itertools/
zip_eq_impl.rs

1use super::size_hint;
2
3/// An iterator which iterates two other iterators simultaneously
4/// and panic if they have different lengths.
5///
6/// See [`.zip_eq()`](crate::Itertools::zip_eq) for more information.
7#[derive(Clone, Debug)]
8#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
9pub struct ZipEq<I, J> {
10    a: I,
11    b: J,
12}
13
14/// Zips two iterators but **panics** if they are not of the same length.
15///
16/// [`IntoIterator`] enabled version of [`Itertools::zip_eq`](crate::Itertools::zip_eq).
17///
18/// ```
19/// use itertools::zip_eq;
20///
21/// let data = [1, 2, 3, 4, 5];
22/// for (a, b) in zip_eq(&data[..data.len() - 1], &data[1..]) {
23///     /* loop body */
24///     # let _ = (a, b);
25/// }
26/// ```
27pub fn zip_eq<I, J>(i: I, j: J) -> ZipEq<I::IntoIter, J::IntoIter>
28where
29    I: IntoIterator,
30    J: IntoIterator,
31{
32    ZipEq {
33        a: i.into_iter(),
34        b: j.into_iter(),
35    }
36}
37
38impl<I, J> Iterator for ZipEq<I, J>
39where
40    I: Iterator,
41    J: Iterator,
42{
43    type Item = (I::Item, J::Item);
44
45    fn next(&mut self) -> Option<Self::Item> {
46        match (self.a.next(), self.b.next()) {
47            (None, None) => None,
48            (Some(a), Some(b)) => Some((a, b)),
49            (None, Some(_)) | (Some(_), None) => {
50                panic!("itertools: .zip_eq() reached end of one iterator before the other")
51            }
52        }
53    }
54
55    fn size_hint(&self) -> (usize, Option<usize>) {
56        size_hint::min(self.a.size_hint(), self.b.size_hint())
57    }
58}
59
60impl<I, J> ExactSizeIterator for ZipEq<I, J>
61where
62    I: ExactSizeIterator,
63    J: ExactSizeIterator,
64{
65}
itertools/zip_eq_impl.rs

itertools/
zip_eq_impl.rs
