alloc/vec/
spec_extend.rs

1use core::clone::TrivialClone;
2use core::iter::TrustedLen;
3use core::slice;
4
5use super::{IntoIter, Vec};
6use crate::alloc::Allocator;
7
8// Specialization trait used for Vec::extend
9pub(super) trait SpecExtend<T, I> {
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    default fn spec_extend(&mut self, iter: I) {
18        self.extend_desugared(iter)
19    }
20}
21
22impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
23where
24    I: TrustedLen<Item = T>,
25{
26    default fn spec_extend(&mut self, iterator: I) {
27        self.extend_trusted(iterator)
28    }
29}
30
31impl<T, A1: Allocator, A2: Allocator> SpecExtend<T, IntoIter<T, A2>> for Vec<T, A1> {
32    fn spec_extend(&mut self, iterator: IntoIter<T, A2>) {
33        // ignore-tidy-undocumented-unsafe
34        unsafe {
35            self.append_elements(iterator.as_slice() as _);
36        }
37        iterator.forget_remaining_elements_and_dealloc();
38    }
39}
40
41impl<'a, T: 'a, I, A: Allocator> SpecExtend<&'a T, I> for Vec<T, A>
42where
43    I: Iterator<Item = &'a T>,
44    T: Clone,
45{
46    default fn spec_extend(&mut self, iterator: I) {
47        self.spec_extend(iterator.cloned())
48    }
49}
50
51impl<'a, T: 'a, A: Allocator> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
52where
53    T: TrivialClone,
54{
55    fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
56        let slice = iterator.as_slice();
57        // ignore-tidy-undocumented-unsafe
58        unsafe { self.append_elements(slice) };
59    }
60}
alloc/vec/spec_extend.rs

alloc/vec/
spec_extend.rs
