1 files changed, 101 insertions, 0 deletions
diff --git a/src/iterators.rs b/src/iterators.rs
new file mode 100644
index 0000000..2d7a673
--- /dev/null
+++ b/src/iterators.rs
@@ -0,0 +1,101 @@
+use ::tree;
+use ::node;
+use std::collections::Bound;
+
+pub struct RangePairIter<'a, K:'a+Ord+Copy,D:'a> {
+    tree: &'a tree::AVLTree<K, D>,
+    from: Bound<K>,
+    to: Bound<K>,
+    prev: Option<&'a K>,
+}
+
+impl<'a, K:'a+Ord+Copy,D:'a> RangePairIter<'a, K, D> {
+
+    pub fn new(tree: &'a tree::AVLTree<K,D>, lower: Bound<K>, upper: Bound<K>) -> RangePairIter<'a,K,D>{
+        RangePairIter{tree: tree, from: lower, to: upper, prev:None}
+    }
+
+    fn get_next_key_under(&mut self, root: &'a Box<node::Node<K,D>>) -> Option<(&'a K,&'a D)>{
+        let res = self.get_next_pair(root).and_then(|p| self.check_upper_bound(p));
+        if let Some((key,_)) = res { self.prev = Some(key) }
+        return res
+    }
+
+    fn get_next_pair(&mut self, root: &'a Box<node::Node<K,D>>) -> Option<(&'a K, &'a D)>{
+        match self.prev{
+            None => self.get_lower_bound_pair(root),
+            Some(key) => node::min_after::<K,D>(key, root)
+        }
+    }
+
+    fn get_lower_bound_pair(&self, root: &'a Box<node::Node<K,D>>) -> Option<(&'a K, &'a D)>{
+        match self.from {
+            Bound::Included(ref key) => node::search_pair(key, root).or_else(|| node::min_after(key, root)),
+            Bound::Excluded(ref key) => node::min_after(key, root),
+            Bound::Unbounded => Some(node::min_pair(root))
+        }
+    }
+
+    fn check_upper_bound(&self, current: (&'a K, &'a D)) -> Option<(&'a K, &'a D)> {
+        let ok = match self.to {
+            Bound::Included(ref key) => current.0 <= key,
+            Bound::Excluded(ref key) => current.0 < key,
+            Bound::Unbounded => true
+        };
+        return if ok { Some(current) } else { None };
+    }
+}
+
+impl<'a, K:'a+Ord+Copy,D:'a> Iterator for RangePairIter<'a, K, D> {
+
+    type Item = (&'a K,&'a D);
+
+    fn next(&mut self) -> Option<(&'a K,&'a D)> {
+        self.tree.root.as_ref().map_or(None,|node| self.get_next_key_under(node))
+    }
+
+
+}
+
+#[test]
+fn test_iterators(){
+    let mut tree = tree::AVLTree::<u64,i32>::new();
+    tree.insert(18, 1337);
+    tree.insert(13, 1338);
+    tree.insert(17, 1339);
+    tree.insert(10, 1321);
+    tree.insert(1, 1321);
+    tree.insert(3, 1322);
+    let init_key = 0;
+    let mut iter = RangePairIter::<u64,i32>{tree: &tree, prev: Some(&init_key), from: Bound::Unbounded, to: Bound::Unbounded};
+    assert_eq!(iter.next().expect("should have a few values").0, &1);
+    assert_eq!(iter.next().expect("should have a few values").0, &3);
+    assert_eq!(iter.next().expect("should have a few values").0, &10);
+    assert_eq!(iter.next().expect("should have a few values").0, &13);
+    assert_eq!(iter.next().expect("should have a few values").0, &17);
+    assert_eq!(iter.next().expect("should have a few values").0, &18);
+    assert!(iter.next().is_none());
+
+    let mut iter = RangePairIter::new(&tree, Bound::Unbounded, Bound::Unbounded);
+    assert_eq!(iter.next().expect("should have a few values").0, &1);
+    assert_eq!(iter.next().expect("should have a few values").0, &3);
+    assert_eq!(iter.next().expect("should have a few values").0, &10);
+    assert_eq!(iter.next().expect("should have a few values").0, &13);
+    assert_eq!(iter.next().expect("should have a few values").0, &17);
+    assert_eq!(iter.next().expect("should have a few values").0, &18);
+    assert!(iter.next().is_none());
+
+    let mut iter = RangePairIter::new(&tree, Bound::Included(3), Bound::Included(17));
+    assert_eq!(iter.next().expect("should have a few values").0, &3);
+    assert_eq!(iter.next().expect("should have a few values").0, &10);
+    assert_eq!(iter.next().expect("should have a few values").0, &13);
+    assert_eq!(iter.next().expect("should have a few values").0, &17);
+    assert!(iter.next().is_none());
+
+    let mut iter = RangePairIter::new(&tree, Bound::Excluded(1), Bound::Excluded(18));
+    assert_eq!(iter.next().expect("should have a few values").0, &3);
+    assert_eq!(iter.next().expect("should have a few values").0, &10);
+    assert_eq!(iter.next().expect("should have a few values").0, &13);
+    assert_eq!(iter.next().expect("should have a few values").0, &17);
+    assert!(iter.next().is_none());
+}