3 * Copyright (C) 2005-2006 Mathias Froehlich
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
21 #ifndef SGReferenced_HXX
22 #define SGReferenced_HXX
24 #include "SGAtomic.hxx"
26 /// Base class for all reference counted SimGear objects
27 /// Classes derived from this one are meant to be managed with
28 /// the SGSharedPtr class.
29 /// For more info see @SGSharedPtr.
33 SGReferenced(void) : _refcount(0u)
35 /// Do not copy reference counts. Each new object has it's own counter
36 SGReferenced(const SGReferenced&) : _refcount(0u)
38 /// Do not copy reference counts. Each object has it's own counter
39 SGReferenced& operator=(const SGReferenced&)
42 static unsigned get(const SGReferenced* ref)
43 { if (ref) return ++(ref->_refcount); else return ~0u; }
44 static unsigned put(const SGReferenced* ref)
45 { if (ref) return --(ref->_refcount); else return ~0u; }
46 static unsigned count(const SGReferenced* ref)
47 { if (ref) return ref->_refcount; else return ~0u; }
48 static bool shared(const SGReferenced* ref)
49 { if (ref) return 1u < ref->_refcount; else return false; }
52 mutable SGAtomic _refcount;