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@mina86
mina86 committed Jan 21, 2024
1 parent 755cfbf commit 50cbbef
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Showing 2 changed files with 20 additions and 178 deletions.
194 changes: 18 additions & 176 deletions library/core/src/slice/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2034,37 +2034,38 @@ impl<T> [T] {
unsafe { (from_raw_parts_mut(ptr, mid), from_raw_parts_mut(ptr.add(mid), len - mid)) }
}

/// Divides one slice into two at an index returning, `None` if slice is too
/// short.
/// Divides one slice into two at an index, returning `None` if the slice is
/// too short.
///
/// 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).
/// If `mid ≤ len` returns a pair of slices where 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).
///
/// Returns `None` if `mid > len`.
/// Otherwise, if `mid > len`, returns `None`.
///
/// # Examples
///
/// ```
/// #![feature(split_at_checked)]
///
/// let v = [1, 2, 3, 4, 5, 6];
/// let v = [1, -2, 3, -4, 5, -6];
///
/// {
/// let (left, right) = v.split_at_checked(0).unwrap();
/// assert_eq!(left, []);
/// assert_eq!(right, [1, 2, 3, 4, 5, 6]);
/// assert_eq!(right, [1, -2, 3, -4, 5, -6]);
/// }
///
/// {
/// let (left, right) = v.split_at_checked(2).unwrap();
/// assert_eq!(left, [1, 2]);
/// assert_eq!(right, [3, 4, 5, 6]);
/// assert_eq!(left, [1, -2]);
/// assert_eq!(right, [3, -4, 5, -6]);
/// }
///
/// {
/// let (left, right) = v.split_at_checked(6).unwrap();
/// assert_eq!(left, [1, 2, 3, 4, 5, 6]);
/// assert_eq!(left, [1, -2, 3, -4, 5, -6]);
/// assert_eq!(right, []);
/// }
///
Expand All @@ -2073,7 +2074,6 @@ impl<T> [T] {
#[unstable(feature = "split_at_checked", reason = "new API", issue = "119128")]
#[rustc_const_unstable(feature = "split_at_checked", issue = "119128")]
#[inline]
#[track_caller]
#[must_use]
pub const fn split_at_checked(&self, mid: usize) -> Option<(&[T], &[T])> {
if mid <= self.len() {
Expand All @@ -2085,14 +2085,15 @@ impl<T> [T] {
}
}

/// Divides one mutable slice into two at an index, returning `None` if
/// Divides one mutable slice into two at an index, returning `None` if the
/// slice is too short.
///
/// 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).
/// If `mid ≤ len` returns a pair of slices where 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).
///
/// Returns `None` if `mid > len`.
/// Otherwise, if `mid > len`, returns `None`.
///
/// # Examples
///
Expand All @@ -2114,7 +2115,6 @@ impl<T> [T] {
#[unstable(feature = "split_at_checked", reason = "new API", issue = "119128")]
#[rustc_const_unstable(feature = "split_at_checked", issue = "119128")]
#[inline]
#[track_caller]
#[must_use]
pub const fn split_at_mut_checked(&mut self, mid: usize) -> Option<(&mut [T], &mut [T])> {
if mid <= self.len() {
Expand All @@ -2126,164 +2126,6 @@ impl<T> [T] {
}
}

/// Divides one slice into an array and a remainder slice at an index.
///
/// The array will contain all indices from `[0, N)` (excluding
/// the index `N` itself) and the slice will contain all
/// indices from `[N, len)` (excluding the index `len` itself).
///
/// # Panics
///
/// Panics if `N > len`.
///
/// # Examples
///
/// ```
/// #![feature(split_array)]
///
/// let v = &[1, 2, 3, 4, 5, 6][..];
///
/// {
/// let (left, right) = v.split_array_ref::<0>();
/// assert_eq!(left, &[]);
/// assert_eq!(right, [1, 2, 3, 4, 5, 6]);
/// }
///
/// {
/// let (left, right) = v.split_array_ref::<2>();
/// assert_eq!(left, &[1, 2]);
/// assert_eq!(right, [3, 4, 5, 6]);
/// }
///
/// {
/// let (left, right) = v.split_array_ref::<6>();
/// assert_eq!(left, &[1, 2, 3, 4, 5, 6]);
/// assert_eq!(right, []);
/// }
/// ```
#[unstable(feature = "split_array", reason = "new API", issue = "90091")]
#[inline]
#[track_caller]
#[must_use]
pub fn split_array_ref<const N: usize>(&self) -> (&[T; N], &[T]) {
let (a, b) = self.split_at(N);
// SAFETY: a points to [T; N]? Yes it's [T] of length N (checked by split_at)
unsafe { (&*(a.as_ptr() as *const [T; N]), b) }
}

/// Divides one mutable slice into an array and a remainder slice at an index.
///
/// The array will contain all indices from `[0, N)` (excluding
/// the index `N` itself) and the slice will contain all
/// indices from `[N, len)` (excluding the index `len` itself).
///
/// # Panics
///
/// Panics if `N > len`.
///
/// # Examples
///
/// ```
/// #![feature(split_array)]
///
/// let mut v = &mut [1, 0, 3, 0, 5, 6][..];
/// let (left, right) = v.split_array_mut::<2>();
/// assert_eq!(left, &mut [1, 0]);
/// assert_eq!(right, [3, 0, 5, 6]);
/// left[1] = 2;
/// right[1] = 4;
/// assert_eq!(v, [1, 2, 3, 4, 5, 6]);
/// ```
#[unstable(feature = "split_array", reason = "new API", issue = "90091")]
#[inline]
#[track_caller]
#[must_use]
pub fn split_array_mut<const N: usize>(&mut self) -> (&mut [T; N], &mut [T]) {
let (a, b) = self.split_at_mut(N);
// SAFETY: a points to [T; N]? Yes it's [T] of length N (checked by split_at_mut)
unsafe { (&mut *(a.as_mut_ptr() as *mut [T; N]), b) }
}

/// Divides one slice into an array and a remainder slice at an index from
/// the end.
///
/// The slice will contain all indices from `[0, len - N)` (excluding
/// the index `len - N` itself) and the array will contain all
/// indices from `[len - N, len)` (excluding the index `len` itself).
///
/// # Panics
///
/// Panics if `N > len`.
///
/// # Examples
///
/// ```
/// #![feature(split_array)]
///
/// let v = &[1, 2, 3, 4, 5, 6][..];
///
/// {
/// let (left, right) = v.rsplit_array_ref::<0>();
/// assert_eq!(left, [1, 2, 3, 4, 5, 6]);
/// assert_eq!(right, &[]);
/// }
///
/// {
/// let (left, right) = v.rsplit_array_ref::<2>();
/// assert_eq!(left, [1, 2, 3, 4]);
/// assert_eq!(right, &[5, 6]);
/// }
///
/// {
/// let (left, right) = v.rsplit_array_ref::<6>();
/// assert_eq!(left, []);
/// assert_eq!(right, &[1, 2, 3, 4, 5, 6]);
/// }
/// ```
#[unstable(feature = "split_array", reason = "new API", issue = "90091")]
#[inline]
#[must_use]
pub fn rsplit_array_ref<const N: usize>(&self) -> (&[T], &[T; N]) {
assert!(N <= self.len());
let (a, b) = self.split_at(self.len() - N);
// SAFETY: b points to [T; N]? Yes it's [T] of length N (checked by split_at)
unsafe { (a, &*(b.as_ptr() as *const [T; N])) }
}

/// Divides one mutable slice into an array and a remainder slice at an
/// index from the end.
///
/// The slice will contain all indices from `[0, len - N)` (excluding
/// the index `N` itself) and the array will contain all
/// indices from `[len - N, len)` (excluding the index `len` itself).
///
/// # Panics
///
/// Panics if `N > len`.
///
/// # Examples
///
/// ```
/// #![feature(split_array)]
///
/// let mut v = &mut [1, 0, 3, 0, 5, 6][..];
/// let (left, right) = v.rsplit_array_mut::<4>();
/// assert_eq!(left, [1, 0]);
/// assert_eq!(right, &mut [3, 0, 5, 6]);
/// left[1] = 2;
/// right[1] = 4;
/// assert_eq!(v, [1, 2, 3, 4, 5, 6]);
/// ```
#[unstable(feature = "split_array", reason = "new API", issue = "90091")]
#[inline]
#[must_use]
pub fn rsplit_array_mut<const N: usize>(&mut self) -> (&mut [T], &mut [T; N]) {
assert!(N <= self.len());
let (a, b) = self.split_at_mut(self.len() - N);
// SAFETY: b points to [T; N]? Yes it's [T] of length N (checked by split_at_mut)
unsafe { (a, &mut *(b.as_mut_ptr() as *mut [T; N])) }
}

/// Returns an iterator over subslices separated by elements that match
/// `pred`. The matched element is not contained in the subslices.
///
Expand Down
4 changes: 2 additions & 2 deletions library/core/src/str/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -642,7 +642,7 @@ impl str {
/// # Panics
///
/// Panics if `mid` is not on a UTF-8 code point boundary, or if it is past
/// the end of the last code point of the string slice. For non-panicking
/// the end of the last code point of the string slice. For a non-panicking
/// alternative see [`split_at_checked`](str::split_at_checked).
///
/// # Examples
Expand Down Expand Up @@ -680,7 +680,7 @@ impl str {
/// # Panics
///
/// Panics if `mid` is not on a UTF-8 code point boundary, or if it is past
/// the end of the last code point of the string slice. For non-panicking
/// the end of the last code point of the string slice. For a non-panicking
/// alternative see [`split_at_mut_checked`](str::split_at_mut_checked).
///
/// # Examples
Expand Down

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