diff options
Diffstat (limited to '')
| -rw-r--r-- | library/core/src/slice/mod.rs | 53 |
1 files changed, 33 insertions, 20 deletions
diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs index e6ca6ef82..6a7150d29 100644 --- a/library/core/src/slice/mod.rs +++ b/library/core/src/slice/mod.rs @@ -656,10 +656,11 @@ impl<T> [T] { #[unstable(feature = "slice_swap_unchecked", issue = "88539")] #[rustc_const_unstable(feature = "const_swap", issue = "83163")] pub const unsafe fn swap_unchecked(&mut self, a: usize, b: usize) { - let ptr = self.as_mut_ptr(); + let this = self; + let ptr = this.as_mut_ptr(); // SAFETY: caller has to guarantee that `a < self.len()` and `b < self.len()` unsafe { - assert_unsafe_precondition!(a < self.len() && b < self.len()); + assert_unsafe_precondition!([T](a: usize, b: usize, this: &mut [T]) => a < this.len() && b < this.len()); ptr::swap(ptr.add(a), ptr.add(b)); } } @@ -674,8 +675,9 @@ impl<T> [T] { /// assert!(v == [3, 2, 1]); /// ``` #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_reverse", issue = "100784")] #[inline] - pub fn reverse(&mut self) { + pub const fn reverse(&mut self) { let half_len = self.len() / 2; let Range { start, end } = self.as_mut_ptr_range(); @@ -698,9 +700,9 @@ impl<T> [T] { revswap(front_half, back_half, half_len); #[inline] - fn revswap<T>(a: &mut [T], b: &mut [T], n: usize) { - debug_assert_eq!(a.len(), n); - debug_assert_eq!(b.len(), n); + const fn revswap<T>(a: &mut [T], b: &mut [T], n: usize) { + debug_assert!(a.len() == n); + debug_assert!(b.len() == n); // Because this function is first compiled in isolation, // this check tells LLVM that the indexing below is @@ -708,8 +710,10 @@ impl<T> [T] { // lengths of the slices are known -- it's removed. let (a, b) = (&mut a[..n], &mut b[..n]); - for i in 0..n { + let mut i = 0; + while i < n { mem::swap(&mut a[i], &mut b[n - 1 - i]); + i += 1; } } } @@ -969,9 +973,10 @@ impl<T> [T] { #[inline] #[must_use] pub unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]] { + let this = self; // SAFETY: Caller must guarantee that `N` is nonzero and exactly divides the slice length let new_len = unsafe { - assert_unsafe_precondition!(N != 0 && self.len() % N == 0); + assert_unsafe_precondition!([T](this: &[T], N: usize) => N != 0 && this.len() % N == 0); exact_div(self.len(), N) }; // SAFETY: We cast a slice of `new_len * N` elements into @@ -1108,10 +1113,11 @@ impl<T> [T] { #[inline] #[must_use] pub unsafe fn as_chunks_unchecked_mut<const N: usize>(&mut self) -> &mut [[T; N]] { + let this = &*self; // SAFETY: Caller must guarantee that `N` is nonzero and exactly divides the slice length let new_len = unsafe { - assert_unsafe_precondition!(N != 0 && self.len() % N == 0); - exact_div(self.len(), N) + assert_unsafe_precondition!([T](this: &[T], N: usize) => N != 0 && this.len() % N == 0); + exact_div(this.len(), N) }; // SAFETY: We cast a slice of `new_len * N` elements into // a slice of `new_len` many `N` elements chunks. @@ -1538,13 +1544,14 @@ impl<T> [T] { /// } /// ``` #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_slice_split_at_not_mut", issue = "101158")] #[inline] #[track_caller] #[must_use] - pub fn split_at(&self, mid: usize) -> (&[T], &[T]) { + pub const fn split_at(&self, mid: usize) -> (&[T], &[T]) { assert!(mid <= self.len()); // SAFETY: `[ptr; mid]` and `[mid; len]` are inside `self`, which - // fulfills the requirements of `from_raw_parts_mut`. + // fulfills the requirements of `split_at_unchecked`. unsafe { self.split_at_unchecked(mid) } } @@ -1623,11 +1630,19 @@ impl<T> [T] { /// } /// ``` #[unstable(feature = "slice_split_at_unchecked", reason = "new API", issue = "76014")] + #[rustc_const_unstable(feature = "slice_split_at_unchecked", issue = "76014")] #[inline] #[must_use] - pub unsafe fn split_at_unchecked(&self, mid: usize) -> (&[T], &[T]) { + pub const unsafe fn split_at_unchecked(&self, mid: usize) -> (&[T], &[T]) { + // HACK: the const function `from_raw_parts` is used to make this + // function const; previously the implementation used + // `(self.get_unchecked(..mid), self.get_unchecked(mid..))` + + let len = self.len(); + let ptr = self.as_ptr(); + // SAFETY: Caller has to check that `0 <= mid <= self.len()` - unsafe { (self.get_unchecked(..mid), self.get_unchecked(mid..)) } + unsafe { (from_raw_parts(ptr, mid), from_raw_parts(ptr.add(mid), len - mid)) } } /// Divides one mutable slice into two at an index, without doing bounds checking. @@ -1675,7 +1690,7 @@ impl<T> [T] { // `[ptr; mid]` and `[mid; len]` are not overlapping, so returning a mutable reference // is fine. unsafe { - assert_unsafe_precondition!(mid <= len); + assert_unsafe_precondition!((mid: usize, len: usize) => mid <= len); (from_raw_parts_mut(ptr, mid), from_raw_parts_mut(ptr.add(mid), len - mid)) } } @@ -2309,7 +2324,7 @@ impl<T> [T] { } /// Binary searches this slice for a given element. - /// This behaves similary to [`contains`] if this slice is sorted. + /// This behaves similarly to [`contains`] if this slice is sorted. /// /// If the value is found then [`Result::Ok`] is returned, containing the /// index of the matching element. If there are multiple matches, then any @@ -2921,7 +2936,7 @@ impl<T> [T] { let prev_ptr_write = ptr.add(next_write - 1); if !same_bucket(&mut *ptr_read, &mut *prev_ptr_write) { if next_read != next_write { - let ptr_write = prev_ptr_write.offset(1); + let ptr_write = prev_ptr_write.add(1); mem::swap(&mut *ptr_read, &mut *ptr_write); } next_write += 1; @@ -3518,7 +3533,7 @@ impl<T> [T] { // alignment targeted for U. // `crate::ptr::align_offset` is called with a correctly aligned and // valid pointer `ptr` (it comes from a reference to `self`) and with - // a size that is a power of two (since it comes from the alignement for U), + // a size that is a power of two (since it comes from the alignment for U), // satisfying its safety constraints. let offset = unsafe { crate::ptr::align_offset(ptr, mem::align_of::<U>()) }; if offset > self.len() { @@ -4101,7 +4116,6 @@ impl<T, const N: usize> [[T; N]] { } } -#[cfg(not(bootstrap))] #[cfg(not(test))] impl [f32] { /// Sorts the slice of floats. @@ -4131,7 +4145,6 @@ impl [f32] { } } -#[cfg(not(bootstrap))] #[cfg(not(test))] impl [f64] { /// Sorts the slice of floats. |