[cfe-commits] [libcxx] r126581 - /libcxx/trunk/include/algorithm

[Howard Hinnant]

Author: hhinnant
Date: Sun Feb 27 14:55:39 2011
New Revision: 126581

URL: http://llvm.org/viewvc/llvm-project?rev=126581&view=rev
Log:
Fix copy_n to increment only n-1 times for an input iterator.  This works much better with std::istream_iterator<int>(std::cin).  Credit: Matan Nassau.

Modified:
    libcxx/trunk/include/algorithm

Modified: libcxx/trunk/include/algorithm
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/algorithm?rev=126581&r1=126580&r2=126581&view=diff
==============================================================================
--- libcxx/trunk/include/algorithm (original)
+++ libcxx/trunk/include/algorithm Sun Feb 27 14:55:39 2011
@@ -1559,8 +1559,17 @@
 >::type
 copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
 {
-    for (; __n > 0; --__n, ++__first, ++__result)
+    if (__n > 0)
+    {
         *__result = *__first;
+        ++__result;
+        for (--__n; __n > 0; --__n)
+        {
+            ++__first;
+            *__result = *__first;
+            ++__result;
+        }
+    }
     return __result;
 }