itertools/
zip_eq_impl.rs

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

itertools/
zip_eq_impl.rs
