1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
//! Implement Fallible HashMap
use super::TryClone;
use crate::TryReserveError;
use core::borrow::Borrow;
use core::default::Default;
use core::hash::Hash;
type HashMap<K, V> = hashbrown::hash_map::HashMap<K, V>;
#[derive(Default)]
pub struct TryHashMap<K, V> {
inner: HashMap<K, V>,
}
impl<K, V> TryHashMap<K, V>
where
K: Eq + Hash,
{
pub fn with_capacity(capacity: usize) -> Result<Self, TryReserveError> {
let mut map = Self {
inner: HashMap::new(),
};
map.reserve(capacity)?;
Ok(map)
}
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
self.inner.get(k)
}
pub fn insert(&mut self, k: K, v: V) -> Result<Option<V>, TryReserveError> {
self.reserve(if self.inner.capacity() == 0 { 4 } else { 1 })?;
Ok(self.inner.insert(k, v))
}
pub fn iter(&self) -> hashbrown::hash_map::Iter<'_, K, V> {
self.inner.iter()
}
pub fn len(&self) -> usize {
self.inner.len()
}
pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
self.inner.remove(k)
}
fn reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
self.inner.try_reserve(additional)
}
}
impl<K, V> IntoIterator for TryHashMap<K, V> {
type Item = (K, V);
type IntoIter = hashbrown::hash_map::IntoIter<K, V>;
fn into_iter(self) -> Self::IntoIter {
self.inner.into_iter()
}
}
impl<K, V> TryClone for TryHashMap<K, V>
where
K: Eq + Hash + TryClone,
V: TryClone,
{
fn try_clone(&self) -> Result<Self, TryReserveError> {
let mut clone = Self::with_capacity(self.inner.len())?;
for (key, value) in self.inner.iter() {
clone.insert(key.try_clone()?, value.try_clone()?)?;
}
Ok(clone)
}
}
#[test]
fn tryhashmap_oom() {
match TryHashMap::<char, char>::default().reserve(core::usize::MAX) {
Ok(_) => panic!("it should be OOM"),
_ => (),
}
}
|
