read more
Constructs a new instance of Self from the given filelike object. Read more
Constructs a new instance of Self from the given filelike object converted from into_owned. Read more
Constructs a new instance of Self from the given socketlike object.
Constructs a new instance of Self from the given socketlike object converted from into_owned.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The output that the future will produce on completion.
Which kind of future are we turning this into?
Creates a future from a value. Read more
The type of the elements being iterated over.
Which kind of iterator are we turning this into?
Creates an iterator from a value. Read more
Convert to the intended resettable type
Convert to the intended resettable type
Returns true if this is a terminal. Read more
Choose one element at random from the iterator. Read more
Collects values at random from the iterator into a supplied buffer until that buffer is filled. Read more
Collects amount values at random from the iterator into a vector. Read more
Choose one element at random from the iterator. Read more
Choose one element at random from the iterator. Read more
Collects values at random from the iterator into a supplied buffer until that buffer is filled. Read more
Collects amount values at random from the iterator into a vector. Read more
Alternate elements from two iterators until both have run out. Read more
Alternate elements from two iterators until at least one of them has run out. Read more
An iterator adaptor to insert a particular value between each element of the adapted iterator. Read more
An iterator adaptor to insert a particular value created by a function between each element of the adapted iterator. Read more
Create an iterator which iterates over both this and the specified iterator simultaneously, yielding pairs of two optional elements. Read more
Create an iterator which iterates over both this and the specified iterator simultaneously, yielding pairs of elements. Read more
A “meta iterator adaptor”. Its closure receives a reference to the iterator and may pick off as many elements as it likes, to produce the next iterator element. Read more
Return an iterable that can group iterator elements. Consecutive elements that map to the same key (“runs”), are assigned to the same group. Read more
Return an iterable that can chunk the iterator. Read more
Return an iterator over all contiguous windows producing tuples of a specific size (up to 12). Read more
Return an iterator over all windows, wrapping back to the first elements when the window would otherwise exceed the length of the iterator, producing tuples of a specific size (up to 12). Read more
Return an iterator that groups the items in tuples of a specific size (up to 12). Read more
Split into an iterator pair that both yield all elements from the original iterator. Read more
👎Deprecated since 0.8.0: Use std .step_by() instead
Return an iterator adaptor that steps n elements in the base iterator for each iteration. Read more
Convert each item of the iterator using the Into trait. Read more
👎Deprecated since 0.10.0: Use .map_ok() instead
See .map_ok().
Return an iterator adaptor that applies the provided closure to every Result::Ok value. Result::Err values are unchanged. Read more
Return an iterator adaptor that filters every Result::Ok value with the provided closure. Result::Err values are unchanged. Read more
Return an iterator adaptor that filters and transforms every Result::Ok value with the provided closure. Result::Err values are unchanged. Read more
Return an iterator adaptor that flattens every Result::Ok value into a series of Result::Ok values. Result::Err values are unchanged. Read more
Return an iterator adaptor that merges the two base iterators in ascending order. If both base iterators are sorted (ascending), the result is sorted. Read more
Return an iterator adaptor that merges the two base iterators in order. This is much like .merge() but allows for a custom ordering. Read more
Create an iterator that merges items from both this and the specified iterator in ascending order. Read more
Return an iterator adaptor that flattens an iterator of iterators by merging them in ascending order. Read more
Return an iterator adaptor that flattens an iterator of iterators by merging them according to the given closure. Read more
Return an iterator adaptor that iterates over the cartesian product of the element sets of two iterators self and J. Read more
Return an iterator adaptor that iterates over the cartesian product of all subiterators returned by meta-iterator self. Read more
Return an iterator adaptor that uses the passed-in closure to optionally merge together consecutive elements. Read more
Remove duplicates from sections of consecutive identical elements. If the iterator is sorted, all elements will be unique. Read more
Remove duplicates from sections of consecutive identical elements, determining equality using a comparison function. If the iterator is sorted, all elements will be unique. Read more
Remove duplicates from sections of consecutive identical elements, while keeping a count of how many repeated elements were present. If the iterator is sorted, all elements will be unique. Read more
Remove duplicates from sections of consecutive identical elements, while keeping a count of how many repeated elements were present. This will determine equality using a comparison function. If the iterator is sorted, all elements will be unique. Read more
Return an iterator adaptor that produces elements that appear more than once during the iteration. Duplicates are detected using hash and equality. Read more
Return an iterator adaptor that produces elements that appear more than once during the iteration. Duplicates are detected using hash and equality. Read more
Return an iterator adaptor that filters out elements that have already been produced once during the iteration. Duplicates are detected using hash and equality. Read more
Return an iterator adaptor that filters out elements that have already been produced once during the iteration. Read more
Return an iterator adaptor that borrows from this iterator and takes items while the closure accept returns true. Read more
Return an iterator adaptor that borrows from a Clone-able iterator to only pick off elements while the predicate accept returns true. Read more
Return an iterator adaptor that filters Option<A> iterator elements and produces A. Stops on the first None encountered. Read more
Return an iterator adaptor that iterates over the combinations of the elements from an iterator. Read more
Return an iterator adaptor that iterates over the k-length combinations of the elements from an iterator. Read more
Return an iterator that iterates over the k-length combinations of the elements from an iterator, with replacement. Read more
Return an iterator adaptor that iterates over all k-permutations of the elements from an iterator. Read more
Return an iterator that iterates through the powerset of the elements from an iterator. Read more
Return an iterator adaptor that pads the sequence to a minimum length of min by filling missing elements using a closure f. Read more
Return an iterator adaptor that wraps each element in a Position to ease special-case handling of the first or last elements. Read more
Return an iterator adaptor that yields the indices of all elements satisfying a predicate, counted from the start of the iterator. Read more
Return an iterator adaptor that applies a mutating function to each element before yielding it. Read more
Advances the iterator and returns the next items grouped in a tuple of a specific size (up to 12). Read more
Collects all items from the iterator into a tuple of a specific size (up to 12). Read more
Find the position and value of the first element satisfying a predicate. Read more
Find the value of the first element satisfying a predicate or return the last element, if any. Read more
Find the value of the first element satisfying a predicate or return the first element, if any. Read more
Returns true if the given item is present in this iterator. Read more
Check whether all elements compare equal. Read more
Check whether all elements are unique (non equal). Read more
Consume the first n elements from the iterator eagerly, and return the same iterator again. Read more
Consume the last n elements from the iterator eagerly, and return the same iterator again. Read more
👎Deprecated since 0.8.0: Use .for_each() instead
Run the closure f eagerly on each element of the iterator. Read more
Combine all an iterator’s elements into one element by using Extend. Read more
.collect_vec() is simply a type specialization of Iterator::collect, for convenience.
.try_collect() is more convenient way of writing .collect::<Result<_, _>>() Read more
Assign to each reference in self from the from iterator, stopping at the shortest of the two iterators. Read more
Combine all iterator elements into one String, separated by sep. Read more
Format all iterator elements, separated by sep. Read more
Format all iterator elements, separated by sep. Read more
👎Deprecated since 0.10.0: Use .fold_ok() instead
See .fold_ok().
Fold Result values from an iterator. Read more
Fold Option values from an iterator. Read more
👎Deprecated since 0.10.2: Use Iterator::reduce instead
Accumulator of the elements in the iterator. Read more
Accumulate the elements in the iterator in a tree-like manner. Read more
An iterator method that applies a function, producing a single, final value. Read more
Iterate over the entire iterator and add all the elements. Read more
Iterate over the entire iterator and multiply all the elements. Read more
Sort all iterator elements into a new iterator in ascending order. Read more
Sort all iterator elements into a new iterator in ascending order. Read more
Sort all iterator elements into a new iterator in ascending order. Read more
Sort all iterator elements into a new iterator in ascending order. Read more
Sort all iterator elements into a new iterator in ascending order. Read more
Sort all iterator elements into a new iterator in ascending order. Read more
Sort all iterator elements into a new iterator in ascending order. The key function is called exactly once per key. Read more
Sort the k smallest elements into a new iterator, in ascending order. Read more
Collect all iterator elements into one of two partitions. Unlike Iterator::partition, each partition may have a distinct type. Read more
Partition a sequence of Results into one list of all the Ok elements and another list of all the Err elements. Read more
Return a HashMap of keys mapped to Vecs of values. Keys and values are taken from (Key, Value) tuple pairs yielded by the input iterator. Read more
Return an Iterator on a HashMap. Keys mapped to Vecs of values. The key is specified in the closure. Read more
Constructs a GroupingMap to be used later with one of the efficient group-and-fold operations it allows to perform. Read more
Constructs a GroupingMap to be used later with one of the efficient group-and-fold operations it allows to perform. Read more
Return all minimum elements of an iterator. Read more
Return all minimum elements of an iterator, as determined by the specified function. Read more
Return all minimum elements of an iterator, as determined by the specified function. Read more
Return all maximum elements of an iterator. Read more
Return all maximum elements of an iterator, as determined by the specified function. Read more
Return all minimum elements of an iterator, as determined by the specified function. Read more
Return the minimum and maximum elements in the iterator. Read more
Return the minimum and maximum element of an iterator, as determined by the specified function. Read more
Return the minimum and maximum element of an iterator, as determined by the specified comparison function. Read more
Return the position of the maximum element in the iterator. Read more
Return the position of the maximum element in the iterator, as determined by the specified function. Read more
Return the position of the maximum element in the iterator, as determined by the specified comparison function. Read more
Return the position of the minimum element in the iterator. Read more
Return the position of the minimum element in the iterator, as determined by the specified function. Read more
Return the position of the minimum element in the iterator, as determined by the specified comparison function. Read more
Return the positions of the minimum and maximum elements in the iterator. Read more
Return the postions of the minimum and maximum elements of an iterator, as determined by the specified function. Read more
Return the postions of the minimum and maximum elements of an iterator, as determined by the specified comparison function. Read more
If the iterator yields exactly one element, that element will be returned, otherwise an error will be returned containing an iterator that has the same output as the input iterator. Read more
If the iterator yields no elements, Ok(None) will be returned. If the iterator yields exactly one element, that element will be returned, otherwise an error will be returned containing an iterator that has the same output as the input iterator. Read more
An iterator adaptor that allows the user to peek at multiple .next() values without advancing the base iterator. Read more
Collect the items in this iterator and return a HashMap which contains each item that appears in the iterator and the number of times it appears. Read more
Collect the items in this iterator and return a HashMap which contains each item that appears in the iterator and the number of times it appears, determining identity using a keying function. Read more
Converts an iterator of tuples into a tuple of containers. Read more
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
Unzip this iterator into multiple collections.
🔬This is a nightly-only experimental API. (pattern)
Associated searcher for this pattern
🔬This is a nightly-only experimental API. (pattern)
Constructs the associated searcher from self and the haystack to search in.
🔬This is a nightly-only experimental API. (pattern)
Checks whether the pattern matches anywhere in the haystack
🔬This is a nightly-only experimental API. (pattern)
Checks whether the pattern matches at the front of the haystack
🔬This is a nightly-only experimental API. (pattern)
Removes the pattern from the front of haystack, if it matches.
🔬This is a nightly-only experimental API. (pattern)
Checks whether the pattern matches at the back of the haystack
🔬This is a nightly-only experimental API. (pattern)
Removes the pattern from the back of haystack, if it matches.
🔬This is a nightly-only experimental API. (provide_any)
Data providers should implement this method to provide all values they are able to provide by using demand. Read more
Appends text to dst to replace the current match. Read more
Return a fixed unchanging replacement string. Read more
Return a Replacer that borrows and wraps this Replacer. Read more
Appends text to dst to replace the current match. Read more
Return a fixed unchanging replacement byte string. Read more
Return a Replacer that borrows and wraps this Replacer. Read more
Return a random value supporting the Standard distribution. Read more
Generate a random value in the range [low, high), i.e. inclusive of low and exclusive of high. Read more
Sample a new value, using the given distribution. Read more
Create an iterator that generates values using the given distribution. Read more
Fill dest entirely with random bytes (uniform value distribution), where dest is any type supporting AsByteSliceMut, namely slices and arrays over primitive integer types (i8, i16, u32, etc.). Read more
Fill dest entirely with random bytes (uniform value distribution), where dest is any type supporting AsByteSliceMut, namely slices and arrays over primitive integer types (i8, i16, u32, etc.). Read more
Return a bool with a probability p of being true. Read more
Return a bool with a probability of numerator/denominator of being true. I.e. gen_ratio(2, 3) has chance of 2 in 3, or about 67%, of returning true. If numerator == denominator, then the returned value is guaranteed to be true. If numerator == 0, then the returned value is guaranteed to be false. Read more
Return a random value supporting the Standard distribution. Read more
Generate a random value in the given range. Read more
Sample a new value, using the given distribution. Read more
Create an iterator that generates values using the given distribution. Read more
Fill any type implementing Fill with random data Read more
Fill any type implementing Fill with random data Read more
Return a bool with a probability p of being true. Read more
Return a bool with a probability of numerator/denominator of being true. I.e. gen_ratio(2, 3) has chance of 2 in 3, or about 67%, of returning true. If numerator == denominator, then the returned value is guaranteed to be true. If numerator == 0, then the returned value is guaranteed to be false. Read more
Should always be Self
Encode as base32 and write it to the supplied writer Implementations shouldn’t allocate.
Convert Self to base32 vector
Encode the hex strict representing self into the result. Lower case letters are used (e.g. f9b4ca)
Encode the hex strict representing self into the result. Upper case letters are used (e.g. F9B4CA)
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Converts the given value to a String. Read more
Used to optimize single value loading of endpoint arguments.
Version of top_encode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.
Attempt to serialize the value to ouput.
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Argument’s value type
Parse the argument value Read more
Parse the argument value Read more
Reflect on enumerated value properties Read more
Adapt a TypedValueParser from one value to another Read more
Adapt a TypedValueParser from one value to another Read more