1 // The template and inlines for the -*- C++ -*- slice_array class.
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
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14 // GNU General Public License for more details.
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21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
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30 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
32 /** @file slice_array.h
33 * This is an internal header file, included by other library headers.
34 * You should not attempt to use it directly.
37 #ifndef _SLICE_ARRAY_H
38 #define _SLICE_ARRAY_H 1
40 #pragma GCC system_header
45 * @brief Class defining one-dimensional subset of an array.
47 * The slice class represents a one-dimensional subset of an array,
48 * specified by three parameters: start offset, size, and stride. The
49 * start offset is the index of the first element of the array that is part
50 * of the subset. The size is the total number of elements in the subset.
51 * Stride is the distance between each successive array element to include
54 * For example, with an array of size 10, and a slice with offset 1, size 3
55 * and stride 2, the subset consists of array elements 1, 3, and 5.
60 /// Construct an empty slice.
64 * @brief Construct a slice.
66 * @param o Offset in array of first element.
67 * @param d Number of elements in slice.
68 * @param s Stride between array elements.
70 slice(size_t, size_t, size_t);
72 /// Return array offset of first slice element.
74 /// Return size of slice.
76 /// Return array stride of slice.
77 size_t stride() const;
80 size_t _M_off; // offset
82 size_t _M_st; // stride unit
85 // The default constructor constructor is not required to initialize
86 // data members with any meaningful values, so we choose to do nothing.
91 slice::slice(size_t __o, size_t __d, size_t __s)
92 : _M_off(__o), _M_sz(__d), _M_st(__s) {}
103 slice::stride() const
107 * @brief Reference to one-dimensional subset of an array.
109 * A slice_array is a reference to the actual elements of an array
110 * specified by a slice. The way to get a slice_array is to call
111 * operator[](slice) on a valarray. The returned slice_array then permits
112 * carrying operations out on the referenced subset of elements in the
113 * original valarray. For example, operator+=(valarray) will add values
114 * to the subset of elements in the underlying valarray this slice_array
117 * @param Tp Element type.
119 template<typename _Tp>
123 typedef _Tp value_type;
125 // This constructor is implemented since we need to return a value.
126 /// Copy constructor. Both slices refer to the same underlying array.
127 slice_array(const slice_array&);
129 // This operator must be public. See DR-253.
130 /// Assignment operator. Assigns slice elements to corresponding
131 /// elements of @a a.
132 slice_array& operator=(const slice_array&);
134 /// Assign slice elements to corresponding elements of @a v.
135 void operator=(const valarray<_Tp>&) const;
136 /// Multiply slice elements by corresponding elements of @a v.
137 void operator*=(const valarray<_Tp>&) const;
138 /// Divide slice elements by corresponding elements of @a v.
139 void operator/=(const valarray<_Tp>&) const;
140 /// Modulo slice elements by corresponding elements of @a v.
141 void operator%=(const valarray<_Tp>&) const;
142 /// Add corresponding elements of @a v to slice elements.
143 void operator+=(const valarray<_Tp>&) const;
144 /// Subtract corresponding elements of @a v from slice elements.
145 void operator-=(const valarray<_Tp>&) const;
146 /// Logical xor slice elements with corresponding elements of @a v.
147 void operator^=(const valarray<_Tp>&) const;
148 /// Logical and slice elements with corresponding elements of @a v.
149 void operator&=(const valarray<_Tp>&) const;
150 /// Logical or slice elements with corresponding elements of @a v.
151 void operator|=(const valarray<_Tp>&) const;
152 /// Left shift slice elements by corresponding elements of @a v.
153 void operator<<=(const valarray<_Tp>&) const;
154 /// Right shift slice elements by corresponding elements of @a v.
155 void operator>>=(const valarray<_Tp>&) const;
156 /// Assign all slice elements to @a t.
157 void operator=(const _Tp &) const;
161 void operator=(const _Expr<_Dom,_Tp>&) const;
163 void operator*=(const _Expr<_Dom,_Tp>&) const;
165 void operator/=(const _Expr<_Dom,_Tp>&) const;
167 void operator%=(const _Expr<_Dom,_Tp>&) const;
169 void operator+=(const _Expr<_Dom,_Tp>&) const;
171 void operator-=(const _Expr<_Dom,_Tp>&) const;
173 void operator^=(const _Expr<_Dom,_Tp>&) const;
175 void operator&=(const _Expr<_Dom,_Tp>&) const;
177 void operator|=(const _Expr<_Dom,_Tp>&) const;
179 void operator<<=(const _Expr<_Dom,_Tp>&) const;
181 void operator>>=(const _Expr<_Dom,_Tp>&) const;
184 friend class valarray<_Tp>;
185 slice_array(_Array<_Tp>, const slice&);
188 const size_t _M_stride;
189 const _Array<_Tp> _M_array;
195 template<typename _Tp>
197 slice_array<_Tp>::slice_array(_Array<_Tp> __a, const slice& __s)
198 : _M_sz(__s.size()), _M_stride(__s.stride()),
199 _M_array(__a.begin() + __s.start()) {}
201 template<typename _Tp>
203 slice_array<_Tp>::slice_array(const slice_array<_Tp>& a)
204 : _M_sz(a._M_sz), _M_stride(a._M_stride), _M_array(a._M_array) {}
206 // template<typename _Tp>
207 // inline slice_array<_Tp>::~slice_array () {}
209 template<typename _Tp>
210 inline slice_array<_Tp>&
211 slice_array<_Tp>::operator=(const slice_array<_Tp>& __a)
213 std::__valarray_copy(__a._M_array, __a._M_sz, __a._M_stride,
214 _M_array, _M_stride);
218 template<typename _Tp>
220 slice_array<_Tp>::operator=(const _Tp& __t) const
221 { std::__valarray_fill(_M_array, _M_sz, _M_stride, __t); }
223 template<typename _Tp>
225 slice_array<_Tp>::operator=(const valarray<_Tp>& __v) const
226 { std::__valarray_copy(_Array<_Tp>(__v), _M_array, _M_sz, _M_stride); }
228 template<typename _Tp>
231 slice_array<_Tp>::operator=(const _Expr<_Dom,_Tp>& __e) const
232 { std::__valarray_copy(__e, _M_sz, _M_array, _M_stride); }
234 #undef _DEFINE_VALARRAY_OPERATOR
235 #define _DEFINE_VALARRAY_OPERATOR(_Op,_Name) \
236 template<typename _Tp> \
238 slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \
240 _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\
243 template<typename _Tp> \
244 template<class _Dom> \
246 slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
248 _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz); \
252 _DEFINE_VALARRAY_OPERATOR(*, __multiplies)
253 _DEFINE_VALARRAY_OPERATOR(/, __divides)
254 _DEFINE_VALARRAY_OPERATOR(%, __modulus)
255 _DEFINE_VALARRAY_OPERATOR(+, __plus)
256 _DEFINE_VALARRAY_OPERATOR(-, __minus)
257 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
258 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
259 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
260 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
261 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
263 #undef _DEFINE_VALARRAY_OPERATOR
267 #endif /* _SLICE_ARRAY_H */