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Stabilize some of alloc_layout_extras

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CAD97
2020-02-21 15:38:29 -05:00
parent 42abbd8878
commit 1b76bb03fe
1 changed files with 11 additions and 14 deletions
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25
src/libcore/alloc/layout.rs
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@@ -162,7 +162,7 @@ impl Layout {
/// Returns an error if the combination of `self.size()` and the given
/// `align` violates the conditions listed in
/// [`Layout::from_size_align`](#method.from_size_align).
#[unstable(feature = "alloc_layout_extra", issue = "55724")]
#[stable(feature = "alloc_layout_manipulation", since = "1.44.0")]
#[inline]
pub fn align_to(&self, align: usize) -> Result<Self, LayoutErr> {
Layout::from_size_align(self.size(), cmp::max(self.align(), align))
@@ -218,7 +218,7 @@ impl Layout {
///
/// This is equivalent to adding the result of `padding_needed_for`
/// to the layout's current size.
#[unstable(feature = "alloc_layout_extra", issue = "55724")]
#[stable(feature = "alloc_layout_manipulation", since = "1.44.0")]
#[inline]
pub fn pad_to_align(&self) -> Layout {
let pad = self.padding_needed_for(self.align());
@@ -258,19 +258,17 @@ impl Layout {
/// Creates a layout describing the record for `self` followed by
/// `next`, including any necessary padding to ensure that `next`
/// will be properly aligned. Note that the resulting layout will
/// satisfy the alignment properties of both `self` and `next`.
/// will be properly aligned, but no trailing padding. Note that
/// the resulting layout will satisfy the alignment properties of
/// both `self` and `next`, in order to ensure field alignment.
///
/// The resulting layout will be the same as that of a C struct containing
/// two fields with the layouts of `self` and `next`, in that order.
///
/// Returns `Some((k, offset))`, where `k` is layout of the concatenated
/// Returns `Ok((k, offset))`, where `k` is layout of the concatenated
/// record and `offset` is the relative location, in bytes, of the
/// start of the `next` embedded within the concatenated record
/// (assuming that the record itself starts at offset 0).
///
/// On arithmetic overflow, returns `LayoutErr`.
#[unstable(feature = "alloc_layout_extra", issue = "55724")]
#[stable(feature = "alloc_layout_manipulation", since = "1.44.0")]
#[inline]
pub fn extend(&self, next: Self) -> Result<(Self, usize), LayoutErr> {
let new_align = cmp::max(self.align(), next.align());
@@ -318,13 +316,12 @@ impl Layout {
/// Creates a layout describing the record for a `[T; n]`.
///
/// On arithmetic overflow, returns `LayoutErr`.
#[unstable(feature = "alloc_layout_extra", issue = "55724")]
#[stable(feature = "alloc_layout_manipulation", since = "1.44.0")]
#[inline]
pub fn array<T>(n: usize) -> Result<Self, LayoutErr> {
Layout::new::<T>().repeat(n).map(|(k, offs)| {
debug_assert!(offs == mem::size_of::<T>());
k
})
let (layout, offset) = Layout::new::<T>().repeat(n)?;
debug_assert_eq!(offset, mem::size_of::<T>());
Ok(layout.pad_to_align())
}
}