Merge branch 'master' of ssh://crater.dragonflybsd.org/repository/git/dragonfly
[dragonfly.git] / contrib / gcc-3.4 / libstdc++-v3 / include / bits / gslice.h
CommitLineData
003757ed
MD
1// The template and inlines for the -*- C++ -*- gslice class.
2
3// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2004
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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
32
33/** @file gslice.h
34 * This is an internal header file, included by other library headers.
35 * You should not attempt to use it directly.
36 */
37
38#ifndef _GSLICE_H
39#define _GSLICE_H 1
40
41#pragma GCC system_header
42
43namespace std {
44
45 /**
46 * @brief Class defining multi-dimensional subset of an array.
47 *
48 * The slice class represents a multi-dimensional subset of an array,
49 * specified by three parameter sets: start offset, size array, and stride
50 * array. The start offset is the index of the first element of the array
51 * that is part of the subset. The size and stride array describe each
52 * dimension of the slice. Size is the number of elements in that
53 * dimension, and stride is the distance in the array between successive
54 * elements in that dimension. Each dimension's size and stride is taken
55 * to begin at an array element described by the previous dimension. The
56 * size array and stride array must be the same size.
57 *
58 * For example, if you have offset==3, stride[0]==11, size[1]==3,
59 * stride[1]==3, then slice[0,0]==array[3], slice[0,1]==array[6],
60 * slice[0,2]==array[9], slice[1,0]==array[14], slice[1,1]==array[17],
61 * slice[1,2]==array[20].
62 */
63 class gslice
64 {
65 public:
66 /// Construct an empty slice.
67 gslice ();
68
69 /**
70 * @brief Construct a slice.
71 *
72 * Constructs a slice with as many dimensions as the length of the @a l
73 * and @a s arrays.
74 *
75 * @param o Offset in array of first element.
76 * @param l Array of dimension lengths.
77 * @param s Array of dimension strides between array elements.
78 */
79 gslice(size_t, const valarray<size_t>&, const valarray<size_t>&);
80
81 // XXX: the IS says the copy-ctor and copy-assignment operators are
82 // synthetized by the compiler but they are just unsuitable
83 // for a ref-counted semantic
84 /// Copy constructor.
85 gslice(const gslice&);
86
87 /// Destructor.
88 ~gslice();
89
90 // XXX: See the note above.
91 /// Assignment operator.
92 gslice& operator=(const gslice&);
93
94 /// Return array offset of first slice element.
95 size_t start() const;
96
97 /// Return array of sizes of slice dimensions.
98 valarray<size_t> size() const;
99
100 /// Return array of array strides for each dimension.
101 valarray<size_t> stride() const;
102
103 private:
104 struct _Indexer {
105 size_t _M_count;
106 size_t _M_start;
107 valarray<size_t> _M_size;
108 valarray<size_t> _M_stride;
109 valarray<size_t> _M_index; // Linear array of referenced indices
110 _Indexer(size_t, const valarray<size_t>&,
111 const valarray<size_t>&);
112 void _M_increment_use() { ++_M_count; }
113 size_t _M_decrement_use() { return --_M_count; }
114 };
115
116 _Indexer* _M_index;
117
118 template<typename _Tp> friend class valarray;
119 };
120
121 inline size_t
122 gslice::start () const
123 { return _M_index ? _M_index->_M_start : 0; }
124
125 inline valarray<size_t>
126 gslice::size () const
127 { return _M_index ? _M_index->_M_size : valarray<size_t>(); }
128
129 inline valarray<size_t>
130 gslice::stride () const
131 { return _M_index ? _M_index->_M_stride : valarray<size_t>(); }
132
133 inline gslice::gslice () : _M_index(0) {}
134
135 inline
136 gslice::gslice(size_t __o, const valarray<size_t>& __l,
137 const valarray<size_t>& __s)
138 : _M_index(new gslice::_Indexer(__o, __l, __s)) {}
139
140 inline
141 gslice::gslice(const gslice& __g) : _M_index(__g._M_index)
142 { if (_M_index) _M_index->_M_increment_use(); }
143
144 inline
145 gslice::~gslice()
146 { if (_M_index && _M_index->_M_decrement_use() == 0) delete _M_index; }
147
148 inline gslice&
149 gslice::operator= (const gslice& __g)
150 {
151 if (__g._M_index) __g._M_index->_M_increment_use();
152 if (_M_index && _M_index->_M_decrement_use() == 0) delete _M_index;
153 _M_index = __g._M_index;
154 return *this;
155 }
156
157
158} // std::
159
160
161#endif /* _GSLICE_H */
162
163// Local Variables:
164// mode:c++
165// End: