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
use std::collections::HashMap;
use std::hash::{BuildHasher, Hash};
use std::pin::Pin;
use crate::prelude::*;
use crate::stream::{self, IntoStream};
impl<K, V, H> stream::Extend<(K, V)> for HashMap<K, V, H>
where
K: Eq + Hash + Send,
V: Send,
H: BuildHasher + Default + Send,
{
fn extend<'a, S: IntoStream<Item = (K, V)> + 'a>(
&'a mut self,
stream: S,
) -> Pin<Box<dyn Future<Output = ()> + 'a + Send>>
where
<S as IntoStream>::IntoStream: Send,
{
let stream = stream.into_stream();
let additional = if self.is_empty() {
stream.size_hint().0
} else {
(stream.size_hint().0 + 1) / 2
};
self.reserve(additional);
Box::pin(stream.for_each(move |(k, v)| {
self.insert(k, v);
}))
}
}