auto merge of #7788 : MarkJr94/rust/from_iter, r=cmr

Added Iterators for HashMap/Set, TreeMap/Set, TrieMap/Set, and PriorityQueue as per Issue #7626 

1 files changed, 27 insertions, 0 deletions

diff --git a/src/libextra/priority_queue.rs b/src/libextra/priority_queue.rs
index 1f7ba9f6530..58bf4ba9247 100644
--- a/src/libextra/priority_queue.rs
+++ b/src/libextra/priority_queue.rs
@@ -16,6 +16,7 @@
 use std::unstable::intrinsics::{move_val_init, init};
 use std::util::{replace, swap};
 use std::vec;
+use std::iterator::FromIterator;
 
 /// A priority queue implemented with a binary heap
 pub struct PriorityQueue<T> {
@@ -191,6 +192,21 @@ impl<'self, T> Iterator<&'self T> for PriorityQueueIterator<'self, T> {
     fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
 }
 
+impl<T: Ord, Iter: Iterator<T>> FromIterator<T, Iter> for PriorityQueue<T> {
+    pub fn from_iterator(iter: &mut Iter) -> PriorityQueue<T> {
+        let (lower, _) = iter.size_hint();
+
+        let mut q = PriorityQueue::new();
+        q.reserve_at_least(lower);
+
+        for iter.advance |elem| {
+            q.push(elem);
+        }
+
+        q
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use sort::merge_sort;
@@ -341,4 +357,15 @@ mod tests {
     #[should_fail]
     #[ignore(cfg(windows))]
     fn test_empty_replace() { let mut heap = PriorityQueue::new(); heap.replace(5); }
+
+    #[test]
+    fn test_from_iter() {
+        let xs = ~[9u, 8, 7, 6, 5, 4, 3, 2, 1];
+
+        let mut q: PriorityQueue<uint> = xs.rev_iter().transform(|&x| x).collect();
+
+        for xs.iter().advance |&x| {
+            assert_eq!(q.pop(), x);
+        }
+    }
 }