Struct NonZeroLayout 

pub struct NonZeroLayout { /* private fields */ }

A Layout with size > 0 and a power-of-two alignment.

All primitives in this crate take NonZeroLayout rather than Layout. ZST handling happens once, at the StdCompat boundary, instead of being reinvented in every implementor.

Implementations

impl NonZeroLayout

pub const fn new( size: NonZero<usize>, align: NonZero<usize>, ) -> Result<NonZeroLayout, LayoutError>

Construct from a non-zero size and non-zero alignment.

Returns LayoutError if align is not a power of two or if rounding size up to align would overflow isize::MAX.

pub const fn from_size_align( size: usize, align: usize, ) -> Result<NonZeroLayout, LayoutError>

Construct from raw usize size and alignment. Convenience wrapper.

pub const fn for_type<T>() -> Option<NonZeroLayout>

Layout for storing one T. Returns None if T is a ZST.

pub const fn array<T>(n: usize) -> Option<NonZeroLayout>

Layout for an array of n Ts. Returns None if T is a ZST, n is zero, or the resulting size overflows.

Mirrors core::alloc::Layout::array::<T>(n)’s padding rules: each element is padded out to align_of::<T>() (which size_of::<T>() already encodes via the trailing-pad rule, so for sized types the product is identical). The explicit pad_to_align step keeps the math correct if a future repr ever lets size_of skip the trailing pad — #[repr(C, packed)] types stay correct because their align is 1 and pad_to_align is a no-op.

pub const fn size(&self) -> NonZero<usize>

Size in bytes. Guaranteed nonzero.

pub const fn align(&self) -> NonZero<usize>

Alignment in bytes. Guaranteed nonzero and a power of two.

pub const fn pad_to_align(&self) -> NonZeroLayout

Round size up so the layout’s total footprint is a multiple of align. Useful for packing arrays of this layout end-to-end.

pub const fn to_layout(&self) -> Layout

Convert to a standard core::alloc::Layout. Always succeeds.

Trait Implementations

impl Clone for NonZeroLayout

fn clone(&self) -> NonZeroLayout

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for NonZeroLayout

impl Debug for NonZeroLayout

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Eq for NonZeroLayout

impl PartialEq for NonZeroLayout

fn eq(&self, other: &NonZeroLayout) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for NonZeroLayout

impl TryFrom<Layout> for NonZeroLayout

type Error = LayoutError

The type returned in the event of a conversion error.

fn try_from( value: Layout, ) -> Result<NonZeroLayout, <NonZeroLayout as TryFrom<Layout>>::Error>

Performs the conversion.