diff options
Diffstat (limited to 'rust/kernel/alloc')
| -rw-r--r-- | rust/kernel/alloc/kvec.rs | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs index ca30fad90de5..7671867165a0 100644 --- a/rust/kernel/alloc/kvec.rs +++ b/rust/kernel/alloc/kvec.rs @@ -201,6 +201,26 @@ where self.len = new_len; } + /// Decreases `self.len` by `count`. + /// + /// Returns a mutable slice to the elements forgotten by the vector. It is the caller's + /// responsibility to drop these elements if necessary. + /// + /// # Safety + /// + /// - `count` must be less than or equal to `self.len`. + #[expect(unused)] + unsafe fn dec_len(&mut self, count: usize) -> &mut [T] { + debug_assert!(count <= self.len()); + // INVARIANT: We relinquish ownership of the elements within the range `[self.len - count, + // self.len)`, hence the updated value of `set.len` represents the exact number of elements + // stored within `self`. + self.len -= count; + // SAFETY: The memory after `self.len()` is guaranteed to contain `count` initialized + // elements of type `T`. + unsafe { slice::from_raw_parts_mut(self.as_mut_ptr().add(self.len), count) } + } + /// Returns a slice of the entire vector. #[inline] pub fn as_slice(&self) -> &[T] { |