1 files changed, 10 insertions, 4 deletions
diff --git a/common/nextpnr.h b/common/nextpnr.h
index f9376fea..5fa946e1 100644
--- a/common/nextpnr.h
+++ b/common/nextpnr.h
@@ -631,15 +631,21 @@ struct DeterministicRNG
             rng64();
     }
 
-    template <typename T> void shuffle(std::vector<T> &a)
+    template <typename Iter> void shuffle(const Iter& begin, const Iter& end)
     {
-        for (size_t i = 0; i != a.size(); i++) {
-            size_t j = i + rng(a.size() - i);
+        size_t size = end - begin;
+        for (size_t i = 0; i != size; i++) {
+            size_t j = i + rng(size - i);
             if (j > i)
-                std::swap(a[i], a[j]);
+                std::swap(*(begin + i), *(begin + j));
         }
     }
 
+    template <typename T> void shuffle(std::vector<T> &a)
+    {
+        shuffle(a.begin(), a.end());
+    }
+
     template <typename T> void sorted_shuffle(std::vector<T> &a)
     {
         std::sort(a.begin(), a.end());