alloc/vec/
spec_extend.rs

1use core::iter::TrustedLen;
2use core::slice::{self};
3
4use super::{IntoIter, Vec};
5use crate::alloc::Allocator;
6
7// Specialization trait used for Vec::extend
8pub(super) trait SpecExtend<T, I> {
9    fn spec_extend(&mut self, iter: I);
10}
11
12impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
13where
14    I: Iterator<Item = T>,
15{
16    default fn spec_extend(&mut self, iter: I) {
17        self.extend_desugared(iter)
18    }
19}
20
21impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
22where
23    I: TrustedLen<Item = T>,
24{
25    default fn spec_extend(&mut self, iterator: I) {
26        self.extend_trusted(iterator)
27    }
28}
29
30impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
31    fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
32        unsafe {
33            self.append_elements(iterator.as_slice() as _);
34        }
35        iterator.forget_remaining_elements();
36    }
37}
38
39impl<'a, T: 'a, I, A: Allocator> SpecExtend<&'a T, I> for Vec<T, A>
40where
41    I: Iterator<Item = &'a T>,
42    T: Clone,
43{
44    default fn spec_extend(&mut self, iterator: I) {
45        self.spec_extend(iterator.cloned())
46    }
47}
48
49impl<'a, T: 'a, A: Allocator> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
50where
51    T: Copy,
52{
53    fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
54        let slice = iterator.as_slice();
55        unsafe { self.append_elements(slice) };
56    }
57}
alloc/vec/spec_extend.rs

alloc/vec/
spec_extend.rs
