Struct vm_allocator::Constraint

pub struct Constraint { /* private fields */ }

A resource allocation constraint.

Example

use vm_allocator::{AllocPolicy, Constraint, Error, IdAllocator, DEFAULT_CONSTRAINT_ALIGN};

let constraint =
    Constraint::new(0x4, DEFAULT_CONSTRAINT_ALIGN, AllocPolicy::FirstMatch).unwrap();
assert_eq!(constraint.size(), 0x4);
assert_eq!(constraint.align(), 0x4);

// Alignments need to be a power of 2, otherwise an error is returned.
assert_eq!(
    Constraint::new(0x4, 0x3, AllocPolicy::LastMatch).unwrap_err(),
    Error::InvalidAlignment
);

// When using the ExactMatch policy, the start address must also be aligned, otherwise
// an error is returned.
assert_eq!(
    Constraint::new(0x4, 0x4, AllocPolicy::ExactMatch(0x3)).unwrap_err(),
    Error::UnalignedAddress
);

Implementations

impl Constraint

pub fn new(size: u64, align: u64, policy: AllocPolicy) -> Result<Self>

Creates a new constraint based on the passed configuration.

When the ExactMatch policy is used, the start address MUST be aligned to the alignment passed as a parameter.

Arguments:

• size: size to allocate.
• align: alignment to be used for the allocated resources. Valid alignments are a power of 2.
• policy: allocation policy.

pub fn align(self) -> u64

Returns the alignment constraint.

pub fn size(self) -> u64

Returns the size constraint.

Trait Implementations

impl Clone for Constraint

fn clone(&self) -> Constraint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Constraint

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

Formats the value using the given formatter.

impl PartialEq<Constraint> for Constraint

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Copy for Constraint

impl StructuralPartialEq for Constraint