Struct ordermap::Pos

pub(crate) struct Pos {
    pub(crate) index: u64,
}

Pos is stored in the indices array and it points to the index of a Bucket in self.entries.

Pos can be interpreted either as a 64-bit index, or as a 32-bit index and a 32-bit hash.

Storing the truncated hash next to the index saves loading the hash from the entry, increasing the cache efficiency.

Note that the lower 32 bits of the hash is enough to compute desired position and probe distance in a hash map with less than 2**32 buckets.

The OrderMap will simply query its current raw capacity to see what its current size class is, and dispatch to the 32-bit or 64-bit lookup code as appropriate. Only the growth code needs some extra logic to handle the transition from one class to another

Fields

index: u64

Implementations

impl Pos

pub(crate) fn none() -> Self

pub(crate) fn is_none(&self) -> bool

pub(crate) fn pos(&self) -> Option<usize>

Return the index part of the Pos value inside Some(_) if the position is not none, otherwise return None.

pub(crate) fn set_pos<Sz>(&mut self, i: usize)

where Sz: Size,

Set the index part of the Pos value to i

pub(crate) fn with_hash<Sz>(i: usize, hash: HashValue) -> Self

where Sz: Size,

pub(crate) fn resolve<Sz>(&self) -> Option<(usize, ShortHashProxy<Sz>)>

where Sz: Size,

“Resolve” the Pos into a combination of its index value and a proxy value to the hash (whether it contains the hash or not depends on the size class of the hash map).

pub(crate) fn resolve_existing_index<Sz>(&self) -> usize

where Sz: Size,

Like resolve, but the Pos must be non-none. Return its index.

Trait Implementations

impl Clone for Pos

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Pos

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

Formats the value using the given formatter.

impl Copy for Pos