re PR libstdc++/50119 ([C++0x] copy_n advances InputIterator one more time than neces...

2011-08-18  Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/50119
	* include/bits/stl_algo.h (__copy_n(_InputIterator, _Size,
	_OutputIterator, input_iterator_tag)): Fix.
	* testsuite/25_algorithms/copy_n/50119.cc: New.

From-SVN: r177871

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index e45c891df2444c4010576ca198e723d1180fc470..2145f89ea6d6171a80d46bceb0e1070de4458807 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,7 +1,14 @@
+2011-08-18  Paolo Carlini  <paolo.carlini@oracle.com>
+
+       PR libstdc++/50119
+       * include/bits/stl_algo.h (__copy_n(_InputIterator, _Size,
+       _OutputIterator, input_iterator_tag)): Fix.
+       * testsuite/25_algorithms/copy_n/50119.cc: New.
+
 2011-08-18  Marc Glisse  <marc.glisse@normalesup.org>
            Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
-       PR libstdc++-v3/1773
+       PR libstdc++/1773
        * config/os/solaris2.7: Rename to config/os/solaris2.9.
        * config/os/solaris/solaris2.9/os_defines.h
        (__CORRECT_ISO_CPP_MATH_H_PROTO1)

diff --git a/libstdc++-v3/include/bits/stl_algo.h b/libstdc++-v3/include/bits/stl_algo.h
index ba49228dfb4dd715ced926478b5eea0dec0d1e0f..10c7e2d0756344f95dc00903dd273249d12c096d 100644 (file)
--- a/libstdc++-v3/include/bits/stl_algo.h
+++ b/libstdc++-v3/include/bits/stl_algo.h
@@ -979,11 +979,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     __copy_n(_InputIterator __first, _Size __n,
             _OutputIterator __result, input_iterator_tag)
     {
-      for (; __n > 0; --__n)
+      if (__n > 0)
        {
-         *__result = *__first;
-         ++__first;
-         ++__result;
+         while (true)
+           {
+             *__result = *__first;
+             ++__result;
+             if (--__n > 0)
+               ++__first;
+             else
+               break;
+           }
        }
       return __result;
     }

diff --git a/libstdc++-v3/testsuite/25_algorithms/copy_n/50119.cc b/libstdc++-v3/testsuite/25_algorithms/copy_n/50119.cc
new file mode 100644 (file)
index 0000000..6803f96
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/copy_n/50119.cc
@@ -0,0 +1,52 @@
+// { dg-options "-std=gnu++0x" }
+
+// Copyright (C) 2011 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without Pred the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <algorithm>
+#include <vector>
+#include <sstream>
+#include <iterator>
+#include <testsuite_hooks.h>
+
+// libstdc++/50119
+void test01()
+{
+  using namespace std;
+  bool test __attribute__((unused)) = true;
+
+  vector<int> v;
+  istringstream s("1 2 3 4 5");
+
+  copy_n(istream_iterator<int>(s), 2, back_inserter(v));
+  VERIFY( v.size() == 2 );
+  VERIFY( v[0] == 1 );
+  VERIFY( v[1] == 2 );
+
+  copy_n(istream_iterator<int>(s), 2, back_inserter(v));
+  VERIFY( v.size() == 4 );
+  VERIFY( v[0] == 1 );
+  VERIFY( v[1] == 2 );
+  VERIFY( v[2] == 3 );
+  VERIFY( v[3] == 4 );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}