Struct Alignment

pub struct Alignment(/* private fields */);

Type representing an alignment, which is always a power of two.

It is used to validate that a given value is a valid alignment, and to perform masking and alignment operations.

This is a temporary substitute for the Alignment nightly type from the standard library, and to be eventually replaced by it.

Invariants

An alignment is always a power of two.

Implementations

impl Alignment

pub const fn new<const ALIGN: usize>() -> Self

Validates that ALIGN is a power of two at build-time, and returns an Alignment of the same value.

A build error is triggered if ALIGN is not a power of two.

Examples

use kernel::ptr::Alignment;

let v = Alignment::new::<16>();
assert_eq!(v.as_usize(), 16);

pub const fn new_checked(align: usize) -> Option<Self>

Validates that align is a power of two at runtime, and returns an Alignment of the same value.

Returns None if align is not a power of two.

Examples

use kernel::ptr::Alignment;

assert_eq!(Alignment::new_checked(16), Some(Alignment::new::<16>()));
assert_eq!(Alignment::new_checked(15), None);
assert_eq!(Alignment::new_checked(1), Some(Alignment::new::<1>()));
assert_eq!(Alignment::new_checked(0), None);

pub const fn of<T>() -> Self

Returns the alignment of T.

This is equivalent to align_of, but with the return value provided as an Alignment.

pub const fn as_usize(self) -> usize

Returns this alignment as a usize.

It is guaranteed to be a power of two.

Examples

use kernel::ptr::Alignment;

assert_eq!(Alignment::new::<16>().as_usize(), 16);

pub const fn as_nonzero(self) -> NonZero<usize>

Returns this alignment as a NonZero.

It is guaranteed to be a power of two.

Examples

use kernel::ptr::Alignment;

assert_eq!(Alignment::new::<16>().as_nonzero().get(), 16);

pub const fn log2(self) -> u32

Returns the base-2 logarithm of the alignment.

Examples

use kernel::ptr::Alignment;

assert_eq!(Alignment::of::<u8>().log2(), 0);
assert_eq!(Alignment::new::<16>().log2(), 4);

pub const fn mask(self) -> usize

Returns the mask for this alignment.

This is equivalent to !(self.as_usize() - 1).

Examples

use kernel::ptr::Alignment;

assert_eq!(Alignment::new::<0x10>().mask(), !0xf);

Trait Implementations

impl Clone for Alignment

fn clone(&self) -> Alignment

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Alignment

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

Formats the value using the given formatter.

impl Hash for Alignment

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Alignment

fn cmp(&self, other: &Alignment) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Alignment

fn eq(&self, other: &Alignment) -> 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 PartialOrd for Alignment

fn partial_cmp(&self, other: &Alignment) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Alignment

impl Eq for Alignment

impl StructuralPartialEq for Alignment