| 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 |
| } |
| } |
| } |