android/vendor/rayon-1.9.0/src/range_inclusive.rs - toolchain/cargo-deny - Git at Google

 //! 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)));
 }
	//! 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)));
	}