[−][src]Struct uninit::out_ref::Out
Wrapper expressing the semantics of &out T
references
In other words, this has the semantics of &'out mut MaybeUninit<T>
but
for the ability to write garbage (MaybeUninit::uninit()
) into it
(else coercing &mut T
to &out T = Out<T>
would be
unsound).
This means that the reference may point to uninitialized memory (or not),
and thus that writes to the pointee will not call the .drop()
destructor.
This type can be trivially constructed from:
-
a
&'out mut MaybeUninit<T>
(main point of the type), -
a
&'out mut T
(to keep the ergonomics of being able to overwrite an already initialized value).- To avoid "accidentally" leaking memory in this second case,
either
T
must beCopy
(sufficient condition to prove there is no drop glue), or you must first call.manually_drop_mut()
before the.as_out()
"coercion".
- To avoid "accidentally" leaking memory in this second case,
either
Implementations
impl<'out, T: 'out + ?Sized> Out<'out, T>
[src]
pub fn reborrow<'reborrow>(
self: &'reborrow mut Out<'out, T>
) -> Out<'reborrow, T> where
'out: 'reborrow,
[src]
self: &'reborrow mut Out<'out, T>
) -> Out<'reborrow, T> where
'out: 'reborrow,
Reborrows the &out _
reference for a shorter lifetime.
pub fn r<'reborrow>(self: &'reborrow mut Out<'out, T>) -> Out<'reborrow, T> where
'out: 'reborrow,
[src]
'out: 'reborrow,
Shorthand for .reborrow()
.
impl<'out, T: 'out> Out<'out, T>
[src]
pub fn write(self: Out<'out, T>, value: T) -> &'out mut T
[src]
Write a value
into the pointee, returning an .assume_init()
-ed
reference to it.
Guarantees (that unsafe
code may rely on)
After the function returns, the pointee is guaranteed to have been
initialized; it is thus sound to use that property to manually
assume_init()
it or any chunk of such items.
pub fn replace(
mut self: Out<'out, T>,
value: T
) -> (MaybeUninit<T>, &'out mut T)
[src]
mut self: Out<'out, T>,
value: T
) -> (MaybeUninit<T>, &'out mut T)
Similar to .write()
, but getting the previous value
back. Such previous value may or may not be initialized.
Guarantees (that unsafe
code may rely on)
-
After the function returns, the pointee is guaranteed to have been initialized; it is thus sound to use that property to manually
assume_init()
it or any chunk of such items. -
there is no such guarantee regarding the previous value, which is thus only sound to
assume_init()
if the pointee already was (before the call to.replace()
).
pub fn as_mut_ptr(self: &mut Out<'out, T>) -> *mut T
[src]
Returns a raw mutable pointer to the pointee.
Guarantees (that unsafe
code may rely on)
-
The returned pointer does point to the pointee, meaning that if such returned pointer is used to
.write()
to the pointee, then it is safe toassume_init()
it. -
The returned pointer is non null, well-aligned, and writeable.
It is also technically readable:
-
you can read a
MaybeUninit<T>
out of it after.cast()
ing it, -
otherwise, except when sound to
assume_init()
, the obtained pointer cannot be used to read the value: T
of the pointee!
-
pub unsafe fn assume_init(mut self: Out<'out, T>) -> &'out mut T
[src]
Upgrades the &out _
(write-only) reference to a read-writeable
&mut _
.
Safety
Don't be lured by the &mut
reference: Rust validity invariants
imply that an &mut
reference is only sound to produce if it points
to an initialized value; it is otherwise instant UB. See
MaybeUninit::assume_init
for more info about it. Thus:
- The pointee must have been initialized.
This is a validity invariant, meaning that UB does happen from just calling that function to produce an ill-formed reference, even if the obtained reference is "never actually used".
Counterexample
The following program exhibits Undefined Behavior:
use ::uninit::prelude::*; let mut x = MaybeUninit::uninit(); let _unused: &mut u8 = unsafe { x .as_out() .assume_init() // UB! };
pub unsafe fn as_mut_uninit(self: Out<'out, T>) -> &'out mut MaybeUninit<T>
[src]
Upgrades the &out _
(write-valid-values-only) reference to a
&mut MaybeUninit<_>
(write-anything) reference.
Safety
-
The obtained reference cannot be used to write garbage (
MaybeUninit::uninit()
) into the pointee.This means that it can thus not be fed to opaque APIs!!
-
Exception: if the given
&out
reference has originated from a&mut MaybeUninit<_>
, then calling.as_mut_uninit()
is a sound way to make the trip back.
This is a safety invariant (i.e., even if it is never "instant"
UB to produce such a value, it does break the safety invariant of
&mut MaybeUninit<_>
(that of being allowed to write
MaybeUninit::uninit()
garbage into the pointee), so UB can happen
afterwards). This is different than .assume_init()
soundness relying
on a validity invariant, meaning that UB does happen from just calling
that function to produce an ill-formed reference, even if the obtained
reference is never actually used.
Counter-example
The following code is Undefined Behavior:
use ::uninit::prelude::*; let mut my_box = Box::new(42); let at_my_box: Out<'_, Box<i32>> = my_box .manually_drop_mut() .as_out() ; // Overwrite `my_box` with uninitialized bytes / garbage content. unsafe { *at_my_box.as_mut_uninit() = MaybeUninit::uninit(); } // Runs the destructor for a `Box<i32>` using a garbage pointer that // may thus point anywhere in memory! drop(my_box)
A function from an external library must always be seen as opaque
(unless its documentation makes implementation-detail guarantees, such
as this very crate does), so one cannot rely on its implementation
(unless the lib is open source AND you pin-point to that version of the
crate, either through version = "=x.y.z"
or through git = ..., rev = ...
in Cargo.toml
).
// `fn zeroize (out: &'_ mut MaybeUninit<u8>) -> &'_ mut u8;` // The author of the crate says it uses that `out` reference to write // `0` to the pointee. use ::some_lib::zeroize; let mut x = 42; let at_x = x.as_out(); // Unsound! The lib implementation is free to write // `MaybeUninit::uninit()` garbage to the pointee! zeroize(unsafe { at_x.as_mut_uninit() });
impl<'out, T: 'out> Out<'out, [T]>
[src]
pub fn from_out(out: Out<'out, T>) -> Out<'out, [T]>
[src]
Converts a single item out reference into a 1
-long out slice.
This is the &out
version of
slice::from_ref
and slice::from_mut
.
pub fn as_ptr(&self) -> *const T
[src]
Obtains a read-only non-NULL and well-aligned raw pointer to a
potentially uninitialized T
.
Unless maybe with interior mutability through raw pointers, there is
no case where using this function is more useful than going through
<[MaybeUninit<_>]>::assume_init_by_ref()
.
Worse, the lack of unsafe
-ty of the method (ignoring the one needed
to use the pointer) and its "boring" name may lead to code
read-dereferencing the pointer (which implicitly assume_init()
s it)
without having ensured the soundness of such (implicit) assume_init()
.
pub fn as_mut_ptr(&mut self) -> *mut T
[src]
Returns a raw mutable pointer to the pointee.
See Out::as_mut_ptr
for more info regarding safety and guarantees.
pub unsafe fn as_mut_uninit(self: Out<'out, [T]>) -> &'out mut [MaybeUninit<T>]ⓘ
[src]
Upgrades the &out _
(write-valid-values-only) reference to a
&mut MaybeUninit<_>
(write-anything) reference.
See Out::as_mut_uninit
for more info regarding safety.
pub fn get_out<Index>(self: Out<'out, [T]>, idx: Index) -> Option<Index::Output> where
Index: UsizeOrRange<'out, T>,
[src]
Index: UsizeOrRange<'out, T>,
Main indexing operation on an &out [_]
.
The type Index
of idx
may be:
-
a
usize
, and thenIndex::Output
is aOut<T>
reference to a single element. -
a
Range<usize>
(e.g.,a .. b
), and thenIndex::Output
is aOut<[T]>
reference to a subslice.
Example
use ::uninit::prelude::*; let src: &[u8] = b"Hello, World!"; // Stack-allocate an uninitialized buffer. let mut buf = uninit_array![u8; 256]; // copy `src` into this stack allocated buffer, effectively initializing it. let buf: &mut [u8] = // buf[.. src.len()].as_out() buf.as_out().get_out(.. src.len()).unwrap() .copy_from_slice(src) ; assert_eq!(buf, b"Hello, World!"); buf[7 ..].copy_from_slice(b"Earth!"); assert_eq!(buf, b"Hello, Earth!");
pub unsafe fn get_unchecked_out<Index>(
self: Out<'out, [T]>,
idx: Index
) -> Index::Output where
Index: UsizeOrRange<'out, T>,
[src]
self: Out<'out, [T]>,
idx: Index
) -> Index::Output where
Index: UsizeOrRange<'out, T>,
Same as .get_out()
, but with the bound check being elided.
Safety
The given idx
mut be in bounds:
-
if
idx: usize
, thenidx
must be< self.len()
. -
if
idx
is an upper-bounded range (e.g.,.. b
,a ..= b
), then the upper bound (b
in the example) must be< self.len()
. -
etc.
See .get_unchecked_mut()
for more info about the safety of such call.
pub fn as_uninit(self: Out<'out, [T]>) -> &'out [MaybeUninit<T>]ⓘ
[src]
Downgrades the Out<'_, [T]>
slice into a &'_ [MaybeUninit<T>]
.
This leads to a read-only1 "unreadable" slice which is thus
only useful for accessing &'_ []
metadata, mainly the length of the
slice.
In practice, calling this function explicitely is not even needed given
that Out<'_, [T]> : Deref<Target = [MaybeUninit<T>]
, so one can do:
use ::uninit::prelude::*; let mut backing_array = uninit_array![_; 42]; let buf: Out<'_, [u8]> = backing_array.as_out(); assert_eq!(buf.len(), 42); // no need to `.r().as_uninit()`
1 Unless Interior Mutability is involved; speaking of which:
Interior Mutability
The whole design of Out
references is to forbid any non-unsafe API
that would allow writing MaybeUninit::uninit()
garbage into the
pointee. So, for instance, this crate does not offer any API like:
use ::core::{cell::Cell, mem::MaybeUninit}; // /!\ This is UNSOUND when combined with the `::uninit` crate! fn swap_mb_uninit_and_cell<T> ( p: &'_ MaybeUninit<Cell<T>>, ) -> &'_ Cell<MaybeUninit<T>> { unsafe { // Safety: both `Cell` and `MaybeUninit` are `#[repr(transparent)]` ::core::mem::transmute(p) } }
Indeed, if both such non-unsafe
API and the uninit
crate were
present, then one could trigger UB with:
let mut x = [Cell::new(42)]; let at_mb_uninit_cell: &'_ MaybeUninit<Cell<u8>> = &x.as_out().as_uninit()[0] ; swap_mb_uninit_and_cell(at_mb_uninit_cell) .set(MaybeUninit::uninit()) // UB! ;
The author of the crate believes that such UB is the responsibility of
the one who defined swap_mb_uninit_and_cell
, and that in general that
function is unsound: MaybeUninit
-ness and interior mutability do
not commute!
- the
Safety
annotation in the given example only justifies that it is not breaking any layout-based validity invariants, but it is actually impossible to semantically prove that it is safe for these properties to commute.
If you are strongly convinced of the opposite, please file an issue (if there isn't already one: since this question is not that clear the author is very likely to create an issue themself).
pub unsafe fn assume_all_init(mut self: Out<'out, [T]>) -> &'out mut [T]ⓘ
[src]
Upgrades the &out [_]
(write-only) reference to a read-writeable
&mut [_]
.
Safety
Don't be lured by the &mut
reference: Rust validity invariants
imply that an &mut
reference is only sound to produce if it points
to initialized values; it is otherwise instant UB. See
MaybeUninit::assume_init
for more info about it. Thus:
- The pointee(s) must have been initialized.
This is a validity invariant, meaning that UB does happen from just calling that function to produce an ill-formed reference, even if the obtained reference is "never actually used".
pub fn copy_from_slice(
mut self: Out<'out, [T]>,
source_slice: &[T]
) -> &'out mut [T]ⓘ where
T: Copy,
[src]
mut self: Out<'out, [T]>,
source_slice: &[T]
) -> &'out mut [T]ⓘ where
T: Copy,
Initialize the buffer with a copy from another (already initialized) buffer.
It returns a read-writable slice to the initialized bytes for
convenience (automatically
assume_init
-ed).
Panic
The function panics if the slices' lengths are not equal.
Guarantees (that unsafe
code may rely on)
A non-panic!
king return from this function guarantees that the input
slice has been (successfully) initialized, and that it is thus then
sound to .assume_init()
.
It also guarantees that the returned slice does correspond to the input
slice (e.g., for crate::ReadIntoUninit
's safety guarantees).
Example
use ::uninit::prelude::*; let mut array = uninit_array![_; 13]; assert_eq!( array.as_out().copy_from_slice(b"Hello, World!"), b"Hello, World!", ); // we can thus soundly `assume_init` our array: let array = unsafe { mem::transmute::< [MaybeUninit<u8>; 13], [ u8 ; 13], >(array) }; assert_eq!( array, *b"Hello, World!", );
pub fn init_with(
mut self: Out<'out, [T]>,
iterable: impl IntoIterator<Item = T>
) -> &'out mut [T]ⓘ
[src]
mut self: Out<'out, [T]>,
iterable: impl IntoIterator<Item = T>
) -> &'out mut [T]ⓘ
Fills the buffer with values from up to the first self.len()
elements
of an iterable
.
Guarantees (that unsafe
code may rely on)
A non-panicking return from this function guarantees that the first k
values of the buffer have been initialized and are thus sound to
.assume_init()
, where k
, the numbers of elements that iterable
has yielded (capped at self.len()
), is the length of the returned
buffer.
pub fn iter_out<'reborrow>(
self: &'reborrow mut Out<'out, [T]>
) -> IterOut<'reborrow, T>ⓘ
[src]
self: &'reborrow mut Out<'out, [T]>
) -> IterOut<'reborrow, T>ⓘ
.reborrow().into_iter()
pub fn split_at_out(
self: Out<'out, [T]>,
idx: usize
) -> (Out<'out, [T]>, Out<'out, [T]>)
[src]
self: Out<'out, [T]>,
idx: usize
) -> (Out<'out, [T]>, Out<'out, [T]>)
Methods from Deref<Target = [MaybeUninit<T>]>
pub const fn len(&self) -> usize
1.0.0 (const: 1.32.0)[src]
pub const fn is_empty(&self) -> bool
1.0.0 (const: 1.32.0)[src]
pub fn first(&self) -> Option<&T>
1.0.0[src]
Returns the first element of the slice, or None
if it is empty.
Examples
let v = [10, 40, 30]; assert_eq!(Some(&10), v.first()); let w: &[i32] = &[]; assert_eq!(None, w.first());
pub fn split_first(&self) -> Option<(&T, &[T])>
1.5.0[src]
Returns the first and all the rest of the elements of the slice, or None
if it is empty.
Examples
let x = &[0, 1, 2]; if let Some((first, elements)) = x.split_first() { assert_eq!(first, &0); assert_eq!(elements, &[1, 2]); }
pub fn split_last(&self) -> Option<(&T, &[T])>
1.5.0[src]
Returns the last and all the rest of the elements of the slice, or None
if it is empty.
Examples
let x = &[0, 1, 2]; if let Some((last, elements)) = x.split_last() { assert_eq!(last, &2); assert_eq!(elements, &[0, 1]); }
pub fn last(&self) -> Option<&T>
1.0.0[src]
Returns the last element of the slice, or None
if it is empty.
Examples
let v = [10, 40, 30]; assert_eq!(Some(&30), v.last()); let w: &[i32] = &[]; assert_eq!(None, w.last());
pub fn get<I>(&self, index: I) -> Option<&<I as SliceIndex<[T]>>::Output> where
I: SliceIndex<[T]>,
1.0.0[src]
I: SliceIndex<[T]>,
Returns a reference to an element or subslice depending on the type of index.
- If given a position, returns a reference to the element at that
position or
None
if out of bounds. - If given a range, returns the subslice corresponding to that range,
or
None
if out of bounds.
Examples
let v = [10, 40, 30]; assert_eq!(Some(&40), v.get(1)); assert_eq!(Some(&[10, 40][..]), v.get(0..2)); assert_eq!(None, v.get(3)); assert_eq!(None, v.get(0..4));
pub unsafe fn get_unchecked<I>(
&self,
index: I
) -> &<I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,
1.0.0[src]
&self,
index: I
) -> &<I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,
Returns a reference to an element or subslice, without doing bounds checking.
For a safe alternative see get
.
Safety
Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.
Examples
let x = &[1, 2, 4]; unsafe { assert_eq!(x.get_unchecked(1), &2); }
pub const fn as_ptr(&self) -> *const T
1.0.0 (const: 1.32.0)[src]
Returns a raw pointer to the slice's buffer.
The caller must ensure that the slice outlives the pointer this function returns, or else it will end up pointing to garbage.
The caller must also ensure that the memory the pointer (non-transitively) points to
is never written to (except inside an UnsafeCell
) using this pointer or any pointer
derived from it. If you need to mutate the contents of the slice, use as_mut_ptr
.
Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.
Examples
let x = &[1, 2, 4]; let x_ptr = x.as_ptr(); unsafe { for i in 0..x.len() { assert_eq!(x.get_unchecked(i), &*x_ptr.add(i)); } }
pub const fn as_ptr_range(&self) -> Range<*const T>
1.48.0[src]
Returns the two raw pointers spanning the slice.
The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.
See as_ptr
for warnings on using these pointers. The end pointer
requires extra caution, as it does not point to a valid element in the
slice.
This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.
It can also be useful to check if a pointer to an element refers to an element of this slice:
let a = [1, 2, 3]; let x = &a[1] as *const _; let y = &5 as *const _; assert!(a.as_ptr_range().contains(&x)); assert!(!a.as_ptr_range().contains(&y));
pub fn iter(&self) -> Iter<'_, T>
1.0.0[src]
Returns an iterator over the slice.
Examples
let x = &[1, 2, 4]; let mut iterator = x.iter(); assert_eq!(iterator.next(), Some(&1)); assert_eq!(iterator.next(), Some(&2)); assert_eq!(iterator.next(), Some(&4)); assert_eq!(iterator.next(), None);
pub fn windows(&self, size: usize) -> Windows<'_, T>
1.0.0[src]
Returns an iterator over all contiguous windows of length
size
. The windows overlap. If the slice is shorter than
size
, the iterator returns no values.
Panics
Panics if size
is 0.
Examples
let slice = ['r', 'u', 's', 't']; let mut iter = slice.windows(2); assert_eq!(iter.next().unwrap(), &['r', 'u']); assert_eq!(iter.next().unwrap(), &['u', 's']); assert_eq!(iter.next().unwrap(), &['s', 't']); assert!(iter.next().is_none());
If the slice is shorter than size
:
let slice = ['f', 'o', 'o']; let mut iter = slice.windows(4); assert!(iter.next().is_none());
pub fn chunks(&self, chunk_size: usize) -> Chunks<'_, T>
1.0.0[src]
Returns an iterator over chunk_size
elements of the slice at a time, starting at the
beginning of the slice.
The chunks are slices and do not overlap. If chunk_size
does not divide the length of the
slice, then the last chunk will not have length chunk_size
.
See chunks_exact
for a variant of this iterator that returns chunks of always exactly
chunk_size
elements, and rchunks
for the same iterator but starting at the end of the
slice.
Panics
Panics if chunk_size
is 0.
Examples
let slice = ['l', 'o', 'r', 'e', 'm']; let mut iter = slice.chunks(2); assert_eq!(iter.next().unwrap(), &['l', 'o']); assert_eq!(iter.next().unwrap(), &['r', 'e']); assert_eq!(iter.next().unwrap(), &['m']); assert!(iter.next().is_none());
pub fn chunks_exact(&self, chunk_size: usize) -> ChunksExact<'_, T>
1.31.0[src]
Returns an iterator over chunk_size
elements of the slice at a time, starting at the
beginning of the slice.
The chunks are slices and do not overlap. If chunk_size
does not divide the length of the
slice, then the last up to chunk_size-1
elements will be omitted and can be retrieved
from the remainder
function of the iterator.
Due to each chunk having exactly chunk_size
elements, the compiler can often optimize the
resulting code better than in the case of chunks
.
See chunks
for a variant of this iterator that also returns the remainder as a smaller
chunk, and rchunks_exact
for the same iterator but starting at the end of the slice.
Panics
Panics if chunk_size
is 0.
Examples
let slice = ['l', 'o', 'r', 'e', 'm']; let mut iter = slice.chunks_exact(2); assert_eq!(iter.next().unwrap(), &['l', 'o']); assert_eq!(iter.next().unwrap(), &['r', 'e']); assert!(iter.next().is_none()); assert_eq!(iter.remainder(), &['m']);
pub unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]]ⓘ
[src]
slice_as_chunks
)Splits the slice into a slice of N
-element arrays,
assuming that there's no remainder.
Safety
This may only be called when
- The slice splits exactly into
N
-element chunks (akaself.len() % N == 0
). N != 0
.
Examples
#![feature(slice_as_chunks)] let slice: &[char] = &['l', 'o', 'r', 'e', 'm', '!']; let chunks: &[[char; 1]] = // SAFETY: 1-element chunks never have remainder unsafe { slice.as_chunks_unchecked() }; assert_eq!(chunks, &[['l'], ['o'], ['r'], ['e'], ['m'], ['!']]); let chunks: &[[char; 3]] = // SAFETY: The slice length (6) is a multiple of 3 unsafe { slice.as_chunks_unchecked() }; assert_eq!(chunks, &[['l', 'o', 'r'], ['e', 'm', '!']]); // These would be unsound: // let chunks: &[[_; 5]] = slice.as_chunks_unchecked() // The slice length is not a multiple of 5 // let chunks: &[[_; 0]] = slice.as_chunks_unchecked() // Zero-length chunks are never allowed
pub fn as_chunks<const N: usize>(&self) -> (&[[T; N]], &[T])
[src]
slice_as_chunks
)Splits the slice into a slice of N
-element arrays,
starting at the beginning of the slice,
and a remainder slice with length strictly less than N
.
Panics
Panics if N
is 0. This check will most probably get changed to a compile time
error before this method gets stabilized.
Examples
#![feature(slice_as_chunks)] let slice = ['l', 'o', 'r', 'e', 'm']; let (chunks, remainder) = slice.as_chunks(); assert_eq!(chunks, &[['l', 'o'], ['r', 'e']]); assert_eq!(remainder, &['m']);
pub fn as_rchunks<const N: usize>(&self) -> (&[T], &[[T; N]])
[src]
slice_as_chunks
)Splits the slice into a slice of N
-element arrays,
starting at the end of the slice,
and a remainder slice with length strictly less than N
.
Panics
Panics if N
is 0. This check will most probably get changed to a compile time
error before this method gets stabilized.
Examples
#![feature(slice_as_chunks)] let slice = ['l', 'o', 'r', 'e', 'm']; let (remainder, chunks) = slice.as_rchunks(); assert_eq!(remainder, &['l']); assert_eq!(chunks, &[['o', 'r'], ['e', 'm']]);
pub fn array_chunks<const N: usize>(&self) -> ArrayChunks<'_, T, N>
[src]
array_chunks
)Returns an iterator over N
elements of the slice at a time, starting at the
beginning of the slice.
The chunks are array references and do not overlap. If N
does not divide the
length of the slice, then the last up to N-1
elements will be omitted and can be
retrieved from the remainder
function of the iterator.
This method is the const generic equivalent of chunks_exact
.
Panics
Panics if N
is 0. This check will most probably get changed to a compile time
error before this method gets stabilized.
Examples
#![feature(array_chunks)] let slice = ['l', 'o', 'r', 'e', 'm']; let mut iter = slice.array_chunks(); assert_eq!(iter.next().unwrap(), &['l', 'o']); assert_eq!(iter.next().unwrap(), &['r', 'e']); assert!(iter.next().is_none()); assert_eq!(iter.remainder(), &['m']);
pub fn array_windows<const N: usize>(&self) -> ArrayWindows<'_, T, N>
[src]
array_windows
)Returns an iterator over overlapping windows of N
elements of a slice,
starting at the beginning of the slice.
This is the const generic equivalent of windows
.
If N
is greater than the size of the slice, it will return no windows.
Panics
Panics if N
is 0. This check will most probably get changed to a compile time
error before this method gets stabilized.
Examples
#![feature(array_windows)] let slice = [0, 1, 2, 3]; let mut iter = slice.array_windows(); assert_eq!(iter.next().unwrap(), &[0, 1]); assert_eq!(iter.next().unwrap(), &[1, 2]); assert_eq!(iter.next().unwrap(), &[2, 3]); assert!(iter.next().is_none());
pub fn rchunks(&self, chunk_size: usize) -> RChunks<'_, T>
1.31.0[src]
Returns an iterator over chunk_size
elements of the slice at a time, starting at the end
of the slice.
The chunks are slices and do not overlap. If chunk_size
does not divide the length of the
slice, then the last chunk will not have length chunk_size
.
See rchunks_exact
for a variant of this iterator that returns chunks of always exactly
chunk_size
elements, and chunks
for the same iterator but starting at the beginning
of the slice.
Panics
Panics if chunk_size
is 0.
Examples
let slice = ['l', 'o', 'r', 'e', 'm']; let mut iter = slice.rchunks(2); assert_eq!(iter.next().unwrap(), &['e', 'm']); assert_eq!(iter.next().unwrap(), &['o', 'r']); assert_eq!(iter.next().unwrap(), &['l']); assert!(iter.next().is_none());
pub fn rchunks_exact(&self, chunk_size: usize) -> RChunksExact<'_, T>
1.31.0[src]
Returns an iterator over chunk_size
elements of the slice at a time, starting at the
end of the slice.
The chunks are slices and do not overlap. If chunk_size
does not divide the length of the
slice, then the last up to chunk_size-1
elements will be omitted and can be retrieved
from the remainder
function of the iterator.
Due to each chunk having exactly chunk_size
elements, the compiler can often optimize the
resulting code better than in the case of chunks
.
See rchunks
for a variant of this iterator that also returns the remainder as a smaller
chunk, and chunks_exact
for the same iterator but starting at the beginning of the
slice.
Panics
Panics if chunk_size
is 0.
Examples
let slice = ['l', 'o', 'r', 'e', 'm']; let mut iter = slice.rchunks_exact(2); assert_eq!(iter.next().unwrap(), &['e', 'm']); assert_eq!(iter.next().unwrap(), &['o', 'r']); assert!(iter.next().is_none()); assert_eq!(iter.remainder(), &['l']);
pub fn group_by<F>(&self, pred: F) -> GroupBy<'_, T, F> where
F: FnMut(&T, &T) -> bool,
[src]
F: FnMut(&T, &T) -> bool,
slice_group_by
)Returns an iterator over the slice producing non-overlapping runs of elements using the predicate to separate them.
The predicate is called on two elements following themselves,
it means the predicate is called on slice[0]
and slice[1]
then on slice[1]
and slice[2]
and so on.
Examples
#![feature(slice_group_by)] let slice = &[1, 1, 1, 3, 3, 2, 2, 2]; let mut iter = slice.group_by(|a, b| a == b); assert_eq!(iter.next(), Some(&[1, 1, 1][..])); assert_eq!(iter.next(), Some(&[3, 3][..])); assert_eq!(iter.next(), Some(&[2, 2, 2][..])); assert_eq!(iter.next(), None);
This method can be used to extract the sorted subslices:
#![feature(slice_group_by)] let slice = &[1, 1, 2, 3, 2, 3, 2, 3, 4]; let mut iter = slice.group_by(|a, b| a <= b); assert_eq!(iter.next(), Some(&[1, 1, 2, 3][..])); assert_eq!(iter.next(), Some(&[2, 3][..])); assert_eq!(iter.next(), Some(&[2, 3, 4][..])); assert_eq!(iter.next(), None);
pub fn split_at(&self, mid: usize) -> (&[T], &[T])
1.0.0[src]
Divides one slice into two at an index.
The first will contain all indices from [0, mid)
(excluding
the index mid
itself) and the second will contain all
indices from [mid, len)
(excluding the index len
itself).
Panics
Panics if mid > len
.
Examples
let v = [1, 2, 3, 4, 5, 6]; { let (left, right) = v.split_at(0); assert_eq!(left, []); assert_eq!(right, [1, 2, 3, 4, 5, 6]); } { let (left, right) = v.split_at(2); assert_eq!(left, [1, 2]); assert_eq!(right, [3, 4, 5, 6]); } { let (left, right) = v.split_at(6); assert_eq!(left, [1, 2, 3, 4, 5, 6]); assert_eq!(right, []); }
pub fn split<F>(&self, pred: F) -> Split<'_, T, F> where
F: FnMut(&T) -> bool,
1.0.0[src]
F: FnMut(&T) -> bool,
Returns an iterator over subslices separated by elements that match
pred
. The matched element is not contained in the subslices.
Examples
let slice = [10, 40, 33, 20]; let mut iter = slice.split(|num| num % 3 == 0); assert_eq!(iter.next().unwrap(), &[10, 40]); assert_eq!(iter.next().unwrap(), &[20]); assert!(iter.next().is_none());
If the first element is matched, an empty slice will be the first item returned by the iterator. Similarly, if the last element in the slice is matched, an empty slice will be the last item returned by the iterator:
let slice = [10, 40, 33]; let mut iter = slice.split(|num| num % 3 == 0); assert_eq!(iter.next().unwrap(), &[10, 40]); assert_eq!(iter.next().unwrap(), &[]); assert!(iter.next().is_none());
If two matched elements are directly adjacent, an empty slice will be present between them:
let slice = [10, 6, 33, 20]; let mut iter = slice.split(|num| num % 3 == 0); assert_eq!(iter.next().unwrap(), &[10]); assert_eq!(iter.next().unwrap(), &[]); assert_eq!(iter.next().unwrap(), &[20]); assert!(iter.next().is_none());
pub fn split_inclusive<F>(&self, pred: F) -> SplitInclusive<'_, T, F> where
F: FnMut(&T) -> bool,
1.51.0[src]
F: FnMut(&T) -> bool,
Returns an iterator over subslices separated by elements that match
pred
. The matched element is contained in the end of the previous
subslice as a terminator.
Examples
let slice = [10, 40, 33, 20]; let mut iter = slice.split_inclusive(|num| num % 3 == 0); assert_eq!(iter.next().unwrap(), &[10, 40, 33]); assert_eq!(iter.next().unwrap(), &[20]); assert!(iter.next().is_none());
If the last element of the slice is matched, that element will be considered the terminator of the preceding slice. That slice will be the last item returned by the iterator.
let slice = [3, 10, 40, 33]; let mut iter = slice.split_inclusive(|num| num % 3 == 0); assert_eq!(iter.next().unwrap(), &[3]); assert_eq!(iter.next().unwrap(), &[10, 40, 33]); assert!(iter.next().is_none());
pub fn rsplit<F>(&self, pred: F) -> RSplit<'_, T, F> where
F: FnMut(&T) -> bool,
1.27.0[src]
F: FnMut(&T) -> bool,
Returns an iterator over subslices separated by elements that match
pred
, starting at the end of the slice and working backwards.
The matched element is not contained in the subslices.
Examples
let slice = [11, 22, 33, 0, 44, 55]; let mut iter = slice.rsplit(|num| *num == 0); assert_eq!(iter.next().unwrap(), &[44, 55]); assert_eq!(iter.next().unwrap(), &[11, 22, 33]); assert_eq!(iter.next(), None);
As with split()
, if the first or last element is matched, an empty
slice will be the first (or last) item returned by the iterator.
let v = &[0, 1, 1, 2, 3, 5, 8]; let mut it = v.rsplit(|n| *n % 2 == 0); assert_eq!(it.next().unwrap(), &[]); assert_eq!(it.next().unwrap(), &[3, 5]); assert_eq!(it.next().unwrap(), &[1, 1]); assert_eq!(it.next().unwrap(), &[]); assert_eq!(it.next(), None);
pub fn splitn<F>(&self, n: usize, pred: F) -> SplitN<'_, T, F> where
F: FnMut(&T) -> bool,
1.0.0[src]
F: FnMut(&T) -> bool,
Returns an iterator over subslices separated by elements that match
pred
, limited to returning at most n
items. The matched element is
not contained in the subslices.
The last element returned, if any, will contain the remainder of the slice.
Examples
Print the slice split once by numbers divisible by 3 (i.e., [10, 40]
,
[20, 60, 50]
):
let v = [10, 40, 30, 20, 60, 50]; for group in v.splitn(2, |num| *num % 3 == 0) { println!("{:?}", group); }
pub fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<'_, T, F> where
F: FnMut(&T) -> bool,
1.0.0[src]
F: FnMut(&T) -> bool,
Returns an iterator over subslices separated by elements that match
pred
limited to returning at most n
items. This starts at the end of
the slice and works backwards. The matched element is not contained in
the subslices.
The last element returned, if any, will contain the remainder of the slice.
Examples
Print the slice split once, starting from the end, by numbers divisible
by 3 (i.e., [50]
, [10, 40, 30, 20]
):
let v = [10, 40, 30, 20, 60, 50]; for group in v.rsplitn(2, |num| *num % 3 == 0) { println!("{:?}", group); }
pub fn contains(&self, x: &T) -> bool where
T: PartialEq<T>,
1.0.0[src]
T: PartialEq<T>,
Returns true
if the slice contains an element with the given value.
Examples
let v = [10, 40, 30]; assert!(v.contains(&30)); assert!(!v.contains(&50));
If you do not have an &T
, but just an &U
such that T: Borrow<U>
(e.g. String: Borrow<str>
), you can use iter().any
:
let v = [String::from("hello"), String::from("world")]; // slice of `String` assert!(v.iter().any(|e| e == "hello")); // search with `&str` assert!(!v.iter().any(|e| e == "hi"));
pub fn starts_with(&self, needle: &[T]) -> bool where
T: PartialEq<T>,
1.0.0[src]
T: PartialEq<T>,
Returns true
if needle
is a prefix of the slice.
Examples
let v = [10, 40, 30]; assert!(v.starts_with(&[10])); assert!(v.starts_with(&[10, 40])); assert!(!v.starts_with(&[50])); assert!(!v.starts_with(&[10, 50]));
Always returns true
if needle
is an empty slice:
let v = &[10, 40, 30]; assert!(v.starts_with(&[])); let v: &[u8] = &[]; assert!(v.starts_with(&[]));
pub fn ends_with(&self, needle: &[T]) -> bool where
T: PartialEq<T>,
1.0.0[src]
T: PartialEq<T>,
Returns true
if needle
is a suffix of the slice.
Examples
let v = [10, 40, 30]; assert!(v.ends_with(&[30])); assert!(v.ends_with(&[40, 30])); assert!(!v.ends_with(&[50])); assert!(!v.ends_with(&[50, 30]));
Always returns true
if needle
is an empty slice:
let v = &[10, 40, 30]; assert!(v.ends_with(&[])); let v: &[u8] = &[]; assert!(v.ends_with(&[]));
#[must_use = "returns the subslice without modifying the original"]pub fn strip_prefix<P>(&self, prefix: &P) -> Option<&[T]> where
T: PartialEq<T>,
P: SlicePattern<Item = T> + ?Sized,
1.51.0[src]
T: PartialEq<T>,
P: SlicePattern<Item = T> + ?Sized,
Returns a subslice with the prefix removed.
If the slice starts with prefix
, returns the subslice after the prefix, wrapped in Some
.
If prefix
is empty, simply returns the original slice.
If the slice does not start with prefix
, returns None
.
Examples
let v = &[10, 40, 30]; assert_eq!(v.strip_prefix(&[10]), Some(&[40, 30][..])); assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..])); assert_eq!(v.strip_prefix(&[50]), None); assert_eq!(v.strip_prefix(&[10, 50]), None); let prefix : &str = "he"; assert_eq!(b"hello".strip_prefix(prefix.as_bytes()), Some(b"llo".as_ref()));
#[must_use = "returns the subslice without modifying the original"]pub fn strip_suffix<P>(&self, suffix: &P) -> Option<&[T]> where
T: PartialEq<T>,
P: SlicePattern<Item = T> + ?Sized,
1.51.0[src]
T: PartialEq<T>,
P: SlicePattern<Item = T> + ?Sized,
Returns a subslice with the suffix removed.
If the slice ends with suffix
, returns the subslice before the suffix, wrapped in Some
.
If suffix
is empty, simply returns the original slice.
If the slice does not end with suffix
, returns None
.
Examples
let v = &[10, 40, 30]; assert_eq!(v.strip_suffix(&[30]), Some(&[10, 40][..])); assert_eq!(v.strip_suffix(&[40, 30]), Some(&[10][..])); assert_eq!(v.strip_suffix(&[50]), None); assert_eq!(v.strip_suffix(&[50, 30]), None);
pub fn binary_search(&self, x: &T) -> Result<usize, usize> where
T: Ord,
1.0.0[src]
T: Ord,
Binary searches this sorted slice for a given element.
If the value is found then Result::Ok
is returned, containing the
index of the matching element. If there are multiple matches, then any
one of the matches could be returned. If the value is not found then
Result::Err
is returned, containing the index where a matching
element could be inserted while maintaining sorted order.
Examples
Looks up a series of four elements. The first is found, with a
uniquely determined position; the second and third are not
found; the fourth could match any position in [1, 4]
.
let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]; assert_eq!(s.binary_search(&13), Ok(9)); assert_eq!(s.binary_search(&4), Err(7)); assert_eq!(s.binary_search(&100), Err(13)); let r = s.binary_search(&1); assert!(match r { Ok(1..=4) => true, _ => false, });
If you want to insert an item to a sorted vector, while maintaining sort order:
let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]; let num = 42; let idx = s.binary_search(&num).unwrap_or_else(|x| x); s.insert(idx, num); assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);
pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize> where
F: FnMut(&'a T) -> Ordering,
1.0.0[src]
F: FnMut(&'a T) -> Ordering,
Binary searches this sorted slice with a comparator function.
The comparator function should implement an order consistent
with the sort order of the underlying slice, returning an
order code that indicates whether its argument is Less
,
Equal
or Greater
the desired target.
If the value is found then Result::Ok
is returned, containing the
index of the matching element. If there are multiple matches, then any
one of the matches could be returned. If the value is not found then
Result::Err
is returned, containing the index where a matching
element could be inserted while maintaining sorted order.
Examples
Looks up a series of four elements. The first is found, with a
uniquely determined position; the second and third are not
found; the fourth could match any position in [1, 4]
.
let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]; let seek = 13; assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9)); let seek = 4; assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7)); let seek = 100; assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13)); let seek = 1; let r = s.binary_search_by(|probe| probe.cmp(&seek)); assert!(match r { Ok(1..=4) => true, _ => false, });
pub fn binary_search_by_key<'a, B, F>(
&'a self,
b: &B,
f: F
) -> Result<usize, usize> where
B: Ord,
F: FnMut(&'a T) -> B,
1.10.0[src]
&'a self,
b: &B,
f: F
) -> Result<usize, usize> where
B: Ord,
F: FnMut(&'a T) -> B,
Binary searches this sorted slice with a key extraction function.
Assumes that the slice is sorted by the key, for instance with
sort_by_key
using the same key extraction function.
If the value is found then Result::Ok
is returned, containing the
index of the matching element. If there are multiple matches, then any
one of the matches could be returned. If the value is not found then
Result::Err
is returned, containing the index where a matching
element could be inserted while maintaining sorted order.
Examples
Looks up a series of four elements in a slice of pairs sorted by
their second elements. The first is found, with a uniquely
determined position; the second and third are not found; the
fourth could match any position in [1, 4]
.
let s = [(0, 0), (2, 1), (4, 1), (5, 1), (3, 1), (1, 2), (2, 3), (4, 5), (5, 8), (3, 13), (1, 21), (2, 34), (4, 55)]; assert_eq!(s.binary_search_by_key(&13, |&(a, b)| b), Ok(9)); assert_eq!(s.binary_search_by_key(&4, |&(a, b)| b), Err(7)); assert_eq!(s.binary_search_by_key(&100, |&(a, b)| b), Err(13)); let r = s.binary_search_by_key(&1, |&(a, b)| b); assert!(match r { Ok(1..=4) => true, _ => false, });
pub unsafe fn align_to<U>(&self) -> (&[T], &[U], &[T])
1.30.0[src]
Transmute the slice to a slice of another type, ensuring alignment of the types is maintained.
This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The method may make the middle slice the greatest length possible for a given type and input slice, but only your algorithm's performance should depend on that, not its correctness. It is permissible for all of the input data to be returned as the prefix or suffix slice.
This method has no purpose when either input element T
or output element U
are
zero-sized and will return the original slice without splitting anything.
Safety
This method is essentially a transmute
with respect to the elements in the returned
middle slice, so all the usual caveats pertaining to transmute::<T, U>
also apply here.
Examples
Basic usage:
unsafe { let bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7]; let (prefix, shorts, suffix) = bytes.align_to::<u16>(); // less_efficient_algorithm_for_bytes(prefix); // more_efficient_algorithm_for_aligned_shorts(shorts); // less_efficient_algorithm_for_bytes(suffix); }
pub fn is_sorted(&self) -> bool where
T: PartialOrd<T>,
[src]
T: PartialOrd<T>,
🔬 This is a nightly-only experimental API. (is_sorted
)
new API
Checks if the elements of this slice are sorted.
That is, for each element a
and its following element b
, a <= b
must hold. If the
slice yields exactly zero or one element, true
is returned.
Note that if Self::Item
is only PartialOrd
, but not Ord
, the above definition
implies that this function returns false
if any two consecutive items are not
comparable.
Examples
#![feature(is_sorted)] let empty: [i32; 0] = []; assert!([1, 2, 2, 9].is_sorted()); assert!(![1, 3, 2, 4].is_sorted()); assert!([0].is_sorted()); assert!(empty.is_sorted()); assert!(![0.0, 1.0, f32::NAN].is_sorted());
pub fn is_sorted_by<F>(&self, compare: F) -> bool where
F: FnMut(&T, &T) -> Option<Ordering>,
[src]
F: FnMut(&T, &T) -> Option<Ordering>,
🔬 This is a nightly-only experimental API. (is_sorted
)
new API
Checks if the elements of this slice are sorted using the given comparator function.
Instead of using PartialOrd::partial_cmp
, this function uses the given compare
function to determine the ordering of two elements. Apart from that, it's equivalent to
is_sorted
; see its documentation for more information.
pub fn is_sorted_by_key<F, K>(&self, f: F) -> bool where
K: PartialOrd<K>,
F: FnMut(&T) -> K,
[src]
K: PartialOrd<K>,
F: FnMut(&T) -> K,
🔬 This is a nightly-only experimental API. (is_sorted
)
new API
Checks if the elements of this slice are sorted using the given key extraction function.
Instead of comparing the slice's elements directly, this function compares the keys of the
elements, as determined by f
. Apart from that, it's equivalent to is_sorted
; see its
documentation for more information.
Examples
#![feature(is_sorted)] assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len())); assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
pub fn partition_point<P>(&self, pred: P) -> usize where
P: FnMut(&T) -> bool,
[src]
P: FnMut(&T) -> bool,
🔬 This is a nightly-only experimental API. (partition_point
)
new API
Returns the index of the partition point according to the given predicate (the index of the first element of the second partition).
The slice is assumed to be partitioned according to the given predicate. This means that all elements for which the predicate returns true are at the start of the slice and all elements for which the predicate returns false are at the end. For example, [7, 15, 3, 5, 4, 12, 6] is a partitioned under the predicate x % 2 != 0 (all odd numbers are at the start, all even at the end).
If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.
Examples
#![feature(partition_point)] let v = [1, 2, 3, 3, 5, 6, 7]; let i = v.partition_point(|&x| x < 5); assert_eq!(i, 4); assert!(v[..i].iter().all(|&x| x < 5)); assert!(v[i..].iter().all(|&x| !(x < 5)));
pub fn is_ascii(&self) -> bool
1.23.0[src]
Checks if all bytes in this slice are within the ASCII range.
pub fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool
1.23.0[src]
Checks that two slices are an ASCII case-insensitive match.
Same as to_ascii_lowercase(a) == to_ascii_lowercase(b)
,
but without allocating and copying temporaries.
pub fn to_vec(&self) -> Vec<T, Global> where
T: Clone,
1.0.0[src]
T: Clone,
Copies self
into a new Vec
.
Examples
let s = [10, 40, 30]; let x = s.to_vec(); // Here, `s` and `x` can be modified independently.
pub fn to_vec_in<A>(&self, alloc: A) -> Vec<T, A> where
T: Clone,
A: Allocator,
[src]
T: Clone,
A: Allocator,
allocator_api
)Copies self
into a new Vec
with an allocator.
Examples
#![feature(allocator_api)] use std::alloc::System; let s = [10, 40, 30]; let x = s.to_vec_in(System); // Here, `s` and `x` can be modified independently.
pub fn repeat(&self, n: usize) -> Vec<T, Global> where
T: Copy,
1.40.0[src]
T: Copy,
Creates a vector by repeating a slice n
times.
Panics
This function will panic if the capacity would overflow.
Examples
Basic usage:
assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
A panic upon overflow:
// this will panic at runtime b"0123456789abcdef".repeat(usize::MAX);
pub fn concat<Item>(&self) -> <[T] as Concat<Item>>::Outputⓘ where
Item: ?Sized,
[T]: Concat<Item>,
1.0.0[src]
Item: ?Sized,
[T]: Concat<Item>,
Flattens a slice of T
into a single value Self::Output
.
Examples
assert_eq!(["hello", "world"].concat(), "helloworld"); assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);
pub fn join<Separator>(
&self,
sep: Separator
) -> <[T] as Join<Separator>>::Outputⓘ where
[T]: Join<Separator>,
1.3.0[src]
&self,
sep: Separator
) -> <[T] as Join<Separator>>::Outputⓘ where
[T]: Join<Separator>,
Flattens a slice of T
into a single value Self::Output
, placing a
given separator between each.
Examples
assert_eq!(["hello", "world"].join(" "), "hello world"); assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]); assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);
pub fn connect<Separator>(
&self,
sep: Separator
) -> <[T] as Join<Separator>>::Outputⓘ where
[T]: Join<Separator>,
1.0.0[src]
&self,
sep: Separator
) -> <[T] as Join<Separator>>::Outputⓘ where
[T]: Join<Separator>,
renamed to join
Flattens a slice of T
into a single value Self::Output
, placing a
given separator between each.
Examples
assert_eq!(["hello", "world"].connect(" "), "hello world"); assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);
pub fn to_ascii_uppercase(&self) -> Vec<u8, Global>
1.23.0[src]
Returns a vector containing a copy of this slice where each byte is mapped to its ASCII upper case equivalent.
ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', but non-ASCII letters are unchanged.
To uppercase the value in-place, use make_ascii_uppercase
.
pub fn to_ascii_lowercase(&self) -> Vec<u8, Global>
1.23.0[src]
Returns a vector containing a copy of this slice where each byte is mapped to its ASCII lower case equivalent.
ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', but non-ASCII letters are unchanged.
To lowercase the value in-place, use make_ascii_lowercase
.
Trait Implementations
impl<'out, T: Debug + 'out + ?Sized> Debug for Out<'out, T>
[src]
impl<'out, T: 'out> Default for Out<'out, [T]>
[src]
This can be useful to get a Out<'long ...>
out of a
&'short mut Out<'long ...>
by mem::replace
-ing with a Out::default()
(e.g., to implement an Iterator
).
impl<'out, T: 'out> Deref for Out<'out, [T]>
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Deref
into [MaybeUninit<T>]
to get access to the slice length related
getters.
type Target = [MaybeUninit<T>]
The resulting type after dereferencing.
fn deref(&self) -> &[MaybeUninit<T>]ⓘ
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impl<'out, T: 'out> From<&'out mut [ManuallyDrop<T>]> for Out<'out, [T]>
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fn from(slice: &'out mut [ManuallyDrop<T>]) -> Out<'out, [T]>
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impl<'out, T: 'out> From<&'out mut [MaybeUninit<T>]> for Out<'out, [T]>
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fn from(slice: &'out mut [MaybeUninit<T>]) -> Out<'out, [T]>
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impl<'out, T: 'out> From<&'out mut [T]> for Out<'out, [T]> where
T: Copy,
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T: Copy,
impl<'out, T: 'out> From<&'out mut ManuallyDrop<T>> for Out<'out, T>
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For non-Copy
types, explicitely transmuting the mut
reference into one
that points to a ManuallyDrop
is required, so as to express how likely it
is that memory be leaked. This can be safely achieved by using the
ManuallyDropMut
helper.
fn from(p: &'out mut ManuallyDrop<T>) -> Out<'out, T>
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impl<'out, T: 'out> From<&'out mut MaybeUninit<T>> for Out<'out, T>
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fn from(p: &'out mut MaybeUninit<T>) -> Out<'out, T>
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impl<'out, T: 'out> From<&'out mut T> for Out<'out, T> where
T: Copy,
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T: Copy,
impl<'out, T: 'out> IntoIterator for Out<'out, [T]>
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type Item = Out<'out, T>
The type of the elements being iterated over.
type IntoIter = IterOut<'out, T>
Which kind of iterator are we turning this into?
fn into_iter(self: Out<'out, [T]>) -> IterOut<'out, T>ⓘ
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impl<'out, 'inner: 'out, T: 'inner> IntoIterator for &'out mut Out<'inner, [T]>
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type Item = Out<'out, T>
The type of the elements being iterated over.
type IntoIter = IterOut<'out, T>
Which kind of iterator are we turning this into?
fn into_iter(self: &'out mut Out<'inner, [T]>) -> IterOut<'out, T>ⓘ
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impl<'out, T: ?Sized + 'out> Send for Out<'out, T> where
&'out mut T: Send,
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&'out mut T: Send,
impl<'out, T: ?Sized + 'out> Sync for Out<'out, T> where
&'out mut T: Sync,
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&'out mut T: Sync,
Auto Trait Implementations
impl<'out, T: ?Sized> RefUnwindSafe for Out<'out, T> where
T: RefUnwindSafe,
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T: RefUnwindSafe,
impl<'out, T: ?Sized> Unpin for Out<'out, T>
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impl<'out, T> !UnwindSafe for Out<'out, T>
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Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,