query/detail/segmented_find_if.hpp

0001 /*=============================================================================
0002     Copyright (c) 2011 Eric Niebler
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 ==============================================================================*/
0007 #if !defined(BOOST_FUSION_SEGMENTED_FIND_IF_HPP_INCLUDED)
0008 #define BOOST_FUSION_SEGMENTED_FIND_IF_HPP_INCLUDED
0009
0010 #include <boost/fusion/support/config.hpp>
0011 #include <boost/mpl/eval_if.hpp>
0012 #include <boost/mpl/identity.hpp>
0013 #include <boost/fusion/algorithm/query/find_if_fwd.hpp>
0014 #include <boost/fusion/iterator/equal_to.hpp>
0015 #include <boost/fusion/sequence/intrinsic/end.hpp>
0016 #include <boost/fusion/support/segmented_fold_until.hpp>
0017
0018 namespace boost { namespace fusion { namespace detail
0019 {
0020     template <typename Pred>
0021     struct segmented_find_if_fun
0022     {
0023         template <typename Sequence, typename State, typename Context>
0024         struct apply
0025         {
0026             typedef
0027                 typename result_of::find_if<Sequence, Pred>::type
0028             iterator_type;
0029
0030             typedef
0031                 typename result_of::equal_to<
0032                     iterator_type
0033                   , typename result_of::end<Sequence>::type
0034                 >::type
0035             continue_type;
0036
0037             typedef
0038                 typename mpl::eval_if<
0039                     continue_type
0040                   , mpl::identity<State>
0041                   , result_of::make_segmented_iterator<
0042                         iterator_type
0043                       , Context
0044                     >
0045                 >::type
0046             type;
0047
0048             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0049             static type call(Sequence& seq, State const&state, Context const& context, segmented_find_if_fun)
0050             {
0051                 return call_impl(seq, state, context, continue_type());
0052             }
0053
0054             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0055             static type call_impl(Sequence&, State const&state, Context const&, mpl::true_)
0056             {
0057                 return state;
0058             }
0059
0060             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0061             static type call_impl(Sequence& seq, State const&, Context const& context, mpl::false_)
0062             {
0063                 return fusion::make_segmented_iterator(fusion::find_if<Pred>(seq), context);
0064             }
0065         };
0066     };
0067
0068     template <typename Sequence, typename Pred>
0069     struct result_of_segmented_find_if
0070     {
0071         struct filter
0072         {
0073             typedef
0074                 typename result_of::segmented_fold_until<
0075                     Sequence
0076                   , typename result_of::end<Sequence>::type
0077                   , segmented_find_if_fun<Pred>
0078                 >::type
0079             type;
0080
0081             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0082             static type call(Sequence& seq)
0083             {
0084                 return fusion::segmented_fold_until(
0085                     seq
0086                   , fusion::end(seq)
0087                   , segmented_find_if_fun<Pred>());
0088             }
0089         };
0090
0091         typedef typename filter::type type;
0092     };
0093 }}}
0094
0095 #endif