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/*-----------------------------------------------------------------
LOG
GEM - Graphics Environment for Multimedia
WorkerThread.h
- part of GEM
- baseclass for queueing/dequeueing workloads for threaded
Copyright (c) 2011-2011 IOhannes m zmölnig. forum::für::umläute. IEM. zmoelnig@iem.at
For information on usage and redistribution, and for a DISCLAIMER OF ALL
WARRANTIES, see the file, "GEM.LICENSE.TERMS" in this distribution.
-----------------------------------------------------------------*/
#ifndef _INCLUDE__GEM_GEM_WORKERTHREAD_H_
#define _INCLUDE__GEM_GEM_WORKERTHREAD_H_
#include "Gem/ExportDef.h"
namespace gem
{
namespace thread
{
class GEM_EXTERN WorkerThread
{
private:
class PIMPL;
PIMPL*m_pimpl;
friend class PIMPL;
/* dummy implementations */
WorkerThread(const WorkerThread&);
WorkerThread&operator=(const WorkerThread&);
public:
WorkerThread(void);
virtual ~WorkerThread(void);
////
// start/stop thread(s)
virtual bool start(void);
virtual bool stop(bool wait=true);
typedef unsigned int id_t;
static const id_t INVALID;
static const id_t IMMEDIATE;
// queue a 'data' chunk onto the TODO queue
// the returned 'ID' can be used to interact with the queues
// if queuing failed, FALSE is returned and ID is set to INVALID
virtual bool queue(id_t&ID, void*data);
//////
// cancel a datachunk from the TODO-queue
// if the chunk was successfully removed, returns TRUE
// (FALSE is returned, if e.g. the given datachunk was not found in the queue)
// note that items already processed cannot be cancelled anymore
virtual bool cancel(const id_t ID);
// dequeue the next datachunk from the DONE queue
// if the queue is empty, FALSE is returned and ID is set to INVALID
virtual bool dequeue(id_t&ID, void*&data);
protected:
////
// the worker!
// get's called from an alternative thread(s)
// when the queue is non-empty,
// the first element is removed from the TODO queue,
// and this function is called with the 1st element as data
// the result returned is added to the done queue (alongside the ID)
virtual void* process(id_t ID, void*data) = 0;
////
// this get's called to indicate that new data is in the DONE queue
// you can use it to set a semaphore in the main thread, to fetch
// the data
// it get's called once after process() has been successful
// and will not be called before dequeue has been called at least once
//
virtual void signal(void);
};
};
};
#endif /* _INCLUDE__GEM_GEM_WORKERTHREAD_H_ */
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