Paul Davis
29f178aa4b
PBD::Semaphore can really be used instead of this class now, but it didn't exist when I needed this class and it is header only, which causes some problems because windows.h is included
69 lines
1.4 KiB
C++
69 lines
1.4 KiB
C++
/*
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Copyright (C) 2010 Tim Mayberry
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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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., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "pbd/glib_semaphore.h"
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namespace PBD {
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GlibSemaphore::GlibSemaphore (gint initial_val)
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:
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m_counter(initial_val)
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{ }
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void
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GlibSemaphore::wait ()
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{
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Glib::Threads::Mutex::Lock guard (m_mutex);
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while (m_counter.get() < 1) {
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m_cond.wait(m_mutex);
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}
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// this shouldn't need to be inside the lock
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--m_counter;
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}
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bool
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GlibSemaphore::try_wait ()
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{
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if (!m_mutex.trylock())
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{
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return false;
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}
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// lock successful
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while (m_counter.get() < 1) {
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m_cond.wait(m_mutex);
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}
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// the order of these should not matter
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--m_counter;
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m_mutex.unlock();
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return true;
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}
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void
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GlibSemaphore::post ()
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{
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// atomic, no locking required
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++m_counter;
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m_cond.signal();
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}
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} // namespace PBD
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