61 lines
1.5 KiB
Rust
61 lines
1.5 KiB
Rust
use super::size_hint;
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/// An iterator which iterates two other iterators simultaneously
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///
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/// See [`.zip_eq()`](crate::Itertools::zip_eq) for more information.
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#[derive(Clone, Debug)]
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#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
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pub struct ZipEq<I, J> {
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a: I,
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b: J,
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}
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/// Iterate `i` and `j` in lock step.
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///
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/// **Panics** if the iterators are not of the same length.
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///
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/// [`IntoIterator`] enabled version of [`Itertools::zip_eq`](crate::Itertools::zip_eq).
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///
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/// ```
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/// use itertools::zip_eq;
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///
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/// let data = [1, 2, 3, 4, 5];
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/// for (a, b) in zip_eq(&data[..data.len() - 1], &data[1..]) {
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/// /* loop body */
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/// }
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/// ```
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pub fn zip_eq<I, J>(i: I, j: J) -> ZipEq<I::IntoIter, J::IntoIter>
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where I: IntoIterator,
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J: IntoIterator
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{
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ZipEq {
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a: i.into_iter(),
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b: j.into_iter(),
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}
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}
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impl<I, J> Iterator for ZipEq<I, J>
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where I: Iterator,
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J: Iterator
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{
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type Item = (I::Item, J::Item);
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fn next(&mut self) -> Option<Self::Item> {
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match (self.a.next(), self.b.next()) {
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(None, None) => None,
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(Some(a), Some(b)) => Some((a, b)),
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(None, Some(_)) | (Some(_), None) =>
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panic!("itertools: .zip_eq() reached end of one iterator before the other")
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}
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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size_hint::min(self.a.size_hint(), self.b.size_hint())
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}
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}
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impl<I, J> ExactSizeIterator for ZipEq<I, J>
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where I: ExactSizeIterator,
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J: ExactSizeIterator
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{}
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