Struct ChampMap 

pub struct ChampMap<K, V> { /* private fields */ }

Persistent hash map based on a CHAMP trie, single-threaded.

Same set of key-value pairs always produces the same trie structure (canonical form), enabling O(1) structural equality via adhash.

Implementations

impl<K, V> ChampMap<K, V>

pub const fn new() -> Self

Creates an empty map.

pub const fn len(&self) -> usize

Returns the number of key-value pairs.

pub const fn is_empty(&self) -> bool

Returns true if the map contains no entries.

pub const fn adhash(&self) -> u64

Returns the current AdHash value.

Two maps with the same AdHash and the same length contain the same entries with overwhelming probability (2⁻⁶⁴ collision chance).

pub fn checkpoint(&self) -> ChampCheckpoint<K, V>

Saves the current map state for later rollback.

pub fn arena_len(&self) -> (usize, usize, usize)

Returns the total number of allocated items in each arena: (nodes, entries, children).

Includes dead COW copies — reflects true memory footprint.

pub fn rollback(&mut self, cp: ChampCheckpoint<K, V>)

Restores the map to a previously saved checkpoint.

All changes made after the checkpoint are discarded.

impl<K: Hash + Eq, V> ChampMap<K, V>

pub fn get(&self, key: &K) -> Option<&V>

Returns a reference to the value associated with key.

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

Returns true if the map contains the given key.

impl<K: Hash + Eq + Clone, V: Hash + Clone> ChampMap<K, V>

pub fn insert(&mut self, key: K, value: V) -> Option<V>

Inserts a key-value pair into the map.

Returns None if the key was new, or Some(old_value) if an existing value was replaced.

Panics

Panics if internal arena allocation returns an unexpected None.

pub fn remove(&mut self, key: &K) -> Option<V>

Removes a key from the map. Returns the removed value, or None if the key was not present.

impl<K, V> ChampMap<K, V>

pub fn iter(&self) -> Iter<'_, K, V>

Returns an iterator over (&K, &V) pairs.

Trait Implementations

impl<K, V> Debug for ChampMap<K, V>

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

Formats the value using the given formatter.

impl<K, V> Default for ChampMap<K, V>

fn default() -> Self

Returns the “default value” for a type.

impl<K: Hash + Eq + Clone, V: Hash + Clone> Extend<(K, V)> for ChampMap<K, V>

fn extend<I: IntoIterator<Item = (K, V)>>(&mut self, iter: I)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<K: Hash + Eq + Clone, V: Hash + Clone> FromIterator<(K, V)> for ChampMap<K, V>

fn from_iter<I: IntoIterator<Item = (K, V)>>(iter: I) -> Self

Creates a value from an iterator.

impl<K: Hash + Eq, V> Index<&K> for ChampMap<K, V>

type Output = V

The returned type after indexing.

fn index(&self, key: &K) -> &V

Performs the indexing (container[index]) operation.

impl<'a, K, V> IntoIterator for &'a ChampMap<K, V>

type Item = (&'a K, &'a V)

The type of the elements being iterated over.

type IntoIter = Iter<'a, K, V>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Iter<'a, K, V>

Creates an iterator from a value.