1use super::Vec;
2use crate::borrow::Cow;
3
4#[stable(feature = "cow_from_vec", since = "1.8.0")]
5impl<'a, T: Clone> From<&'a [T]> for Cow<'a, [T]> {
6 /// Creates a [`Borrowed`] variant of [`Cow`]
7 /// from a slice.
8 ///
9 /// This conversion does not allocate or clone the data.
10 ///
11 /// [`Borrowed`]: crate::borrow::Cow::Borrowed
12 fn from(s: &'a [T]) -> Cow<'a, [T]> {
13 Cow::Borrowed(s)
14 }
15}
16
17#[stable(feature = "cow_from_array_ref", since = "1.77.0")]
18impl<'a, T: Clone, const N: usize> From<&'a [T; N]> for Cow<'a, [T]> {
19 /// Creates a [`Borrowed`] variant of [`Cow`]
20 /// from a reference to an array.
21 ///
22 /// This conversion does not allocate or clone the data.
23 ///
24 /// [`Borrowed`]: crate::borrow::Cow::Borrowed
25 fn from(s: &'a [T; N]) -> Cow<'a, [T]> {
26 Cow::Borrowed(s as &[_])
27 }
28}
29
30#[stable(feature = "cow_from_vec", since = "1.8.0")]
31impl<'a, T: Clone> From<Vec<T>> for Cow<'a, [T]> {
32 /// Creates an [`Owned`] variant of [`Cow`]
33 /// from an owned instance of [`Vec`].
34 ///
35 /// This conversion does not allocate or clone the data.
36 ///
37 /// [`Owned`]: crate::borrow::Cow::Owned
38 fn from(v: Vec<T>) -> Cow<'a, [T]> {
39 Cow::Owned(v)
40 }
41}
42
43#[stable(feature = "cow_from_vec_ref", since = "1.28.0")]
44impl<'a, T: Clone> From<&'a Vec<T>> for Cow<'a, [T]> {
45 /// Creates a [`Borrowed`] variant of [`Cow`]
46 /// from a reference to [`Vec`].
47 ///
48 /// This conversion does not allocate or clone the data.
49 ///
50 /// [`Borrowed`]: crate::borrow::Cow::Borrowed
51 fn from(v: &'a Vec<T>) -> Cow<'a, [T]> {
52 Cow::Borrowed(v.as_slice())
53 }
54}
55
56#[stable(feature = "rust1", since = "1.0.0")]
57impl<'a, T> FromIterator<T> for Cow<'a, [T]>
58where
59 T: Clone,
60{
61 #[track_caller]
62 fn from_iter<I: IntoIterator<Item = T>>(it: I) -> Cow<'a, [T]> {
63 Cow::Owned(FromIterator::from_iter(it))
64 }
65}
66