1 // The template and inlines for the -*- C++ -*- mask_array class.
2
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005
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 2, 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 // You should have received a copy of the GNU General Public License along
18 // with this library; see the file COPYING. If not, write to the Free
19 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
20 // USA.
21
22 // As a special exception, you may use this file as part of a free software
23 // library without restriction. Specifically, if other files instantiate
24 // templates or use macros or inline functions from this file, or you compile
25 // this file and link it with other files to produce an executable, this
26 // file does not by itself cause the resulting executable to be covered by
27 // the GNU General Public License. This exception does not however
28 // invalidate any other reasons why the executable file might be covered by
29 // the GNU General Public License.
30
31 /** @file mask_array.h
32 * This is an internal header file, included by other library headers.
33 * You should not attempt to use it directly.
34 */
35
36 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
37
38 #ifndef _MASK_ARRAY_H
39 #define _MASK_ARRAY_H 1
40
41 #pragma GCC system_header
42
_GLIBCXX_BEGIN_NAMESPACE(std)43 _GLIBCXX_BEGIN_NAMESPACE(std)
44
45 /**
46 * @brief Reference to selected subset of an array.
47 *
48 * A mask_array is a reference to the actual elements of an array specified
49 * by a bitmask in the form of an array of bool. The way to get a
50 * mask_array is to call operator[](valarray<bool>) on a valarray. The
51 * returned mask_array then permits carrying operations out on the
52 * referenced subset of elements in the original valarray.
53 *
54 * For example, if a mask_array is obtained using the array (false, true,
55 * false, true) as an argument, the mask array has two elements referring
56 * to array[1] and array[3] in the underlying array.
57 *
58 * @param Tp Element type.
59 */
60 template <class _Tp>
61 class mask_array
62 {
63 public:
64 typedef _Tp value_type;
65
66 // _GLIBCXX_RESOLVE_LIB_DEFECTS
67 // 253. valarray helper functions are almost entirely useless
68
69 /// Copy constructor. Both slices refer to the same underlying array.
70 mask_array (const mask_array&);
71
72 /// Assignment operator. Assigns elements to corresponding elements
73 /// of @a a.
74 mask_array& operator=(const mask_array&);
75
76 void operator=(const valarray<_Tp>&) const;
77 /// Multiply slice elements by corresponding elements of @a v.
78 void operator*=(const valarray<_Tp>&) const;
79 /// Divide slice elements by corresponding elements of @a v.
80 void operator/=(const valarray<_Tp>&) const;
81 /// Modulo slice elements by corresponding elements of @a v.
82 void operator%=(const valarray<_Tp>&) const;
83 /// Add corresponding elements of @a v to slice elements.
84 void operator+=(const valarray<_Tp>&) const;
85 /// Subtract corresponding elements of @a v from slice elements.
86 void operator-=(const valarray<_Tp>&) const;
87 /// Logical xor slice elements with corresponding elements of @a v.
88 void operator^=(const valarray<_Tp>&) const;
89 /// Logical and slice elements with corresponding elements of @a v.
90 void operator&=(const valarray<_Tp>&) const;
91 /// Logical or slice elements with corresponding elements of @a v.
92 void operator|=(const valarray<_Tp>&) const;
93 /// Left shift slice elements by corresponding elements of @a v.
94 void operator<<=(const valarray<_Tp>&) const;
95 /// Right shift slice elements by corresponding elements of @a v.
96 void operator>>=(const valarray<_Tp>&) const;
97 /// Assign all slice elements to @a t.
98 void operator=(const _Tp&) const;
99
100 // ~mask_array ();
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 mask_array(_Array<_Tp>, size_t, _Array<bool>);
127 friend class valarray<_Tp>;
128
129 const size_t _M_sz;
130 const _Array<bool> _M_mask;
131 const _Array<_Tp> _M_array;
132
133 // not implemented
134 mask_array();
135 };
136
137 template<typename _Tp>
mask_array(const mask_array<_Tp> & a)138 inline mask_array<_Tp>::mask_array(const mask_array<_Tp>& a)
139 : _M_sz(a._M_sz), _M_mask(a._M_mask), _M_array(a._M_array) {}
140
141 template<typename _Tp>
142 inline
mask_array(_Array<_Tp> __a,size_t __s,_Array<bool> __m)143 mask_array<_Tp>::mask_array(_Array<_Tp> __a, size_t __s, _Array<bool> __m)
144 : _M_sz(__s), _M_mask(__m), _M_array(__a) {}
145
146 template<typename _Tp>
147 inline mask_array<_Tp>&
148 mask_array<_Tp>::operator=(const mask_array<_Tp>& __a)
149 {
150 std::__valarray_copy(__a._M_array, __a._M_mask,
151 _M_sz, _M_array, _M_mask);
152 return *this;
153 }
154
155 template<typename _Tp>
156 inline void
157 mask_array<_Tp>::operator=(const _Tp& __t) const
158 { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
159
160 template<typename _Tp>
161 inline void
162 mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
163 { std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask); }
164
165 template<typename _Tp>
166 template<class _Ex>
167 inline void
168 mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
169 { std::__valarray_copy(__e, __e.size(), _M_array, _M_mask); }
170
171 #undef _DEFINE_VALARRAY_OPERATOR
172 #define _DEFINE_VALARRAY_OPERATOR(_Op, _Name) \
173 template<typename _Tp> \
174 inline void \
175 mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \
176 { \
177 _Array_augmented_##_Name(_M_array, _M_mask, \
178 _Array<_Tp>(__v), __v.size()); \
179 } \
180 \
181 template<typename _Tp> \
182 template<class _Dom> \
183 inline void \
184 mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
185 { \
186 _Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size()); \
187 }
188
189 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
190 _DEFINE_VALARRAY_OPERATOR(/, __divides)
191 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
192 _DEFINE_VALARRAY_OPERATOR(+, __plus)
193 _DEFINE_VALARRAY_OPERATOR(-, __minus)
194 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
195 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
196 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
197 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
198 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
199
200 #undef _DEFINE_VALARRAY_OPERATOR
201
202 _GLIBCXX_END_NAMESPACE
203
204 #endif /* _MASK_ARRAY_H */
205