156 lines
4.3 KiB
C++
156 lines
4.3 KiB
C++
///////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 2005, Industrial Light & Magic, a division of Lucas
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// Digital Ltd. LLC
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Industrial Light & Magic nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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///////////////////////////////////////////////////////////////////////////
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//-----------------------------------------------------------------------------
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//
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// class Semaphore -- implementation for for platforms that do
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// support Posix threads but do not support Posix semaphores,
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// for example, OS X
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//
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//-----------------------------------------------------------------------------
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#include "IlmBaseConfig.h"
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#if HAVE_PTHREAD && !HAVE_POSIX_SEMAPHORES
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#include "IlmThreadSemaphore.h"
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#include "Iex.h"
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#include <assert.h>
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namespace IlmThread {
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Semaphore::Semaphore (unsigned int value)
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{
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if (int error = ::pthread_mutex_init (&_semaphore.mutex, 0))
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Iex::throwErrnoExc ("Cannot initialize mutex (%T).", error);
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if (int error = ::pthread_cond_init (&_semaphore.nonZero, 0))
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Iex::throwErrnoExc ("Cannot initialize condition variable (%T).",
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error);
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_semaphore.count = value;
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_semaphore.numWaiting = 0;
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}
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Semaphore::~Semaphore ()
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{
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int error = ::pthread_cond_destroy (&_semaphore.nonZero);
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assert (error == 0);
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error = ::pthread_mutex_destroy (&_semaphore.mutex);
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assert (error == 0);
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}
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void
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Semaphore::wait ()
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{
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::pthread_mutex_lock (&_semaphore.mutex);
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_semaphore.numWaiting++;
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while (_semaphore.count == 0)
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{
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if (int error = ::pthread_cond_wait (&_semaphore.nonZero,
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&_semaphore.mutex))
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{
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::pthread_mutex_unlock (&_semaphore.mutex);
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Iex::throwErrnoExc ("Cannot wait on condition variable (%T).",
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error);
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}
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}
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_semaphore.numWaiting--;
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_semaphore.count--;
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::pthread_mutex_unlock (&_semaphore.mutex);
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}
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bool
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Semaphore::tryWait ()
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{
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::pthread_mutex_lock (&_semaphore.mutex);
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if (_semaphore.count == 0)
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{
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::pthread_mutex_unlock (&_semaphore.mutex);
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return false;
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}
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else
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{
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_semaphore.count--;
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::pthread_mutex_unlock (&_semaphore.mutex);
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return true;
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}
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}
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void
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Semaphore::post ()
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{
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::pthread_mutex_lock (&_semaphore.mutex);
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if (_semaphore.numWaiting > 0)
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{
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if (int error = ::pthread_cond_signal (&_semaphore.nonZero))
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{
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::pthread_mutex_unlock (&_semaphore.mutex);
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Iex::throwErrnoExc ("Cannot signal condition variable (%T).",
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error);
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}
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}
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_semaphore.count++;
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::pthread_mutex_unlock (&_semaphore.mutex);
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}
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int
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Semaphore::value () const
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{
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::pthread_mutex_lock (&_semaphore.mutex);
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int value = _semaphore.count;
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::pthread_mutex_unlock (&_semaphore.mutex);
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return value;
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}
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} // namespace IlmThread
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#endif
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