vendor/llvm-project/llvmorg-15-init-17485-ga3e38b4a206b

1 files changed, 19 insertions, 6 deletions

diff --git a/libcxx/include/__algorithm/shuffle.h b/libcxx/include/__algorithm/shuffle.h
index 6c6ff5675dad..e32c6a7608ba 100644
--- a/libcxx/include/__algorithm/shuffle.h
+++ b/libcxx/include/__algorithm/shuffle.h
@@ -9,11 +9,13 @@
 #ifndef _LIBCPP___ALGORITHM_SHUFFLE_H
 #define _LIBCPP___ALGORITHM_SHUFFLE_H
 
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__debug>
 #include <__iterator/iterator_traits.h>
 #include <__random/uniform_int_distribution.h>
-#include <__utility/swap.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
 #include <cstddef>
 #include <cstdint>
 
@@ -134,13 +136,15 @@ random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
 }
 #endif
 
-template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
-    void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
-                 _UniformRandomNumberGenerator&& __g)
-{
+template <class _AlgPolicy, class _RandomAccessIterator, class _Sentinel, class _UniformRandomNumberGenerator>
+_RandomAccessIterator __shuffle(
+    _RandomAccessIterator __first, _Sentinel __last_sentinel, _UniformRandomNumberGenerator&& __g) {
     typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
     typedef uniform_int_distribution<ptrdiff_t> _Dp;
     typedef typename _Dp::param_type _Pp;
+
+    auto __original_last = _IterOps<_AlgPolicy>::next(__first, __last_sentinel);
+    auto __last = __original_last;
     difference_type __d = __last - __first;
     if (__d > 1)
     {
@@ -149,9 +153,18 @@ template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
         {
             difference_type __i = __uid(__g, _Pp(0, __d));
             if (__i != difference_type(0))
-                swap(*__first, *(__first + __i));
+                _IterOps<_AlgPolicy>::iter_swap(__first, __first + __i);
         }
     }
+
+    return __original_last;
+}
+
+template <class _RandomAccessIterator, class _UniformRandomNumberGenerator>
+void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+             _UniformRandomNumberGenerator&& __g) {
+  (void)std::__shuffle<_ClassicAlgPolicy>(
+      std::move(__first), std::move(__last), std::forward<_UniformRandomNumberGenerator>(__g));
 }
 
 _LIBCPP_END_NAMESPACE_STD