]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | //---------------------------------------------------------------------------// |
2 | // Copyright (c) 2013 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_COUNTING_ITERATOR_HPP | |
12 | #define BOOST_COMPUTE_ITERATOR_COUNTING_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 counting_iterator<T> | |
28 | template<class T> class counting_iterator; | |
29 | ||
30 | namespace detail { | |
31 | ||
32 | // helper class which defines the iterator_facade super-class | |
33 | // type for counting_iterator<T> | |
34 | template<class T> | |
35 | class counting_iterator_base | |
36 | { | |
37 | public: | |
38 | typedef ::boost::iterator_facade< | |
39 | ::boost::compute::counting_iterator<T>, | |
40 | T, | |
41 | ::std::random_access_iterator_tag | |
42 | > type; | |
43 | }; | |
44 | ||
45 | template<class T, class IndexExpr> | |
46 | struct counting_iterator_index_expr | |
47 | { | |
48 | typedef T result_type; | |
49 | ||
50 | counting_iterator_index_expr(const T &init, const IndexExpr &expr) | |
51 | : m_init(init), | |
52 | m_expr(expr) | |
53 | { | |
54 | } | |
55 | ||
56 | const T &m_init; | |
57 | IndexExpr m_expr; | |
58 | }; | |
59 | ||
60 | template<class T, class IndexExpr> | |
61 | inline meta_kernel& operator<<(meta_kernel &kernel, | |
62 | const counting_iterator_index_expr<T, IndexExpr> &expr) | |
63 | { | |
64 | return kernel << '(' << expr.m_init << '+' << expr.m_expr << ')'; | |
65 | } | |
66 | ||
67 | } // end detail namespace | |
68 | ||
69 | /// \class counting_iterator | |
70 | /// \brief The counting_iterator class implements a counting iterator. | |
71 | /// | |
72 | /// A counting iterator returns an internal value (initialized with \p init) | |
73 | /// which is incremented each time the iterator is incremented. | |
74 | /// | |
75 | /// For example, this could be used to implement the iota() algorithm in terms | |
76 | /// of the copy() algorithm by copying from a range of counting iterators: | |
77 | /// | |
78 | /// \snippet test/test_counting_iterator.cpp iota_with_copy | |
79 | /// | |
80 | /// \see make_counting_iterator() | |
81 | template<class T> | |
82 | class counting_iterator : public detail::counting_iterator_base<T>::type | |
83 | { | |
84 | public: | |
85 | typedef typename detail::counting_iterator_base<T>::type super_type; | |
86 | typedef typename super_type::reference reference; | |
87 | typedef typename super_type::difference_type difference_type; | |
88 | ||
89 | counting_iterator(const T &init) | |
90 | : m_init(init) | |
91 | { | |
92 | } | |
93 | ||
94 | counting_iterator(const counting_iterator<T> &other) | |
95 | : m_init(other.m_init) | |
96 | { | |
97 | } | |
98 | ||
99 | counting_iterator<T>& operator=(const counting_iterator<T> &other) | |
100 | { | |
101 | if(this != &other){ | |
102 | m_init = other.m_init; | |
103 | } | |
104 | ||
105 | return *this; | |
106 | } | |
107 | ||
108 | ~counting_iterator() | |
109 | { | |
110 | } | |
111 | ||
112 | size_t get_index() const | |
113 | { | |
114 | return 0; | |
115 | } | |
116 | ||
117 | template<class Expr> | |
118 | detail::counting_iterator_index_expr<T, Expr> | |
119 | operator[](const Expr &expr) const | |
120 | { | |
121 | return detail::counting_iterator_index_expr<T, Expr>(m_init, expr); | |
122 | } | |
123 | ||
124 | private: | |
125 | friend class ::boost::iterator_core_access; | |
126 | ||
127 | reference dereference() const | |
128 | { | |
129 | return m_init; | |
130 | } | |
131 | ||
132 | bool equal(const counting_iterator<T> &other) const | |
133 | { | |
134 | return m_init == other.m_init; | |
135 | } | |
136 | ||
137 | void increment() | |
138 | { | |
139 | m_init++; | |
140 | } | |
141 | ||
142 | void decrement() | |
143 | { | |
144 | m_init--; | |
145 | } | |
146 | ||
147 | void advance(difference_type n) | |
148 | { | |
149 | m_init += static_cast<T>(n); | |
150 | } | |
151 | ||
152 | difference_type distance_to(const counting_iterator<T> &other) const | |
153 | { | |
154 | return difference_type(other.m_init) - difference_type(m_init); | |
155 | } | |
156 | ||
157 | private: | |
158 | T m_init; | |
159 | }; | |
160 | ||
161 | /// Returns a new counting_iterator starting at \p init. | |
162 | /// | |
163 | /// \param init the initial value | |
164 | /// | |
165 | /// \return a counting_iterator with \p init. | |
166 | /// | |
167 | /// For example, to create a counting iterator which returns unsigned integers | |
168 | /// and increments from one: | |
169 | /// \code | |
170 | /// auto iter = make_counting_iterator<uint_>(1); | |
171 | /// \endcode | |
172 | template<class T> | |
173 | inline counting_iterator<T> make_counting_iterator(const T &init) | |
174 | { | |
175 | return counting_iterator<T>(init); | |
176 | } | |
177 | ||
178 | /// \internal_ (is_device_iterator specialization for counting_iterator) | |
179 | template<class T> | |
180 | struct is_device_iterator<counting_iterator<T> > : boost::true_type {}; | |
181 | ||
182 | } // end compute namespace | |
183 | } // end boost namespace | |
184 | ||
185 | #endif // BOOST_COMPUTE_ITERATOR_COUNTING_ITERATOR_HPP |