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1 | /*============================================================================= |
2 | Copyright (c) 2001-2011 Joel de Guzman | |
3 | ||
4 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
5 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | ==============================================================================*/ | |
7 | #if !defined(FUSION_POP_BACK_09172005_1038) | |
8 | #define FUSION_POP_BACK_09172005_1038 | |
9 | ||
10 | #include <boost/fusion/support/config.hpp> | |
11 | #include <boost/fusion/view/iterator_range/iterator_range.hpp> | |
12 | #include <boost/fusion/sequence/intrinsic/begin.hpp> | |
13 | #include <boost/fusion/sequence/intrinsic/end.hpp> | |
14 | #include <boost/fusion/sequence/intrinsic/empty.hpp> | |
15 | #include <boost/fusion/iterator/iterator_adapter.hpp> | |
16 | #include <boost/fusion/iterator/next.hpp> | |
17 | #include <boost/mpl/minus.hpp> | |
18 | #include <boost/mpl/int.hpp> | |
19 | #include <boost/mpl/if.hpp> | |
20 | ||
21 | namespace boost { namespace fusion | |
22 | { | |
23 | template <typename Iterator_, bool IsLast> | |
24 | struct pop_back_iterator | |
25 | : iterator_adapter< | |
26 | pop_back_iterator<Iterator_, IsLast> | |
27 | , Iterator_> | |
28 | { | |
29 | typedef iterator_adapter< | |
30 | pop_back_iterator<Iterator_, IsLast> | |
31 | , Iterator_> | |
32 | base_type; | |
33 | ||
34 | static bool const is_last = IsLast; | |
35 | ||
36 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
37 | pop_back_iterator(Iterator_ const& iterator_base) | |
38 | : base_type(iterator_base) {} | |
39 | ||
40 | template <typename BaseIterator> | |
41 | struct make | |
42 | { | |
43 | typedef pop_back_iterator<BaseIterator, is_last> type; | |
44 | ||
45 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
46 | static type | |
47 | call(BaseIterator const& i) | |
48 | { | |
49 | return type(i); | |
50 | } | |
51 | }; | |
52 | ||
53 | template <typename I, bool IsLast_> | |
54 | struct equal_to_helper | |
55 | : mpl::identity<typename I::iterator_base_type> | |
56 | {}; | |
57 | ||
58 | template <typename I> | |
59 | struct equal_to_helper<I, true> | |
60 | : result_of::next< | |
61 | typename I::iterator_base_type> | |
62 | {}; | |
63 | ||
64 | template <typename I1, typename I2> | |
65 | struct equal_to | |
66 | : result_of::equal_to< | |
67 | typename equal_to_helper<I1, | |
68 | (I2::is_last && !I1::is_last)>::type | |
69 | , typename equal_to_helper<I2, | |
70 | (I1::is_last && !I2::is_last)>::type | |
71 | > | |
72 | {}; | |
73 | ||
74 | template <typename First, typename Last> | |
75 | struct distance | |
76 | : mpl::minus< | |
77 | typename result_of::distance< | |
78 | typename First::iterator_base_type | |
79 | , typename Last::iterator_base_type | |
80 | >::type | |
81 | , mpl::int_<(Last::is_last?1:0)> | |
82 | >::type | |
83 | {}; | |
84 | ||
85 | ||
86 | template <typename Iterator, bool IsLast_> | |
87 | struct prior_impl | |
88 | { | |
89 | typedef typename Iterator::iterator_base_type base_type; | |
90 | ||
91 | typedef typename | |
92 | result_of::prior<base_type>::type | |
93 | base_prior; | |
94 | ||
95 | typedef pop_back_iterator<base_prior, false> type; | |
96 | ||
97 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
98 | static type | |
99 | call(Iterator const& i) | |
100 | { | |
101 | return type(fusion::prior(i.iterator_base)); | |
102 | } | |
103 | }; | |
104 | ||
105 | template <typename Iterator> | |
106 | struct prior_impl<Iterator, true> | |
107 | { | |
108 | // If this is the last iterator, we'll have to double back | |
109 | typedef typename Iterator::iterator_base_type base_type; | |
110 | ||
111 | typedef typename | |
112 | result_of::prior< | |
113 | typename result_of::prior<base_type>::type | |
114 | >::type | |
115 | base_prior; | |
116 | ||
117 | typedef pop_back_iterator<base_prior, false> type; | |
118 | ||
119 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
120 | static type | |
121 | call(Iterator const& i) | |
122 | { | |
123 | return type(fusion::prior( | |
124 | fusion::prior(i.iterator_base))); | |
125 | } | |
126 | }; | |
127 | ||
128 | template <typename Iterator> | |
129 | struct prior : prior_impl<Iterator, Iterator::is_last> | |
130 | {}; | |
131 | }; | |
132 | ||
133 | namespace result_of | |
134 | { | |
135 | template <typename Sequence> | |
136 | struct pop_back | |
137 | { | |
138 | BOOST_MPL_ASSERT_NOT((result_of::empty<Sequence>)); | |
139 | ||
140 | typedef pop_back_iterator< | |
141 | typename begin<Sequence>::type, false> | |
142 | begin_type; | |
143 | ||
144 | typedef pop_back_iterator< | |
145 | typename end<Sequence>::type, true> | |
146 | end_type; | |
147 | ||
148 | typedef | |
149 | iterator_range<begin_type, end_type> | |
150 | type; | |
151 | }; | |
152 | } | |
153 | ||
154 | template <typename Sequence> | |
155 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED | |
156 | inline typename result_of::pop_back<Sequence const>::type | |
157 | pop_back(Sequence const& seq) | |
158 | { | |
159 | typedef result_of::pop_back<Sequence const> comp; | |
160 | typedef typename comp::begin_type begin_type; | |
161 | typedef typename comp::end_type end_type; | |
162 | typedef typename comp::type result; | |
163 | ||
164 | return result( | |
165 | begin_type(fusion::begin(seq)) | |
166 | , end_type(fusion::end(seq)) | |
167 | ); | |
168 | } | |
169 | }} | |
170 | ||
171 | #endif | |
172 |