diff options
Diffstat (limited to 'rust/alloc/slice.rs')
| -rw-r--r-- | rust/alloc/slice.rs | 890 |
1 files changed, 0 insertions, 890 deletions
diff --git a/rust/alloc/slice.rs b/rust/alloc/slice.rs deleted file mode 100644 index 1181836da5f4..000000000000 --- a/rust/alloc/slice.rs +++ /dev/null @@ -1,890 +0,0 @@ -// SPDX-License-Identifier: Apache-2.0 OR MIT - -//! Utilities for the slice primitive type. -//! -//! *[See also the slice primitive type](slice).* -//! -//! Most of the structs in this module are iterator types which can only be created -//! using a certain function. For example, `slice.iter()` yields an [`Iter`]. -//! -//! A few functions are provided to create a slice from a value reference -//! or from a raw pointer. -#![stable(feature = "rust1", since = "1.0.0")] -// Many of the usings in this module are only used in the test configuration. -// It's cleaner to just turn off the unused_imports warning than to fix them. -#![cfg_attr(test, allow(unused_imports, dead_code))] - -use core::borrow::{Borrow, BorrowMut}; -#[cfg(not(no_global_oom_handling))] -use core::cmp::Ordering::{self, Less}; -#[cfg(not(no_global_oom_handling))] -use core::mem::{self, SizedTypeProperties}; -#[cfg(not(no_global_oom_handling))] -use core::ptr; -#[cfg(not(no_global_oom_handling))] -use core::slice::sort; - -use crate::alloc::Allocator; -#[cfg(not(no_global_oom_handling))] -use crate::alloc::{self, Global}; -#[cfg(not(no_global_oom_handling))] -use crate::borrow::ToOwned; -use crate::boxed::Box; -use crate::vec::Vec; - -#[cfg(test)] -mod tests; - -#[unstable(feature = "slice_range", issue = "76393")] -pub use core::slice::range; -#[unstable(feature = "array_chunks", issue = "74985")] -pub use core::slice::ArrayChunks; -#[unstable(feature = "array_chunks", issue = "74985")] -pub use core::slice::ArrayChunksMut; -#[unstable(feature = "array_windows", issue = "75027")] -pub use core::slice::ArrayWindows; -#[stable(feature = "inherent_ascii_escape", since = "1.60.0")] -pub use core::slice::EscapeAscii; -#[stable(feature = "slice_get_slice", since = "1.28.0")] -pub use core::slice::SliceIndex; -#[stable(feature = "from_ref", since = "1.28.0")] -pub use core::slice::{from_mut, from_ref}; -#[unstable(feature = "slice_from_ptr_range", issue = "89792")] -pub use core::slice::{from_mut_ptr_range, from_ptr_range}; -#[stable(feature = "rust1", since = "1.0.0")] -pub use core::slice::{from_raw_parts, from_raw_parts_mut}; -#[stable(feature = "rust1", since = "1.0.0")] -pub use core::slice::{Chunks, Windows}; -#[stable(feature = "chunks_exact", since = "1.31.0")] -pub use core::slice::{ChunksExact, ChunksExactMut}; -#[stable(feature = "rust1", since = "1.0.0")] -pub use core::slice::{ChunksMut, Split, SplitMut}; -#[unstable(feature = "slice_group_by", issue = "80552")] -pub use core::slice::{GroupBy, GroupByMut}; -#[stable(feature = "rust1", since = "1.0.0")] -pub use core::slice::{Iter, IterMut}; -#[stable(feature = "rchunks", since = "1.31.0")] -pub use core::slice::{RChunks, RChunksExact, RChunksExactMut, RChunksMut}; -#[stable(feature = "slice_rsplit", since = "1.27.0")] -pub use core::slice::{RSplit, RSplitMut}; -#[stable(feature = "rust1", since = "1.0.0")] -pub use core::slice::{RSplitN, RSplitNMut, SplitN, SplitNMut}; -#[stable(feature = "split_inclusive", since = "1.51.0")] -pub use core::slice::{SplitInclusive, SplitInclusiveMut}; - -//////////////////////////////////////////////////////////////////////////////// -// Basic slice extension methods -//////////////////////////////////////////////////////////////////////////////// - -// HACK(japaric) needed for the implementation of `vec!` macro during testing -// N.B., see the `hack` module in this file for more details. -#[cfg(test)] -pub use hack::into_vec; - -// HACK(japaric) needed for the implementation of `Vec::clone` during testing -// N.B., see the `hack` module in this file for more details. -#[cfg(test)] -pub use hack::to_vec; - -// HACK(japaric): With cfg(test) `impl [T]` is not available, these three -// functions are actually methods that are in `impl [T]` but not in -// `core::slice::SliceExt` - we need to supply these functions for the -// `test_permutations` test -pub(crate) mod hack { - use core::alloc::Allocator; - - use crate::boxed::Box; - use crate::vec::Vec; - - // We shouldn't add inline attribute to this since this is used in - // `vec!` macro mostly and causes perf regression. See #71204 for - // discussion and perf results. - pub fn into_vec<T, A: Allocator>(b: Box<[T], A>) -> Vec<T, A> { - unsafe { - let len = b.len(); - let (b, alloc) = Box::into_raw_with_allocator(b); - Vec::from_raw_parts_in(b as *mut T, len, len, alloc) - } - } - - #[cfg(not(no_global_oom_handling))] - #[inline] - pub fn to_vec<T: ConvertVec, A: Allocator>(s: &[T], alloc: A) -> Vec<T, A> { - T::to_vec(s, alloc) - } - - #[cfg(not(no_global_oom_handling))] - pub trait ConvertVec { - fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> - where - Self: Sized; - } - - #[cfg(not(no_global_oom_handling))] - impl<T: Clone> ConvertVec for T { - #[inline] - default fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> { - struct DropGuard<'a, T, A: Allocator> { - vec: &'a mut Vec<T, A>, - num_init: usize, - } - impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> { - #[inline] - fn drop(&mut self) { - // SAFETY: - // items were marked initialized in the loop below - unsafe { - self.vec.set_len(self.num_init); - } - } - } - let mut vec = Vec::with_capacity_in(s.len(), alloc); - let mut guard = DropGuard { vec: &mut vec, num_init: 0 }; - let slots = guard.vec.spare_capacity_mut(); - // .take(slots.len()) is necessary for LLVM to remove bounds checks - // and has better codegen than zip. - for (i, b) in s.iter().enumerate().take(slots.len()) { - guard.num_init = i; - slots[i].write(b.clone()); - } - core::mem::forget(guard); - // SAFETY: - // the vec was allocated and initialized above to at least this length. - unsafe { - vec.set_len(s.len()); - } - vec - } - } - - #[cfg(not(no_global_oom_handling))] - impl<T: Copy> ConvertVec for T { - #[inline] - fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> { - let mut v = Vec::with_capacity_in(s.len(), alloc); - // SAFETY: - // allocated above with the capacity of `s`, and initialize to `s.len()` in - // ptr::copy_to_non_overlapping below. - unsafe { - s.as_ptr().copy_to_nonoverlapping(v.as_mut_ptr(), s.len()); - v.set_len(s.len()); - } - v - } - } -} - -#[cfg(not(test))] -impl<T> [T] { - /// Sorts the slice. - /// - /// This sort is stable (i.e., does not reorder equal elements) and *O*(*n* \* log(*n*)) worst-case. - /// - /// When applicable, unstable sorting is preferred because it is generally faster than stable - /// sorting and it doesn't allocate auxiliary memory. - /// See [`sort_unstable`](slice::sort_unstable). - /// - /// # Current implementation - /// - /// The current algorithm is an adaptive, iterative merge sort inspired by - /// [timsort](https://en.wikipedia.org/wiki/Timsort). - /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of - /// two or more sorted sequences concatenated one after another. - /// - /// Also, it allocates temporary storage half the size of `self`, but for short slices a - /// non-allocating insertion sort is used instead. - /// - /// # Examples - /// - /// ``` - /// let mut v = [-5, 4, 1, -3, 2]; - /// - /// v.sort(); - /// assert!(v == [-5, -3, 1, 2, 4]); - /// ``` - #[cfg(not(no_global_oom_handling))] - #[rustc_allow_incoherent_impl] - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub fn sort(&mut self) - where - T: Ord, - { - stable_sort(self, T::lt); - } - - /// Sorts the slice with a comparator function. - /// - /// This sort is stable (i.e., does not reorder equal elements) and *O*(*n* \* log(*n*)) worst-case. - /// - /// The comparator function must define a total ordering for the elements in the slice. If - /// the ordering is not total, the order of the elements is unspecified. An order is a - /// total order if it is (for all `a`, `b` and `c`): - /// - /// * total and antisymmetric: exactly one of `a < b`, `a == b` or `a > b` is true, and - /// * transitive, `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`. - /// - /// For example, while [`f64`] doesn't implement [`Ord`] because `NaN != NaN`, we can use - /// `partial_cmp` as our sort function when we know the slice doesn't contain a `NaN`. - /// - /// ``` - /// let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0]; - /// floats.sort_by(|a, b| a.partial_cmp(b).unwrap()); - /// assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]); - /// ``` - /// - /// When applicable, unstable sorting is preferred because it is generally faster than stable - /// sorting and it doesn't allocate auxiliary memory. - /// See [`sort_unstable_by`](slice::sort_unstable_by). - /// - /// # Current implementation - /// - /// The current algorithm is an adaptive, iterative merge sort inspired by - /// [timsort](https://en.wikipedia.org/wiki/Timsort). - /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of - /// two or more sorted sequences concatenated one after another. - /// - /// Also, it allocates temporary storage half the size of `self`, but for short slices a - /// non-allocating insertion sort is used instead. - /// - /// # Examples - /// - /// ``` - /// let mut v = [5, 4, 1, 3, 2]; - /// v.sort_by(|a, b| a.cmp(b)); - /// assert!(v == [1, 2, 3, 4, 5]); - /// - /// // reverse sorting - /// v.sort_by(|a, b| b.cmp(a)); - /// assert!(v == [5, 4, 3, 2, 1]); - /// ``` - #[cfg(not(no_global_oom_handling))] - #[rustc_allow_incoherent_impl] - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub fn sort_by<F>(&mut self, mut compare: F) - where - F: FnMut(&T, &T) -> Ordering, - { - stable_sort(self, |a, b| compare(a, b) == Less); - } - - /// Sorts the slice with a key extraction function. - /// - /// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* \* log(*n*)) - /// worst-case, where the key function is *O*(*m*). - /// - /// For expensive key functions (e.g. functions that are not simple property accesses or - /// basic operations), [`sort_by_cached_key`](slice::sort_by_cached_key) is likely to be - /// significantly faster, as it does not recompute element keys. - /// - /// When applicable, unstable sorting is preferred because it is generally faster than stable - /// sorting and it doesn't allocate auxiliary memory. - /// See [`sort_unstable_by_key`](slice::sort_unstable_by_key). - /// - /// # Current implementation - /// - /// The current algorithm is an adaptive, iterative merge sort inspired by - /// [timsort](https://en.wikipedia.org/wiki/Timsort). - /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of - /// two or more sorted sequences concatenated one after another. - /// - /// Also, it allocates temporary storage half the size of `self`, but for short slices a - /// non-allocating insertion sort is used instead. - /// - /// # Examples - /// - /// ``` - /// let mut v = [-5i32, 4, 1, -3, 2]; - /// - /// v.sort_by_key(|k| k.abs()); - /// assert!(v == [1, 2, -3, 4, -5]); - /// ``` - #[cfg(not(no_global_oom_handling))] - #[rustc_allow_incoherent_impl] - #[stable(feature = "slice_sort_by_key", since = "1.7.0")] - #[inline] - pub fn sort_by_key<K, F>(&mut self, mut f: F) - where - F: FnMut(&T) -> K, - K: Ord, - { - stable_sort(self, |a, b| f(a).lt(&f(b))); - } - - /// Sorts the slice with a key extraction function. - /// - /// During sorting, the key function is called at most once per element, by using - /// temporary storage to remember the results of key evaluation. - /// The order of calls to the key function is unspecified and may change in future versions - /// of the standard library. - /// - /// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* + *n* \* log(*n*)) - /// worst-case, where the key function is *O*(*m*). - /// - /// For simple key functions (e.g., functions that are property accesses or - /// basic operations), [`sort_by_key`](slice::sort_by_key) is likely to be - /// faster. - /// - /// # Current implementation - /// - /// The current algorithm is based on [pattern-defeating quicksort][pdqsort] by Orson Peters, - /// which combines the fast average case of randomized quicksort with the fast worst case of - /// heapsort, while achieving linear time on slices with certain patterns. It uses some - /// randomization to avoid degenerate cases, but with a fixed seed to always provide - /// deterministic behavior. - /// - /// In the worst case, the algorithm allocates temporary storage in a `Vec<(K, usize)>` the - /// length of the slice. - /// - /// # Examples - /// - /// ``` - /// let mut v = [-5i32, 4, 32, -3, 2]; - /// - /// v.sort_by_cached_key(|k| k.to_string()); - /// assert!(v == [-3, -5, 2, 32, 4]); - /// ``` - /// - /// [pdqsort]: https://github.com/orlp/pdqsort - #[cfg(not(no_global_oom_handling))] - #[rustc_allow_incoherent_impl] - #[stable(feature = "slice_sort_by_cached_key", since = "1.34.0")] - #[inline] - pub fn sort_by_cached_key<K, F>(&mut self, f: F) - where - F: FnMut(&T) -> K, - K: Ord, - { - // Helper macro for indexing our vector by the smallest possible type, to reduce allocation. - macro_rules! sort_by_key { - ($t:ty, $slice:ident, $f:ident) => {{ - let mut indices: Vec<_> = - $slice.iter().map($f).enumerate().map(|(i, k)| (k, i as $t)).collect(); - // The elements of `indices` are unique, as they are indexed, so any sort will be - // stable with respect to the original slice. We use `sort_unstable` here because - // it requires less memory allocation. - indices.sort_unstable(); - for i in 0..$slice.len() { - let mut index = indices[i].1; - while (index as usize) < i { - index = indices[index as usize].1; - } - indices[i].1 = index; - $slice.swap(i, index as usize); - } - }}; - } - - let sz_u8 = mem::size_of::<(K, u8)>(); - let sz_u16 = mem::size_of::<(K, u16)>(); - let sz_u32 = mem::size_of::<(K, u32)>(); - let sz_usize = mem::size_of::<(K, usize)>(); - - let len = self.len(); - if len < 2 { - return; - } - if sz_u8 < sz_u16 && len <= (u8::MAX as usize) { - return sort_by_key!(u8, self, f); - } - if sz_u16 < sz_u32 && len <= (u16::MAX as usize) { - return sort_by_key!(u16, self, f); - } - if sz_u32 < sz_usize && len <= (u32::MAX as usize) { - return sort_by_key!(u32, self, f); - } - sort_by_key!(usize, self, f) - } - - /// Copies `self` into a new `Vec`. - /// - /// # Examples - /// - /// ``` - /// let s = [10, 40, 30]; - /// let x = s.to_vec(); - /// // Here, `s` and `x` can be modified independently. - /// ``` - #[cfg(not(no_global_oom_handling))] - #[rustc_allow_incoherent_impl] - #[rustc_conversion_suggestion] - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub fn to_vec(&self) -> Vec<T> - where - T: Clone, - { - self.to_vec_in(Global) - } - - /// Copies `self` into a new `Vec` with an allocator. - /// - /// # Examples - /// - /// ``` - /// #![feature(allocator_api)] - /// - /// use std::alloc::System; - /// - /// let s = [10, 40, 30]; - /// let x = s.to_vec_in(System); - /// // Here, `s` and `x` can be modified independently. - /// ``` - #[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> - where - T: Clone, - { - // N.B., see the `hack` module in this file for more details. - hack::to_vec(self, alloc) - } - - /// Converts `self` into a vector without clones or allocation. - /// - /// 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", suggestion = "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[..] - } -} - -// Specializable trait for implementing ToOwned::clone_into. This is -// public in the crate and has the Allocator parameter so that -// vec::clone_from use it too. -#[cfg(not(no_global_oom_handling))] -pub(crate) trait SpecCloneIntoVec<T, A: Allocator> { - fn clone_into(&self, target: &mut Vec<T, A>); -} - -#[cfg(not(no_global_oom_handling))] -impl<T: Clone, A: Allocator> SpecCloneIntoVec<T, A> for [T] { - default fn clone_into(&self, target: &mut Vec<T, A>) { - // 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); - } -} - -#[cfg(not(no_global_oom_handling))] -impl<T: Copy, A: Allocator> SpecCloneIntoVec<T, A> for [T] { - fn clone_into(&self, target: &mut Vec<T, A>) { - target.clear(); - target.extend_from_slice(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>) { - SpecCloneIntoVec::clone_into(self, target); - } -} - -//////////////////////////////////////////////////////////////////////////////// -// 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); -} |