1 
2 #ifndef BOOST_MPL_AUX_JOINT_ITER_HPP_INCLUDED
3 #define BOOST_MPL_AUX_JOINT_ITER_HPP_INCLUDED
4 
5 // Copyright Aleksey Gurtovoy 2000-2004
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/next_prior.hpp>
18 #include <boost/mpl/deref.hpp>
19 #include <boost/mpl/iterator_tags.hpp>
20 #include <boost/mpl/aux_/lambda_spec.hpp>
21 #include <boost/mpl/aux_/config/ctps.hpp>
22 
23 #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
24 #   include <boost/type_traits/is_same.hpp>
25 #endif
26 
27 namespace boost { namespace mpl {
28 
29 #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
30 
31 template<
32       typename Iterator1
33     , typename LastIterator1
34     , typename Iterator2
35     >
36 struct joint_iter
37 {
38     typedef Iterator1 base;
39     typedef forward_iterator_tag category;
40 };
41 
42 template<
43       typename LastIterator1
44     , typename Iterator2
45     >
46 struct joint_iter<LastIterator1,LastIterator1,Iterator2>
47 {
48     typedef Iterator2 base;
49     typedef forward_iterator_tag category;
50 };
51 
52 
53 template< typename I1, typename L1, typename I2 >
54 struct deref< joint_iter<I1,L1,I2> >
55 {
56     typedef typename joint_iter<I1,L1,I2>::base base_;
57     typedef typename deref<base_>::type type;
58 };
59 
60 template< typename I1, typename L1, typename I2 >
61 struct next< joint_iter<I1,L1,I2> >
62 {
63     typedef joint_iter< typename mpl::next<I1>::type,L1,I2 > type;
64 };
65 
66 template< typename L1, typename I2 >
67 struct next< joint_iter<L1,L1,I2> >
68 {
69     typedef joint_iter< L1,L1,typename mpl::next<I2>::type > type;
70 };
71 
72 #else // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
73 
74 template<
75       typename Iterator1
76     , typename LastIterator1
77     , typename Iterator2
78     >
79 struct joint_iter;
80 
81 template< bool > struct joint_iter_impl
82 {
83     template< typename I1, typename L1, typename I2 > struct result_
84     {
85         typedef I1 base;
86         typedef forward_iterator_tag category;
87         typedef joint_iter< typename mpl::next<I1>::type,L1,I2 > next;
88         typedef typename deref<I1>::type type;
89     };
90 };
91 
92 template<> struct joint_iter_impl<true>
93 {
94     template< typename I1, typename L1, typename I2 > struct result_
95     {
96         typedef I2 base;
97         typedef forward_iterator_tag category;
98         typedef joint_iter< L1,L1,typename mpl::next<I2>::type > next;
99         typedef typename deref<I2>::type type;
100     };
101 };
102 
103 template<
104       typename Iterator1
105     , typename LastIterator1
106     , typename Iterator2
107     >
108 struct joint_iter
109     : joint_iter_impl< is_same<Iterator1,LastIterator1>::value >
110         ::template result_<Iterator1,LastIterator1,Iterator2>
111 {
112 };
113 
114 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
115 
116 BOOST_MPL_AUX_PASS_THROUGH_LAMBDA_SPEC(3, joint_iter)
117 
118 }}
119 
120 #endif // BOOST_MPL_AUX_JOINT_ITER_HPP_INCLUDED
121