Unit test heapsort

2 files changed, 11 insertions, 2 deletions

diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index 53cbdd84c3a..6f8b199f886 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -2253,6 +2253,15 @@ pub unsafe fn from_raw_parts_mut<'a, T>(p: *mut T, len: usize) -> &'a mut [T] {
     mem::transmute(Repr { data: p, len: len })
 }
 
+// This function is public only because there is no other way to unit test heapsort.
+#[unstable(feature = "sort_internals", reason = "internal to sort module", issue = "0")]
+#[doc(hidden)]
+pub fn heapsort<T, F>(v: &mut [T], mut is_less: F)
+    where F: FnMut(&T, &T) -> bool
+{
+    sort::heapsort(v, &mut is_less);
+}
+
 //
 // Comparison traits
 //
diff --git a/src/libcore/slice/sort.rs b/src/libcore/slice/sort.rs
index a015c8fc120..fdfba33f8a9 100644
--- a/src/libcore/slice/sort.rs
+++ b/src/libcore/slice/sort.rs
@@ -57,7 +57,7 @@ fn shift_head<T, F>(v: &mut [T], is_less: &mut F)
             ptr::copy_nonoverlapping(v.get_unchecked(1), v.get_unchecked_mut(0), 1);
 
             for i in 2..len {
-                if !is_less(&v[i], &tmp.value) {
+                if !is_less(v.get_unchecked(i), &tmp.value) {
                     break;
                 }
 
@@ -159,7 +159,7 @@ fn insertion_sort<T, F>(v: &mut [T], is_less: &mut F)
 
 /// Sorts `v` using heapsort, which guarantees `O(n log n)` worst-case.
 #[cold]
-fn heapsort<T, F>(v: &mut [T], is_less: &mut F)
+pub fn heapsort<T, F>(v: &mut [T], is_less: &mut F)
     where F: FnMut(&T, &T) -> bool
 {
     // This binary heap respects the invariant `parent >= child`.