1 files changed, 166 insertions, 0 deletions
diff --git a/vendor/array_tool/src/iter.rs b/vendor/array_tool/src/iter.rs
new file mode 100644
index 000000000..a176d5c79
--- /dev/null
+++ b/vendor/array_tool/src/iter.rs
@@ -0,0 +1,166 @@
+use std::cmp;
+use std::iter::IntoIterator;
+
+#[doc(hidden)]
+#[derive(Clone, Debug)]
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+pub struct ZipOption<A, B> {
+  a: A,
+  b: B,
+  // index and len are only used by the specialized version of zip
+  index: usize,
+  len: usize,
+}
+
+/// Zips to iterators together to the longest length
+/// via Option<(Option<A>, Option<B>)>
+pub trait ZipOpt {
+  /// Zip to iterators to longest length via Option<(Option<A>, Option<B>)> results.
+  /// # Example
+  /// ```
+  /// use array_tool::iter::ZipOpt;
+  ///
+  /// let a = vec!["a","b","c", "d"];
+  /// let b = vec!["c","d"];
+  /// let mut x = a.iter().zip_option(b.iter());
+  ///
+  /// assert_eq!(x.next(), Some((Some(&"a"), Some(&"c"))));
+  /// assert_eq!(x.next(), Some((Some(&"b"), Some(&"d"))));
+  /// assert_eq!(x.next(), Some((Some(&"c"), None)));
+  /// assert_eq!(x.next(), Some((Some(&"d"), None)));
+  /// assert_eq!(x.next(), None);
+  /// ```
+  ///
+  /// # Output
+  /// ```text
+  /// vec![ "a", "b", "c", "d" ]
+  /// ```
+  fn zip_option<U>(self, other: U) -> ZipOption<Self, U::IntoIter>
+    where Self: Sized, U: IntoIterator;
+}
+
+impl<I: Iterator> ZipOpt for I {
+  #[inline]
+  fn zip_option<U>(self, other: U) -> ZipOption<Self, U::IntoIter>
+    where Self: Sized, U: IntoIterator {
+
+    ZipOption::new(self, other.into_iter())
+  }
+}
+
+impl<A, B> Iterator for ZipOption<A, B> where A: Iterator, B: Iterator {
+  type Item = (Option<A::Item>, Option<B::Item>);
+
+  #[inline]
+  fn next(&mut self) -> Option<Self::Item> {
+    ZipImpl::next(self)
+  }
+
+  #[inline]
+  fn size_hint(&self) -> (usize, Option<usize>) {
+    ZipImpl::size_hint(self)
+  }
+
+  #[inline]
+  fn nth(&mut self, n: usize) -> Option<Self::Item> {
+    ZipImpl::nth(self, n)
+  }
+}
+
+#[doc(hidden)]
+impl<A, B> DoubleEndedIterator for ZipOption<A, B> where
+A: DoubleEndedIterator + ExactSizeIterator,
+B: DoubleEndedIterator + ExactSizeIterator,
+{
+  #[inline]
+  fn next_back(&mut self) -> Option<(Option<A::Item>, Option<B::Item>)> {
+    ZipImpl::next_back(self)
+  }
+}
+
+#[doc(hidden)]
+trait ZipImpl<A, B> {
+  type Item;
+  fn new(a: A, b: B) -> Self;
+  fn next(&mut self) -> Option<Self::Item>;
+  fn size_hint(&self) -> (usize, Option<usize>);
+  fn nth(&mut self, n: usize) -> Option<Self::Item>;
+  fn super_nth(&mut self, mut n: usize) -> Option<Self::Item> {
+    while let Some(x) = self.next() {
+      if n == 0 { return Some(x) }
+      n -= 1;
+    }
+    None
+  }
+  fn next_back(&mut self) -> Option<Self::Item>
+    where A: DoubleEndedIterator + ExactSizeIterator,
+          B: DoubleEndedIterator + ExactSizeIterator;
+}
+
+#[doc(hidden)]
+impl<A, B> ZipImpl<A, B> for ZipOption<A, B>
+  where A: Iterator, B: Iterator {
+  type Item = (Option<A::Item>, Option<B::Item>);
+  fn new(a: A, b: B) -> Self {
+    ZipOption {
+      a,
+      b,
+      index: 0, // unused
+      len: 0, // unused
+    }
+  }
+
+  #[inline]
+  fn next(&mut self) -> Option<(Option<A::Item>, Option<B::Item>)> {
+    let first = self.a.next();
+    let second = self.b.next();
+
+    if first.is_some() || second.is_some() {
+      Some((first, second))
+    } else {
+      None
+    }
+  }
+
+  #[inline]
+  fn nth(&mut self, n: usize) -> Option<Self::Item> {
+    self.super_nth(n)
+  }
+
+  #[inline]
+  fn next_back(&mut self) -> Option<(Option<A::Item>, Option<B::Item>)>
+    where A: DoubleEndedIterator + ExactSizeIterator,
+          B: DoubleEndedIterator + ExactSizeIterator {
+    let a_sz = self.a.len();
+    let b_sz = self.b.len();
+    if a_sz != b_sz {
+      // Adjust a, b to equal length
+      if a_sz > b_sz {
+        for _ in 0..a_sz - b_sz { self.a.next_back(); }
+      } else {
+        for _ in 0..b_sz - a_sz { self.b.next_back(); }
+      }
+    }
+    match (self.a.next_back(), self.b.next_back()) {
+      (None, None) => None,
+      (f,s) => Some((f, s)),
+    }
+  }
+
+  #[inline]
+  fn size_hint(&self) -> (usize, Option<usize>) {
+    let (a_lower, a_upper) = self.a.size_hint();
+    let (b_lower, b_upper) = self.b.size_hint();
+
+    let lower = cmp::min(a_lower, b_lower);
+
+    let upper = match (a_upper, b_upper) {
+      (Some(x), Some(y)) => Some(cmp::max(x,y)),
+      (Some(x), None) => Some(x),
+      (None, Some(y)) => Some(y),
+      (None, None) => None
+    };
+
+    (lower, upper)
+  }
+}