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Hoist IS_ZST check out of RawVecInner::from_*_in

This commit is contained in:
Ben Kimock 2024-07-29 22:50:22 -04:00 committed by Ben Kimock
parent d5b55436e9
commit 4e98bc6730
1 changed files with 15 additions and 6 deletions
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21
library/alloc/src/raw_vec.rs
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@ -40,6 +40,13 @@ struct Cap(usize);
impl Cap {
const ZERO: Cap = unsafe { Cap(0) };
/// `Cap(cap)`, except if `T` is a ZST then `Cap::ZERO`.
///
/// # Safety: cap must be <= `isize::MAX`.
unsafe fn new<T>(cap: usize) -> Self {
if T::IS_ZST { Cap::ZERO } else { unsafe { Self(cap) } }
}
}
/// A low-level utility for more ergonomically allocating, reallocating, and deallocating
@ -258,6 +265,8 @@ impl<T, A: Allocator> RawVec<T, A> {
pub unsafe fn from_raw_parts_in(ptr: *mut T, capacity: usize, alloc: A) -> Self {
// SAFETY: Precondition passed to the caller
unsafe {
let ptr = ptr.cast();
let capacity = Cap::new::<T>(capacity);
Self {
inner: RawVecInner::from_raw_parts_in(ptr, capacity, alloc),
_marker: PhantomData,
@ -274,6 +283,8 @@ impl<T, A: Allocator> RawVec<T, A> {
pub unsafe fn from_nonnull_in(ptr: NonNull<T>, capacity: usize, alloc: A) -> Self {
// SAFETY: Precondition passed to the caller
unsafe {
let ptr = ptr.cast();
let capacity = Cap::new::<T>(capacity);
Self { inner: RawVecInner::from_nonnull_in(ptr, capacity, alloc), _marker: PhantomData }
}
}
@ -474,15 +485,13 @@ impl<A: Allocator> RawVecInner<A> {
}
#[inline]
unsafe fn from_raw_parts_in<T>(ptr: *mut T, capacity: usize, alloc: A) -> Self {
let cap = if T::IS_ZST { Cap::ZERO } else { unsafe { Cap(capacity) } };
Self { ptr: unsafe { Unique::new_unchecked(ptr.cast()) }, cap, alloc }
unsafe fn from_raw_parts_in(ptr: *mut u8, cap: Cap, alloc: A) -> Self {
Self { ptr: unsafe { Unique::new_unchecked(ptr) }, cap, alloc }
}
#[inline]
unsafe fn from_nonnull_in<T>(ptr: NonNull<T>, capacity: usize, alloc: A) -> Self {
let cap = if T::IS_ZST { Cap::ZERO } else { unsafe { Cap(capacity) } };
Self { ptr: Unique::from(ptr.cast()), cap, alloc }
unsafe fn from_nonnull_in(ptr: NonNull<u8>, cap: Cap, alloc: A) -> Self {
Self { ptr: Unique::from(ptr), cap, alloc }
}
#[inline]