868 lines
30 KiB
Rust
868 lines
30 KiB
Rust
// SPDX-License-Identifier: Apache-2.0 OR MIT
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//! Utilities for the slice primitive type.
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//!
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//! *[See also the slice primitive type](slice).*
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//!
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//! Most of the structs in this module are iterator types which can only be created
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//! using a certain function. For example, `slice.iter()` yields an [`Iter`].
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//!
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//! A few functions are provided to create a slice from a value reference
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//! or from a raw pointer.
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#![stable(feature = "rust1", since = "1.0.0")]
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// Many of the usings in this module are only used in the test configuration.
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// It's cleaner to just turn off the unused_imports warning than to fix them.
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#![cfg_attr(test, allow(unused_imports, dead_code))]
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use core::borrow::{Borrow, BorrowMut};
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#[cfg(not(no_global_oom_handling))]
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use core::cmp::Ordering::{self, Less};
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#[cfg(not(no_global_oom_handling))]
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use core::mem::{self, SizedTypeProperties};
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#[cfg(not(no_global_oom_handling))]
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use core::ptr;
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#[cfg(not(no_global_oom_handling))]
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use core::slice::sort;
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use crate::alloc::Allocator;
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#[cfg(not(no_global_oom_handling))]
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use crate::alloc::{self, Global};
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#[cfg(not(no_global_oom_handling))]
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use crate::borrow::ToOwned;
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use crate::boxed::Box;
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use crate::vec::Vec;
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#[cfg(test)]
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mod tests;
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#[unstable(feature = "slice_range", issue = "76393")]
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pub use core::slice::range;
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#[unstable(feature = "array_chunks", issue = "74985")]
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pub use core::slice::ArrayChunks;
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#[unstable(feature = "array_chunks", issue = "74985")]
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pub use core::slice::ArrayChunksMut;
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#[unstable(feature = "array_windows", issue = "75027")]
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pub use core::slice::ArrayWindows;
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#[stable(feature = "inherent_ascii_escape", since = "1.60.0")]
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pub use core::slice::EscapeAscii;
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#[stable(feature = "slice_get_slice", since = "1.28.0")]
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pub use core::slice::SliceIndex;
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#[stable(feature = "from_ref", since = "1.28.0")]
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pub use core::slice::{from_mut, from_ref};
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#[unstable(feature = "slice_from_ptr_range", issue = "89792")]
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pub use core::slice::{from_mut_ptr_range, from_ptr_range};
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#[stable(feature = "rust1", since = "1.0.0")]
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pub use core::slice::{from_raw_parts, from_raw_parts_mut};
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#[stable(feature = "rust1", since = "1.0.0")]
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pub use core::slice::{Chunks, Windows};
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#[stable(feature = "chunks_exact", since = "1.31.0")]
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pub use core::slice::{ChunksExact, ChunksExactMut};
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#[stable(feature = "rust1", since = "1.0.0")]
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pub use core::slice::{ChunksMut, Split, SplitMut};
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#[unstable(feature = "slice_group_by", issue = "80552")]
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pub use core::slice::{GroupBy, GroupByMut};
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#[stable(feature = "rust1", since = "1.0.0")]
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pub use core::slice::{Iter, IterMut};
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#[stable(feature = "rchunks", since = "1.31.0")]
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pub use core::slice::{RChunks, RChunksExact, RChunksExactMut, RChunksMut};
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#[stable(feature = "slice_rsplit", since = "1.27.0")]
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pub use core::slice::{RSplit, RSplitMut};
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#[stable(feature = "rust1", since = "1.0.0")]
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pub use core::slice::{RSplitN, RSplitNMut, SplitN, SplitNMut};
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#[stable(feature = "split_inclusive", since = "1.51.0")]
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pub use core::slice::{SplitInclusive, SplitInclusiveMut};
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////////////////////////////////////////////////////////////////////////////////
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// Basic slice extension methods
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////////////////////////////////////////////////////////////////////////////////
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// HACK(japaric) needed for the implementation of `vec!` macro during testing
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// N.B., see the `hack` module in this file for more details.
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#[cfg(test)]
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pub use hack::into_vec;
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// HACK(japaric) needed for the implementation of `Vec::clone` during testing
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// N.B., see the `hack` module in this file for more details.
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#[cfg(test)]
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pub use hack::to_vec;
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// HACK(japaric): With cfg(test) `impl [T]` is not available, these three
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// functions are actually methods that are in `impl [T]` but not in
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// `core::slice::SliceExt` - we need to supply these functions for the
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// `test_permutations` test
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pub(crate) mod hack {
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use core::alloc::Allocator;
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use crate::boxed::Box;
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use crate::vec::Vec;
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// We shouldn't add inline attribute to this since this is used in
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// `vec!` macro mostly and causes perf regression. See #71204 for
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// discussion and perf results.
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pub fn into_vec<T, A: Allocator>(b: Box<[T], A>) -> Vec<T, A> {
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unsafe {
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let len = b.len();
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let (b, alloc) = Box::into_raw_with_allocator(b);
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Vec::from_raw_parts_in(b as *mut T, len, len, alloc)
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}
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}
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#[cfg(not(no_global_oom_handling))]
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#[inline]
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pub fn to_vec<T: ConvertVec, A: Allocator>(s: &[T], alloc: A) -> Vec<T, A> {
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T::to_vec(s, alloc)
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}
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#[cfg(not(no_global_oom_handling))]
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pub trait ConvertVec {
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fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A>
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where
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Self: Sized;
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}
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#[cfg(not(no_global_oom_handling))]
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impl<T: Clone> ConvertVec for T {
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#[inline]
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default fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> {
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struct DropGuard<'a, T, A: Allocator> {
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vec: &'a mut Vec<T, A>,
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num_init: usize,
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}
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impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> {
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#[inline]
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fn drop(&mut self) {
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// SAFETY:
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// items were marked initialized in the loop below
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unsafe {
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self.vec.set_len(self.num_init);
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}
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}
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}
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let mut vec = Vec::with_capacity_in(s.len(), alloc);
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let mut guard = DropGuard { vec: &mut vec, num_init: 0 };
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let slots = guard.vec.spare_capacity_mut();
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// .take(slots.len()) is necessary for LLVM to remove bounds checks
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// and has better codegen than zip.
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for (i, b) in s.iter().enumerate().take(slots.len()) {
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guard.num_init = i;
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slots[i].write(b.clone());
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}
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core::mem::forget(guard);
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// SAFETY:
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// the vec was allocated and initialized above to at least this length.
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unsafe {
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vec.set_len(s.len());
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}
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vec
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}
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}
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#[cfg(not(no_global_oom_handling))]
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impl<T: Copy> ConvertVec for T {
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#[inline]
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fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> {
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let mut v = Vec::with_capacity_in(s.len(), alloc);
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// SAFETY:
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// allocated above with the capacity of `s`, and initialize to `s.len()` in
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// ptr::copy_to_non_overlapping below.
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unsafe {
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s.as_ptr().copy_to_nonoverlapping(v.as_mut_ptr(), s.len());
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v.set_len(s.len());
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}
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v
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}
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}
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}
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#[cfg(not(test))]
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impl<T> [T] {
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/// Sorts the slice.
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///
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/// This sort is stable (i.e., does not reorder equal elements) and *O*(*n* \* log(*n*)) worst-case.
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///
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/// When applicable, unstable sorting is preferred because it is generally faster than stable
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/// sorting and it doesn't allocate auxiliary memory.
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/// See [`sort_unstable`](slice::sort_unstable).
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///
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/// # Current implementation
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///
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/// The current algorithm is an adaptive, iterative merge sort inspired by
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/// [timsort](https://en.wikipedia.org/wiki/Timsort).
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/// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
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/// two or more sorted sequences concatenated one after another.
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///
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/// Also, it allocates temporary storage half the size of `self`, but for short slices a
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/// non-allocating insertion sort is used instead.
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///
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/// # Examples
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///
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/// ```
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/// let mut v = [-5, 4, 1, -3, 2];
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///
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/// v.sort();
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/// assert!(v == [-5, -3, 1, 2, 4]);
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/// ```
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#[cfg(not(no_global_oom_handling))]
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#[rustc_allow_incoherent_impl]
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#[stable(feature = "rust1", since = "1.0.0")]
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#[inline]
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pub fn sort(&mut self)
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where
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T: Ord,
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{
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stable_sort(self, T::lt);
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}
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/// Sorts the slice with a comparator function.
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///
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/// This sort is stable (i.e., does not reorder equal elements) and *O*(*n* \* log(*n*)) worst-case.
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///
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/// The comparator function must define a total ordering for the elements in the slice. If
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/// the ordering is not total, the order of the elements is unspecified. An order is a
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/// total order if it is (for all `a`, `b` and `c`):
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///
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/// * total and antisymmetric: exactly one of `a < b`, `a == b` or `a > b` is true, and
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/// * transitive, `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.
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///
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/// For example, while [`f64`] doesn't implement [`Ord`] because `NaN != NaN`, we can use
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/// `partial_cmp` as our sort function when we know the slice doesn't contain a `NaN`.
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///
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/// ```
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/// let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
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/// floats.sort_by(|a, b| a.partial_cmp(b).unwrap());
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/// assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);
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/// ```
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///
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/// When applicable, unstable sorting is preferred because it is generally faster than stable
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/// sorting and it doesn't allocate auxiliary memory.
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/// See [`sort_unstable_by`](slice::sort_unstable_by).
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///
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/// # Current implementation
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///
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/// The current algorithm is an adaptive, iterative merge sort inspired by
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/// [timsort](https://en.wikipedia.org/wiki/Timsort).
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/// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
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/// two or more sorted sequences concatenated one after another.
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///
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/// Also, it allocates temporary storage half the size of `self`, but for short slices a
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/// non-allocating insertion sort is used instead.
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///
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/// # Examples
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///
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/// ```
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/// let mut v = [5, 4, 1, 3, 2];
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/// v.sort_by(|a, b| a.cmp(b));
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/// assert!(v == [1, 2, 3, 4, 5]);
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///
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/// // reverse sorting
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/// v.sort_by(|a, b| b.cmp(a));
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/// assert!(v == [5, 4, 3, 2, 1]);
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/// ```
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#[cfg(not(no_global_oom_handling))]
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#[rustc_allow_incoherent_impl]
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#[stable(feature = "rust1", since = "1.0.0")]
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#[inline]
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pub fn sort_by<F>(&mut self, mut compare: F)
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where
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F: FnMut(&T, &T) -> Ordering,
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{
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stable_sort(self, |a, b| compare(a, b) == Less);
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}
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/// Sorts the slice with a key extraction function.
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///
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/// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* \* log(*n*))
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/// worst-case, where the key function is *O*(*m*).
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///
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/// For expensive key functions (e.g. functions that are not simple property accesses or
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/// basic operations), [`sort_by_cached_key`](slice::sort_by_cached_key) is likely to be
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/// significantly faster, as it does not recompute element keys.
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///
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/// When applicable, unstable sorting is preferred because it is generally faster than stable
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/// sorting and it doesn't allocate auxiliary memory.
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/// See [`sort_unstable_by_key`](slice::sort_unstable_by_key).
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///
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/// # Current implementation
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///
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/// The current algorithm is an adaptive, iterative merge sort inspired by
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/// [timsort](https://en.wikipedia.org/wiki/Timsort).
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/// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
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/// two or more sorted sequences concatenated one after another.
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///
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/// Also, it allocates temporary storage half the size of `self`, but for short slices a
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/// non-allocating insertion sort is used instead.
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///
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/// # Examples
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///
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/// ```
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/// let mut v = [-5i32, 4, 1, -3, 2];
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///
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/// v.sort_by_key(|k| k.abs());
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/// assert!(v == [1, 2, -3, 4, -5]);
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/// ```
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#[cfg(not(no_global_oom_handling))]
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#[rustc_allow_incoherent_impl]
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#[stable(feature = "slice_sort_by_key", since = "1.7.0")]
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#[inline]
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pub fn sort_by_key<K, F>(&mut self, mut f: F)
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where
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F: FnMut(&T) -> K,
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K: Ord,
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{
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stable_sort(self, |a, b| f(a).lt(&f(b)));
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}
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/// Sorts the slice with a key extraction function.
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///
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/// During sorting, the key function is called at most once per element, by using
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/// temporary storage to remember the results of key evaluation.
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/// The order of calls to the key function is unspecified and may change in future versions
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/// of the standard library.
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///
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/// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* + *n* \* log(*n*))
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/// worst-case, where the key function is *O*(*m*).
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///
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/// For simple key functions (e.g., functions that are property accesses or
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/// basic operations), [`sort_by_key`](slice::sort_by_key) is likely to be
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/// faster.
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///
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/// # Current implementation
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///
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/// The current algorithm is based on [pattern-defeating quicksort][pdqsort] by Orson Peters,
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/// which combines the fast average case of randomized quicksort with the fast worst case of
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/// heapsort, while achieving linear time on slices with certain patterns. It uses some
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/// randomization to avoid degenerate cases, but with a fixed seed to always provide
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/// deterministic behavior.
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///
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/// In the worst case, the algorithm allocates temporary storage in a `Vec<(K, usize)>` the
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/// length of the slice.
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///
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/// # Examples
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///
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/// ```
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/// let mut v = [-5i32, 4, 32, -3, 2];
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///
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/// v.sort_by_cached_key(|k| k.to_string());
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/// assert!(v == [-3, -5, 2, 32, 4]);
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/// ```
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///
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/// [pdqsort]: https://github.com/orlp/pdqsort
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#[cfg(not(no_global_oom_handling))]
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#[rustc_allow_incoherent_impl]
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#[stable(feature = "slice_sort_by_cached_key", since = "1.34.0")]
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#[inline]
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pub fn sort_by_cached_key<K, F>(&mut self, f: F)
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where
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F: FnMut(&T) -> K,
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K: Ord,
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{
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// Helper macro for indexing our vector by the smallest possible type, to reduce allocation.
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macro_rules! sort_by_key {
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($t:ty, $slice:ident, $f:ident) => {{
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let mut indices: Vec<_> =
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$slice.iter().map($f).enumerate().map(|(i, k)| (k, i as $t)).collect();
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// The elements of `indices` are unique, as they are indexed, so any sort will be
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// stable with respect to the original slice. We use `sort_unstable` here because
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// it requires less memory allocation.
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indices.sort_unstable();
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for i in 0..$slice.len() {
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let mut index = indices[i].1;
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while (index as usize) < i {
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index = indices[index as usize].1;
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}
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indices[i].1 = index;
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$slice.swap(i, index as usize);
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}
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}};
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}
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let sz_u8 = mem::size_of::<(K, u8)>();
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let sz_u16 = mem::size_of::<(K, u16)>();
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let sz_u32 = mem::size_of::<(K, u32)>();
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let sz_usize = mem::size_of::<(K, usize)>();
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let len = self.len();
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if len < 2 {
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return;
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}
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if sz_u8 < sz_u16 && len <= (u8::MAX as usize) {
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return sort_by_key!(u8, self, f);
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}
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if sz_u16 < sz_u32 && len <= (u16::MAX as usize) {
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return sort_by_key!(u16, self, f);
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}
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if sz_u32 < sz_usize && len <= (u32::MAX as usize) {
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return sort_by_key!(u32, self, f);
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}
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sort_by_key!(usize, self, f)
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}
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/// Copies `self` into a new `Vec`.
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///
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/// # Examples
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///
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/// ```
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/// let s = [10, 40, 30];
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/// let x = s.to_vec();
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/// // Here, `s` and `x` can be modified independently.
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/// ```
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#[cfg(not(no_global_oom_handling))]
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#[rustc_allow_incoherent_impl]
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#[rustc_conversion_suggestion]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[inline]
|
|
pub fn to_vec(&self) -> Vec<T>
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|
where
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T: Clone,
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{
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self.to_vec_in(Global)
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}
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|
|
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/// Copies `self` into a new `Vec` with an allocator.
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///
|
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/// # Examples
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|
///
|
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/// ```
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/// #![feature(allocator_api)]
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///
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/// use std::alloc::System;
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///
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/// let s = [10, 40, 30];
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/// let x = s.to_vec_in(System);
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/// // Here, `s` and `x` can be modified independently.
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/// ```
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|
#[cfg(not(no_global_oom_handling))]
|
|
#[rustc_allow_incoherent_impl]
|
|
#[inline]
|
|
#[unstable(feature = "allocator_api", issue = "32838")]
|
|
pub fn to_vec_in<A: Allocator>(&self, alloc: A) -> Vec<T, A>
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|
where
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|
T: Clone,
|
|
{
|
|
// N.B., see the `hack` module in this file for more details.
|
|
hack::to_vec(self, alloc)
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|
}
|
|
|
|
/// Converts `self` into a vector without clones or allocation.
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|
///
|
|
/// The resulting vector can be converted back into a box via
|
|
/// `Vec<T>`'s `into_boxed_slice` method.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let s: Box<[i32]> = Box::new([10, 40, 30]);
|
|
/// let x = s.into_vec();
|
|
/// // `s` cannot be used anymore because it has been converted into `x`.
|
|
///
|
|
/// assert_eq!(x, vec![10, 40, 30]);
|
|
/// ```
|
|
#[rustc_allow_incoherent_impl]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[inline]
|
|
pub fn into_vec<A: Allocator>(self: Box<Self, A>) -> Vec<T, A> {
|
|
// N.B., see the `hack` module in this file for more details.
|
|
hack::into_vec(self)
|
|
}
|
|
|
|
/// Creates a vector by copying a slice `n` times.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This function will panic if the capacity would overflow.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Basic usage:
|
|
///
|
|
/// ```
|
|
/// assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
|
|
/// ```
|
|
///
|
|
/// A panic upon overflow:
|
|
///
|
|
/// ```should_panic
|
|
/// // this will panic at runtime
|
|
/// b"0123456789abcdef".repeat(usize::MAX);
|
|
/// ```
|
|
#[rustc_allow_incoherent_impl]
|
|
#[cfg(not(no_global_oom_handling))]
|
|
#[stable(feature = "repeat_generic_slice", since = "1.40.0")]
|
|
pub fn repeat(&self, n: usize) -> Vec<T>
|
|
where
|
|
T: Copy,
|
|
{
|
|
if n == 0 {
|
|
return Vec::new();
|
|
}
|
|
|
|
// If `n` is larger than zero, it can be split as
|
|
// `n = 2^expn + rem (2^expn > rem, expn >= 0, rem >= 0)`.
|
|
// `2^expn` is the number represented by the leftmost '1' bit of `n`,
|
|
// and `rem` is the remaining part of `n`.
|
|
|
|
// Using `Vec` to access `set_len()`.
|
|
let capacity = self.len().checked_mul(n).expect("capacity overflow");
|
|
let mut buf = Vec::with_capacity(capacity);
|
|
|
|
// `2^expn` repetition is done by doubling `buf` `expn`-times.
|
|
buf.extend(self);
|
|
{
|
|
let mut m = n >> 1;
|
|
// If `m > 0`, there are remaining bits up to the leftmost '1'.
|
|
while m > 0 {
|
|
// `buf.extend(buf)`:
|
|
unsafe {
|
|
ptr::copy_nonoverlapping(
|
|
buf.as_ptr(),
|
|
(buf.as_mut_ptr() as *mut T).add(buf.len()),
|
|
buf.len(),
|
|
);
|
|
// `buf` has capacity of `self.len() * n`.
|
|
let buf_len = buf.len();
|
|
buf.set_len(buf_len * 2);
|
|
}
|
|
|
|
m >>= 1;
|
|
}
|
|
}
|
|
|
|
// `rem` (`= n - 2^expn`) repetition is done by copying
|
|
// first `rem` repetitions from `buf` itself.
|
|
let rem_len = capacity - buf.len(); // `self.len() * rem`
|
|
if rem_len > 0 {
|
|
// `buf.extend(buf[0 .. rem_len])`:
|
|
unsafe {
|
|
// This is non-overlapping since `2^expn > rem`.
|
|
ptr::copy_nonoverlapping(
|
|
buf.as_ptr(),
|
|
(buf.as_mut_ptr() as *mut T).add(buf.len()),
|
|
rem_len,
|
|
);
|
|
// `buf.len() + rem_len` equals to `buf.capacity()` (`= self.len() * n`).
|
|
buf.set_len(capacity);
|
|
}
|
|
}
|
|
buf
|
|
}
|
|
|
|
/// Flattens a slice of `T` into a single value `Self::Output`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// assert_eq!(["hello", "world"].concat(), "helloworld");
|
|
/// assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);
|
|
/// ```
|
|
#[rustc_allow_incoherent_impl]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn concat<Item: ?Sized>(&self) -> <Self as Concat<Item>>::Output
|
|
where
|
|
Self: Concat<Item>,
|
|
{
|
|
Concat::concat(self)
|
|
}
|
|
|
|
/// Flattens a slice of `T` into a single value `Self::Output`, placing a
|
|
/// given separator between each.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// assert_eq!(["hello", "world"].join(" "), "hello world");
|
|
/// assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
|
|
/// assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);
|
|
/// ```
|
|
#[rustc_allow_incoherent_impl]
|
|
#[stable(feature = "rename_connect_to_join", since = "1.3.0")]
|
|
pub fn join<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
|
|
where
|
|
Self: Join<Separator>,
|
|
{
|
|
Join::join(self, sep)
|
|
}
|
|
|
|
/// Flattens a slice of `T` into a single value `Self::Output`, placing a
|
|
/// given separator between each.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![allow(deprecated)]
|
|
/// assert_eq!(["hello", "world"].connect(" "), "hello world");
|
|
/// assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);
|
|
/// ```
|
|
#[rustc_allow_incoherent_impl]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[deprecated(since = "1.3.0", note = "renamed to join")]
|
|
pub fn connect<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
|
|
where
|
|
Self: Join<Separator>,
|
|
{
|
|
Join::join(self, sep)
|
|
}
|
|
}
|
|
|
|
#[cfg(not(test))]
|
|
impl [u8] {
|
|
/// Returns a vector containing a copy of this slice where each byte
|
|
/// is mapped to its ASCII upper case equivalent.
|
|
///
|
|
/// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
|
|
/// but non-ASCII letters are unchanged.
|
|
///
|
|
/// To uppercase the value in-place, use [`make_ascii_uppercase`].
|
|
///
|
|
/// [`make_ascii_uppercase`]: slice::make_ascii_uppercase
|
|
#[cfg(not(no_global_oom_handling))]
|
|
#[rustc_allow_incoherent_impl]
|
|
#[must_use = "this returns the uppercase bytes as a new Vec, \
|
|
without modifying the original"]
|
|
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
|
|
#[inline]
|
|
pub fn to_ascii_uppercase(&self) -> Vec<u8> {
|
|
let mut me = self.to_vec();
|
|
me.make_ascii_uppercase();
|
|
me
|
|
}
|
|
|
|
/// Returns a vector containing a copy of this slice where each byte
|
|
/// is mapped to its ASCII lower case equivalent.
|
|
///
|
|
/// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
|
|
/// but non-ASCII letters are unchanged.
|
|
///
|
|
/// To lowercase the value in-place, use [`make_ascii_lowercase`].
|
|
///
|
|
/// [`make_ascii_lowercase`]: slice::make_ascii_lowercase
|
|
#[cfg(not(no_global_oom_handling))]
|
|
#[rustc_allow_incoherent_impl]
|
|
#[must_use = "this returns the lowercase bytes as a new Vec, \
|
|
without modifying the original"]
|
|
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
|
|
#[inline]
|
|
pub fn to_ascii_lowercase(&self) -> Vec<u8> {
|
|
let mut me = self.to_vec();
|
|
me.make_ascii_lowercase();
|
|
me
|
|
}
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Extension traits for slices over specific kinds of data
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
/// Helper trait for [`[T]::concat`](slice::concat).
|
|
///
|
|
/// Note: the `Item` type parameter is not used in this trait,
|
|
/// but it allows impls to be more generic.
|
|
/// Without it, we get this error:
|
|
///
|
|
/// ```error
|
|
/// error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predica
|
|
/// --> library/alloc/src/slice.rs:608:6
|
|
/// |
|
|
/// 608 | impl<T: Clone, V: Borrow<[T]>> Concat for [V] {
|
|
/// | ^ unconstrained type parameter
|
|
/// ```
|
|
///
|
|
/// This is because there could exist `V` types with multiple `Borrow<[_]>` impls,
|
|
/// such that multiple `T` types would apply:
|
|
///
|
|
/// ```
|
|
/// # #[allow(dead_code)]
|
|
/// pub struct Foo(Vec<u32>, Vec<String>);
|
|
///
|
|
/// impl std::borrow::Borrow<[u32]> for Foo {
|
|
/// fn borrow(&self) -> &[u32] { &self.0 }
|
|
/// }
|
|
///
|
|
/// impl std::borrow::Borrow<[String]> for Foo {
|
|
/// fn borrow(&self) -> &[String] { &self.1 }
|
|
/// }
|
|
/// ```
|
|
#[unstable(feature = "slice_concat_trait", issue = "27747")]
|
|
pub trait Concat<Item: ?Sized> {
|
|
#[unstable(feature = "slice_concat_trait", issue = "27747")]
|
|
/// The resulting type after concatenation
|
|
type Output;
|
|
|
|
/// Implementation of [`[T]::concat`](slice::concat)
|
|
#[unstable(feature = "slice_concat_trait", issue = "27747")]
|
|
fn concat(slice: &Self) -> Self::Output;
|
|
}
|
|
|
|
/// Helper trait for [`[T]::join`](slice::join)
|
|
#[unstable(feature = "slice_concat_trait", issue = "27747")]
|
|
pub trait Join<Separator> {
|
|
#[unstable(feature = "slice_concat_trait", issue = "27747")]
|
|
/// The resulting type after concatenation
|
|
type Output;
|
|
|
|
/// Implementation of [`[T]::join`](slice::join)
|
|
#[unstable(feature = "slice_concat_trait", issue = "27747")]
|
|
fn join(slice: &Self, sep: Separator) -> Self::Output;
|
|
}
|
|
|
|
#[cfg(not(no_global_oom_handling))]
|
|
#[unstable(feature = "slice_concat_ext", issue = "27747")]
|
|
impl<T: Clone, V: Borrow<[T]>> Concat<T> for [V] {
|
|
type Output = Vec<T>;
|
|
|
|
fn concat(slice: &Self) -> Vec<T> {
|
|
let size = slice.iter().map(|slice| slice.borrow().len()).sum();
|
|
let mut result = Vec::with_capacity(size);
|
|
for v in slice {
|
|
result.extend_from_slice(v.borrow())
|
|
}
|
|
result
|
|
}
|
|
}
|
|
|
|
#[cfg(not(no_global_oom_handling))]
|
|
#[unstable(feature = "slice_concat_ext", issue = "27747")]
|
|
impl<T: Clone, V: Borrow<[T]>> Join<&T> for [V] {
|
|
type Output = Vec<T>;
|
|
|
|
fn join(slice: &Self, sep: &T) -> Vec<T> {
|
|
let mut iter = slice.iter();
|
|
let first = match iter.next() {
|
|
Some(first) => first,
|
|
None => return vec![],
|
|
};
|
|
let size = slice.iter().map(|v| v.borrow().len()).sum::<usize>() + slice.len() - 1;
|
|
let mut result = Vec::with_capacity(size);
|
|
result.extend_from_slice(first.borrow());
|
|
|
|
for v in iter {
|
|
result.push(sep.clone());
|
|
result.extend_from_slice(v.borrow())
|
|
}
|
|
result
|
|
}
|
|
}
|
|
|
|
#[cfg(not(no_global_oom_handling))]
|
|
#[unstable(feature = "slice_concat_ext", issue = "27747")]
|
|
impl<T: Clone, V: Borrow<[T]>> Join<&[T]> for [V] {
|
|
type Output = Vec<T>;
|
|
|
|
fn join(slice: &Self, sep: &[T]) -> Vec<T> {
|
|
let mut iter = slice.iter();
|
|
let first = match iter.next() {
|
|
Some(first) => first,
|
|
None => return vec![],
|
|
};
|
|
let size =
|
|
slice.iter().map(|v| v.borrow().len()).sum::<usize>() + sep.len() * (slice.len() - 1);
|
|
let mut result = Vec::with_capacity(size);
|
|
result.extend_from_slice(first.borrow());
|
|
|
|
for v in iter {
|
|
result.extend_from_slice(sep);
|
|
result.extend_from_slice(v.borrow())
|
|
}
|
|
result
|
|
}
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Standard trait implementations for slices
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T, A: Allocator> Borrow<[T]> for Vec<T, A> {
|
|
fn borrow(&self) -> &[T] {
|
|
&self[..]
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T, A: Allocator> BorrowMut<[T]> for Vec<T, A> {
|
|
fn borrow_mut(&mut self) -> &mut [T] {
|
|
&mut self[..]
|
|
}
|
|
}
|
|
|
|
#[cfg(not(no_global_oom_handling))]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Clone> ToOwned for [T] {
|
|
type Owned = Vec<T>;
|
|
#[cfg(not(test))]
|
|
fn to_owned(&self) -> Vec<T> {
|
|
self.to_vec()
|
|
}
|
|
|
|
#[cfg(test)]
|
|
fn to_owned(&self) -> Vec<T> {
|
|
hack::to_vec(self, Global)
|
|
}
|
|
|
|
fn clone_into(&self, target: &mut Vec<T>) {
|
|
// drop anything in target that will not be overwritten
|
|
target.truncate(self.len());
|
|
|
|
// target.len <= self.len due to the truncate above, so the
|
|
// slices here are always in-bounds.
|
|
let (init, tail) = self.split_at(target.len());
|
|
|
|
// reuse the contained values' allocations/resources.
|
|
target.clone_from_slice(init);
|
|
target.extend_from_slice(tail);
|
|
}
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Sorting
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#[inline]
|
|
#[cfg(not(no_global_oom_handling))]
|
|
fn stable_sort<T, F>(v: &mut [T], mut is_less: F)
|
|
where
|
|
F: FnMut(&T, &T) -> bool,
|
|
{
|
|
if T::IS_ZST {
|
|
// Sorting has no meaningful behavior on zero-sized types. Do nothing.
|
|
return;
|
|
}
|
|
|
|
let elem_alloc_fn = |len: usize| -> *mut T {
|
|
// SAFETY: Creating the layout is safe as long as merge_sort never calls this with len >
|
|
// v.len(). Alloc in general will only be used as 'shadow-region' to store temporary swap
|
|
// elements.
|
|
unsafe { alloc::alloc(alloc::Layout::array::<T>(len).unwrap_unchecked()) as *mut T }
|
|
};
|
|
|
|
let elem_dealloc_fn = |buf_ptr: *mut T, len: usize| {
|
|
// SAFETY: Creating the layout is safe as long as merge_sort never calls this with len >
|
|
// v.len(). The caller must ensure that buf_ptr was created by elem_alloc_fn with the same
|
|
// len.
|
|
unsafe {
|
|
alloc::dealloc(buf_ptr as *mut u8, alloc::Layout::array::<T>(len).unwrap_unchecked());
|
|
}
|
|
};
|
|
|
|
let run_alloc_fn = |len: usize| -> *mut sort::TimSortRun {
|
|
// SAFETY: Creating the layout is safe as long as merge_sort never calls this with an
|
|
// obscene length or 0.
|
|
unsafe {
|
|
alloc::alloc(alloc::Layout::array::<sort::TimSortRun>(len).unwrap_unchecked())
|
|
as *mut sort::TimSortRun
|
|
}
|
|
};
|
|
|
|
let run_dealloc_fn = |buf_ptr: *mut sort::TimSortRun, len: usize| {
|
|
// SAFETY: The caller must ensure that buf_ptr was created by elem_alloc_fn with the same
|
|
// len.
|
|
unsafe {
|
|
alloc::dealloc(
|
|
buf_ptr as *mut u8,
|
|
alloc::Layout::array::<sort::TimSortRun>(len).unwrap_unchecked(),
|
|
);
|
|
}
|
|
};
|
|
|
|
sort::merge_sort(v, &mut is_less, elem_alloc_fn, elem_dealloc_fn, run_alloc_fn, run_dealloc_fn);
|
|
}
|