1 
2 #ifndef BOOST_MPL_ITER_FOLD_IF_HPP_INCLUDED
3 #define BOOST_MPL_ITER_FOLD_IF_HPP_INCLUDED
4 
5 // Copyright Aleksey Gurtovoy 2003-2004
6 // Copyright Eric Friedman 2003
7 //
8 // Distributed under the Boost Software License, Version 1.0.
9 // (See accompanying file LICENSE_1_0.txt or copy at
10 // http://www.boost.org/LICENSE_1_0.txt)
11 //
12 // See http://www.boost.org/libs/mpl for documentation.
13 
14 // $Id: iter_fold_if.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
15 // $Date: 2008-10-10 23:19:02 -0700 (Fri, 10 Oct 2008) $
16 // $Revision: 49267 $
17 
18 #include <boost/mpl/begin_end.hpp>
19 #include <boost/mpl/logical.hpp>
20 #include <boost/mpl/always.hpp>
21 #include <boost/mpl/eval_if.hpp>
22 #include <boost/mpl/if.hpp>
23 #include <boost/mpl/pair.hpp>
24 #include <boost/mpl/apply.hpp>
25 #include <boost/mpl/aux_/iter_fold_if_impl.hpp>
26 #include <boost/mpl/aux_/na_spec.hpp>
27 #include <boost/mpl/aux_/lambda_support.hpp>
28 #include <boost/mpl/aux_/config/forwarding.hpp>
29 #include <boost/mpl/aux_/config/workaround.hpp>
30 
31 #include <boost/type_traits/is_same.hpp>
32 
33 namespace boost { namespace mpl {
34 
35 namespace aux {
36 
37 template< typename Predicate, typename LastIterator >
38 struct iter_fold_if_pred
39 {
40     template< typename State, typename Iterator > struct apply
41 #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
42         : and_<
43               not_< is_same<Iterator,LastIterator> >
44             , apply1<Predicate,Iterator>
45             >
46     {
47 #else
48     {
49         typedef and_<
50               not_< is_same<Iterator,LastIterator> >
51             , apply1<Predicate,Iterator>
52             > type;
53 #endif
54     };
55 };
56 
57 } // namespace aux
58 
59 template<
60       typename BOOST_MPL_AUX_NA_PARAM(Sequence)
61     , typename BOOST_MPL_AUX_NA_PARAM(State)
62     , typename BOOST_MPL_AUX_NA_PARAM(ForwardOp)
63     , typename BOOST_MPL_AUX_NA_PARAM(ForwardPredicate)
64     , typename BOOST_MPL_AUX_NA_PARAM(BackwardOp)
65     , typename BOOST_MPL_AUX_NA_PARAM(BackwardPredicate)
66     >
67 struct iter_fold_if
68 {
69 
70     typedef typename begin<Sequence>::type first_;
71     typedef typename end<Sequence>::type last_;
72 
73     typedef typename eval_if<
74           is_na<BackwardPredicate>
75         , if_< is_na<BackwardOp>, always<false_>, always<true_> >
76         , identity<BackwardPredicate>
77         >::type backward_pred_;
78 
79 // cwpro8 doesn't like 'cut-off' type here (use typedef instead)
80 #if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) && !BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
81     struct result_ :
82 #else
83     typedef
84 #endif
85         aux::iter_fold_if_impl<
86           first_
87         , State
88         , ForwardOp
89         , protect< aux::iter_fold_if_pred< ForwardPredicate,last_ > >
90         , BackwardOp
91         , backward_pred_
92         >
93 #if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) && !BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
94     { };
95 #else
96     result_;
97 #endif
98 
99 public:
100 
101     typedef pair<
102           typename result_::state
103         , typename result_::iterator
104         > type;
105 
106     BOOST_MPL_AUX_LAMBDA_SUPPORT(
107           6
108         , iter_fold_if
109         , (Sequence,State,ForwardOp,ForwardPredicate,BackwardOp,BackwardPredicate)
110         )
111 };
112 
113 BOOST_MPL_AUX_NA_SPEC(6, iter_fold_if)
114 
115 }}
116 
117 #endif // BOOST_MPL_ITER_FOLD_IF_HPP_INCLUDED
118