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authorJonathan Wakely <jwakely.gcc@gmail.com>2013-05-18 16:18:35 +0000
committerJonathan Wakely <redi@gcc.gnu.org>2013-05-18 17:18:35 +0100
commitc98b05982b100875144e2074ec7ecbdeee15bc4f (patch)
treef2b2b59742efeb4164b966ee4103f5f852051c65
parenta9769eb0d92ea9ffa19fac1f7a30c1b31caae4be (diff)
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utility (exchange): Define.
* include/std/utility (exchange): Define. * testsuite/20_util/exchange/1.cc: New. From-SVN: r199061
-rw-r--r--libstdc++-v3/ChangeLog5
-rw-r--r--libstdc++-v3/include/std/utility12
-rw-r--r--libstdc++-v3/testsuite/20_util/exchange/1.cc103
3 files changed, 120 insertions, 0 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 3fba85c..0f9cee8 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,10 @@
2013-05-18 Jonathan Wakely <jwakely.gcc@gmail.com>
+ * include/std/utility (exchange): Define.
+ * testsuite/20_util/exchange/1.cc: New.
+
+2013-05-18 Jonathan Wakely <jwakely.gcc@gmail.com>
+
* include/bits/unique_ptr.h (make_unique): Define.
* testsuite/20_util/unique_ptr/creation/single.cc: New.
* testsuite/20_util/unique_ptr/creation/array.cc: New.
diff --git a/libstdc++-v3/include/std/utility b/libstdc++-v3/include/std/utility
index 8142ea4..ee8c6b1 100644
--- a/libstdc++-v3/include/std/utility
+++ b/libstdc++-v3/include/std/utility
@@ -152,6 +152,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
get(const std::pair<_Tp1, _Tp2>& __in) noexcept
{ return __pair_get<_Int>::__const_get(__in); }
+#if __cplusplus > 201103L
+ /// Assign @p __new_val to @p __obj and return its previous value.
+ template <class _Tp, class _Up = _Tp>
+ inline _Tp
+ exchange(_Tp& __obj, _Up&& __new_val)
+ {
+ _Tp __old_val = std::move(__obj);
+ __obj = std::forward<_Up>(__new_val);
+ return __old_val;
+ }
+#endif
+
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
diff --git a/libstdc++-v3/testsuite/20_util/exchange/1.cc b/libstdc++-v3/testsuite/20_util/exchange/1.cc
new file mode 100644
index 0000000..d16d9e9
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/exchange/1.cc
@@ -0,0 +1,103 @@
+// { dg-options "-std=gnu++1y" }
+
+// Copyright (C) 2013 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 even 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/>.
+
+// 20.2.3 exchange [utility.exchange]
+
+#include <utility>
+#include <type_traits>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+ const unsigned val = 4;
+ int i = 1;
+ auto prev = std::exchange(i, val);
+ static_assert( std::is_same<decltype(prev), int>::value, "return type" );
+ VERIFY( i == 4 );
+ VERIFY( prev == 1 );
+ prev = std::exchange(i, 3);
+ VERIFY( i == 3 );
+ VERIFY( prev == 4 );
+}
+
+// Default construction from empty braces
+void
+test02()
+{
+ bool test __attribute__((unused)) = true;
+
+ struct DefaultConstructible
+ {
+ DefaultConstructible(int i = 0) : value(i) { }
+ int value;
+ };
+
+ DefaultConstructible x = 1;
+ auto old = std::exchange(x, {});
+ VERIFY( x.value == 0 );
+ VERIFY( old.value == 1 );
+}
+
+// Deduce type of overloaded function
+void
+test03()
+{
+ bool test __attribute__((unused)) = true;
+
+ int (*fp)(int);
+ int f(int);
+ double f(double);
+ std::exchange(fp, &f);
+ VERIFY( fp != nullptr );
+}
+
+void test04()
+{
+ struct From { };
+ struct To {
+ int value = 0;
+ To() = default;
+ To(const To&) = default;
+ To(const From&) = delete;
+ To& operator=(const From&) { value = 1; }
+ To& operator=(From&&) { value = 2; }
+ };
+
+ To t;
+ From f;
+
+ auto prev = std::exchange(t, f);
+ VERIFY( t.value == 1 );
+ VERIFY( prev.value == 0 );
+
+ prev = std::exchange(t, From{});
+ VERIFY( t.value == 2 );
+ VERIFY( prev.value == 1 );
+}
+
+int
+main()
+{
+ test01();
+ test02();
+ test03();
+ test04();
+ return 0;
+}