Enum compact_map::OccupiedEntry

pub enum OccupiedEntry<'a, K: 'a, V: 'a, const N: usize> {
    Heapless(HeaplessEntry<'a, K, V, N>),
    Spilled(OccupiedEntry<'a, K, V>),
}

A view into an occupied entry in a CompactMap. It is part of the Entry enum.

Variants

Heapless(HeaplessEntry<'a, K, V, N>)

An entry in the heapless state.

Spilled(OccupiedEntry<'a, K, V>)

An entry in the spilled state.

Implementations

impl<'a, K, V, const N: usize> OccupiedEntry<'a, K, V, N>

pub fn key(&self) -> &K

Gets a reference to the key in the entry.

Examples

use compact_map::CompactMap;

let mut map: CompactMap<&str, u32, 16> = CompactMap::new();
map.entry("poneyland").or_insert(12);
assert_eq!(map.entry("poneyland").key(), &"poneyland");

pub fn remove_entry(self) -> (K, V)

Take the ownership of the key and value from the map.

Examples

use compact_map::{CompactMap, Entry};

let mut map: CompactMap<&str, u32, 16> = CompactMap::new();
map.entry("poneyland").or_insert(12);

if let Entry::Occupied(o) = map.entry("poneyland") {
    // We delete the entry from the map.
    o.remove_entry();
}

assert_eq!(map.contains_key("poneyland"), false);

pub fn get(&self) -> &V

Gets a reference to the value in the entry.

Examples

use compact_map::{CompactMap, Entry};

let mut map: CompactMap<&str, u32, 16> = CompactMap::new();
map.entry("poneyland").or_insert(12);

if let Entry::Occupied(o) = map.entry("poneyland") {
    assert_eq!(o.get(), &12);
}

pub fn get_mut(&mut self) -> &mut V

Gets a mutable reference to the value in the entry.

If you need a reference to the OccupiedEntry which may outlive the destruction of the Entry value, see into_mut.

Examples

use compact_map::{CompactMap, Entry};

let mut map: CompactMap<&str, u32, 16> = CompactMap::new();
map.entry("poneyland").or_insert(12);

assert_eq!(map["poneyland"], 12);
if let Entry::Occupied(mut o) = map.entry("poneyland") {
    *o.get_mut() += 10;
    assert_eq!(*o.get(), 22);

    // We can use the same Entry multiple times.
    *o.get_mut() += 2;
}

assert_eq!(map["poneyland"], 24);

pub fn into_mut(self) -> &'a mut V

Converts the OccupiedEntry into a mutable reference to the value in the entry with a lifetime bound to the map itself.

If you need multiple references to the OccupiedEntry, see get_mut.

Examples

use compact_map::{CompactMap, Entry};

let mut map: CompactMap<&str, u32, 16> = CompactMap::new();
map.entry("poneyland").or_insert(12);

assert_eq!(map["poneyland"], 12);
if let Entry::Occupied(o) = map.entry("poneyland") {
    *o.into_mut() += 10;
}

assert_eq!(map["poneyland"], 22);

pub fn insert(&mut self, value: V) -> V

Sets the value of the entry, and returns the entry’s old value.

Examples

use compact_map::{CompactMap, Entry};

let mut map: CompactMap<&str, u32, 16> = CompactMap::new();
map.entry("poneyland").or_insert(12);

if let Entry::Occupied(mut o) = map.entry("poneyland") {
    assert_eq!(o.insert(15), 12);
}

assert_eq!(map["poneyland"], 15);

pub fn remove(self) -> V

Takes the value out of the entry, and returns it.

Examples

use compact_map::{CompactMap, Entry};

let mut map: CompactMap<&str, u32, 16> = CompactMap::new();
map.entry("poneyland").or_insert(12);

if let Entry::Occupied(o) = map.entry("poneyland") {
    assert_eq!(o.remove(), 12);
}

assert_eq!(map.contains_key("poneyland"), false);

impl<'a, K: Clone, V, const N: usize> OccupiedEntry<'a, K, V, N>

pub fn replace_entry(self, value: V) -> (K, V)

Available on crate feature map_entry_replace only.

Replaces the entry, returning the old key and value. The new key in the hash map will be the key used to create this entry.

Examples

use compact_map::{CompactMap, Entry};
use std::rc::Rc;

let mut map: CompactMap<Rc<String>, u32, 16> = CompactMap::new();
map.insert(Rc::new("Stringthing".to_string()), 15);

let my_key = Rc::new("Stringthing".to_string());

if let Entry::Occupied(entry) = map.entry(my_key) {
    // Also replace the key with a handle to our other key.
    let (old_key, old_value): (Rc<String>, u32) = entry.replace_entry(16);
}

pub fn replace_key(self) -> K

Available on crate feature map_entry_replace only.

Replaces the key in the hash map with the key used to create this entry.

Examples

use compact_map::{CompactMap, Entry};
use std::rc::Rc;

let mut map: CompactMap<Rc<String>, u32, 16> = CompactMap::new();
let known_strings: Vec<Rc<String>> = Vec::new();

// Initialise known strings, run program, etc.

reclaim_memory(&mut map, &known_strings);

fn reclaim_memory(map: &mut CompactMap<Rc<String>, u32, 16>, known_strings: &[Rc<String>] ) {
    for s in known_strings {
        if let Entry::Occupied(entry) = map.entry(Rc::clone(s)) {
            // Replaces the entry's key with our version of it in `known_strings`.
            entry.replace_key();
        }
    }
}

Trait Implementations

impl<K: Debug, V: Debug, const N: usize> Debug for OccupiedEntry<'_, K, V, N>

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

Formats the value using the given formatter.