alloc/vec/
spec_extend.rs

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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    #[track_caller]
10    fn spec_extend(&mut self, iter: I);
11}
12
13impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
14where
15    I: Iterator<Item = T>,
16{
17    #[track_caller]
18    default fn spec_extend(&mut self, iter: I) {
19        self.extend_desugared(iter)
20    }
21}
22
23impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
24where
25    I: TrustedLen<Item = T>,
26{
27    #[track_caller]
28    default fn spec_extend(&mut self, iterator: I) {
29        self.extend_trusted(iterator)
30    }
31}
32
33impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
34    #[track_caller]
35    fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
36        unsafe {
37            self.append_elements(iterator.as_slice() as _);
38        }
39        iterator.forget_remaining_elements();
40    }
41}
42
43impl<'a, T: 'a, I, A: Allocator> SpecExtend<&'a T, I> for Vec<T, A>
44where
45    I: Iterator<Item = &'a T>,
46    T: Clone,
47{
48    #[track_caller]
49    default fn spec_extend(&mut self, iterator: I) {
50        self.spec_extend(iterator.cloned())
51    }
52}
53
54impl<'a, T: 'a, A: Allocator> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
55where
56    T: Copy,
57{
58    #[track_caller]
59    fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
60        let slice = iterator.as_slice();
61        unsafe { self.append_elements(slice) };
62    }
63}
alloc/vec/spec_extend.rs

alloc/vec/
spec_extend.rs
