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_PERMUTATION_ITERATOR_HPP
12 #define BOOST_COMPUTE_ITERATOR_PERMUTATION_ITERATOR_HPP
13
14 #include <string>
15 #include <cstddef>
16 #include <iterator>
17
18 #include <boost/config.hpp>
19 #include <boost/iterator/iterator_adaptor.hpp>
20
21 #include <boost/compute/functional.hpp>
22 #include <boost/compute/detail/meta_kernel.hpp>
23 #include <boost/compute/detail/is_buffer_iterator.hpp>
24 #include <boost/compute/detail/read_write_single_value.hpp>
25 #include <boost/compute/iterator/detail/get_base_iterator_buffer.hpp>
26 #include <boost/compute/type_traits/is_device_iterator.hpp>
27
28 namespace boost {
29 namespace compute {
30
31 // forward declaration for transform_iterator
32 template<class ElementIterator, class IndexIterator>
33 class permutation_iterator;
34
35 namespace detail {
36
37 // helper class which defines the iterator_adaptor super-class
38 // type for permutation_iterator
39 template<class ElementIterator, class IndexIterator>
40 class permutation_iterator_base
41 {
42 public:
43 typedef ::boost::iterator_adaptor<
44 ::boost::compute::permutation_iterator<ElementIterator, IndexIterator>,
45 ElementIterator
46 > type;
47 };
48
49 template<class ElementIterator, class IndexIterator, class IndexExpr>
50 struct permutation_iterator_access_expr
51 {
52 typedef typename std::iterator_traits<ElementIterator>::value_type result_type;
53
permutation_iterator_access_exprboost::compute::detail::permutation_iterator_access_expr54 permutation_iterator_access_expr(const ElementIterator &e,
55 const IndexIterator &i,
56 const IndexExpr &expr)
57 : m_element_iter(e),
58 m_index_iter(i),
59 m_expr(expr)
60 {
61 }
62
63 const ElementIterator m_element_iter;
64 const IndexIterator m_index_iter;
65 const IndexExpr m_expr;
66 };
67
68 template<class ElementIterator, class IndexIterator, class IndexExpr>
operator <<(meta_kernel & kernel,const permutation_iterator_access_expr<ElementIterator,IndexIterator,IndexExpr> & expr)69 inline meta_kernel& operator<<(meta_kernel &kernel,
70 const permutation_iterator_access_expr<ElementIterator,
71 IndexIterator,
72 IndexExpr> &expr)
73 {
74 return kernel << expr.m_element_iter[expr.m_index_iter[expr.m_expr]];
75 }
76
77 } // end detail namespace
78
79 /// \class permutation_iterator
80 /// \brief The permutation_iterator class provides a permuation iterator
81 ///
82 /// A permutation iterator iterates over a value range and an index range. When
83 /// dereferenced, it returns the value from the value range using the current
84 /// index from the index range.
85 ///
86 /// For example, to reverse a range using the copy() algorithm and a permutation
87 /// sequence:
88 ///
89 /// \snippet test/test_permutation_iterator.cpp reverse_range
90 ///
91 /// \see make_permutation_iterator()
92 template<class ElementIterator, class IndexIterator>
93 class permutation_iterator
94 : public detail::permutation_iterator_base<ElementIterator,
95 IndexIterator>::type
96 {
97 public:
98 typedef typename
99 detail::permutation_iterator_base<ElementIterator,
100 IndexIterator>::type super_type;
101 typedef typename super_type::value_type value_type;
102 typedef typename super_type::reference reference;
103 typedef typename super_type::base_type base_type;
104 typedef typename super_type::difference_type difference_type;
105 typedef IndexIterator index_iterator;
106
permutation_iterator(ElementIterator e,IndexIterator i)107 permutation_iterator(ElementIterator e, IndexIterator i)
108 : super_type(e),
109 m_map(i)
110 {
111 }
112
permutation_iterator(const permutation_iterator<ElementIterator,IndexIterator> & other)113 permutation_iterator(const permutation_iterator<ElementIterator,
114 IndexIterator> &other)
115 : super_type(other),
116 m_map(other.m_map)
117 {
118 }
119
120 permutation_iterator<ElementIterator, IndexIterator>&
operator =(const permutation_iterator<ElementIterator,IndexIterator> & other)121 operator=(const permutation_iterator<ElementIterator,
122 IndexIterator> &other)
123 {
124 if(this != &other){
125 super_type::operator=(other);
126 m_map = other.m_map;
127 }
128
129 return *this;
130 }
131
~permutation_iterator()132 ~permutation_iterator()
133 {
134 }
135
get_index() const136 size_t get_index() const
137 {
138 return super_type::base().get_index();
139 }
140
get_buffer() const141 const buffer& get_buffer() const
142 {
143 return detail::get_base_iterator_buffer(*this);
144 }
145
146 template<class IndexExpr>
147 detail::permutation_iterator_access_expr<ElementIterator,
148 IndexIterator,
149 IndexExpr>
operator [](const IndexExpr & expr) const150 operator[](const IndexExpr &expr) const
151 {
152 return detail::permutation_iterator_access_expr<ElementIterator,
153 IndexIterator,
154 IndexExpr>(super_type::base(),
155 m_map,
156 expr);
157 }
158
159 private:
160 friend class ::boost::iterator_core_access;
161
dereference() const162 reference dereference() const
163 {
164 return reference();
165 }
166
167 private:
168 IndexIterator m_map;
169 };
170
171 /// Returns a permutation_iterator for \p e using indices from \p i.
172 ///
173 /// \param e the element range iterator
174 /// \param i the index range iterator
175 ///
176 /// \return a \c permutation_iterator for \p e using \p i
177 template<class ElementIterator, class IndexIterator>
178 inline permutation_iterator<ElementIterator, IndexIterator>
make_permutation_iterator(ElementIterator e,IndexIterator i)179 make_permutation_iterator(ElementIterator e, IndexIterator i)
180 {
181 return permutation_iterator<ElementIterator, IndexIterator>(e, i);
182 }
183
184 /// \internal_ (is_device_iterator specialization for permutation_iterator)
185 template<class ElementIterator, class IndexIterator>
186 struct is_device_iterator<
187 permutation_iterator<ElementIterator, IndexIterator> > : boost::true_type {};
188
189 } // end compute namespace
190 } // end boost namespace
191
192 #endif // BOOST_COMPUTE_ITERATOR_PERMUTATION_ITERATOR_HPP
193