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 | |
173 | |