1 // The template and inlines for the -*- C++ -*- mask_array class.
2
3 // Copyright (C) 1997-2023 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 #if __cplusplus < 201103L
135 // not implemented
136 mask_array();
137 #else
138 public:
139 mask_array() = delete;
140 #endif
141 };
142
143 template<typename _Tp>
144 inline mask_array<_Tp>::mask_array(const mask_array<_Tp>& __a)
145 : _M_sz(__a._M_sz), _M_mask(__a._M_mask), _M_array(__a._M_array) {}
146
147 template<typename _Tp>
148 inline
149 mask_array<_Tp>::mask_array(_Array<_Tp> __a, size_t __s, _Array<bool> __m)
150 : _M_sz(__s), _M_mask(__m), _M_array(__a) {}
151
152 template<typename _Tp>
153 inline mask_array<_Tp>&
154 mask_array<_Tp>::operator=(const mask_array<_Tp>& __a)
155 {
156 __glibcxx_assert(__a._M_sz == _M_sz);
157 std::__valarray_copy(__a._M_array, __a._M_mask,
158 _M_sz, _M_array, _M_mask);
159 return *this;
160 }
161
162 template<typename _Tp>
163 inline void
164 mask_array<_Tp>::operator=(const _Tp& __t) const
165 { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
166
167 template<typename _Tp>
168 inline void
169 mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
170 {
171 __glibcxx_assert(__v.size() == _M_sz);
172 std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask);
173 }
174
175 template<typename _Tp>
176 template<class _Ex>
177 inline void
178 mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
179 {
180 __glibcxx_assert(__e.size() == _M_sz);
181 std::__valarray_copy(__e, __e.size(), _M_array, _M_mask);
182 }
183
184 /// @cond undocumented
185 #undef _DEFINE_VALARRAY_OPERATOR
186 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name) \
187 template<typename _Tp> \
188 inline void \
189 mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \
190 { \
191 __glibcxx_assert(__v.size() == _M_sz); \
192 _Array_augmented_##_Name(_M_array, _M_mask, \
193 _Array<_Tp>(__v), __v.size()); \
194 } \
195 \
196 template<typename _Tp> \
197 template<class _Dom> \
198 inline void \
199 mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
200 { \
201 __glibcxx_assert(__e.size() == _M_sz); \
202 _Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size()); \
203 }
204
205 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
206 _DEFINE_VALARRAY_OPERATOR(/, __divides)
207 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
208 _DEFINE_VALARRAY_OPERATOR(+, __plus)
209 _DEFINE_VALARRAY_OPERATOR(-, __minus)
210 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
211 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
212 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
213 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
214 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
215
216 #undef _DEFINE_VALARRAY_OPERATOR
217 /// @endcond
218
219 /// @} group numeric_arrays
220
221 _GLIBCXX_END_NAMESPACE_VERSION
222 } // namespace
223
224 #endif /* _MASK_ARRAY_H */