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/*
Copyright (C) 2010 Tim Mayberry
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "pbd/glib_semaphore.h"
namespace PBD {
GlibSemaphore::GlibSemaphore (gint initial_val)
:
m_counter(initial_val)
{ }
void
GlibSemaphore::wait ()
{
Glib::Threads::Mutex::Lock guard (m_mutex);
while (m_counter.get() < 1) {
m_cond.wait(m_mutex);
}
// this shouldn't need to be inside the lock
--m_counter;
}
bool
GlibSemaphore::try_wait ()
{
if (!m_mutex.trylock())
{
return false;
}
// lock successful
while (m_counter.get() < 1) {
m_cond.wait(m_mutex);
}
// the order of these should not matter
--m_counter;
m_mutex.unlock();
return true;
}
void
GlibSemaphore::post ()
{
// atomic, no locking required
++m_counter;
m_cond.signal();
}
} // namespace PBD
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