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authorValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
committerValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
commit1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch)
tree7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/rayon/src/range_inclusive.rs
parent5ecd8cf2cba827454317368b68571df0d13d7842 (diff)
downloadfparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz
fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
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+//! Parallel iterator types for [inclusive 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.RangeInclusive.html
+
+use crate::iter::plumbing::*;
+use crate::iter::*;
+use std::char;
+use std::ops::RangeInclusive;
+
+/// Parallel iterator over an inclusive range, implemented for all integer types and `char`.
+///
+/// **Note:** The `zip` operation requires `IndexedParallelIterator`
+/// which is only implemented for `u8`, `i8`, `u16`, `i16`, and `char`.
+///
+/// ```
+/// use rayon::prelude::*;
+///
+/// let p = (0..=25u16).into_par_iter()
+/// .zip(0..=25u16)
+/// .filter(|&(x, y)| x % 5 == 0 || y % 5 == 0)
+/// .map(|(x, y)| x * y)
+/// .sum::<u16>();
+///
+/// let s = (0..=25u16).zip(0..=25u16)
+/// .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: RangeInclusive<T>,
+}
+
+impl<T> Iter<T>
+where
+ RangeInclusive<T>: Eq,
+ T: Ord + Copy,
+{
+ /// Returns `Some((start, end))` for `start..=end`, or `None` if it is exhausted.
+ ///
+ /// Note that `RangeInclusive` does not specify the bounds of an exhausted iterator,
+ /// so this is a way for us to figure out what we've got. Thankfully, all of the
+ /// integer types we care about can be trivially cloned.
+ fn bounds(&self) -> Option<(T, T)> {
+ let start = *self.range.start();
+ let end = *self.range.end();
+ if start <= end && self.range == (start..=end) {
+ // If the range is still nonempty, this is obviously true
+ // If the range is exhausted, either start > end or
+ // the range does not equal start..=end.
+ Some((start, end))
+ } else {
+ None
+ }
+ }
+}
+
+/// Implemented for ranges of all primitive integer types and `char`.
+impl<T> IntoParallelIterator for RangeInclusive<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 }
+ }
+}
+
+/// 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! convert {
+ ( $iter:ident . $method:ident ( $( $arg:expr ),* ) ) => {
+ if let Some((start, end)) = $iter.bounds() {
+ if let Some(end) = end.checked_add(1) {
+ (start..end).into_par_iter().$method($( $arg ),*)
+ } else {
+ (start..end).into_par_iter().chain(once(end)).$method($( $arg ),*)
+ }
+ } else {
+ empty::<Self>().$method($( $arg ),*)
+ }
+ };
+}
+
+macro_rules! parallel_range_impl {
+ ( $t:ty ) => {
+ impl RangeInteger for $t {
+ private_impl! {}
+
+ fn drive_unindexed<C>(iter: Iter<$t>, consumer: C) -> C::Result
+ where
+ C: UnindexedConsumer<$t>,
+ {
+ convert!(iter.drive_unindexed(consumer))
+ }
+
+ fn opt_len(iter: &Iter<$t>) -> Option<usize> {
+ convert!(iter.opt_len())
+ }
+ }
+ };
+}
+
+macro_rules! indexed_range_impl {
+ ( $t:ty ) => {
+ parallel_range_impl! { $t }
+
+ impl IndexedRangeInteger for $t {
+ private_impl! {}
+
+ fn drive<C>(iter: Iter<$t>, consumer: C) -> C::Result
+ where
+ C: Consumer<$t>,
+ {
+ convert!(iter.drive(consumer))
+ }
+
+ fn len(iter: &Iter<$t>) -> usize {
+ iter.range.len()
+ }
+
+ fn with_producer<CB>(iter: Iter<$t>, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<$t>,
+ {
+ convert!(iter.with_producer(callback))
+ }
+ }
+ };
+}
+
+// all RangeInclusive<T> with ExactSizeIterator
+indexed_range_impl! {u8}
+indexed_range_impl! {u16}
+indexed_range_impl! {i8}
+indexed_range_impl! {i16}
+
+// other RangeInclusive<T> with just Iterator
+parallel_range_impl! {usize}
+parallel_range_impl! {isize}
+parallel_range_impl! {u32}
+parallel_range_impl! {i32}
+parallel_range_impl! {u64}
+parallel_range_impl! {i64}
+parallel_range_impl! {u128}
+parallel_range_impl! {i128}
+
+// char is special
+macro_rules! convert_char {
+ ( $self:ident . $method:ident ( $( $arg:expr ),* ) ) => {
+ if let Some((start, end)) = $self.bounds() {
+ let start = start as u32;
+ let end = end as u32;
+ if start < 0xD800 && 0xE000 <= end {
+ // chain the before and after surrogate range fragments
+ (start..0xD800)
+ .into_par_iter()
+ .chain(0xE000..end + 1) // cannot use RangeInclusive, so add one to end
+ .map(|codepoint| unsafe { char::from_u32_unchecked(codepoint) })
+ .$method($( $arg ),*)
+ } else {
+ // no surrogate range to worry about
+ (start..end + 1) // cannot use RangeInclusive, so add one to end
+ .into_par_iter()
+ .map(|codepoint| unsafe { char::from_u32_unchecked(codepoint) })
+ .$method($( $arg ),*)
+ }
+ } else {
+ empty::<char>().$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())
+ }
+}
+
+// Range<u32> is broken on 16 bit platforms, may as well benefit from it
+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 {
+ if let Some((start, end)) = self.bounds() {
+ // Taken from <char as Step>::steps_between
+ let start = start as u32;
+ let end = end as u32;
+ let mut count = end - start;
+ if start < 0xD800 && 0xE000 <= end {
+ count -= 0x800
+ }
+ (count + 1) as usize // add one for inclusive
+ } else {
+ 0
+ }
+ }
+
+ fn with_producer<CB>(self, callback: CB) -> CB::Output
+ where
+ CB: ProducerCallback<Self::Item>,
+ {
+ convert_char!(self.with_producer(callback))
+ }
+}
+
+#[test]
+#[cfg(target_pointer_width = "64")]
+fn test_u32_opt_len() {
+ use std::u32;
+ assert_eq!(Some(101), (0..=100u32).into_par_iter().opt_len());
+ assert_eq!(
+ Some(u32::MAX as usize),
+ (0..=u32::MAX - 1).into_par_iter().opt_len()
+ );
+ assert_eq!(
+ Some(u32::MAX as usize + 1),
+ (0..=u32::MAX).into_par_iter().opt_len()
+ );
+}
+
+#[test]
+fn test_u64_opt_len() {
+ use std::{u64, usize};
+ assert_eq!(Some(101), (0..=100u64).into_par_iter().opt_len());
+ assert_eq!(
+ Some(usize::MAX),
+ (0..=usize::MAX as u64 - 1).into_par_iter().opt_len()
+ );
+ assert_eq!(None, (0..=usize::MAX as u64).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(101), (0..=100u128).into_par_iter().opt_len());
+ assert_eq!(
+ Some(usize::MAX),
+ (0..=usize::MAX as u128 - 1).into_par_iter().opt_len()
+ );
+ assert_eq!(None, (0..=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 + 3));
+
+ // 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)));
+}
+
+#[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)));
+}