libstdc++
mask_array.h
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1 // The template and inlines for the -*- C++ -*- mask_array class.
2 
3 // Copyright (C) 1997-2021 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 
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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.
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>
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>&
155  {
156  std::__valarray_copy(__a._M_array, __a._M_mask,
157  _M_sz, _M_array, _M_mask);
158  return *this;
159  }
160 
161  template<typename _Tp>
162  inline void
163  mask_array<_Tp>::operator=(const _Tp& __t) const
164  { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
165 
166  template<typename _Tp>
167  inline void
168  mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
169  { std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask); }
170 
171  template<typename _Tp>
172  template<class _Ex>
173  inline void
174  mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
175  { std::__valarray_copy(__e, __e.size(), _M_array, _M_mask); }
176 
177 #undef _DEFINE_VALARRAY_OPERATOR
178 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name) \
179  template<typename _Tp> \
180  inline void \
181  mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \
182  { \
183  _Array_augmented_##_Name(_M_array, _M_mask, \
184  _Array<_Tp>(__v), __v.size()); \
185  } \
186  \
187  template<typename _Tp> \
188  template<class _Dom> \
189  inline void \
190  mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
191  { \
192  _Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size()); \
193  }
194 
195 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
196 _DEFINE_VALARRAY_OPERATOR(/, __divides)
197 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
198 _DEFINE_VALARRAY_OPERATOR(+, __plus)
199 _DEFINE_VALARRAY_OPERATOR(-, __minus)
200 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
201 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
202 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
203 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
204 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
205 
206 #undef _DEFINE_VALARRAY_OPERATOR
207 
208  /// @} group numeric_arrays
209 
210 _GLIBCXX_END_NAMESPACE_VERSION
211 } // namespace
212 
213 #endif /* _MASK_ARRAY_H */
void operator*=(const valarray< _Tp > &) const
Multiply slice elements by corresponding elements of v.
Definition: mask_array.h:195
size_t size() const
Return the number of elements in array.
Definition: valarray:937
void operator+=(const valarray< _Tp > &) const
Add corresponding elements of v to slice elements.
Definition: mask_array.h:198
void operator&=(const valarray< _Tp > &) const
Logical and slice elements with corresponding elements of v.
Definition: mask_array.h:201
void operator|=(const valarray< _Tp > &) const
Logical or slice elements with corresponding elements of v.
Definition: mask_array.h:202
void operator-=(const valarray< _Tp > &) const
Subtract corresponding elements of v from slice elements.
Definition: mask_array.h:199
void operator>>=(const valarray< _Tp > &) const
Right shift slice elements by corresponding elements of v.
Definition: mask_array.h:204
void operator%=(const valarray< _Tp > &) const
Modulo slice elements by corresponding elements of v.
Definition: mask_array.h:197
void operator^=(const valarray< _Tp > &) const
Logical xor slice elements with corresponding elements of v.
Definition: mask_array.h:200
void operator/=(const valarray< _Tp > &) const
Divide slice elements by corresponding elements of v.
Definition: mask_array.h:196
mask_array & operator=(const mask_array &)
Assignment operator. Assigns elements to corresponding elements of a.
Definition: mask_array.h:154
void operator<<=(const valarray< _Tp > &) const
Left shift slice elements by corresponding elements of v.
Definition: mask_array.h:203
ISO C++ entities toplevel namespace is std.
Smart array designed to support numeric processing.
Definition: valarray:128
Reference to selected subset of an array.
Definition: mask_array.h:63