Struct RawEntryBuilderMut 

pub struct RawEntryBuilderMut<'a, K, V, S, A = Global>
where
    A: Allocator,
{ /* private fields */ }

A builder for computing where in a HashMap a key-value pair would be stored.

See the HashMap::raw_entry_mut docs for usage examples.

Examples

use core::hash::{BuildHasher, Hash};
use rune::alloc::hash_map::{RawEntryBuilderMut, RawEntryMut::Vacant, RawEntryMut::Occupied};
use rune::alloc::HashMap;
use rune::alloc::prelude::*;

let mut map = HashMap::new();
map.try_extend([(1, 11), (2, 12), (3, 13), (4, 14), (5, 15), (6, 16)])?;
assert_eq!(map.len(), 6);

fn compute_hash<K, S>(hash_builder: &S, key: &K) -> u64
where
    K: ?Sized + Hash,
    S: BuildHasher,
{
    use core::hash::Hasher;
    let mut state = hash_builder.build_hasher();
    key.hash(&mut state);
    state.finish()
}

let builder: RawEntryBuilderMut<_, _, _> = map.raw_entry_mut();

// Existing key
match builder.from_key(&6) {
    Vacant(_) => unreachable!(),
    Occupied(view) => assert_eq!(view.get(), &16),
}

for key in 0..12 {
    let hash = compute_hash(map.hasher(), &key);
    let value = map.get(&key).cloned();
    let key_value = value.as_ref().map(|v| (&key, v));

    println!("Key: {} and value: {:?}", key, value);

    match map.raw_entry_mut().from_key(&key) {
        Occupied(mut o) => assert_eq!(Some(o.get_key_value()), key_value),
        Vacant(_) => assert_eq!(value, None),
    }
    match map.raw_entry_mut().from_key_hashed_nocheck(hash, &key) {
        Occupied(mut o) => assert_eq!(Some(o.get_key_value()), key_value),
        Vacant(_) => assert_eq!(value, None),
    }
    match map.raw_entry_mut().from_hash(hash, |q| *q == key) {
        Occupied(mut o) => assert_eq!(Some(o.get_key_value()), key_value),
        Vacant(_) => assert_eq!(value, None),
    }
}

assert_eq!(map.len(), 6);