1 | #ifndef _theplu_yat_utility_stride_iterator_ |
---|
2 | #define _theplu_yat_utility_stride_iterator_ |
---|
3 | |
---|
4 | // $Id: StrideIterator.h 1038 2008-02-05 20:46:37Z peter $ |
---|
5 | |
---|
6 | /* |
---|
7 | Copyright (C) 2008 Peter Johansson |
---|
8 | |
---|
9 | This file is part of the yat library, http://trac.thep.lu.se/yat |
---|
10 | |
---|
11 | The yat library is free software; you can redistribute it and/or |
---|
12 | modify it under the terms of the GNU General Public License as |
---|
13 | published by the Free Software Foundation; either version 2 of the |
---|
14 | License, or (at your option) any later version. |
---|
15 | |
---|
16 | The yat library is distributed in the hope that it will be useful, |
---|
17 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
---|
18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
---|
19 | General Public License for more details. |
---|
20 | |
---|
21 | You should have received a copy of the GNU General Public License |
---|
22 | along with this program; if not, write to the Free Software |
---|
23 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA |
---|
24 | 02111-1307, USA. |
---|
25 | */ |
---|
26 | |
---|
27 | #include "yat_assert.h" |
---|
28 | |
---|
29 | #include <iterator> |
---|
30 | |
---|
31 | namespace theplu { |
---|
32 | namespace yat { |
---|
33 | namespace utility { |
---|
34 | |
---|
35 | /** |
---|
36 | @brief Stride Iterator |
---|
37 | |
---|
38 | Works as a pointer except that all arithmetic is using the stride value |
---|
39 | */ |
---|
40 | template<typename T> |
---|
41 | class StrideIterator |
---|
42 | : public std::iterator<std::random_access_iterator_tag, T> |
---|
43 | { |
---|
44 | public: |
---|
45 | typedef typename std::iterator_traits<T*>::difference_type difference_type; |
---|
46 | typedef typename std::iterator_traits<T*>::reference reference; |
---|
47 | typedef typename std::iterator_traits<T*>::pointer pointer; |
---|
48 | |
---|
49 | /** |
---|
50 | \brief Constructor |
---|
51 | */ |
---|
52 | explicit StrideIterator(pointer p, difference_type stride=1) |
---|
53 | : pointer_(p), stride_(stride) {} |
---|
54 | |
---|
55 | operator StrideIterator<const T>() |
---|
56 | { return StrideIterator<const T>(pointer_, stride_); } |
---|
57 | |
---|
58 | /** |
---|
59 | \return element |
---|
60 | */ |
---|
61 | reference operator*(void) const |
---|
62 | { return *pointer_; } |
---|
63 | |
---|
64 | /** |
---|
65 | */ |
---|
66 | pointer operator->() const { return &(operator*()); } |
---|
67 | |
---|
68 | /** |
---|
69 | \return element \a n steps forward |
---|
70 | */ |
---|
71 | reference operator[](difference_type n) const |
---|
72 | { |
---|
73 | return pointer_[stride_*n]; |
---|
74 | } |
---|
75 | |
---|
76 | /** |
---|
77 | \brief pre-increment |
---|
78 | |
---|
79 | \return reference to *this |
---|
80 | */ |
---|
81 | StrideIterator& operator++(void) { pointer_+=stride_; return *this; } |
---|
82 | |
---|
83 | /** |
---|
84 | \brief post-increment |
---|
85 | |
---|
86 | \return copy of iterator prior increment |
---|
87 | */ |
---|
88 | StrideIterator operator++(int) |
---|
89 | { StrideIterator tmp(*this); pointer_+=stride_; return tmp;} |
---|
90 | |
---|
91 | /** |
---|
92 | \brief iterate \f$ n \f$ steps forward |
---|
93 | |
---|
94 | \return reference to resulting iterator |
---|
95 | */ |
---|
96 | StrideIterator& operator+=(int n) { pointer_+=stride_*n; return *this; } |
---|
97 | |
---|
98 | /** |
---|
99 | \brief post-decrement |
---|
100 | |
---|
101 | \return copy of iterator prior decrement |
---|
102 | */ |
---|
103 | StrideIterator operator--(int) |
---|
104 | { StrideIterator tmp(*this); pointer_-=stride_; return tmp;} |
---|
105 | |
---|
106 | /** |
---|
107 | \brief pre-decrement |
---|
108 | |
---|
109 | \return reference to resulting iterator |
---|
110 | */ |
---|
111 | StrideIterator& operator--(void) { pointer_-=stride_; return *this; } |
---|
112 | |
---|
113 | /** |
---|
114 | \brief iterate \f$ n \f$ steps backwards |
---|
115 | |
---|
116 | \return reference to resulting iterator |
---|
117 | */ |
---|
118 | StrideIterator& operator-=(int n) { pointer_-=n*stride_; return *this; } |
---|
119 | |
---|
120 | /** |
---|
121 | \brief addition operator |
---|
122 | |
---|
123 | \return copy of resulting iterator |
---|
124 | */ |
---|
125 | friend StrideIterator operator+(const StrideIterator& lhs,difference_type n) |
---|
126 | { StrideIterator tmp(lhs); tmp+=n; return tmp; } |
---|
127 | |
---|
128 | /** |
---|
129 | \brief subtraction operator |
---|
130 | |
---|
131 | \return copy of resulting iterator |
---|
132 | */ |
---|
133 | friend StrideIterator operator-(const StrideIterator& lhs, |
---|
134 | difference_type n) |
---|
135 | { StrideIterator tmp(lhs); tmp-=n; return tmp; } |
---|
136 | |
---|
137 | /** |
---|
138 | \brief difference operator |
---|
139 | |
---|
140 | \return distance between \a lhs and \a rhs |
---|
141 | */ |
---|
142 | friend difference_type operator-(const StrideIterator& lhs, |
---|
143 | const StrideIterator& rhs) |
---|
144 | { |
---|
145 | yat_assert<std::runtime_error>(lhs.stride_==rhs.stride_, |
---|
146 | "StrideIterator::operator- different stride in lhs and rhs."); |
---|
147 | return static_cast<difference_type>( (lhs.pointer_-rhs.pointer_)/ |
---|
148 | lhs.stride_); |
---|
149 | } |
---|
150 | |
---|
151 | |
---|
152 | /** |
---|
153 | \brief Equality operator |
---|
154 | |
---|
155 | \return True if \a lhs and \a rhs are pointing to same element |
---|
156 | */ |
---|
157 | friend bool operator==(const StrideIterator& lhs, const StrideIterator& rhs) |
---|
158 | { return lhs.pointer_==rhs.pointer_; } |
---|
159 | |
---|
160 | /** |
---|
161 | \brief Non-equality operator |
---|
162 | |
---|
163 | \return False if \a lhs and \a rhs are pointing to same element |
---|
164 | */ |
---|
165 | friend bool operator!=(const StrideIterator& lhs, const StrideIterator& rhs) |
---|
166 | { return !(lhs==rhs); } |
---|
167 | |
---|
168 | /** |
---|
169 | \brief Less operator |
---|
170 | */ |
---|
171 | friend bool operator<(const StrideIterator& lhs, const StrideIterator& rhs) |
---|
172 | { return lhs.pointer_<rhs.pointer_; } |
---|
173 | |
---|
174 | /** |
---|
175 | \brief Less equal operator |
---|
176 | */ |
---|
177 | friend bool operator<=(const StrideIterator& lhs, const StrideIterator& rhs) |
---|
178 | { return !(rhs<lhs); } |
---|
179 | |
---|
180 | /** |
---|
181 | \brief Larger operator |
---|
182 | */ |
---|
183 | friend bool operator>(const StrideIterator& lhs, const StrideIterator& rhs) |
---|
184 | { return rhs<lhs; } |
---|
185 | |
---|
186 | /** |
---|
187 | \brief Larger equal operator |
---|
188 | */ |
---|
189 | friend bool operator>=(const StrideIterator& lhs, const StrideIterator& rhs) |
---|
190 | { return !(lhs<rhs); } |
---|
191 | |
---|
192 | private: |
---|
193 | T* pointer_; |
---|
194 | size_t stride_; |
---|
195 | |
---|
196 | // Using compiler generated copy |
---|
197 | //StrideIterator(const StrideIterator&); |
---|
198 | //StrideIterator& operator=(const StrideIterator&); |
---|
199 | }; |
---|
200 | }}} // of namespace utility, yat, and theplu |
---|
201 | |
---|
202 | #endif |
---|