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Diffstat (limited to 'src/third_party/boost-1.69.0/boost/range/detail/extract_optional_type.hpp')
| -rw-r--r-- | src/third_party/boost-1.69.0/boost/range/detail/extract_optional_type.hpp | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/third_party/boost-1.69.0/boost/range/detail/extract_optional_type.hpp b/src/third_party/boost-1.69.0/boost/range/detail/extract_optional_type.hpp new file mode 100644 index 00000000000..0381434a859 --- /dev/null +++ b/src/third_party/boost-1.69.0/boost/range/detail/extract_optional_type.hpp @@ -0,0 +1,48 @@ +// 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) +# pragma once +#endif + +#include <boost/config.hpp> +#include <boost/preprocessor/cat.hpp> +#include <boost/mpl/has_xxx.hpp> + +#if !defined(BOOST_MPL_CFG_NO_HAS_XXX) + +// 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 ) \ + BOOST_MPL_HAS_XXX_TRAIT_DEF(a_typedef) \ + template< typename C, bool B = BOOST_PP_CAT(has_, a_typedef)<C>::value > \ + struct BOOST_PP_CAT(extract_, a_typedef) \ + {}; \ + template< typename C > \ + struct BOOST_PP_CAT(extract_, a_typedef)< C, true > \ + { \ + typedef BOOST_DEDUCED_TYPENAME C::a_typedef type; \ + }; + +#else + +#define BOOST_RANGE_EXTRACT_OPTIONAL_TYPE( a_typedef ) \ + template< typename C > \ + struct BOOST_PP_CAT(extract_, a_typedef) \ + { \ + typedef BOOST_DEDUCED_TYPENAME C::a_typedef type; \ + }; + +#endif + +#endif // include guard |