1 // The template and inlines for the -*- C++ -*- slice_array class.
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4 // Free Software Foundation, Inc.
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26 /** @file bits/slice_array.h
27 * This is an internal header file, included by other library headers.
28 * Do not attempt to use it directly. @headername{valarray}
31 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
33 #ifndef _SLICE_ARRAY_H
34 #define _SLICE_ARRAY_H 1
36 #pragma GCC system_header
38 _GLIBCXX_BEGIN_NAMESPACE(std
)
41 * @addtogroup numeric_arrays
46 * @brief Class defining one-dimensional subset of an array.
48 * The slice class represents a one-dimensional subset of an array,
49 * specified by three parameters: start offset, size, and stride. The
50 * start offset is the index of the first element of the array that is part
51 * of the subset. The size is the total number of elements in the subset.
52 * Stride is the distance between each successive array element to include
55 * For example, with an array of size 10, and a slice with offset 1, size 3
56 * and stride 2, the subset consists of array elements 1, 3, and 5.
61 /// Construct an empty slice.
65 * @brief Construct a slice.
67 * @param o Offset in array of first element.
68 * @param d Number of elements in slice.
69 * @param s Stride between array elements.
71 slice(size_t, size_t, size_t);
73 /// Return array offset of first slice element.
75 /// Return size of slice.
77 /// Return array stride of slice.
78 size_t stride() const;
81 size_t _M_off
; // offset
83 size_t _M_st
; // stride unit
86 // _GLIBCXX_RESOLVE_LIB_DEFECTS
87 // 543. valarray slice default constructor
90 : _M_off(0), _M_sz(0), _M_st(0) {}
93 slice::slice(size_t __o
, size_t __d
, size_t __s
)
94 : _M_off(__o
), _M_sz(__d
), _M_st(__s
) {}
105 slice::stride() const
109 * @brief Reference to one-dimensional subset of an array.
111 * A slice_array is a reference to the actual elements of an array
112 * specified by a slice. The way to get a slice_array is to call
113 * operator[](slice) on a valarray. The returned slice_array then permits
114 * carrying operations out on the referenced subset of elements in the
115 * original valarray. For example, operator+=(valarray) will add values
116 * to the subset of elements in the underlying valarray this slice_array
119 * @param Tp Element type.
121 template<typename _Tp
>
125 typedef _Tp value_type
;
127 // _GLIBCXX_RESOLVE_LIB_DEFECTS
128 // 253. valarray helper functions are almost entirely useless
130 /// Copy constructor. Both slices refer to the same underlying array.
131 slice_array(const slice_array
&);
133 /// Assignment operator. Assigns slice elements to corresponding
134 /// elements of @a a.
135 slice_array
& operator=(const slice_array
&);
137 /// Assign slice elements to corresponding elements of @a v.
138 void operator=(const valarray
<_Tp
>&) const;
139 /// Multiply slice elements by corresponding elements of @a v.
140 void operator*=(const valarray
<_Tp
>&) const;
141 /// Divide slice elements by corresponding elements of @a v.
142 void operator/=(const valarray
<_Tp
>&) const;
143 /// Modulo slice elements by corresponding elements of @a v.
144 void operator%=(const valarray
<_Tp
>&) const;
145 /// Add corresponding elements of @a v to slice elements.
146 void operator+=(const valarray
<_Tp
>&) const;
147 /// Subtract corresponding elements of @a v from slice elements.
148 void operator-=(const valarray
<_Tp
>&) const;
149 /// Logical xor slice elements with corresponding elements of @a v.
150 void operator^=(const valarray
<_Tp
>&) const;
151 /// Logical and slice elements with corresponding elements of @a v.
152 void operator&=(const valarray
<_Tp
>&) const;
153 /// Logical or slice elements with corresponding elements of @a v.
154 void operator|=(const valarray
<_Tp
>&) const;
155 /// Left shift slice elements by corresponding elements of @a v.
156 void operator<<=(const valarray
<_Tp
>&) const;
157 /// Right shift slice elements by corresponding elements of @a v.
158 void operator>>=(const valarray
<_Tp
>&) const;
159 /// Assign all slice elements to @a t.
160 void operator=(const _Tp
&) const;
164 void operator=(const _Expr
<_Dom
, _Tp
>&) const;
166 void operator*=(const _Expr
<_Dom
, _Tp
>&) const;
168 void operator/=(const _Expr
<_Dom
, _Tp
>&) const;
170 void operator%=(const _Expr
<_Dom
, _Tp
>&) const;
172 void operator+=(const _Expr
<_Dom
, _Tp
>&) const;
174 void operator-=(const _Expr
<_Dom
, _Tp
>&) const;
176 void operator^=(const _Expr
<_Dom
, _Tp
>&) const;
178 void operator&=(const _Expr
<_Dom
, _Tp
>&) const;
180 void operator|=(const _Expr
<_Dom
, _Tp
>&) const;
182 void operator<<=(const _Expr
<_Dom
, _Tp
>&) const;
184 void operator>>=(const _Expr
<_Dom
, _Tp
>&) const;
187 friend class valarray
<_Tp
>;
188 slice_array(_Array
<_Tp
>, const slice
&);
191 const size_t _M_stride
;
192 const _Array
<_Tp
> _M_array
;
198 template<typename _Tp
>
200 slice_array
<_Tp
>::slice_array(_Array
<_Tp
> __a
, const slice
& __s
)
201 : _M_sz(__s
.size()), _M_stride(__s
.stride()),
202 _M_array(__a
.begin() + __s
.start()) {}
204 template<typename _Tp
>
206 slice_array
<_Tp
>::slice_array(const slice_array
<_Tp
>& a
)
207 : _M_sz(a
._M_sz
), _M_stride(a
._M_stride
), _M_array(a
._M_array
) {}
209 // template<typename _Tp>
210 // inline slice_array<_Tp>::~slice_array () {}
212 template<typename _Tp
>
213 inline slice_array
<_Tp
>&
214 slice_array
<_Tp
>::operator=(const slice_array
<_Tp
>& __a
)
216 std::__valarray_copy(__a
._M_array
, __a
._M_sz
, __a
._M_stride
,
217 _M_array
, _M_stride
);
221 template<typename _Tp
>
223 slice_array
<_Tp
>::operator=(const _Tp
& __t
) const
224 { std::__valarray_fill(_M_array
, _M_sz
, _M_stride
, __t
); }
226 template<typename _Tp
>
228 slice_array
<_Tp
>::operator=(const valarray
<_Tp
>& __v
) const
229 { std::__valarray_copy(_Array
<_Tp
>(__v
), _M_array
, _M_sz
, _M_stride
); }
231 template<typename _Tp
>
234 slice_array
<_Tp
>::operator=(const _Expr
<_Dom
,_Tp
>& __e
) const
235 { std::__valarray_copy(__e
, _M_sz
, _M_array
, _M_stride
); }
237 #undef _DEFINE_VALARRAY_OPERATOR
238 #define _DEFINE_VALARRAY_OPERATOR(_Op,_Name) \
239 template<typename _Tp> \
241 slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const \
243 _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\
246 template<typename _Tp> \
247 template<class _Dom> \
249 slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
251 _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz); \
255 _DEFINE_VALARRAY_OPERATOR(*, __multiplies
)
256 _DEFINE_VALARRAY_OPERATOR(/, __divides
)
257 _DEFINE_VALARRAY_OPERATOR(%, __modulus
)
258 _DEFINE_VALARRAY_OPERATOR(+, __plus
)
259 _DEFINE_VALARRAY_OPERATOR(-, __minus
)
260 _DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor
)
261 _DEFINE_VALARRAY_OPERATOR(&, __bitwise_and
)
262 _DEFINE_VALARRAY_OPERATOR(|, __bitwise_or
)
263 _DEFINE_VALARRAY_OPERATOR(<<, __shift_left
)
264 _DEFINE_VALARRAY_OPERATOR(>>, __shift_right
)
266 #undef _DEFINE_VALARRAY_OPERATOR
268 // @} group numeric_arrays
270 _GLIBCXX_END_NAMESPACE
272 #endif /* _SLICE_ARRAY_H */