1 | |
2 | #ifndef BOOST_MPL_INDEX_IF_HPP_INCLUDED |
3 | #define BOOST_MPL_INDEX_IF_HPP_INCLUDED |
4 | |
5 | // Copyright Eric Friedman 2003 |
6 | // |
7 | // Distributed under the Boost Software License, Version 1.0. |
8 | // (See accompanying file LICENSE_1_0.txt or copy at |
9 | // http://www.boost.org/LICENSE_1_0.txt) |
10 | // |
11 | // See http://www.boost.org/libs/mpl for documentation. |
12 | |
13 | // $Id$ |
14 | // $Date$ |
15 | // $Revision$ |
16 | |
17 | #include <boost/mpl/aux_/find_if_pred.hpp> |
18 | #include <boost/mpl/begin_end.hpp> |
19 | #include <boost/mpl/if.hpp> |
20 | #include <boost/mpl/int.hpp> |
21 | #include <boost/mpl/iter_fold_if.hpp> |
22 | #include <boost/mpl/next.hpp> |
23 | #include <boost/mpl/void.hpp> |
24 | #include <boost/mpl/aux_/na_spec.hpp> |
25 | #include <boost/mpl/aux_/lambda_support.hpp> |
26 | #include <boost/type_traits/is_same.hpp> |
27 | |
28 | namespace boost { namespace mpl { |
29 | |
30 | template< |
31 | typename BOOST_MPL_AUX_NA_PARAM(Sequence) |
32 | , typename BOOST_MPL_AUX_NA_PARAM(Predicate) |
33 | > |
34 | struct index_if |
35 | { |
36 | typedef typename iter_fold_if< |
37 | Sequence |
38 | , int_<0> |
39 | , next<> |
40 | , aux::find_if_pred<Predicate> |
41 | >::type result_; |
42 | |
43 | typedef typename end<Sequence>::type not_found_; |
44 | typedef typename first<result_>::type result_index_; |
45 | typedef typename second<result_>::type result_iterator_; |
46 | |
47 | typedef typename if_< |
48 | is_same< result_iterator_,not_found_ > |
49 | , void_ |
50 | , result_index_ |
51 | >::type type; |
52 | |
53 | BOOST_MPL_AUX_LAMBDA_SUPPORT(2,index_if,(Sequence,Predicate)) |
54 | }; |
55 | |
56 | BOOST_MPL_AUX_NA_SPEC(2, index_if) |
57 | |
58 | }} |
59 | |
60 | #endif // BOOST_MPL_INDEX_IF_HPP_INCLUDED |
61 | |