libstdc++
mask_array.h
Go to the documentation of this file.
1 // The template and inlines for the -*- C++ -*- mask_array class.
2 
3 // Copyright (C) 1997-2015 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 <[email protected]>
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>
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>&
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 */
mask_array & operator=(const mask_array &)
Assignment operator. Assigns elements to corresponding elements of a.
Definition: mask_array.h:149
void operator>>=(const valarray< _Tp > &) const
Right shift slice elements by corresponding elements of v.
Definition: mask_array.h:199
mask_array(const mask_array &)
Copy constructor. Both slices refer to the same underlying array.
Definition: mask_array.h:139
void operator&=(const valarray< _Tp > &) const
Logical and slice elements with corresponding elements of v.
Definition: mask_array.h:196
void operator%=(const valarray< _Tp > &) const
Modulo slice elements by corresponding elements of v.
Definition: mask_array.h:192
size_t size() const
Return the number of elements in array.
Definition: valarray:921
void operator*=(const valarray< _Tp > &) const
Multiply slice elements by corresponding elements of v.
Definition: mask_array.h:190
void operator|=(const valarray< _Tp > &) const
Logical or slice elements with 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:195
Smart array designed to support numeric processing.
Definition: valarray:78
Reference to selected subset of an array.
Definition: valarray:83
void operator/=(const valarray< _Tp > &) const
Divide slice elements by corresponding elements of v.
Definition: mask_array.h:191
void operator-=(const valarray< _Tp > &) const
Subtract corresponding elements of v from slice elements.
Definition: mask_array.h:194
ISO C++ entities toplevel namespace is std.
void operator+=(const valarray< _Tp > &) const
Add corresponding elements of v to slice elements.
Definition: mask_array.h:193