Updated boost to v1.55.0

[rsem.git] / boost / range / detail / extract_optional_type.hpp

diff --git a/boost/range/detail/extract_optional_type.hpp b/boost/range/detail/extract_optional_type.hpp
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+++ b/boost/range/detail/extract_optional_type.hpp
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+// Boost.Range library
+//
+//  Copyright Arno Schoedl & Neil Groves 2009.
+//  Use, modification and distribution is subject to 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)
+//
+// For more information, see http://www.boost.org/libs/range/
+//
+#ifndef BOOST_RANGE_DETAIL_EXTRACT_OPTIONAL_TYPE_HPP_INCLUDED
+#define BOOST_RANGE_DETAIL_EXTRACT_OPTIONAL_TYPE_HPP_INCLUDED
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif
+
+#include <boost/config.hpp>
+
+#ifdef BOOST_NO_PARTIAL_SPECIALIZATION_IMPLICIT_DEFAULT_ARGS
+
+#define BOOST_RANGE_EXTRACT_OPTIONAL_TYPE( a_typedef )                         \
+    template< typename C >                                                     \
+    struct extract_ ## a_typedef                                               \
+    {                                                                          \
+        typedef BOOST_DEDUCED_TYPENAME C::a_typedef type;                      \
+    };
+
+#else
+
+namespace boost {
+    namespace range_detail {
+        template< typename T > struct exists { typedef void type; };
+    }
+}
+
+// Defines extract_some_typedef<T> which exposes T::some_typedef as
+// extract_some_typedef<T>::type if T::some_typedef exists. Otherwise
+// extract_some_typedef<T> is empty.
+#define BOOST_RANGE_EXTRACT_OPTIONAL_TYPE( a_typedef )                         \
+    template< typename C, typename Enable=void >                               \
+    struct extract_ ## a_typedef                                               \
+    {};                                                                        \
+    template< typename C >                                                     \
+    struct extract_ ## a_typedef< C                                            \
+    , BOOST_DEDUCED_TYPENAME boost::range_detail::exists< BOOST_DEDUCED_TYPENAME C::a_typedef >::type \
+    > {                                                                        \
+        typedef BOOST_DEDUCED_TYPENAME C::a_typedef type;                      \
+    };
+
+#endif
+
+#endif // include guard