Jakub Kotur | a425e55 | 2020-12-21 17:28:15 +0100 | [diff] [blame] | 1 | use super::size_hint; |
| 2 | |
| 3 | /// An iterator which iterates two other iterators simultaneously |
| 4 | /// |
Joel Galenson | b593e25 | 2021-06-21 13:15:57 -0700 | [diff] [blame] | 5 | /// See [`.zip_eq()`](crate::Itertools::zip_eq) for more information. |
Jakub Kotur | a425e55 | 2020-12-21 17:28:15 +0100 | [diff] [blame] | 6 | #[derive(Clone, Debug)] |
| 7 | #[must_use = "iterator adaptors are lazy and do nothing unless consumed"] |
| 8 | pub 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 | /// |
Joel Galenson | b593e25 | 2021-06-21 13:15:57 -0700 | [diff] [blame] | 17 | /// [`IntoIterator`] enabled version of [`Itertools::zip_eq`](crate::Itertools::zip_eq). |
Jakub Kotur | a425e55 | 2020-12-21 17:28:15 +0100 | [diff] [blame] | 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 | /// ``` |
| 27 | pub 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 | |
| 37 | impl<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 | |
| 57 | impl<I, J> ExactSizeIterator for ZipEq<I, J> |
| 58 | where I: ExactSizeIterator, |
| 59 | J: ExactSizeIterator |
| 60 | {} |