frohlich
0f7b65a921
Extend SGAtomic with atomic exchange and add. Import updates from the original implementation of that in OpenFDM. Modified Files: Makefile.am SGAtomic.cxx SGAtomic.hxx SGReferenced.hxx SGSharedPtr.hxx Added Files: SGWeakPtr.hxx SGWeakReferenced.hxx
56 lines
1.8 KiB
C++
56 lines
1.8 KiB
C++
/* -*-c++-*-
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*
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* Copyright (C) 2005-2006 Mathias Froehlich
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#ifndef SGReferenced_HXX
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#define SGReferenced_HXX
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#include "SGAtomic.hxx"
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/// Base class for all reference counted SimGear objects
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/// Classes derived from this one are meant to be managed with
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/// the SGSharedPtr class.
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/// For more info see @SGSharedPtr.
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class SGReferenced {
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public:
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SGReferenced(void) : _refcount(0u)
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{}
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/// Do not copy reference counts. Each new object has it's own counter
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SGReferenced(const SGReferenced&) : _refcount(0u)
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{}
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/// Do not copy reference counts. Each object has it's own counter
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SGReferenced& operator=(const SGReferenced&)
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{ return *this; }
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static unsigned get(const SGReferenced* ref)
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{ if (ref) return ++(ref->_refcount); else return ~0u; }
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static unsigned put(const SGReferenced* ref)
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{ if (ref) return --(ref->_refcount); else return ~0u; }
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static unsigned count(const SGReferenced* ref)
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{ if (ref) return ref->_refcount; else return ~0u; }
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static bool shared(const SGReferenced* ref)
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{ if (ref) return 1u < ref->_refcount; else return false; }
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private:
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mutable SGAtomic _refcount;
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};
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#endif
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