libstdc++

slice_array.h
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1 // The template and inlines for the -*- C++ -*- slice_array class.
2
3 // Copyright (C) 1997-2013 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 /** @file bits/slice_array.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{valarray}
28 */
29
30 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
31
32 #ifndef _SLICE_ARRAY_H
33 #define _SLICE_ARRAY_H 1
34
35 #pragma GCC system_header
36
37 namespace std _GLIBCXX_VISIBILITY(default)
38 {
39 _GLIBCXX_BEGIN_NAMESPACE_VERSION
40
41 /**
42 * @addtogroup numeric_arrays
43 * @{
44 */
45
46 /**
47 * @brief Class defining one-dimensional subset of an array.
48 *
49 * The slice class represents a one-dimensional subset of an array,
50 * specified by three parameters: start offset, size, and stride. The
51 * start offset is the index of the first element of the array that is part
52 * of the subset. The size is the total number of elements in the subset.
53 * Stride is the distance between each successive array element to include
54 * in the subset.
55 *
56 * For example, with an array of size 10, and a slice with offset 1, size 3
57 * and stride 2, the subset consists of array elements 1, 3, and 5.
58 */
59 class slice
60 {
61 public:
62 /// Construct an empty slice.
63 slice();
64
65 /**
66 * @brief Construct a slice.
67 *
68 * @param __o Offset in array of first element.
69 * @param __d Number of elements in slice.
70 * @param __s Stride between array elements.
71 */
72 slice(size_t __o, size_t __d, size_t __s);
73
74 /// Return array offset of first slice element.
75 size_t start() const;
76 /// Return size of slice.
77 size_t size() const;
78 /// Return array stride of slice.
79 size_t stride() const;
80
81 private:
82 size_t _M_off; // offset
83 size_t _M_sz; // size
84 size_t _M_st; // stride unit
85 };
86
87 // _GLIBCXX_RESOLVE_LIB_DEFECTS
88 // 543. valarray slice default constructor
89 inline
90 slice::slice()
91 : _M_off(0), _M_sz(0), _M_st(0) {}
92
93 inline
94 slice::slice(size_t __o, size_t __d, size_t __s)
95 : _M_off(__o), _M_sz(__d), _M_st(__s) {}
96
97 inline size_t
98 slice::start() const
99 { return _M_off; }
100
101 inline size_t
102 slice::size() const
103 { return _M_sz; }
104
105 inline size_t
106 slice::stride() const
107 { return _M_st; }
108
109 /**
110 * @brief Reference to one-dimensional subset of an array.
111 *
112 * A slice_array is a reference to the actual elements of an array
113 * specified by a slice. The way to get a slice_array is to call
114 * operator[](slice) on a valarray. The returned slice_array then permits
115 * carrying operations out on the referenced subset of elements in the
116 * original valarray. For example, operator+=(valarray) will add values
117 * to the subset of elements in the underlying valarray this slice_array
118 * refers to.
119 *
120 * @param Tp Element type.
121 */
122 template<typename _Tp>
123 class slice_array
124 {
125 public:
126 typedef _Tp value_type;
127
128 // _GLIBCXX_RESOLVE_LIB_DEFECTS
129 // 253. valarray helper functions are almost entirely useless
130
131 /// Copy constructor. Both slices refer to the same underlying array.
132 slice_array(const slice_array&);
133
134 /// Assignment operator. Assigns slice elements to corresponding
135 /// elements of @a a.
136 slice_array& operator=(const slice_array&);
137
138 /// Assign slice elements to corresponding elements of @a v.
139 void operator=(const valarray<_Tp>&) const;
140 /// Multiply slice elements by corresponding elements of @a v.
141 void operator*=(const valarray<_Tp>&) const;
142 /// Divide slice elements by corresponding elements of @a v.
143 void operator/=(const valarray<_Tp>&) const;
144 /// Modulo slice elements by corresponding elements of @a v.
145 void operator%=(const valarray<_Tp>&) const;
146 /// Add corresponding elements of @a v to slice elements.
147 void operator+=(const valarray<_Tp>&) const;
148 /// Subtract corresponding elements of @a v from slice elements.
149 void operator-=(const valarray<_Tp>&) const;
150 /// Logical xor slice elements with corresponding elements of @a v.
151 void operator^=(const valarray<_Tp>&) const;
152 /// Logical and slice elements with corresponding elements of @a v.
153 void operator&=(const valarray<_Tp>&) const;
154 /// Logical or slice elements with corresponding elements of @a v.
155 void operator|=(const valarray<_Tp>&) const;
156 /// Left shift slice elements by corresponding elements of @a v.
157 void operator<<=(const valarray<_Tp>&) const;
158 /// Right shift slice elements by corresponding elements of @a v.
159 void operator>>=(const valarray<_Tp>&) const;
160 /// Assign all slice elements to @a t.
161 void operator=(const _Tp &) const;
162 // ~slice_array ();
163
164 template<class _Dom>
165 void operator=(const _Expr<_Dom, _Tp>&) const;
166 template<class _Dom>
167 void operator*=(const _Expr<_Dom, _Tp>&) const;
168 template<class _Dom>
169 void operator/=(const _Expr<_Dom, _Tp>&) const;
170 template<class _Dom>
171 void operator%=(const _Expr<_Dom, _Tp>&) const;
172 template<class _Dom>
173 void operator+=(const _Expr<_Dom, _Tp>&) const;
174 template<class _Dom>
175 void operator-=(const _Expr<_Dom, _Tp>&) const;
176 template<class _Dom>
177 void operator^=(const _Expr<_Dom, _Tp>&) const;
178 template<class _Dom>
179 void operator&=(const _Expr<_Dom, _Tp>&) const;
180 template<class _Dom>
181 void operator|=(const _Expr<_Dom, _Tp>&) const;
182 template<class _Dom>
183 void operator<<=(const _Expr<_Dom, _Tp>&) const;
184 template<class _Dom>
185 void operator>>=(const _Expr<_Dom, _Tp>&) const;
186
187 private:
188 friend class valarray<_Tp>;
189 slice_array(_Array<_Tp>, const slice&);
190
191 const size_t _M_sz;
192 const size_t _M_stride;
193 const _Array<_Tp> _M_array;
194
195 // not implemented
196 slice_array();
197 };
198
199 template<typename _Tp>
200 inline
201 slice_array<_Tp>::slice_array(_Array<_Tp> __a, const slice& __s)
202 : _M_sz(__s.size()), _M_stride(__s.stride()),
203 _M_array(__a.begin() + __s.start()) {}
204
205 template<typename _Tp>
206 inline
207 slice_array<_Tp>::slice_array(const slice_array<_Tp>& a)
208 : _M_sz(a._M_sz), _M_stride(a._M_stride), _M_array(a._M_array) {}
209
210 // template<typename _Tp>
211 // inline slice_array<_Tp>::~slice_array () {}
212
213 template<typename _Tp>
214 inline slice_array<_Tp>&
215 slice_array<_Tp>::operator=(const slice_array<_Tp>& __a)
216 {
217 std::__valarray_copy(__a._M_array, __a._M_sz, __a._M_stride,
218 _M_array, _M_stride);
219 return *this;
220 }
221
222 template<typename _Tp>
223 inline void
224 slice_array<_Tp>::operator=(const _Tp& __t) const
225 { std::__valarray_fill(_M_array, _M_sz, _M_stride, __t); }
226
227 template<typename _Tp>
228 inline void
229 slice_array<_Tp>::operator=(const valarray<_Tp>& __v) const
230 { std::__valarray_copy(_Array<_Tp>(__v), _M_array, _M_sz, _M_stride); }
231
232 template<typename _Tp>
233 template<class _Dom>
234 inline void
235 slice_array<_Tp>::operator=(const _Expr<_Dom,_Tp>& __e) const
236 { std::__valarray_copy(__e, _M_sz, _M_array, _M_stride); }
237
238 #undef _DEFINE_VALARRAY_OPERATOR
239 #define _DEFINE_VALARRAY_OPERATOR(_Op,_Name) \
240 template<typename _Tp> \
241 inline void \
242 slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \
243 { \
244 _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\
245 } \
246 \
247 template<typename _Tp> \
248 template<class _Dom> \
249 inline void \
250 slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
251 { \
252 _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz); \
253 }
254
255
256 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
257 _DEFINE_VALARRAY_OPERATOR(/, __divides)
258 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
259 _DEFINE_VALARRAY_OPERATOR(+, __plus)
260 _DEFINE_VALARRAY_OPERATOR(-, __minus)
261 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
262 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
263 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
264 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
265 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
266
267 #undef _DEFINE_VALARRAY_OPERATOR
268
269 // @} group numeric_arrays
270
271 _GLIBCXX_END_NAMESPACE_VERSION
272 } // namespace
273
274 #endif /* _SLICE_ARRAY_H */