From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- vendor/itertools/src/ziptuple.rs | 137 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 vendor/itertools/src/ziptuple.rs (limited to 'vendor/itertools/src/ziptuple.rs') diff --git a/vendor/itertools/src/ziptuple.rs b/vendor/itertools/src/ziptuple.rs new file mode 100644 index 000000000..b7902ae53 --- /dev/null +++ b/vendor/itertools/src/ziptuple.rs @@ -0,0 +1,137 @@ +use super::size_hint; + +/// See [`multizip`] for more information. +#[derive(Clone, Debug)] +#[must_use = "iterator adaptors are lazy and do nothing unless consumed"] +pub struct Zip { + t: T, +} + +/// An iterator that generalizes *.zip()* and allows running multiple iterators in lockstep. +/// +/// The iterator `Zip<(I, J, ..., M)>` is formed from a tuple of iterators (or values that +/// implement [`IntoIterator`]) and yields elements +/// until any of the subiterators yields `None`. +/// +/// The iterator element type is a tuple like like `(A, B, ..., E)` where `A` to `E` are the +/// element types of the subiterator. +/// +/// **Note:** The result of this macro is a value of a named type (`Zip<(I, J, +/// ..)>` of each component iterator `I, J, ...`) if each component iterator is +/// nameable. +/// +/// Prefer [`izip!()`] over `multizip` for the performance benefits of using the +/// standard library `.zip()`. Prefer `multizip` if a nameable type is needed. +/// +/// ``` +/// use itertools::multizip; +/// +/// // iterate over three sequences side-by-side +/// let mut results = [0, 0, 0, 0]; +/// let inputs = [3, 7, 9, 6]; +/// +/// for (r, index, input) in multizip((&mut results, 0..10, &inputs)) { +/// *r = index * 10 + input; +/// } +/// +/// assert_eq!(results, [0 + 3, 10 + 7, 29, 36]); +/// ``` +pub fn multizip(t: U) -> Zip + where Zip: From, + Zip: Iterator, +{ + Zip::from(t) +} + +macro_rules! impl_zip_iter { + ($($B:ident),*) => ( + #[allow(non_snake_case)] + impl<$($B: IntoIterator),*> From<($($B,)*)> for Zip<($($B::IntoIter,)*)> { + fn from(t: ($($B,)*)) -> Self { + let ($($B,)*) = t; + Zip { t: ($($B.into_iter(),)*) } + } + } + + #[allow(non_snake_case)] + #[allow(unused_assignments)] + impl<$($B),*> Iterator for Zip<($($B,)*)> + where + $( + $B: Iterator, + )* + { + type Item = ($($B::Item,)*); + + fn next(&mut self) -> Option + { + let ($(ref mut $B,)*) = self.t; + + // NOTE: Just like iter::Zip, we check the iterators + // for None in order. We may finish unevenly (some + // iterators gave n + 1 elements, some only n). + $( + let $B = match $B.next() { + None => return None, + Some(elt) => elt + }; + )* + Some(($($B,)*)) + } + + fn size_hint(&self) -> (usize, Option) + { + let sh = (::std::usize::MAX, None); + let ($(ref $B,)*) = self.t; + $( + let sh = size_hint::min($B.size_hint(), sh); + )* + sh + } + } + + #[allow(non_snake_case)] + impl<$($B),*> ExactSizeIterator for Zip<($($B,)*)> where + $( + $B: ExactSizeIterator, + )* + { } + + #[allow(non_snake_case)] + impl<$($B),*> DoubleEndedIterator for Zip<($($B,)*)> where + $( + $B: DoubleEndedIterator + ExactSizeIterator, + )* + { + #[inline] + fn next_back(&mut self) -> Option { + let ($(ref mut $B,)*) = self.t; + let size = *[$( $B.len(), )*].iter().min().unwrap(); + + $( + if $B.len() != size { + for _ in 0..$B.len() - size { $B.next_back(); } + } + )* + + match ($($B.next_back(),)*) { + ($(Some($B),)*) => Some(($($B,)*)), + _ => None, + } + } + } + ); +} + +impl_zip_iter!(A); +impl_zip_iter!(A, B); +impl_zip_iter!(A, B, C); +impl_zip_iter!(A, B, C, D); +impl_zip_iter!(A, B, C, D, E); +impl_zip_iter!(A, B, C, D, E, F); +impl_zip_iter!(A, B, C, D, E, F, G); +impl_zip_iter!(A, B, C, D, E, F, G, H); +impl_zip_iter!(A, B, C, D, E, F, G, H, I); +impl_zip_iter!(A, B, C, D, E, F, G, H, I, J); +impl_zip_iter!(A, B, C, D, E, F, G, H, I, J, K); +impl_zip_iter!(A, B, C, D, E, F, G, H, I, J, K, L); -- cgit v1.2.3