libstdc++

mask_array.h
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1 // The template and inlines for the -*- C++ -*- mask_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/mask_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 _MASK_ARRAY_H
33 #define _MASK_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 Reference to selected subset of an array.
48 *
49 * A mask_array is a reference to the actual elements of an array specified
50 * by a bitmask in the form of an array of bool. The way to get a
51 * mask_array is to call operator[](valarray<bool>) on a valarray. The
52 * returned mask_array then permits carrying operations out on the
53 * referenced subset of elements in the original valarray.
54 *
55 * For example, if a mask_array is obtained using the array (false, true,
56 * false, true) as an argument, the mask array has two elements referring
57 * to array[1] and array[3] in the underlying array.
58 *
59 * @param Tp Element type.
60 */
61 template <class _Tp>
62 class mask_array
63 {
64 public:
65 typedef _Tp value_type;
66
67 // _GLIBCXX_RESOLVE_LIB_DEFECTS
68 // 253. valarray helper functions are almost entirely useless
69
70 /// Copy constructor. Both slices refer to the same underlying array.
71 mask_array (const mask_array&);
72
73 /// Assignment operator. Assigns elements to corresponding elements
74 /// of @a a.
75 mask_array& operator=(const mask_array&);
76
77 void operator=(const valarray<_Tp>&) const;
78 /// Multiply slice elements by corresponding elements of @a v.
79 void operator*=(const valarray<_Tp>&) const;
80 /// Divide slice elements by corresponding elements of @a v.
81 void operator/=(const valarray<_Tp>&) const;
82 /// Modulo slice elements by corresponding elements of @a v.
83 void operator%=(const valarray<_Tp>&) const;
84 /// Add corresponding elements of @a v to slice elements.
85 void operator+=(const valarray<_Tp>&) const;
86 /// Subtract corresponding elements of @a v from slice elements.
87 void operator-=(const valarray<_Tp>&) const;
88 /// Logical xor slice elements with corresponding elements of @a v.
89 void operator^=(const valarray<_Tp>&) const;
90 /// Logical and slice elements with corresponding elements of @a v.
91 void operator&=(const valarray<_Tp>&) const;
92 /// Logical or slice elements with corresponding elements of @a v.
93 void operator|=(const valarray<_Tp>&) const;
94 /// Left shift slice elements by corresponding elements of @a v.
95 void operator<<=(const valarray<_Tp>&) const;
96 /// Right shift slice elements by corresponding elements of @a v.
97 void operator>>=(const valarray<_Tp>&) const;
98 /// Assign all slice elements to @a t.
99 void operator=(const _Tp&) const;
100
101 // ~mask_array ();
102
103 template<class _Dom>
104 void operator=(const _Expr<_Dom,_Tp>&) const;
105 template<class _Dom>
106 void operator*=(const _Expr<_Dom,_Tp>&) const;
107 template<class _Dom>
108 void operator/=(const _Expr<_Dom,_Tp>&) const;
109 template<class _Dom>
110 void operator%=(const _Expr<_Dom,_Tp>&) const;
111 template<class _Dom>
112 void operator+=(const _Expr<_Dom,_Tp>&) const;
113 template<class _Dom>
114 void operator-=(const _Expr<_Dom,_Tp>&) const;
115 template<class _Dom>
116 void operator^=(const _Expr<_Dom,_Tp>&) const;
117 template<class _Dom>
118 void operator&=(const _Expr<_Dom,_Tp>&) const;
119 template<class _Dom>
120 void operator|=(const _Expr<_Dom,_Tp>&) const;
121 template<class _Dom>
122 void operator<<=(const _Expr<_Dom,_Tp>&) const;
123 template<class _Dom>
124 void operator>>=(const _Expr<_Dom,_Tp>&) const;
125
126 private:
127 mask_array(_Array<_Tp>, size_t, _Array<bool>);
128 friend class valarray<_Tp>;
129
130 const size_t _M_sz;
131 const _Array<bool> _M_mask;
132 const _Array<_Tp> _M_array;
133
134 // not implemented
135 mask_array();
136 };
137
138 template<typename _Tp>
139 inline mask_array<_Tp>::mask_array(const mask_array<_Tp>& a)
140 : _M_sz(a._M_sz), _M_mask(a._M_mask), _M_array(a._M_array) {}
141
142 template<typename _Tp>
143 inline
144 mask_array<_Tp>::mask_array(_Array<_Tp> __a, size_t __s, _Array<bool> __m)
145 : _M_sz(__s), _M_mask(__m), _M_array(__a) {}
146
147 template<typename _Tp>
148 inline mask_array<_Tp>&
149 mask_array<_Tp>::operator=(const mask_array<_Tp>& __a)
150 {
151 std::__valarray_copy(__a._M_array, __a._M_mask,
152 _M_sz, _M_array, _M_mask);
153 return *this;
154 }
155
156 template<typename _Tp>
157 inline void
158 mask_array<_Tp>::operator=(const _Tp& __t) const
159 { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
160
161 template<typename _Tp>
162 inline void
163 mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
164 { std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask); }
165
166 template<typename _Tp>
167 template<class _Ex>
168 inline void
169 mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
170 { std::__valarray_copy(__e, __e.size(), _M_array, _M_mask); }
171
172 #undef _DEFINE_VALARRAY_OPERATOR
173 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name) \
174 template<typename _Tp> \
175 inline void \
176 mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \
177 { \
178 _Array_augmented_##_Name(_M_array, _M_mask, \
179 _Array<_Tp>(__v), __v.size()); \
180 } \
181 \
182 template<typename _Tp> \
183 template<class _Dom> \
184 inline void \
185 mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
186 { \
187 _Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size()); \
188 }
189
190 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
191 _DEFINE_VALARRAY_OPERATOR(/, __divides)
192 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
193 _DEFINE_VALARRAY_OPERATOR(+, __plus)
194 _DEFINE_VALARRAY_OPERATOR(-, __minus)
195 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
196 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
197 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
198 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
199 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
200
201 #undef _DEFINE_VALARRAY_OPERATOR
202
203 // @} group numeric_arrays
204
205 _GLIBCXX_END_NAMESPACE_VERSION
206 } // namespace
207
208 #endif /* _MASK_ARRAY_H */