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/*
* Copyright (C) 2011 University of Szeged
* Copyright (C) 2011 Gabor Loki <loki@webkit.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY UNIVERSITY OF SZEGED ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL UNIVERSITY OF SZEGED OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef ParallelJobsGeneric_h
#define ParallelJobsGeneric_h
#if ENABLE(THREADING_GENERIC)
#include <wtf/RefCounted.h>
#include <wtf/Threading.h>
namespace WTF {
static const unsigned int maxParallelThreads = 2;
class ParallelEnvironment {
WTF_MAKE_FAST_ALLOCATED;
public:
typedef void (*ThreadFunction)(void*);
ParallelEnvironment(ThreadFunction threadFunction, size_t sizeOfParameter, unsigned int requestedJobNumber) :
m_threadFunction(threadFunction),
m_sizeOfParameter(sizeOfParameter)
{
if (!requestedJobNumber || requestedJobNumber > maxParallelThreads)
requestedJobNumber = maxParallelThreads;
if (!s_threadPool)
s_threadPool = new Vector< RefPtr<ThreadPrivate> >();
// The main thread should be also a worker.
unsigned int maxNewThreads = requestedJobNumber - 1;
for (unsigned int i = 0; i < maxParallelThreads && m_threads.size() < maxNewThreads; ++i) {
if (s_threadPool->size() < i + 1)
s_threadPool->append(ThreadPrivate::create());
if ((*s_threadPool)[i]->tryLockFor(this))
m_threads.append((*s_threadPool)[i]);
}
m_numberOfJobs = m_threads.size() + 1;
}
int numberOfJobs()
{
return m_numberOfJobs;
}
void execute(unsigned char* parameters)
{
size_t i;
for (i = 0; i < m_threads.size(); ++i) {
m_threads[i]->execute(m_threadFunction, parameters);
parameters += m_sizeOfParameter;
}
// The work for the main thread
(*m_threadFunction)(parameters);
// Wait until all jobs are done.
for (i = 0; i < m_threads.size(); ++i)
m_threads[i]->waitForFinish();
}
class ThreadPrivate : public RefCounted<ThreadPrivate> {
public:
ThreadPrivate()
: m_threadID(0)
, m_running(false)
, m_parent(0)
{
}
bool tryLockFor(ParallelEnvironment*);
void execute(ThreadFunction, void*);
void waitForFinish();
static PassRefPtr<ThreadPrivate> create()
{
return adoptRef(new ThreadPrivate());
}
static void* workerThread(void*);
private:
ThreadIdentifier m_threadID;
bool m_running;
ParallelEnvironment* m_parent;
mutable Mutex m_mutex;
ThreadCondition m_threadCondition;
ThreadFunction m_threadFunction;
void* m_parameters;
};
private:
ThreadFunction m_threadFunction;
size_t m_sizeOfParameter;
int m_numberOfJobs;
Vector< RefPtr<ThreadPrivate> > m_threads;
static Vector< RefPtr<ThreadPrivate> >* s_threadPool;
};
} // namespace WTF
#endif // ENABLE(THREADING_GENERIC)
#endif // ParallelJobsGeneric_h
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