1 
2 #ifndef BOOST_MPL_UNIQUE_HPP_INCLUDED
3 #define BOOST_MPL_UNIQUE_HPP_INCLUDED
4 
5 // Copyright Aleksey Gurtovoy 2000-2004
6 // Copyright John R. Bandela 2000-2002
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: unique.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
15 // $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $
16 // $Revision: 49267 $
17 
18 #include <boost/mpl/fold.hpp>
19 #include <boost/mpl/reverse_fold.hpp>
20 #include <boost/mpl/eval_if.hpp>
21 #include <boost/mpl/and.hpp>
22 #include <boost/mpl/identity.hpp>
23 #include <boost/mpl/pair.hpp>
24 #include <boost/mpl/apply.hpp>
25 #include <boost/mpl/aux_/inserter_algorithm.hpp>
26 #include <boost/mpl/aux_/na.hpp>
27 #include <boost/mpl/aux_/na_spec.hpp>
28 #include <boost/mpl/aux_/lambda_spec.hpp>
29 
30 namespace boost { namespace mpl {
31 
32 namespace aux {
33 
34 template< typename Predicate, typename Operation >
35 struct unique_op
36 {
37     template< typename Pair, typename T > struct apply
38     {
39         typedef typename Pair::first seq_;
40         typedef typename Pair::second prior_;
41         typedef typename eval_if<
42               and_< is_not_na<prior_>, apply2<Predicate,prior_,T> >
43             , identity<seq_>
44             , apply2<Operation,seq_,T>
45             >::type new_seq_;
46 
47         typedef pair<new_seq_,T> type;
48     };
49 };
50 
51 template<
52       typename Sequence
53     , typename Predicate
54     , typename Inserter
55     >
56 struct unique_impl
57     : first< typename fold<
58           Sequence
59         , pair< typename Inserter::state,na >
60         , protect< aux::unique_op<Predicate,typename Inserter::operation> >
61         >::type >
62 {
63 };
64 
65 template<
66       typename Sequence
67     , typename Predicate
68     , typename Inserter
69     >
70 struct reverse_unique_impl
71     : first< typename reverse_fold<
72           Sequence
73         , pair< typename Inserter::state,na >
74         , protect< aux::unique_op<Predicate,typename Inserter::operation> >
75         >::type >
76 {
77 };
78 
79 } // namespace aux
80 
81 BOOST_MPL_AUX_INSERTER_ALGORITHM_DEF(3, unique)
82 
83 }}
84 
85 #endif // BOOST_MPL_UNIQUE_HPP_INCLUDED
86