Added boost header

test/external/boost/signals2/optional_last_value.hpp

@@ -0,0 +1,65 @@
+// optional_last_value function object (documented as part of Boost.Signals2)
+
+// Copyright Frank Mori Hess 2007-2008.
+// Copyright Douglas Gregor 2001-2003.
+// Distributed under the Boost Software License, Version
+// 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+// See http://www.boost.org/libs/signals2 for library home page.
+
+#ifndef BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
+#define BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
+
+#include <boost/optional.hpp>
+#include <boost/signals2/expired_slot.hpp>
+
+namespace boost {
+  namespace signals2 {
+
+    template<typename T>
+      class optional_last_value
+    {
+    public:
+      typedef optional<T> result_type;
+
+      template<typename InputIterator>
+        optional<T> operator()(InputIterator first, InputIterator last) const
+      {
+        optional<T> value;
+        while (first != last)
+        {
+          try
+          {
+            value = *first;
+          }
+          catch(const expired_slot &) {}
+          ++first;
+        }
+        return value;
+      }
+    };
+
+    template<>
+      class optional_last_value<void>
+    {
+    public:
+      typedef void result_type;
+      template<typename InputIterator>
+        result_type operator()(InputIterator first, InputIterator last) const
+      {
+        while (first != last)
+        {
+          try
+          {
+            *first;
+          }
+          catch(const expired_slot &) {}
+          ++first;
+        }
+        return;
+      }
+    };
+  } // namespace signals2
+} // namespace boost
+#endif // BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP