42 lines
1.3 KiB
Rust
42 lines
1.3 KiB
Rust
use std::mem::MaybeUninit;
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use std::ops::Range;
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use std::slice;
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pub trait VecExt<T> {
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fn split_at_spare_mut_ext(&mut self) -> (&mut [T], &mut [MaybeUninit<T>]);
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fn split_at_spare_mut_bytes_ext(&mut self) -> (&mut [T], &mut [MaybeUninit<u8>]);
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}
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impl<T> VecExt<T> for Vec<T> {
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fn split_at_spare_mut_ext(&mut self) -> (&mut [T], &mut [MaybeUninit<T>]) {
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let Range {
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start: ptr,
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end: spare_ptr,
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} = self.as_mut_ptr_range();
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let spare_ptr = spare_ptr.cast::<MaybeUninit<T>>();
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let spare_len = self.capacity() - self.len();
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unsafe {
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let initialized = slice::from_raw_parts_mut(ptr, self.len());
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let spare = slice::from_raw_parts_mut(spare_ptr, spare_len);
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(initialized, spare)
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}
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}
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fn split_at_spare_mut_bytes_ext(&mut self) -> (&mut [T], &mut [MaybeUninit<u8>]) {
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let (l, r) = self.split_at_spare_mut_ext();
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unsafe { (l, uapi::as_maybe_uninit_bytes_mut2(r)) }
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}
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}
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pub trait UninitVecExt<T> {
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fn set_len_safe(&mut self, n: usize);
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}
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impl<T> UninitVecExt<T> for Vec<MaybeUninit<T>> {
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fn set_len_safe(&mut self, n: usize) {
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assert!(n <= self.capacity());
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unsafe {
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self.set_len(n);
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}
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}
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}
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