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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /library/alloc/src/vec/spec_from_elem.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | library/alloc/src/vec/spec_from_elem.rs | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/library/alloc/src/vec/spec_from_elem.rs b/library/alloc/src/vec/spec_from_elem.rs new file mode 100644 index 000000000..ff364c033 --- /dev/null +++ b/library/alloc/src/vec/spec_from_elem.rs @@ -0,0 +1,61 @@ +use core::ptr; + +use crate::alloc::Allocator; +use crate::raw_vec::RawVec; + +use super::{ExtendElement, IsZero, Vec}; + +// Specialization trait used for Vec::from_elem +pub(super) trait SpecFromElem: Sized { + fn from_elem<A: Allocator>(elem: Self, n: usize, alloc: A) -> Vec<Self, A>; +} + +impl<T: Clone> SpecFromElem for T { + default fn from_elem<A: Allocator>(elem: Self, n: usize, alloc: A) -> Vec<Self, A> { + let mut v = Vec::with_capacity_in(n, alloc); + v.extend_with(n, ExtendElement(elem)); + v + } +} + +impl<T: Clone + IsZero> SpecFromElem for T { + #[inline] + default fn from_elem<A: Allocator>(elem: T, n: usize, alloc: A) -> Vec<T, A> { + if elem.is_zero() { + return Vec { buf: RawVec::with_capacity_zeroed_in(n, alloc), len: n }; + } + let mut v = Vec::with_capacity_in(n, alloc); + v.extend_with(n, ExtendElement(elem)); + v + } +} + +impl SpecFromElem for i8 { + #[inline] + fn from_elem<A: Allocator>(elem: i8, n: usize, alloc: A) -> Vec<i8, A> { + if elem == 0 { + return Vec { buf: RawVec::with_capacity_zeroed_in(n, alloc), len: n }; + } + unsafe { + let mut v = Vec::with_capacity_in(n, alloc); + ptr::write_bytes(v.as_mut_ptr(), elem as u8, n); + v.set_len(n); + v + } + } +} + +impl SpecFromElem for u8 { + #[inline] + fn from_elem<A: Allocator>(elem: u8, n: usize, alloc: A) -> Vec<u8, A> { + if elem == 0 { + return Vec { buf: RawVec::with_capacity_zeroed_in(n, alloc), len: n }; + } + unsafe { + let mut v = Vec::with_capacity_in(n, alloc); + ptr::write_bytes(v.as_mut_ptr(), elem, n); + v.set_len(n); + v + } + } +} |