1 // The template and inlines for the -*- C++ -*- mask_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/mask_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 _MASK_ARRAY_H
34 #define _MASK_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 selected subset of an array.
49    *
50    *  A mask_array is a reference to the actual elements of an array specified
51    *  by a bitmask in the form of an array of bool.  The way to get a
52    *  mask_array is to call operator[](valarray<bool>) on a valarray.  The
53    *  returned mask_array then permits carrying operations out on the
54    *  referenced subset of elements in the original valarray.
55    *
56    *  For example, if a mask_array is obtained using the array (false, true,
57    *  false, true) as an argument, the mask array has two elements referring
58    *  to array[1] and array[3] in the underlying array.
59    *
60    *  @param  Tp  Element type.
61    */
62   template <class _Tp>
63     class mask_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       mask_array (const mask_array&);
73 
74       ///  Assignment operator.  Assigns elements to corresponding elements
75       ///  of @a a.
76       mask_array& operator=(const mask_array&);
77 
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         //        ~mask_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       mask_array(_Array<_Tp>, size_t, _Array<bool>);
129       friend class valarray<_Tp>;
130 
131       const size_t       _M_sz;
132       const _Array<bool> _M_mask;
133       const _Array<_Tp>  _M_array;
134 
135       // not implemented
136       mask_array();
137     };
138 
139   template<typename _Tp>
140     inline mask_array<_Tp>::mask_array(const mask_array<_Tp>& a)
141     : _M_sz(a._M_sz), _M_mask(a._M_mask), _M_array(a._M_array) {}
142 
143   template<typename _Tp>
144     inline
145     mask_array<_Tp>::mask_array(_Array<_Tp> __a, size_t __s, _Array<bool> __m)
146     : _M_sz(__s), _M_mask(__m), _M_array(__a) {}
147 
148   template<typename _Tp>
149     inline mask_array<_Tp>&
150     mask_array<_Tp>::operator=(const mask_array<_Tp>& __a)
151     {
152       std::__valarray_copy(__a._M_array, __a._M_mask,
153 			   _M_sz, _M_array, _M_mask);
154       return *this;
155     }
156 
157   template<typename _Tp>
158     inline void
159     mask_array<_Tp>::operator=(const _Tp& __t) const
160     { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
161 
162   template<typename _Tp>
163     inline void
164     mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
165     { std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask); }
166 
167   template<typename _Tp>
168     template<class _Ex>
169       inline void
170       mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
171       { std::__valarray_copy(__e, __e.size(), _M_array, _M_mask); }
172 
173 #undef _DEFINE_VALARRAY_OPERATOR
174 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name)				\
175   template<typename _Tp>						\
176     inline void								\
177     mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const	\
178     {									\
179       _Array_augmented_##_Name(_M_array, _M_mask,			\
180 			       _Array<_Tp>(__v), __v.size());		\
181     }									\
182 									\
183   template<typename _Tp>                                                \
184     template<class _Dom>			                        \
185       inline void							\
186       mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
187       {									\
188 	_Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size());   \
189       }
190 
191 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
192 _DEFINE_VALARRAY_OPERATOR(/, __divides)
193 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
194 _DEFINE_VALARRAY_OPERATOR(+, __plus)
195 _DEFINE_VALARRAY_OPERATOR(-, __minus)
196 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
197 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
198 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
199 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
200 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
201 
202 #undef _DEFINE_VALARRAY_OPERATOR
203 
204   // @} group numeric_arrays
205 
206 _GLIBCXX_END_NAMESPACE_VERSION
207 } // namespace
208 
209 #endif /* _MASK_ARRAY_H */
210