add lock-free reference counting macros, based on libatomic-ops

git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@1341 fefdeb5f-60dc-0310-8127-8f9354f1896f

src/pulsecore/refcnt.h

@@ -0,0 +1,41 @@
+#ifndef foopulserefcntfoo
+#define foopulserefcntfoo
+
+/* $Id$ */
+
+/***
+  This file is part of PulseAudio.
+ 
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2 of the
+  License, or (at your option) any later version.
+ 
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+ 
+  You should have received a copy of the GNU Lesser General Public
+  License along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#include <atomic_ops.h>
+
+#define PA_REFCNT_DECLARE volatile AO_t _ref
+
+#define PA_REFCNT_INIT(p) \
+  AO_store_release_write(&(p)->_ref,  1)
+
+#define PA_REFCNT_INC(p) \
+  AO_fetch_and_add1_release_write(&(p)->_ref)
+
+#define PA_REFCNT_DEC(p) \
+  (AO_fetch_and_sub1_release_write(&(p)->_ref)-1)
+
+#define PA_REFCNT_VALUE(p) \
+  AO_load_acquire_read(&(p)->_ref)
+
+#endif