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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
commit698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch)
tree173a775858bd501c378080a10dca74132f05bc50 /vendor/rayon/src/range.rs
parentInitial commit. (diff)
downloadrustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz
rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/rayon/src/range.rs')
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diff --git a/vendor/rayon/src/range.rs b/vendor/rayon/src/range.rs
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+//! Parallel iterator types for [ranges][std::range],
+//! the type for values created by `a..b` expressions
+//!
+//! You will rarely need to interact with this module directly unless you have
+//! need to name one of the iterator types.
+//!
+//! ```
+//! use rayon::prelude::*;
+//!
+//! let r = (0..100u64).into_par_iter()
+//! .sum();
+//!
+//! // compare result with sequential calculation
+//! assert_eq!((0..100).sum::<u64>(), r);
+//! ```
+//!
+//! [std::range]: https://doc.rust-lang.org/core/ops/struct.Range.html
+
+use crate::iter::plumbing::*;
+use crate::iter::*;
+use std::char;
+use std::convert::TryFrom;
+use std::ops::Range;
+use std::usize;
+
+/// Parallel iterator over a range, implemented for all integer types and `char`.
+///
+/// **Note:** The `zip` operation requires `IndexedParallelIterator`
+/// which is not implemented for `u64`, `i64`, `u128`, or `i128`.
+///
+/// ```
+/// use rayon::prelude::*;
+///
+/// let p = (0..25usize).into_par_iter()
+/// .zip(0..25usize)
+/// .filter(|&(x, y)| x % 5 == 0 || y % 5 == 0)
+/// .map(|(x, y)| x * y)
+/// .sum::<usize>();
+///
+/// let s = (0..25usize).zip(0..25)
+/// .filter(|&(x, y)| x % 5 == 0 || y % 5 == 0)
+/// .map(|(x, y)| x * y)
+/// .sum();
+///
+/// assert_eq!(p, s);
+/// ```
+#[derive(Debug, Clone)]
+pub struct Iter<T> {
+ range: Range<T>,
+}
+
+/// Implemented for ranges of all primitive integer types and `char`.
+impl<T> IntoParallelIterator for Range<T>
+where
+ Iter<T>: ParallelIterator,
+{
+ type Item = <Iter<T> as ParallelIterator>::Item;
+ type Iter = Iter<T>;
+
+ fn into_par_iter(self) -> Self::Iter {
+ Iter { range: self }
+ }
+}
+
+struct IterProducer<T> {
+ range: Range<T>,
+}
+
+impl<T> IntoIterator for IterProducer<T>
+where
+ Range<T>: Iterator,
+{
+ type Item = <Range<T> as Iterator>::Item;
+ type IntoIter = Range<T>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ self.range
+ }
+}
+
+/// These traits help drive integer type inference. Without them, an unknown `{integer}` type only
+/// has constraints on `Iter<{integer}>`, which will probably give up and use `i32`. By adding
+/// these traits on the item type, the compiler can see a more direct constraint to infer like
+/// `{integer}: RangeInteger`, which works better. See `test_issue_833` for an example.
+///
+/// They have to be `pub` since they're seen in the public `impl ParallelIterator` constraints, but
+/// we put them in a private modules so they're not actually reachable in our public API.
+mod private {
+ use super::*;
+
+ /// Implementation details of `ParallelIterator for Iter<Self>`
+ pub trait RangeInteger: Sized + Send {
+ private_decl! {}
+
+ fn drive_unindexed<C>(iter: Iter<Self>, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<Self>;
+
+ fn opt_len(iter: &Iter<Self>) -> Option<usize>;
+ }
+
+ /// Implementation details of `IndexedParallelIterator for Iter<Self>`
+ pub trait IndexedRangeInteger: RangeInteger {
+ private_decl! {}
+
+ fn drive<C>(iter: Iter<Self>, consumer: C) -> C::Result
+ where
+ C: Consumer<Self>;
+
+ fn len(iter: &Iter<Self>) -> usize;
+
+ fn with_producer<CB>(iter: Iter<Self>, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<Self>;
+ }
+}
+use private::{IndexedRangeInteger, RangeInteger};
+
+impl<T: RangeInteger> ParallelIterator for Iter<T> {
+ type Item = T;
+
+ fn drive_unindexed<C>(self, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<T>,
+ {
+ T::drive_unindexed(self, consumer)
+ }
+
+ #[inline]
+ fn opt_len(&self) -> Option<usize> {
+ T::opt_len(self)
+ }
+}
+
+impl<T: IndexedRangeInteger> IndexedParallelIterator for Iter<T> {
+ fn drive<C>(self, consumer: C) -> C::Result
+ where
+ C: Consumer<T>,
+ {
+ T::drive(self, consumer)
+ }
+
+ #[inline]
+ fn len(&self) -> usize {
+ T::len(self)
+ }
+
+ fn with_producer<CB>(self, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<T>,
+ {
+ T::with_producer(self, callback)
+ }
+}
+
+macro_rules! indexed_range_impl {
+ ( $t:ty ) => {
+ impl RangeInteger for $t {
+ private_impl! {}
+
+ fn drive_unindexed<C>(iter: Iter<$t>, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<$t>,
+ {
+ bridge(iter, consumer)
+ }
+
+ fn opt_len(iter: &Iter<$t>) -> Option<usize> {
+ Some(iter.range.len())
+ }
+ }
+
+ impl IndexedRangeInteger for $t {
+ private_impl! {}
+
+ fn drive<C>(iter: Iter<$t>, consumer: C) -> C::Result
+ where
+ C: Consumer<$t>,
+ {
+ bridge(iter, consumer)
+ }
+
+ fn len(iter: &Iter<$t>) -> usize {
+ iter.range.len()
+ }
+
+ fn with_producer<CB>(iter: Iter<$t>, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<$t>,
+ {
+ callback.callback(IterProducer { range: iter.range })
+ }
+ }
+
+ impl Producer for IterProducer<$t> {
+ type Item = <Range<$t> as Iterator>::Item;
+ type IntoIter = Range<$t>;
+ fn into_iter(self) -> Self::IntoIter {
+ self.range
+ }
+
+ fn split_at(self, index: usize) -> (Self, Self) {
+ assert!(index <= self.range.len());
+ // For signed $t, the length and requested index could be greater than $t::MAX, and
+ // then `index as $t` could wrap to negative, so wrapping_add is necessary.
+ let mid = self.range.start.wrapping_add(index as $t);
+ let left = self.range.start..mid;
+ let right = mid..self.range.end;
+ (IterProducer { range: left }, IterProducer { range: right })
+ }
+ }
+ };
+}
+
+trait UnindexedRangeLen<L> {
+ fn len(&self) -> L;
+}
+
+macro_rules! unindexed_range_impl {
+ ( $t:ty, $len_t:ty ) => {
+ impl UnindexedRangeLen<$len_t> for Range<$t> {
+ fn len(&self) -> $len_t {
+ let &Range { start, end } = self;
+ if end > start {
+ end.wrapping_sub(start) as $len_t
+ } else {
+ 0
+ }
+ }
+ }
+
+ impl RangeInteger for $t {
+ private_impl! {}
+
+ fn drive_unindexed<C>(iter: Iter<$t>, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<$t>,
+ {
+ #[inline]
+ fn offset(start: $t) -> impl Fn(usize) -> $t {
+ move |i| start.wrapping_add(i as $t)
+ }
+
+ if let Some(len) = iter.opt_len() {
+ // Drive this in indexed mode for better `collect`.
+ (0..len)
+ .into_par_iter()
+ .map(offset(iter.range.start))
+ .drive(consumer)
+ } else {
+ bridge_unindexed(IterProducer { range: iter.range }, consumer)
+ }
+ }
+
+ fn opt_len(iter: &Iter<$t>) -> Option<usize> {
+ usize::try_from(iter.range.len()).ok()
+ }
+ }
+
+ impl UnindexedProducer for IterProducer<$t> {
+ type Item = $t;
+
+ fn split(mut self) -> (Self, Option<Self>) {
+ let index = self.range.len() / 2;
+ if index > 0 {
+ let mid = self.range.start.wrapping_add(index as $t);
+ let right = mid..self.range.end;
+ self.range.end = mid;
+ (self, Some(IterProducer { range: right }))
+ } else {
+ (self, None)
+ }
+ }
+
+ fn fold_with<F>(self, folder: F) -> F
+ where
+ F: Folder<Self::Item>,
+ {
+ folder.consume_iter(self)
+ }
+ }
+ };
+}
+
+// all Range<T> with ExactSizeIterator
+indexed_range_impl! {u8}
+indexed_range_impl! {u16}
+indexed_range_impl! {u32}
+indexed_range_impl! {usize}
+indexed_range_impl! {i8}
+indexed_range_impl! {i16}
+indexed_range_impl! {i32}
+indexed_range_impl! {isize}
+
+// other Range<T> with just Iterator
+unindexed_range_impl! {u64, u64}
+unindexed_range_impl! {i64, u64}
+unindexed_range_impl! {u128, u128}
+unindexed_range_impl! {i128, u128}
+
+// char is special because of the surrogate range hole
+macro_rules! convert_char {
+ ( $self:ident . $method:ident ( $( $arg:expr ),* ) ) => {{
+ let start = $self.range.start as u32;
+ let end = $self.range.end as u32;
+ if start < 0xD800 && 0xE000 < end {
+ // chain the before and after surrogate range fragments
+ (start..0xD800)
+ .into_par_iter()
+ .chain(0xE000..end)
+ .map(|codepoint| unsafe { char::from_u32_unchecked(codepoint) })
+ .$method($( $arg ),*)
+ } else {
+ // no surrogate range to worry about
+ (start..end)
+ .into_par_iter()
+ .map(|codepoint| unsafe { char::from_u32_unchecked(codepoint) })
+ .$method($( $arg ),*)
+ }
+ }};
+}
+
+impl ParallelIterator for Iter<char> {
+ type Item = char;
+
+ fn drive_unindexed<C>(self, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<Self::Item>,
+ {
+ convert_char!(self.drive(consumer))
+ }
+
+ fn opt_len(&self) -> Option<usize> {
+ Some(self.len())
+ }
+}
+
+impl IndexedParallelIterator for Iter<char> {
+ // Split at the surrogate range first if we're allowed to
+ fn drive<C>(self, consumer: C) -> C::Result
+ where
+ C: Consumer<Self::Item>,
+ {
+ convert_char!(self.drive(consumer))
+ }
+
+ fn len(&self) -> usize {
+ // Taken from <char as Step>::steps_between
+ let start = self.range.start as u32;
+ let end = self.range.end as u32;
+ if start < end {
+ let mut count = end - start;
+ if start < 0xD800 && 0xE000 <= end {
+ count -= 0x800
+ }
+ count as usize
+ } else {
+ 0
+ }
+ }
+
+ fn with_producer<CB>(self, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<Self::Item>,
+ {
+ convert_char!(self.with_producer(callback))
+ }
+}
+
+#[test]
+fn check_range_split_at_overflow() {
+ // Note, this split index overflows i8!
+ let producer = IterProducer { range: -100i8..100 };
+ let (left, right) = producer.split_at(150);
+ let r1: i32 = left.range.map(i32::from).sum();
+ let r2: i32 = right.range.map(i32::from).sum();
+ assert_eq!(r1 + r2, -100);
+}
+
+#[test]
+fn test_i128_len_doesnt_overflow() {
+ use std::{i128, u128};
+
+ // Using parse because some versions of rust don't allow long literals
+ let octillion: i128 = "1000000000000000000000000000".parse().unwrap();
+ let producer = IterProducer {
+ range: 0..octillion,
+ };
+
+ assert_eq!(octillion as u128, producer.range.len());
+ assert_eq!(octillion as u128, (0..octillion).len());
+ assert_eq!(2 * octillion as u128, (-octillion..octillion).len());
+
+ assert_eq!(u128::MAX, (i128::MIN..i128::MAX).len());
+}
+
+#[test]
+fn test_u64_opt_len() {
+ use std::{u64, usize};
+ assert_eq!(Some(100), (0..100u64).into_par_iter().opt_len());
+ assert_eq!(
+ Some(usize::MAX),
+ (0..usize::MAX as u64).into_par_iter().opt_len()
+ );
+ if (usize::MAX as u64) < u64::MAX {
+ assert_eq!(
+ None,
+ (0..(usize::MAX as u64).wrapping_add(1))
+ .into_par_iter()
+ .opt_len()
+ );
+ assert_eq!(None, (0..u64::MAX).into_par_iter().opt_len());
+ }
+}
+
+#[test]
+fn test_u128_opt_len() {
+ use std::{u128, usize};
+ assert_eq!(Some(100), (0..100u128).into_par_iter().opt_len());
+ assert_eq!(
+ Some(usize::MAX),
+ (0..usize::MAX as u128).into_par_iter().opt_len()
+ );
+ assert_eq!(None, (0..1 + usize::MAX as u128).into_par_iter().opt_len());
+ assert_eq!(None, (0..u128::MAX).into_par_iter().opt_len());
+}
+
+// `usize as i64` can overflow, so make sure to wrap it appropriately
+// when using the `opt_len` "indexed" mode.
+#[test]
+#[cfg(target_pointer_width = "64")]
+fn test_usize_i64_overflow() {
+ use crate::ThreadPoolBuilder;
+ use std::i64;
+
+ let iter = (-2..i64::MAX).into_par_iter();
+ assert_eq!(iter.opt_len(), Some(i64::MAX as usize + 2));
+
+ // always run with multiple threads to split into, or this will take forever...
+ let pool = ThreadPoolBuilder::new().num_threads(8).build().unwrap();
+ pool.install(|| assert_eq!(iter.find_last(|_| true), Some(i64::MAX - 1)));
+}
+
+#[test]
+fn test_issue_833() {
+ fn is_even(n: i64) -> bool {
+ n % 2 == 0
+ }
+
+ // The integer type should be inferred from `is_even`
+ let v: Vec<_> = (1..100).into_par_iter().filter(|&x| is_even(x)).collect();
+ assert!(v.into_iter().eq((2..100).step_by(2)));
+
+ // Try examples with indexed iterators too
+ let pos = (0..100).into_par_iter().position_any(|x| x == 50i16);
+ assert_eq!(pos, Some(50usize));
+
+ assert!((0..100)
+ .into_par_iter()
+ .zip(0..100)
+ .all(|(a, b)| i16::eq(&a, &b)));
+}