boost/mpl/iter_fold_if.hpp

0001
0002 #ifndef BOOST_MPL_ITER_FOLD_IF_HPP_INCLUDED
0003 #define BOOST_MPL_ITER_FOLD_IF_HPP_INCLUDED
0004
0005 // Copyright Aleksey Gurtovoy 2003-2004
0006 // Copyright Eric Friedman 2003
0007 //
0008 // Distributed under the Boost Software License, Version 1.0.
0009 // (See accompanying file LICENSE_1_0.txt or copy at
0010 // http://www.boost.org/LICENSE_1_0.txt)
0011 //
0012 // See http://www.boost.org/libs/mpl for documentation.
0013
0014 // $Id$
0015 // $Date$
0016 // $Revision$
0017
0018 #include <boost/mpl/begin_end.hpp>
0019 #include <boost/mpl/logical.hpp>
0020 #include <boost/mpl/always.hpp>
0021 #include <boost/mpl/eval_if.hpp>
0022 #include <boost/mpl/if.hpp>
0023 #include <boost/mpl/pair.hpp>
0024 #include <boost/mpl/apply.hpp>
0025 #include <boost/mpl/aux_/iter_fold_if_impl.hpp>
0026 #include <boost/mpl/aux_/na_spec.hpp>
0027 #include <boost/mpl/aux_/lambda_support.hpp>
0028 #include <boost/mpl/aux_/config/forwarding.hpp>
0029 #include <boost/mpl/aux_/config/workaround.hpp>
0030
0031 #include <boost/type_traits/is_same.hpp>
0032
0033 namespace boost { namespace mpl {
0034
0035 namespace aux {
0036
0037 template< typename Predicate, typename LastIterator >
0038 struct iter_fold_if_pred
0039 {
0040     template< typename State, typename Iterator > struct apply
0041 #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
0042         : and_<
0043               not_< is_same<Iterator,LastIterator> >
0044             , apply1<Predicate,Iterator>
0045             >
0046     {
0047 #else
0048     {
0049         typedef and_<
0050               not_< is_same<Iterator,LastIterator> >
0051             , apply1<Predicate,Iterator>
0052             > type;
0053 #endif
0054     };
0055 };
0056
0057 } // namespace aux
0058
0059 template<
0060       typename BOOST_MPL_AUX_NA_PARAM(Sequence)
0061     , typename BOOST_MPL_AUX_NA_PARAM(State)
0062     , typename BOOST_MPL_AUX_NA_PARAM(ForwardOp)
0063     , typename BOOST_MPL_AUX_NA_PARAM(ForwardPredicate)
0064     , typename BOOST_MPL_AUX_NA_PARAM(BackwardOp)
0065     , typename BOOST_MPL_AUX_NA_PARAM(BackwardPredicate)
0066     >
0067 struct iter_fold_if
0068 {
0069
0070     typedef typename begin<Sequence>::type first_;
0071     typedef typename end<Sequence>::type last_;
0072
0073     typedef typename eval_if<
0074           is_na<BackwardPredicate>
0075         , if_< is_na<BackwardOp>, always<false_>, always<true_> >
0076         , identity<BackwardPredicate>
0077         >::type backward_pred_;
0078
0079 // cwpro8 doesn't like 'cut-off' type here (use typedef instead)
0080 #if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) && !BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
0081     struct result_ :
0082 #else
0083     typedef
0084 #endif
0085         aux::iter_fold_if_impl<
0086           first_
0087         , State
0088         , ForwardOp
0089         , protect< aux::iter_fold_if_pred< ForwardPredicate,last_ > >
0090         , BackwardOp
0091         , backward_pred_
0092         >
0093 #if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) && !BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
0094     { };
0095 #else
0096     result_;
0097 #endif
0098
0099 public:
0100
0101     typedef pair<
0102           typename result_::state
0103         , typename result_::iterator
0104         > type;
0105
0106     BOOST_MPL_AUX_LAMBDA_SUPPORT(
0107           6
0108         , iter_fold_if
0109         , (Sequence,State,ForwardOp,ForwardPredicate,BackwardOp,BackwardPredicate)
0110         )
0111 };
0112
0113 BOOST_MPL_AUX_NA_SPEC(6, iter_fold_if)
0114
0115 }}
0116
0117 #endif // BOOST_MPL_ITER_FOLD_IF_HPP_INCLUDED