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

   1 // The template and inlines for the -*- C++ -*- gslice class.
   2
   3 // Copyright (C) 1997-1999 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
  34
  35 namespace std {
  36
  37     class gslice
  38     {
  39     public:
  40         gslice ();
  41         gslice (size_t, const valarray<size_t>&, const valarray<size_t>&);
  42         // XXX: the IS says the copy-ctor and copy-assignment operators are
  43         //      synthetized by the compiler but they are just unsuitable
  44         //      for a ref-counted semantic
  45         gslice(const gslice&);
  46         ~gslice();
  47
  48         // XXX: See the note above.
  49         gslice& operator= (const gslice&);
  50
  51         size_t           start () const;
  52         valarray<size_t> size () const;
  53         valarray<size_t> stride () const;
  54
  55     private:
  56         struct _Indexer {
  57             size_t _M_count;
  58             size_t _M_start;
  59             valarray<size_t> _M_size;
  60             valarray<size_t> _M_stride;
  61             valarray<size_t> _M_index;
  62             _Indexer(size_t, const valarray<size_t>&,
  63                      const valarray<size_t>&);
  64             void _M_increment_use() { ++_M_count; }
  65             size_t _M_decrement_use() { return --_M_count; }
  66         };
  67
  68         _Indexer* _M_index;
  69
  70         template<typename _Tp> friend class valarray;
  71     };
  72
  73     inline size_t
  74     gslice::start () const
  75     { return _M_index ? _M_index->_M_start : 0; }
  76
  77     inline valarray<size_t>
  78     gslice::size () const
  79     { return _M_index ? _M_index->_M_size : valarray<size_t>(); }
  80
  81     inline valarray<size_t>
  82     gslice::stride () const
  83     { return _M_index ? _M_index->_M_stride : valarray<size_t>(); }
  84
  85     inline gslice::gslice () : _M_index(0) {}
  86
  87     inline
  88     gslice::gslice(size_t __o, const valarray<size_t>& __l,
  89                    const valarray<size_t>& __s)
  90             : _M_index(new gslice::_Indexer(__o, __l, __s)) {}
  91
  92     inline
  93     gslice::gslice(const gslice& __g) : _M_index(__g._M_index)
  94     { if (_M_index) _M_index->_M_increment_use(); }
  95
  96     inline
  97     gslice::~gslice()
  98     { if (_M_index && _M_index->_M_decrement_use() == 0) delete _M_index; }
  99
 100     inline gslice&
 101     gslice::operator= (const gslice& __g)
 102     {
 103         if (__g._M_index) __g._M_index->_M_increment_use();
 104         if (_M_index && _M_index->_M_decrement_use() == 0) delete _M_index;
 105         _M_index = __g._M_index;
 106         return *this;
 107     }
 108
 109
 110 } // std::
 111
 112
 113 #endif /* _CPP_BITS_GSLICE_H */
 114
 115 // Local Variables:
 116 // mode:c++
 117 // End: