libstdc++
gslice_array.h
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1 // The template and inlines for the -*- C++ -*- gslice_array class.
2 
3 // Copyright (C) 1997-2025 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/gslice_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 _GSLICE_ARRAY_H
33 #define _GSLICE_ARRAY_H 1
34 
35 #ifdef _GLIBCXX_SYSHDR
36 #pragma GCC system_header
37 #endif
38 
39 namespace std _GLIBCXX_VISIBILITY(default)
40 {
41 _GLIBCXX_BEGIN_NAMESPACE_VERSION
42 
43  /**
44  * @addtogroup numeric_arrays
45  * @{
46  */
47 
48  /**
49  * @brief Reference to multi-dimensional subset of an array.
50  *
51  * A gslice_array is a reference to the actual elements of an array
52  * specified by a gslice. The way to get a gslice_array is to call
53  * operator[](gslice) on a valarray. The returned gslice_array then
54  * permits carrying operations out on the referenced subset of elements in
55  * the original valarray. For example, operator+=(valarray) will add
56  * values to the subset of elements in the underlying valarray this
57  * gslice_array refers to.
58  *
59  * @param Tp Element type.
60  */
61  template<typename _Tp>
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  gslice_array(const gslice_array&);
72 
73  /// Assignment operator. Assigns slice elements to corresponding
74  /// elements of @a a.
76 
77  /// Assign slice elements to corresponding elements of @a v.
78  void operator=(const valarray<_Tp>&) const;
79  /// Multiply slice elements by corresponding elements of @a v.
80  void operator*=(const valarray<_Tp>&) const;
81  /// Divide slice elements by corresponding elements of @a v.
82  void operator/=(const valarray<_Tp>&) const;
83  /// Modulo slice elements by corresponding elements of @a v.
84  void operator%=(const valarray<_Tp>&) const;
85  /// Add corresponding elements of @a v to slice elements.
86  void operator+=(const valarray<_Tp>&) const;
87  /// Subtract corresponding elements of @a v from slice elements.
88  void operator-=(const valarray<_Tp>&) const;
89  /// Logical xor slice elements with corresponding elements of @a v.
90  void operator^=(const valarray<_Tp>&) const;
91  /// Logical and slice elements with corresponding elements of @a v.
92  void operator&=(const valarray<_Tp>&) const;
93  /// Logical or slice elements with corresponding elements of @a v.
94  void operator|=(const valarray<_Tp>&) const;
95  /// Left shift slice elements by corresponding elements of @a v.
96  void operator<<=(const valarray<_Tp>&) const;
97  /// Right shift slice elements by corresponding elements of @a v.
98  void operator>>=(const valarray<_Tp>&) const;
99  /// Assign all slice elements to @a t.
100  void operator=(const _Tp&) const;
101 
102  template<class _Dom>
103  void operator=(const _Expr<_Dom, _Tp>&) const;
104  template<class _Dom>
105  void operator*=(const _Expr<_Dom, _Tp>&) const;
106  template<class _Dom>
107  void operator/=(const _Expr<_Dom, _Tp>&) const;
108  template<class _Dom>
109  void operator%=(const _Expr<_Dom, _Tp>&) const;
110  template<class _Dom>
111  void operator+=(const _Expr<_Dom, _Tp>&) const;
112  template<class _Dom>
113  void operator-=(const _Expr<_Dom, _Tp>&) const;
114  template<class _Dom>
115  void operator^=(const _Expr<_Dom, _Tp>&) const;
116  template<class _Dom>
117  void operator&=(const _Expr<_Dom, _Tp>&) const;
118  template<class _Dom>
119  void operator|=(const _Expr<_Dom, _Tp>&) const;
120  template<class _Dom>
121  void operator<<=(const _Expr<_Dom, _Tp>&) const;
122  template<class _Dom>
123  void operator>>=(const _Expr<_Dom, _Tp>&) const;
124 
125  private:
126  _Array<_Tp> _M_array;
127  const valarray<size_t>& _M_index;
128 
129  friend class valarray<_Tp>;
130 
131  gslice_array(_Array<_Tp>, const valarray<size_t>&);
132 
133 #if __cplusplus < 201103L
134  // not implemented
135  gslice_array();
136 #else
137  public:
138  gslice_array() = delete;
139 #endif
140  };
141 
142  template<typename _Tp>
143  inline
144  gslice_array<_Tp>::gslice_array(_Array<_Tp> __a,
145  const valarray<size_t>& __i)
146  : _M_array(__a), _M_index(__i) {}
147 
148  template<typename _Tp>
149  inline
151  : _M_array(__a._M_array), _M_index(__a._M_index) {}
152 
153  template<typename _Tp>
154  inline gslice_array<_Tp>&
156  {
157  std::__valarray_copy(_Array<_Tp>(__a._M_array),
158  _Array<size_t>(__a._M_index), _M_index.size(),
159  _M_array, _Array<size_t>(_M_index));
160  return *this;
161  }
162 
163  template<typename _Tp>
164  inline void
165  gslice_array<_Tp>::operator=(const _Tp& __t) const
166  {
167  std::__valarray_fill(_M_array, _Array<size_t>(_M_index),
168  _M_index.size(), __t);
169  }
170 
171  template<typename _Tp>
172  inline void
174  {
175  std::__valarray_copy(_Array<_Tp>(__v), __v.size(),
176  _M_array, _Array<size_t>(_M_index));
177  }
178 
179  template<typename _Tp>
180  template<class _Dom>
181  inline void
182  gslice_array<_Tp>::operator=(const _Expr<_Dom, _Tp>& __e) const
183  {
184  std::__valarray_copy (__e, _M_index.size(), _M_array,
185  _Array<size_t>(_M_index));
186  }
187 
188  /// @cond undocumented
189 #undef _DEFINE_VALARRAY_OPERATOR
190 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name) \
191  template<typename _Tp> \
192  inline void \
193  gslice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \
194  { \
195  _Array_augmented_##_Name(_M_array, _Array<size_t>(_M_index), \
196  _Array<_Tp>(__v), __v.size()); \
197  } \
198  \
199  template<typename _Tp> \
200  template<class _Dom> \
201  inline void \
202  gslice_array<_Tp>::operator _Op##= (const _Expr<_Dom, _Tp>& __e) const\
203  { \
204  _Array_augmented_##_Name(_M_array, _Array<size_t>(_M_index), __e,\
205  _M_index.size()); \
206  }
207 
208 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
209 _DEFINE_VALARRAY_OPERATOR(/, __divides)
210 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
211 _DEFINE_VALARRAY_OPERATOR(+, __plus)
212 _DEFINE_VALARRAY_OPERATOR(-, __minus)
213 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
214 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
215 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
216 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
217 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
218 
219 #undef _DEFINE_VALARRAY_OPERATOR
220  /// @endcond
221 
222  /// @} group numeric_arrays
223 
224 _GLIBCXX_END_NAMESPACE_VERSION
225 } // namespace
226 
227 #endif /* _GSLICE_ARRAY_H */
size_t size() const
Return the number of elements in array.
Definition: valarray:949
gslice_array & operator=(const gslice_array &)
Assignment operator. Assigns slice elements to corresponding elements of a.
Definition: gslice_array.h:155
ISO C++ entities toplevel namespace is std.
Smart array designed to support numeric processing.
Definition: valarray:132
Reference to multi-dimensional subset of an array.
Definition: gslice_array.h:63
void operator<<=(const valarray< _Tp > &) const
Left shift slice elements by corresponding elements of v.
void operator/=(const valarray< _Tp > &) const
Divide slice elements by corresponding elements of v.
void operator%=(const valarray< _Tp > &) const
Modulo slice elements by corresponding elements of v.
void operator>>=(const valarray< _Tp > &) const
Right shift slice elements by corresponding elements of v.
void operator*=(const valarray< _Tp > &) const
Multiply slice elements by corresponding elements of v.
void operator|=(const valarray< _Tp > &) const
Logical or slice elements with corresponding elements of v.
void operator^=(const valarray< _Tp > &) const
Logical xor slice elements with corresponding elements of v.
void operator-=(const valarray< _Tp > &) const
Subtract corresponding elements of v from slice elements.
void operator+=(const valarray< _Tp > &) const
Add corresponding elements of v to slice elements.
void operator&=(const valarray< _Tp > &) const
Logical and slice elements with corresponding elements of v.