commit 4e5994824958a4615181f50c05eddcbc7c3a6641
author Howard Hinnant <hhinnant@apple.com> Fri Oct 22 15:26:39 2010 +0000
committer Howard Hinnant <hhinnant@apple.com> Fri Oct 22 15:26:39 2010 +0000
tree aed07bdc717f78090df2767aaac5afc4540eda6f
parent bce9c3132d75041bcc1e693fd2cc25a13cc497d6

Fixed bug in random_shuffle to avoid swapping with self

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@117098 91177308-0d34-0410-b5e6-96231b3b80d8

include/algorithm

diff --git a/include/algorithm b/include/algorithm
index 74feafd..b895f03 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -2686,7 +2686,11 @@
         _D __uid;
         __rs_default __g = __rs_get();
         for (--__last, --__d; __first < __last; ++__first, --__d)
-            swap(*__first, *(__first + __uid(__g, _P(0, __d))));
+        {
+            difference_type __i = __uid(__g, _P(0, __d));
+            if (__i != difference_type(0))
+                swap(*__first, *(__first + __i));
+        }
     }
 }
 
@@ -2704,7 +2708,10 @@
     if (__d > 1)
     {
         for (--__last; __first < __last; ++__first, --__d)
-            swap(*__first, *(__first + __rand(__d)));
+        {
+            difference_type __i = __rand(__d);
+            swap(*__first, *(__first + __i));
+        }
     }
 }
 
@@ -2720,7 +2727,11 @@
     {
         _D __uid;
         for (--__last, --__d; __first < __last; ++__first, --__d)
-            swap(*__first, *(__first + __uid(__g, _P(0, __d))));
+        {
+            difference_type __i = __uid(__g, _P(0, __d));
+            if (__i != difference_type(0))
+                swap(*__first, *(__first + __i));
+        }
     }
 }