Struct Map

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

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§

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impl<K> Map<K>
where K: Eq + Hash,

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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.

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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.

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pub fn contains_key<Q>(&self, key: &Q) -> bool
where K: Borrow<Q>, Q: ?Sized + Hash + Eq,

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pub fn len(&self) -> usize

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pub fn is_empty(&self) -> bool

Trait Implementations§

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

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

Returns a duplicate of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<K: Debug + Eq + Hash> Debug for Map<K>

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

Formats the value using the given formatter. Read more
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impl<K: Default + Eq + Hash> Default for Map<K>

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fn default() -> Map<K>

Returns the “default value” for a type. Read more
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impl<K: PartialEq + Eq + Hash> PartialEq for Map<K>

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fn eq(&self, other: &Map<K>) -> bool

Tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<K: Eq + Hash> StructuralPartialEq for Map<K>

Auto Trait Implementations§

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impl<K> Freeze for Map<K>

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impl<K> RefUnwindSafe for Map<K>
where K: RefUnwindSafe,

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impl<K> Send for Map<K>
where K: Send,

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impl<K> Sync for Map<K>
where K: Sync,

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impl<K> Unpin for Map<K>
where K: Unpin,

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impl<K> UnwindSafe for Map<K>
where K: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.