---

yaml
---
r: 94962
b: refs/heads/dist-snap
c: 48499c7
h: refs/heads/master
v: v3

Author: bors

[refs]

@@ -6,7 +6,7 @@ refs/heads/try: c274a6888410ce3e357e014568b43310ed787d36
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: 147ecfdd8221e4a4d4e090486829a06da1e0ca3c
-refs/heads/dist-snap: daee1b4d5c6e1db8563c57ff5529b62d0a29fbde
+refs/heads/dist-snap: 48499c7494d47f505a640157816cea2690b8d407
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503
 refs/heads/try3: 9387340aab40a73e8424c48fd42f0c521a4875c0

branches/dist-snap/src/libextra/ringbuf.rs

@@ -143,6 +143,19 @@ impl<T> RingBuf<T> {
         }
     }
 
+    /// Swap elements at indices `i` and `j`
+    ///
+    /// `i` and `j` may be equal.
+    ///
+    /// Fails if there is no element with the given index
+    pub fn swap(&mut self, i: uint, j: uint) {
+        assert!(i < self.len());
+        assert!(j < self.len());
+        let ri = self.raw_index(i);
+        let rj = self.raw_index(j);
+        self.elts.swap(ri, rj);
+    }
+
     /// Return index in underlying vec for a given logical element index
     fn raw_index(&self, idx: uint) -> uint {
         raw_index(self.lo, self.elts.len(), idx)
@@ -604,6 +617,14 @@ mod tests {
         assert_eq!(d.elts.capacity(), 64);
     }
 
+    #[test]
+    fn test_swap() {
+        let mut d: RingBuf<int> = range(0, 5).collect();
+        d.pop_front();
+        d.swap(0, 3);
+        assert_eq!(d.iter().map(|&x|x).collect::<~[int]>(), ~[4, 2, 3, 1]);
+    }
+
     #[test]
     fn test_iter() {
         let mut d = RingBuf::new();