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use crate::iter::plumbing::*;
use crate::iter::*;
use crate::math::div_round_up;
/// Parallel iterator over immutable non-overlapping chunks of a slice, starting at the end.
#[derive(Debug)]
pub struct RChunks<'data, T: Sync> {
chunk_size: usize,
slice: &'data [T],
}
impl<'data, T: Sync> RChunks<'data, T> {
pub(super) fn new(chunk_size: usize, slice: &'data [T]) -> Self {
Self { chunk_size, slice }
}
}
impl<'data, T: Sync> Clone for RChunks<'data, T> {
fn clone(&self) -> Self {
RChunks { ..*self }
}
}
impl<'data, T: Sync + 'data> ParallelIterator for RChunks<'data, T> {
type Item = &'data [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: Sync + 'data> IndexedParallelIterator for RChunks<'data, T> {
fn drive<C>(self, consumer: C) -> C::Result
where
C: Consumer<Self::Item>,
{
bridge(self, consumer)
}
fn len(&self) -> usize {
div_round_up(self.slice.len(), self.chunk_size)
}
fn with_producer<CB>(self, callback: CB) -> CB::Output
where
CB: ProducerCallback<Self::Item>,
{
callback.callback(RChunksProducer {
chunk_size: self.chunk_size,
slice: self.slice,
})
}
}
struct RChunksProducer<'data, T: Sync> {
chunk_size: usize,
slice: &'data [T],
}
impl<'data, T: 'data + Sync> Producer for RChunksProducer<'data, T> {
type Item = &'data [T];
type IntoIter = ::std::slice::RChunks<'data, T>;
fn into_iter(self) -> Self::IntoIter {
self.slice.rchunks(self.chunk_size)
}
fn split_at(self, index: usize) -> (Self, Self) {
let elem_index = self.slice.len().saturating_sub(index * self.chunk_size);
let (left, right) = self.slice.split_at(elem_index);
(
RChunksProducer {
chunk_size: self.chunk_size,
slice: right,
},
RChunksProducer {
chunk_size: self.chunk_size,
slice: left,
},
)
}
}
/// Parallel iterator over immutable non-overlapping chunks of a slice, starting at the end.
#[derive(Debug)]
pub struct RChunksExact<'data, T: Sync> {
chunk_size: usize,
slice: &'data [T],
rem: &'data [T],
}
impl<'data, T: Sync> RChunksExact<'data, T> {
pub(super) fn new(chunk_size: usize, slice: &'data [T]) -> Self {
let rem_len = slice.len() % chunk_size;
let (rem, slice) = slice.split_at(rem_len);
Self {
chunk_size,
slice,
rem,
}
}
/// Return the remainder of the original slice that is not going to be
/// returned by the iterator. The returned slice has at most `chunk_size-1`
/// elements.
pub fn remainder(&self) -> &'data [T] {
self.rem
}
}
impl<'data, T: Sync> Clone for RChunksExact<'data, T> {
fn clone(&self) -> Self {
RChunksExact { ..*self }
}
}
impl<'data, T: Sync + 'data> ParallelIterator for RChunksExact<'data, T> {
type Item = &'data [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: Sync + 'data> IndexedParallelIterator for RChunksExact<'data, T> {
fn drive<C>(self, consumer: C) -> C::Result
where
C: Consumer<Self::Item>,
{
bridge(self, consumer)
}
fn len(&self) -> usize {
self.slice.len() / self.chunk_size
}
fn with_producer<CB>(self, callback: CB) -> CB::Output
where
CB: ProducerCallback<Self::Item>,
{
callback.callback(RChunksExactProducer {
chunk_size: self.chunk_size,
slice: self.slice,
})
}
}
struct RChunksExactProducer<'data, T: Sync> {
chunk_size: usize,
slice: &'data [T],
}
impl<'data, T: 'data + Sync> Producer for RChunksExactProducer<'data, T> {
type Item = &'data [T];
type IntoIter = ::std::slice::RChunksExact<'data, T>;
fn into_iter(self) -> Self::IntoIter {
self.slice.rchunks_exact(self.chunk_size)
}
fn split_at(self, index: usize) -> (Self, Self) {
let elem_index = self.slice.len() - index * self.chunk_size;
let (left, right) = self.slice.split_at(elem_index);
(
RChunksExactProducer {
chunk_size: self.chunk_size,
slice: right,
},
RChunksExactProducer {
chunk_size: self.chunk_size,
slice: left,
},
)
}
}
/// Parallel iterator over mutable non-overlapping chunks of a slice, starting at the end.
#[derive(Debug)]
pub struct RChunksMut<'data, T: Send> {
chunk_size: usize,
slice: &'data mut [T],
}
impl<'data, T: Send> RChunksMut<'data, T> {
pub(super) fn new(chunk_size: usize, slice: &'data mut [T]) -> Self {
Self { chunk_size, slice }
}
}
impl<'data, T: Send + 'data> ParallelIterator for RChunksMut<'data, T> {
type Item = &'data mut [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 + 'data> IndexedParallelIterator for RChunksMut<'data, T> {
fn drive<C>(self, consumer: C) -> C::Result
where
C: Consumer<Self::Item>,
{
bridge(self, consumer)
}
fn len(&self) -> usize {
div_round_up(self.slice.len(), self.chunk_size)
}
fn with_producer<CB>(self, callback: CB) -> CB::Output
where
CB: ProducerCallback<Self::Item>,
{
callback.callback(RChunksMutProducer {
chunk_size: self.chunk_size,
slice: self.slice,
})
}
}
struct RChunksMutProducer<'data, T: Send> {
chunk_size: usize,
slice: &'data mut [T],
}
impl<'data, T: 'data + Send> Producer for RChunksMutProducer<'data, T> {
type Item = &'data mut [T];
type IntoIter = ::std::slice::RChunksMut<'data, T>;
fn into_iter(self) -> Self::IntoIter {
self.slice.rchunks_mut(self.chunk_size)
}
fn split_at(self, index: usize) -> (Self, Self) {
let elem_index = self.slice.len().saturating_sub(index * self.chunk_size);
let (left, right) = self.slice.split_at_mut(elem_index);
(
RChunksMutProducer {
chunk_size: self.chunk_size,
slice: right,
},
RChunksMutProducer {
chunk_size: self.chunk_size,
slice: left,
},
)
}
}
/// Parallel iterator over mutable non-overlapping chunks of a slice, starting at the end.
#[derive(Debug)]
pub struct RChunksExactMut<'data, T: Send> {
chunk_size: usize,
slice: &'data mut [T],
rem: &'data mut [T],
}
impl<'data, T: Send> RChunksExactMut<'data, T> {
pub(super) fn new(chunk_size: usize, slice: &'data mut [T]) -> Self {
let rem_len = slice.len() % chunk_size;
let (rem, slice) = slice.split_at_mut(rem_len);
Self {
chunk_size,
slice,
rem,
}
}
/// Return the remainder of the original slice that is not going to be
/// returned by the iterator. The returned slice has at most `chunk_size-1`
/// elements.
///
/// Note that this has to consume `self` to return the original lifetime of
/// the data, which prevents this from actually being used as a parallel
/// iterator since that also consumes. This method is provided for parity
/// with `std::iter::RChunksExactMut`, but consider calling `remainder()` or
/// `take_remainder()` as alternatives.
pub fn into_remainder(self) -> &'data mut [T] {
self.rem
}
/// Return the remainder of the original slice that is not going to be
/// returned by the iterator. The returned slice has at most `chunk_size-1`
/// elements.
///
/// Consider `take_remainder()` if you need access to the data with its
/// original lifetime, rather than borrowing through `&mut self` here.
pub fn remainder(&mut self) -> &mut [T] {
self.rem
}
/// Return the remainder of the original slice that is not going to be
/// returned by the iterator. The returned slice has at most `chunk_size-1`
/// elements. Subsequent calls will return an empty slice.
pub fn take_remainder(&mut self) -> &'data mut [T] {
std::mem::take(&mut self.rem)
}
}
impl<'data, T: Send + 'data> ParallelIterator for RChunksExactMut<'data, T> {
type Item = &'data mut [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 + 'data> IndexedParallelIterator for RChunksExactMut<'data, T> {
fn drive<C>(self, consumer: C) -> C::Result
where
C: Consumer<Self::Item>,
{
bridge(self, consumer)
}
fn len(&self) -> usize {
self.slice.len() / self.chunk_size
}
fn with_producer<CB>(self, callback: CB) -> CB::Output
where
CB: ProducerCallback<Self::Item>,
{
callback.callback(RChunksExactMutProducer {
chunk_size: self.chunk_size,
slice: self.slice,
})
}
}
struct RChunksExactMutProducer<'data, T: Send> {
chunk_size: usize,
slice: &'data mut [T],
}
impl<'data, T: 'data + Send> Producer for RChunksExactMutProducer<'data, T> {
type Item = &'data mut [T];
type IntoIter = ::std::slice::RChunksExactMut<'data, T>;
fn into_iter(self) -> Self::IntoIter {
self.slice.rchunks_exact_mut(self.chunk_size)
}
fn split_at(self, index: usize) -> (Self, Self) {
let elem_index = self.slice.len() - index * self.chunk_size;
let (left, right) = self.slice.split_at_mut(elem_index);
(
RChunksExactMutProducer {
chunk_size: self.chunk_size,
slice: right,
},
RChunksExactMutProducer {
chunk_size: self.chunk_size,
slice: left,
},
)
}
}