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1 | //---------------------------------------------------------------------------// | |
2 | // Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@gmail.com> | |
3 | // | |
4 | // Distributed under the Boost Software License, Version 1.0 | |
5 | // See accompanying file LICENSE_1_0.txt or copy at | |
6 | // http://www.boost.org/LICENSE_1_0.txt | |
7 | // | |
8 | // See http://boostorg.github.com/compute for more information. | |
9 | //---------------------------------------------------------------------------// | |
10 | ||
11 | #ifndef BOOST_COMPUTE_ITERATOR_DISCARD_ITERATOR_HPP | |
12 | #define BOOST_COMPUTE_ITERATOR_DISCARD_ITERATOR_HPP | |
13 | ||
14 | #include <string> | |
15 | #include <cstddef> | |
16 | #include <iterator> | |
17 | ||
18 | #include <boost/config.hpp> | |
19 | #include <boost/iterator/iterator_facade.hpp> | |
20 | ||
21 | #include <boost/compute/detail/meta_kernel.hpp> | |
22 | #include <boost/compute/type_traits/is_device_iterator.hpp> | |
23 | ||
24 | namespace boost { | |
25 | namespace compute { | |
26 | ||
27 | // forward declaration for discard_iterator | |
28 | class discard_iterator; | |
29 | ||
30 | namespace detail { | |
31 | ||
32 | // helper class which defines the iterator_facade super-class | |
33 | // type for discard_iterator | |
34 | struct discard_iterator_base | |
35 | { | |
36 | typedef ::boost::iterator_facade< | |
37 | ::boost::compute::discard_iterator, | |
38 | void, | |
39 | ::std::random_access_iterator_tag, | |
40 | void * | |
41 | > type; | |
42 | }; | |
43 | ||
44 | template<class IndexExpr> | |
45 | struct discard_iterator_index_expr | |
46 | { | |
47 | typedef void result_type; | |
48 | ||
49 | discard_iterator_index_expr(const IndexExpr &expr) | |
50 | : m_expr(expr) | |
51 | { | |
52 | } | |
53 | ||
54 | IndexExpr m_expr; | |
55 | }; | |
56 | ||
57 | template<class IndexExpr> | |
58 | inline meta_kernel& operator<<(meta_kernel &kernel, | |
59 | const discard_iterator_index_expr<IndexExpr> &expr) | |
60 | { | |
61 | (void) expr; | |
62 | ||
63 | return kernel; | |
64 | } | |
65 | ||
66 | } // end detail namespace | |
67 | ||
68 | /// \class discard_iterator | |
69 | /// \brief An iterator which discards all values written to it. | |
70 | /// | |
71 | /// \see make_discard_iterator(), constant_iterator | |
72 | class discard_iterator : public detail::discard_iterator_base::type | |
73 | { | |
74 | public: | |
75 | typedef detail::discard_iterator_base::type super_type; | |
76 | typedef super_type::reference reference; | |
77 | typedef super_type::difference_type difference_type; | |
78 | ||
79 | discard_iterator(size_t index = 0) | |
80 | : m_index(index) | |
81 | { | |
82 | } | |
83 | ||
84 | discard_iterator(const discard_iterator &other) | |
85 | : m_index(other.m_index) | |
86 | { | |
87 | } | |
88 | ||
89 | discard_iterator& operator=(const discard_iterator &other) | |
90 | { | |
91 | if(this != &other){ | |
92 | m_index = other.m_index; | |
93 | } | |
94 | ||
95 | return *this; | |
96 | } | |
97 | ||
98 | ~discard_iterator() | |
99 | { | |
100 | } | |
101 | ||
102 | /// \internal_ | |
103 | template<class Expr> | |
104 | detail::discard_iterator_index_expr<Expr> | |
105 | operator[](const Expr &expr) const | |
106 | { | |
107 | return detail::discard_iterator_index_expr<Expr>(expr); | |
108 | } | |
109 | ||
110 | private: | |
111 | friend class ::boost::iterator_core_access; | |
112 | ||
113 | /// \internal_ | |
114 | reference dereference() const | |
115 | { | |
116 | return 0; | |
117 | } | |
118 | ||
119 | /// \internal_ | |
120 | bool equal(const discard_iterator &other) const | |
121 | { | |
122 | return m_index == other.m_index; | |
123 | } | |
124 | ||
125 | /// \internal_ | |
126 | void increment() | |
127 | { | |
128 | m_index++; | |
129 | } | |
130 | ||
131 | /// \internal_ | |
132 | void decrement() | |
133 | { | |
134 | m_index--; | |
135 | } | |
136 | ||
137 | /// \internal_ | |
138 | void advance(difference_type n) | |
139 | { | |
140 | m_index = static_cast<size_t>(static_cast<difference_type>(m_index) + n); | |
141 | } | |
142 | ||
143 | /// \internal_ | |
144 | difference_type distance_to(const discard_iterator &other) const | |
145 | { | |
146 | return static_cast<difference_type>(other.m_index - m_index); | |
147 | } | |
148 | ||
149 | private: | |
150 | size_t m_index; | |
151 | }; | |
152 | ||
153 | /// Returns a new discard_iterator with \p index. | |
154 | /// | |
155 | /// \param index the index of the iterator | |
156 | /// | |
157 | /// \return a \c discard_iterator at \p index | |
158 | inline discard_iterator make_discard_iterator(size_t index = 0) | |
159 | { | |
160 | return discard_iterator(index); | |
161 | } | |
162 | ||
163 | /// internal_ (is_device_iterator specialization for discard_iterator) | |
164 | template<> | |
165 | struct is_device_iterator<discard_iterator> : boost::true_type {}; | |
166 | ||
167 | } // end compute namespace | |
168 | } // end boost namespace | |
169 | ||
170 | #endif // BOOST_COMPUTE_ITERATOR_DISCARD_ITERATOR_HPP |