libstdc++
indirect_array.h
Go to the documentation of this file.
1 // The template and inlines for the -*- C++ -*- indirect_array class.
2 
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2009, 2010
4 // Free Software Foundation, Inc.
5 //
6 // This file is part of the GNU ISO C++ Library. This library is free
7 // software; you can redistribute it and/or modify it under the
8 // terms of the GNU General Public License as published by the
9 // Free Software Foundation; either version 3, or (at your option)
10 // any later version.
11 
12 // This library is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
16 
17 // Under Section 7 of GPL version 3, you are granted additional
18 // permissions described in the GCC Runtime Library Exception, version
19 // 3.1, as published by the Free Software Foundation.
20 
21 // You should have received a copy of the GNU General Public License and
22 // a copy of the GCC Runtime Library Exception along with this program;
23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 // <http://www.gnu.org/licenses/>.
25 
26 /** @file bits/indirect_array.h
27  * This is an internal header file, included by other library headers.
28  * Do not attempt to use it directly. @headername{valarray}
29  */
30 
31 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
32 
33 #ifndef _INDIRECT_ARRAY_H
34 #define _INDIRECT_ARRAY_H 1
35 
36 #pragma GCC system_header
37 
38 namespace std _GLIBCXX_VISIBILITY(default)
39 {
40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
41 
42  /**
43  * @addtogroup numeric_arrays
44  * @{
45  */
46 
47  /**
48  * @brief Reference to arbitrary subset of an array.
49  *
50  * An indirect_array is a reference to the actual elements of an array
51  * specified by an ordered array of indices. The way to get an
52  * indirect_array is to call operator[](valarray<size_t>) on a valarray.
53  * The returned indirect_array then permits carrying operations out on the
54  * referenced subset of elements in the original valarray.
55  *
56  * For example, if an indirect_array is obtained using the array (4,2,0) as
57  * an argument, and then assigned to an array containing (1,2,3), then the
58  * underlying array will have array[0]==3, array[2]==2, and array[4]==1.
59  *
60  * @param Tp Element type.
61  */
62  template <class _Tp>
63  class indirect_array
64  {
65  public:
66  typedef _Tp value_type;
67 
68  // _GLIBCXX_RESOLVE_LIB_DEFECTS
69  // 253. valarray helper functions are almost entirely useless
70 
71  /// Copy constructor. Both slices refer to the same underlying array.
72  indirect_array(const indirect_array&);
73 
74  /// Assignment operator. Assigns elements to corresponding elements
75  /// of @a a.
76  indirect_array& operator=(const indirect_array&);
77 
78  /// Assign slice elements to corresponding elements of @a v.
79  void operator=(const valarray<_Tp>&) const;
80  /// Multiply slice elements by corresponding elements of @a v.
81  void operator*=(const valarray<_Tp>&) const;
82  /// Divide slice elements by corresponding elements of @a v.
83  void operator/=(const valarray<_Tp>&) const;
84  /// Modulo slice elements by corresponding elements of @a v.
85  void operator%=(const valarray<_Tp>&) const;
86  /// Add corresponding elements of @a v to slice elements.
87  void operator+=(const valarray<_Tp>&) const;
88  /// Subtract corresponding elements of @a v from slice elements.
89  void operator-=(const valarray<_Tp>&) const;
90  /// Logical xor slice elements with corresponding elements of @a v.
91  void operator^=(const valarray<_Tp>&) const;
92  /// Logical and slice elements with corresponding elements of @a v.
93  void operator&=(const valarray<_Tp>&) const;
94  /// Logical or slice elements with corresponding elements of @a v.
95  void operator|=(const valarray<_Tp>&) const;
96  /// Left shift slice elements by corresponding elements of @a v.
97  void operator<<=(const valarray<_Tp>&) const;
98  /// Right shift slice elements by corresponding elements of @a v.
99  void operator>>=(const valarray<_Tp>&) const;
100  /// Assign all slice elements to @a t.
101  void operator= (const _Tp&) const;
102  // ~indirect_array();
103 
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  template<class _Dom>
125  void operator>>=(const _Expr<_Dom, _Tp>&) const;
126 
127  private:
128  /// Copy constructor. Both slices refer to the same underlying array.
129  indirect_array(_Array<_Tp>, size_t, _Array<size_t>);
130 
131  friend class valarray<_Tp>;
132  friend class gslice_array<_Tp>;
133 
134  const size_t _M_sz;
135  const _Array<size_t> _M_index;
136  const _Array<_Tp> _M_array;
137 
138  // not implemented
139  indirect_array();
140  };
141 
142  template<typename _Tp>
143  inline
144  indirect_array<_Tp>::indirect_array(const indirect_array<_Tp>& __a)
145  : _M_sz(__a._M_sz), _M_index(__a._M_index), _M_array(__a._M_array) {}
146 
147  template<typename _Tp>
148  inline
149  indirect_array<_Tp>::indirect_array(_Array<_Tp> __a, size_t __s,
150  _Array<size_t> __i)
151  : _M_sz(__s), _M_index(__i), _M_array(__a) {}
152 
153  template<typename _Tp>
154  inline indirect_array<_Tp>&
155  indirect_array<_Tp>::operator=(const indirect_array<_Tp>& __a)
156  {
157  std::__valarray_copy(__a._M_array, _M_sz, __a._M_index, _M_array,
158  _M_index);
159  return *this;
160  }
161 
162  template<typename _Tp>
163  inline void
164  indirect_array<_Tp>::operator=(const _Tp& __t) const
165  { std::__valarray_fill(_M_array, _M_index, _M_sz, __t); }
166 
167  template<typename _Tp>
168  inline void
169  indirect_array<_Tp>::operator=(const valarray<_Tp>& __v) const
170  { std::__valarray_copy(_Array<_Tp>(__v), _M_sz, _M_array, _M_index); }
171 
172  template<typename _Tp>
173  template<class _Dom>
174  inline void
175  indirect_array<_Tp>::operator=(const _Expr<_Dom, _Tp>& __e) const
176  { std::__valarray_copy(__e, _M_sz, _M_array, _M_index); }
177 
178 #undef _DEFINE_VALARRAY_OPERATOR
179 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name) \
180  template<typename _Tp> \
181  inline void \
182  indirect_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const\
183  { \
184  _Array_augmented_##_Name(_M_array, _M_index, _Array<_Tp>(__v), _M_sz); \
185  } \
186  \
187  template<typename _Tp> \
188  template<class _Dom> \
189  inline void \
190  indirect_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
191  { \
192  _Array_augmented_##_Name(_M_array, _M_index, __e, _M_sz); \
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 /* _INDIRECT_ARRAY_H */