AK: Tweak exchange() implementation

Make it constexpr and do perfect forwarding.

1 files changed, 8 insertions, 8 deletions

diff --git a/AK/StdLibExtras.h b/AK/StdLibExtras.h
index 5a714fee2f..0d95585aa0 100644
--- a/AK/StdLibExtras.h
+++ b/AK/StdLibExtras.h
@@ -82,14 +82,6 @@ inline T&& move(T& arg)
 #endif
 
 template<typename T, typename U>
-inline T exchange(T& a, U&& b)
-{
-    T tmp = move(a);
-    a = move(b);
-    return tmp;
-}
-
-template<typename T, typename U>
 inline void swap(T& a, U& b)
 {
     U tmp = move((U&)a);
@@ -370,6 +362,14 @@ struct MakeUnsigned<unsigned long long> {
     typedef unsigned long long type;
 };
 
+template<typename T, typename U = T>
+inline constexpr T exchange(T& slot, U&& value)
+{
+    T old_value = move(slot);
+    slot = forward<U>(value);
+    return old_value;
+}
+
 }
 
 using AK::ceil_div;