libstdc++-v3/include/bits/gslice.h

   1 // The template and inlines for the -*- C++ -*- gslice class.
   2
   3 // Copyright (C) 1997-2001 Free Software Foundation, Inc.
   4 //
   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 2, or (at your option)
   9 // any later version.
  10
  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.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  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
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 // Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
  31
  32 #ifndef _CPP_BITS_GSLICE_H
  33 #define _CPP_BITS_GSLICE_H 1
  34
  35 #pragma GCC system_header
  36
  37 namespace std {
  38
  39     class gslice
  40     {
  41     public:
  42         gslice ();
  43         gslice (size_t, const valarray<size_t>&, const valarray<size_t>&);
  44         // XXX: the IS says the copy-ctor and copy-assignment operators are
  45         //      synthetized by the compiler but they are just unsuitable
  46         //      for a ref-counted semantic
  47         gslice(const gslice&);
  48         ~gslice();
  49
  50         // XXX: See the note above.
  51         gslice& operator= (const gslice&);
  52
  53         size_t           start () const;
  54         valarray<size_t> size () const;
  55         valarray<size_t> stride () const;
  56
  57     private:
  58         struct _Indexer {
  59             size_t _M_count;
  60             size_t _M_start;
  61             valarray<size_t> _M_size;
  62             valarray<size_t> _M_stride;
  63             valarray<size_t> _M_index;
  64             _Indexer(size_t, const valarray<size_t>&,
  65                      const valarray<size_t>&);
  66             void _M_increment_use() { ++_M_count; }
  67             size_t _M_decrement_use() { return --_M_count; }
  68         };
  69
  70         _Indexer* _M_index;
  71
  72         template<typename _Tp> friend class valarray;
  73     };
  74
  75     inline size_t
  76     gslice::start () const
  77     { return _M_index ? _M_index->_M_start : 0; }
  78
  79     inline valarray<size_t>
  80     gslice::size () const
  81     { return _M_index ? _M_index->_M_size : valarray<size_t>(); }
  82
  83     inline valarray<size_t>
  84     gslice::stride () const
  85     { return _M_index ? _M_index->_M_stride : valarray<size_t>(); }
  86
  87     inline gslice::gslice () : _M_index(0) {}
  88
  89     inline
  90     gslice::gslice(size_t __o, const valarray<size_t>& __l,
  91                    const valarray<size_t>& __s)
  92             : _M_index(new gslice::_Indexer(__o, __l, __s)) {}
  93
  94     inline
  95     gslice::gslice(const gslice& __g) : _M_index(__g._M_index)
  96     { if (_M_index) _M_index->_M_increment_use(); }
  97
  98     inline
  99     gslice::~gslice()
 100     { if (_M_index && _M_index->_M_decrement_use() == 0) delete _M_index; }
 101
 102     inline gslice&
 103     gslice::operator= (const gslice& __g)
 104     {
 105         if (__g._M_index) __g._M_index->_M_increment_use();
 106         if (_M_index && _M_index->_M_decrement_use() == 0) delete _M_index;
 107         _M_index = __g._M_index;
 108         return *this;
 109     }
 110
 111
 112 } // std::
 113
 114
 115 #endif /* _CPP_BITS_GSLICE_H */
 116
 117 // Local Variables:
 118 // mode:c++
 119 // End: