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-rw-r--r--vendor/rayon/src/vec.rs283
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+//! Parallel iterator types for [vectors][std::vec] (`Vec<T>`)
+//!
+//! You will rarely need to interact with this module directly unless you need
+//! to name one of the iterator types.
+//!
+//! [std::vec]: https://doc.rust-lang.org/stable/std/vec/
+
+use crate::iter::plumbing::*;
+use crate::iter::*;
+use crate::math::simplify_range;
+use crate::slice::{Iter, IterMut};
+use std::iter;
+use std::mem;
+use std::ops::{Range, RangeBounds};
+use std::ptr;
+use std::slice;
+
+impl<'data, T: Sync + 'data> IntoParallelIterator for &'data Vec<T> {
+ type Item = &'data T;
+ type Iter = Iter<'data, T>;
+
+ fn into_par_iter(self) -> Self::Iter {
+ <&[T]>::into_par_iter(self)
+ }
+}
+
+impl<'data, T: Send + 'data> IntoParallelIterator for &'data mut Vec<T> {
+ type Item = &'data mut T;
+ type Iter = IterMut<'data, T>;
+
+ fn into_par_iter(self) -> Self::Iter {
+ <&mut [T]>::into_par_iter(self)
+ }
+}
+
+/// Parallel iterator that moves out of a vector.
+#[derive(Debug, Clone)]
+pub struct IntoIter<T: Send> {
+ vec: Vec<T>,
+}
+
+impl<T: Send> IntoParallelIterator for Vec<T> {
+ type Item = T;
+ type Iter = IntoIter<T>;
+
+ fn into_par_iter(self) -> Self::Iter {
+ IntoIter { vec: self }
+ }
+}
+
+impl<T: Send> ParallelIterator for IntoIter<T> {
+ type Item = T;
+
+ fn drive_unindexed<C>(self, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<Self::Item>,
+ {
+ bridge(self, consumer)
+ }
+
+ fn opt_len(&self) -> Option<usize> {
+ Some(self.len())
+ }
+}
+
+impl<T: Send> IndexedParallelIterator for IntoIter<T> {
+ fn drive<C>(self, consumer: C) -> C::Result
+ where
+ C: Consumer<Self::Item>,
+ {
+ bridge(self, consumer)
+ }
+
+ fn len(&self) -> usize {
+ self.vec.len()
+ }
+
+ fn with_producer<CB>(mut self, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<Self::Item>,
+ {
+ // Drain every item, and then the vector only needs to free its buffer.
+ self.vec.par_drain(..).with_producer(callback)
+ }
+}
+
+impl<'data, T: Send> ParallelDrainRange<usize> for &'data mut Vec<T> {
+ type Iter = Drain<'data, T>;
+ type Item = T;
+
+ fn par_drain<R: RangeBounds<usize>>(self, range: R) -> Self::Iter {
+ Drain {
+ orig_len: self.len(),
+ range: simplify_range(range, self.len()),
+ vec: self,
+ }
+ }
+}
+
+/// Draining parallel iterator that moves a range out of a vector, but keeps the total capacity.
+#[derive(Debug)]
+pub struct Drain<'data, T: Send> {
+ vec: &'data mut Vec<T>,
+ range: Range<usize>,
+ orig_len: usize,
+}
+
+impl<'data, T: Send> ParallelIterator for Drain<'data, T> {
+ type Item = T;
+
+ fn drive_unindexed<C>(self, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<Self::Item>,
+ {
+ bridge(self, consumer)
+ }
+
+ fn opt_len(&self) -> Option<usize> {
+ Some(self.len())
+ }
+}
+
+impl<'data, T: Send> IndexedParallelIterator for Drain<'data, T> {
+ fn drive<C>(self, consumer: C) -> C::Result
+ where
+ C: Consumer<Self::Item>,
+ {
+ bridge(self, consumer)
+ }
+
+ fn len(&self) -> usize {
+ self.range.len()
+ }
+
+ fn with_producer<CB>(self, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<Self::Item>,
+ {
+ unsafe {
+ // Make the vector forget about the drained items, and temporarily the tail too.
+ self.vec.set_len(self.range.start);
+
+ // Create the producer as the exclusive "owner" of the slice.
+ let producer = DrainProducer::from_vec(self.vec, self.range.len());
+
+ // The producer will move or drop each item from the drained range.
+ callback.callback(producer)
+ }
+ }
+}
+
+impl<'data, T: Send> Drop for Drain<'data, T> {
+ fn drop(&mut self) {
+ let Range { start, end } = self.range;
+ if self.vec.len() == self.orig_len {
+ // We must not have produced, so just call a normal drain to remove the items.
+ self.vec.drain(start..end);
+ } else if start == end {
+ // Empty range, so just restore the length to its original state
+ unsafe {
+ self.vec.set_len(self.orig_len);
+ }
+ } else if end < self.orig_len {
+ // The producer was responsible for consuming the drained items.
+ // Move the tail items to their new place, then set the length to include them.
+ unsafe {
+ let ptr = self.vec.as_mut_ptr().add(start);
+ let tail_ptr = self.vec.as_ptr().add(end);
+ let tail_len = self.orig_len - end;
+ ptr::copy(tail_ptr, ptr, tail_len);
+ self.vec.set_len(start + tail_len);
+ }
+ }
+ }
+}
+
+/// ////////////////////////////////////////////////////////////////////////
+
+pub(crate) struct DrainProducer<'data, T: Send> {
+ slice: &'data mut [T],
+}
+
+impl<T: Send> DrainProducer<'_, T> {
+ /// Creates a draining producer, which *moves* items from the slice.
+ ///
+ /// Unsafe because `!Copy` data must not be read after the borrow is released.
+ pub(crate) unsafe fn new(slice: &mut [T]) -> DrainProducer<'_, T> {
+ DrainProducer { slice }
+ }
+
+ /// Creates a draining producer, which *moves* items from the tail of the vector.
+ ///
+ /// Unsafe because we're moving from beyond `vec.len()`, so the caller must ensure
+ /// that data is initialized and not read after the borrow is released.
+ unsafe fn from_vec(vec: &mut Vec<T>, len: usize) -> DrainProducer<'_, T> {
+ let start = vec.len();
+ assert!(vec.capacity() - start >= len);
+
+ // The pointer is derived from `Vec` directly, not through a `Deref`,
+ // so it has provenance over the whole allocation.
+ let ptr = vec.as_mut_ptr().add(start);
+ DrainProducer::new(slice::from_raw_parts_mut(ptr, len))
+ }
+}
+
+impl<'data, T: 'data + Send> Producer for DrainProducer<'data, T> {
+ type Item = T;
+ type IntoIter = SliceDrain<'data, T>;
+
+ fn into_iter(mut self) -> Self::IntoIter {
+ // replace the slice so we don't drop it twice
+ let slice = mem::take(&mut self.slice);
+ SliceDrain {
+ iter: slice.iter_mut(),
+ }
+ }
+
+ fn split_at(mut self, index: usize) -> (Self, Self) {
+ // replace the slice so we don't drop it twice
+ let slice = mem::take(&mut self.slice);
+ let (left, right) = slice.split_at_mut(index);
+ unsafe { (DrainProducer::new(left), DrainProducer::new(right)) }
+ }
+}
+
+impl<'data, T: 'data + Send> Drop for DrainProducer<'data, T> {
+ fn drop(&mut self) {
+ // extract the slice so we can use `Drop for [T]`
+ let slice_ptr: *mut [T] = mem::take::<&'data mut [T]>(&mut self.slice);
+ unsafe { ptr::drop_in_place::<[T]>(slice_ptr) };
+ }
+}
+
+/// ////////////////////////////////////////////////////////////////////////
+
+// like std::vec::Drain, without updating a source Vec
+pub(crate) struct SliceDrain<'data, T> {
+ iter: slice::IterMut<'data, T>,
+}
+
+impl<'data, T: 'data> Iterator for SliceDrain<'data, T> {
+ type Item = T;
+
+ fn next(&mut self) -> Option<T> {
+ // Coerce the pointer early, so we don't keep the
+ // reference that's about to be invalidated.
+ let ptr: *const T = self.iter.next()?;
+ Some(unsafe { ptr::read(ptr) })
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+
+ fn count(self) -> usize {
+ self.iter.len()
+ }
+}
+
+impl<'data, T: 'data> DoubleEndedIterator for SliceDrain<'data, T> {
+ fn next_back(&mut self) -> Option<Self::Item> {
+ // Coerce the pointer early, so we don't keep the
+ // reference that's about to be invalidated.
+ let ptr: *const T = self.iter.next_back()?;
+ Some(unsafe { ptr::read(ptr) })
+ }
+}
+
+impl<'data, T: 'data> ExactSizeIterator for SliceDrain<'data, T> {
+ fn len(&self) -> usize {
+ self.iter.len()
+ }
+}
+
+impl<'data, T: 'data> iter::FusedIterator for SliceDrain<'data, T> {}
+
+impl<'data, T: 'data> Drop for SliceDrain<'data, T> {
+ fn drop(&mut self) {
+ // extract the iterator so we can use `Drop for [T]`
+ let slice_ptr: *mut [T] = mem::replace(&mut self.iter, [].iter_mut()).into_slice();
+ unsafe { ptr::drop_in_place::<[T]>(slice_ptr) };
+ }
+}