Struct Map

pub struct Map<K: Eq + Hash>(/* private fields */);

A map interface allowing fast checks of whether a newly observed value is greater than any previously observed value for a given key.

The inner map is a HashMap<K, u64>. The signature of Map’s is_new is unique from the others in also requiring a key.

Examples

use incr::Map;
let mut last: Map<&'static str> = Default::default();
assert_eq!(last.is_new("a", 1), true);
assert_eq!(last.is_new("b", 1), true);
assert_eq!(last.is_new("a", 1), false);
assert_eq!(last.is_new("b", 3), true);
assert_eq!(last.is_new("c", 1), true);
assert_eq!(last.is_new("c", 1), false);
assert_eq!(last.get(&"b"), 3);
assert_eq!(last.get(&"not a key"), 0);

Implementations

impl<K> Map<K>

where K: Eq + Hash,

pub fn is_new(&mut self, k: K, val: u64) -> bool

Returns true if val is greater than the highest observed value at key. If key does not exist, inserts val at key and returns true.

pub fn get<Q>(&self, key: &Q) -> u64

where K: Borrow<Q>, Q: ?Sized + Hash + Eq,

Returns the highest observed value at key, or, if key does not exist, returns 0.

pub fn contains_key<Q>(&self, key: &Q) -> bool

where K: Borrow<Q>, Q: ?Sized + Hash + Eq,

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

Trait Implementations

impl<K: Clone + Eq + Hash> Clone for Map<K>

fn clone(&self) -> Map<K>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<K: Debug + Eq + Hash> Debug for Map<K>

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

Formats the value using the given formatter.

impl<K: Default + Eq + Hash> Default for Map<K>

fn default() -> Map<K>

Returns the “default value” for a type.

impl<K: PartialEq + Eq + Hash> PartialEq for Map<K>

fn eq(&self, other: &Map<K>) -> 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<K: Eq + Hash> StructuralPartialEq for Map<K>