1 // The template and inlines for the -*- C++ -*- gslice class.
3 // Copyright (C) 1997-2016 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
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22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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25 /** @file bits/gslice.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{valarray}
30 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
35 #pragma GCC system_header
37 namespace std
_GLIBCXX_VISIBILITY(default)
39 _GLIBCXX_BEGIN_NAMESPACE_VERSION
42 * @addtogroup numeric_arrays
47 * @brief Class defining multi-dimensional subset of an array.
49 * The slice class represents a multi-dimensional subset of an array,
50 * specified by three parameter sets: start offset, size array, and stride
51 * array. The start offset is the index of the first element of the array
52 * that is part of the subset. The size and stride array describe each
53 * dimension of the slice. Size is the number of elements in that
54 * dimension, and stride is the distance in the array between successive
55 * elements in that dimension. Each dimension's size and stride is taken
56 * to begin at an array element described by the previous dimension. The
57 * size array and stride array must be the same size.
59 * For example, if you have offset==3, stride[0]==11, size[1]==3,
60 * stride[1]==3, then slice[0,0]==array[3], slice[0,1]==array[6],
61 * slice[0,2]==array[9], slice[1,0]==array[14], slice[1,1]==array[17],
62 * slice[1,2]==array[20].
67 /// Construct an empty slice.
71 * @brief Construct a slice.
73 * Constructs a slice with as many dimensions as the length of the @a l
76 * @param __o Offset in array of first element.
77 * @param __l Array of dimension lengths.
78 * @param __s Array of dimension strides between array elements.
80 gslice(size_t __o
, const valarray
<size_t>& __l
,
81 const valarray
<size_t>& __s
);
83 // XXX: the IS says the copy-ctor and copy-assignment operators are
84 // synthesized by the compiler but they are just unsuitable
85 // for a ref-counted semantic
87 gslice(const gslice
&);
92 // XXX: See the note above.
93 /// Assignment operator.
94 gslice
& operator=(const gslice
&);
96 /// Return array offset of first slice element.
99 /// Return array of sizes of slice dimensions.
100 valarray
<size_t> size() const;
102 /// Return array of array strides for each dimension.
103 valarray
<size_t> stride() const;
110 valarray
<size_t> _M_size
;
111 valarray
<size_t> _M_stride
;
112 valarray
<size_t> _M_index
; // Linear array of referenced indices
115 : _M_count(1), _M_start(0), _M_size(), _M_stride(), _M_index() {}
117 _Indexer(size_t, const valarray
<size_t>&,
118 const valarray
<size_t>&);
126 { return --_M_count
; }
131 template<typename _Tp
> friend class valarray
;
135 gslice::start() const
136 { return _M_index
? _M_index
->_M_start
: 0; }
138 inline valarray
<size_t>
140 { return _M_index
? _M_index
->_M_size
: valarray
<size_t>(); }
142 inline valarray
<size_t>
143 gslice::stride() const
144 { return _M_index
? _M_index
->_M_stride
: valarray
<size_t>(); }
146 // _GLIBCXX_RESOLVE_LIB_DEFECTS
147 // 543. valarray slice default constructor
150 : _M_index(new gslice::_Indexer()) {}
153 gslice::gslice(size_t __o
, const valarray
<size_t>& __l
,
154 const valarray
<size_t>& __s
)
155 : _M_index(new gslice::_Indexer(__o
, __l
, __s
)) {}
158 gslice::gslice(const gslice
& __g
)
159 : _M_index(__g
._M_index
)
160 { if (_M_index
) _M_index
->_M_increment_use(); }
165 if (_M_index
&& _M_index
->_M_decrement_use() == 0)
170 gslice::operator=(const gslice
& __g
)
173 __g
._M_index
->_M_increment_use();
174 if (_M_index
&& _M_index
->_M_decrement_use() == 0)
176 _M_index
= __g
._M_index
;
180 // @} group numeric_arrays
182 _GLIBCXX_END_NAMESPACE_VERSION
185 #endif /* _GSLICE_H */