Struct PackedFingerprint 

#[repr(packed(1))]
pub struct PackedFingerprint(Fingerprint);

PackedFingerprint wraps a Fingerprint. Its purpose is to behave like a Fingerprint without alignment requirements.

This may be preferable to use in large collections of structs containing fingerprints, as it can reduce memory consumption by preventing the padding that the more strictly-aligned Fingerprint can introduce. An application of this is in the query dependency graph, which contains a large collection of DepNodes. As of this writing, the size of a DepNode decreases by 25% (from 24 bytes to 18) by using the packed representation here, which noticeably decreases total memory usage when compiling large crates.

(Unalignment was previously restricted to x86 and x86_64 hosts, but is now enabled by default for all host architectures, in the hope that the memory and cache savings should outweigh any unaligned access penalty.)

The wrapped Fingerprint is private to reduce the chance of a client invoking undefined behavior by taking a reference to the packed field.

Tuple Fields

0: Fingerprint

Trait Implementations

impl Clone for PackedFingerprint

fn clone(&self) -> PackedFingerprint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PackedFingerprint

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

Formats the value using the given formatter.

impl<D: Decoder> Decodable<D> for PackedFingerprint

fn decode(d: &mut D) -> Self

impl Display for PackedFingerprint

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

Formats the value using the given formatter.

impl<E: Encoder> Encodable<E> for PackedFingerprint

fn encode(&self, s: &mut E)

impl From<Fingerprint> for PackedFingerprint

fn from(f: Fingerprint) -> PackedFingerprint

Converts to this type from the input type.

impl From<PackedFingerprint> for Fingerprint

fn from(f: PackedFingerprint) -> Fingerprint

Converts to this type from the input type.

impl Hash for PackedFingerprint

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 PackedFingerprint

fn cmp(&self, other: &PackedFingerprint) -> 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 PackedFingerprint

fn eq(&self, other: &PackedFingerprint) -> 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 PackedFingerprint

fn partial_cmp(&self, other: &PackedFingerprint) -> 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 PackedFingerprint

impl Eq for PackedFingerprint

impl StructuralPartialEq for PackedFingerprint

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes