libstdc++
indirect_array.h
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1 // The template and inlines for the -*- C++ -*- indirect_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/indirect_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 _INDIRECT_ARRAY_H
33 #define _INDIRECT_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 arbitrary subset of an array.
50  *
51  * An indirect_array is a reference to the actual elements of an array
52  * specified by an ordered array of indices. The way to get an
53  * indirect_array is to call operator[](valarray<size_t>) on a valarray.
54  * The returned indirect_array then permits carrying operations out on the
55  * referenced subset of elements in the original valarray.
56  *
57  * For example, if an indirect_array is obtained using the array (4,2,0) as
58  * an argument, and then assigned to an array containing (1,2,3), then the
59  * underlying array will have array[0]==3, array[2]==2, and array[4]==1.
60  *
61  * @param Tp Element type.
62  */
63  template <class _Tp>
65  {
66  public:
67  typedef _Tp value_type;
68 
69  // _GLIBCXX_RESOLVE_LIB_DEFECTS
70  // 253. valarray helper functions are almost entirely useless
71 
72  /// Copy constructor. Both slices refer to the same underlying array.
74 
75  /// Assignment operator. Assigns elements to corresponding elements
76  /// of @a a.
78 
79  /// Assign slice elements to corresponding elements of @a v.
80  void operator=(const valarray<_Tp>&) const;
81  /// Multiply slice elements by corresponding elements of @a v.
82  void operator*=(const valarray<_Tp>&) const;
83  /// Divide slice elements by corresponding elements of @a v.
84  void operator/=(const valarray<_Tp>&) const;
85  /// Modulo slice elements by corresponding elements of @a v.
86  void operator%=(const valarray<_Tp>&) const;
87  /// Add corresponding elements of @a v to slice elements.
88  void operator+=(const valarray<_Tp>&) const;
89  /// Subtract corresponding elements of @a v from slice elements.
90  void operator-=(const valarray<_Tp>&) const;
91  /// Logical xor slice elements with corresponding elements of @a v.
92  void operator^=(const valarray<_Tp>&) const;
93  /// Logical and slice elements with corresponding elements of @a v.
94  void operator&=(const valarray<_Tp>&) const;
95  /// Logical or slice elements with corresponding elements of @a v.
96  void operator|=(const valarray<_Tp>&) const;
97  /// Left shift slice elements by corresponding elements of @a v.
98  void operator<<=(const valarray<_Tp>&) const;
99  /// Right shift slice elements by corresponding elements of @a v.
100  void operator>>=(const valarray<_Tp>&) const;
101  /// Assign all slice elements to @a t.
102  void operator= (const _Tp&) const;
103  // ~indirect_array();
104 
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  template<class _Dom>
126  void operator>>=(const _Expr<_Dom, _Tp>&) const;
127 
128  private:
129  /// Copy constructor. Both slices refer to the same underlying array.
130  indirect_array(_Array<_Tp>, size_t, _Array<size_t>);
131 
132  friend class valarray<_Tp>;
133  friend class gslice_array<_Tp>;
134 
135  const size_t _M_sz;
136  const _Array<size_t> _M_index;
137  const _Array<_Tp> _M_array;
138 
139  // not implemented
140  indirect_array();
141  };
142 
143  template<typename _Tp>
144  inline
146  : _M_sz(__a._M_sz), _M_index(__a._M_index), _M_array(__a._M_array) {}
147 
148  template<typename _Tp>
149  inline
150  indirect_array<_Tp>::indirect_array(_Array<_Tp> __a, size_t __s,
151  _Array<size_t> __i)
152  : _M_sz(__s), _M_index(__i), _M_array(__a) {}
153 
154  template<typename _Tp>
155  inline indirect_array<_Tp>&
157  {
158  std::__valarray_copy(__a._M_array, _M_sz, __a._M_index, _M_array,
159  _M_index);
160  return *this;
161  }
162 
163  template<typename _Tp>
164  inline void
165  indirect_array<_Tp>::operator=(const _Tp& __t) const
166  { std::__valarray_fill(_M_array, _M_index, _M_sz, __t); }
167 
168  template<typename _Tp>
169  inline void
171  { std::__valarray_copy(_Array<_Tp>(__v), _M_sz, _M_array, _M_index); }
172 
173  template<typename _Tp>
174  template<class _Dom>
175  inline void
176  indirect_array<_Tp>::operator=(const _Expr<_Dom, _Tp>& __e) const
177  { std::__valarray_copy(__e, _M_sz, _M_array, _M_index); }
178 
179  /// @cond undocumented
180 #undef _DEFINE_VALARRAY_OPERATOR
181 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name) \
182  template<typename _Tp> \
183  inline void \
184  indirect_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const\
185  { \
186  _Array_augmented_##_Name(_M_array, _M_index, _Array<_Tp>(__v), _M_sz); \
187  } \
188  \
189  template<typename _Tp> \
190  template<class _Dom> \
191  inline void \
192  indirect_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
193  { \
194  _Array_augmented_##_Name(_M_array, _M_index, __e, _M_sz); \
195  }
196 
197 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
198 _DEFINE_VALARRAY_OPERATOR(/, __divides)
199 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
200 _DEFINE_VALARRAY_OPERATOR(+, __plus)
201 _DEFINE_VALARRAY_OPERATOR(-, __minus)
202 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
203 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
204 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
205 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
206 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
207 
208 #undef _DEFINE_VALARRAY_OPERATOR
209  /// @endcond
210 
211  /// @} group numeric_arrays
212 
213 _GLIBCXX_END_NAMESPACE_VERSION
214 } // namespace
215 
216 #endif /* _INDIRECT_ARRAY_H */
indirect_array & operator=(const indirect_array &)
Assignment operator. Assigns elements to corresponding elements of a.
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
Reference to arbitrary subset of an array.
void operator/=(const valarray< _Tp > &) const
Divide slice elements by 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
Logical or slice elements with corresponding elements of v.
void operator<<=(const valarray< _Tp > &) const
Left shift 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
Subtract corresponding elements of v from slice elements.
void operator*=(const valarray< _Tp > &) const
Multiply slice elements by corresponding elements of v.
void operator&=(const valarray< _Tp > &) const
Logical and slice elements with corresponding elements of v.
void operator+=(const valarray< _Tp > &) const
Add corresponding elements of v to slice elements.
void operator%=(const valarray< _Tp > &) const
Modulo slice elements by corresponding elements of v.