///////////////////////////////////////////////////////////////////////////

//

// Copyright (c) 2005, Industrial Light & Magic, a division of Lucas

// Digital Ltd. LLC

// 

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

// *       Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

// *       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.

// *       Neither the name of Industrial Light & Magic nor the names of

// its contributors may be used to endorse or promote products derived

// from this software without specific prior written permission. 

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

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///////////////////////////////////////////////////////////////////////////

#ifndef INCLUDED_IMF_THREADING_H

#define INCLUDED_IMF_THREADING_H

#include "ImfExport.h"

#include "ImfNamespace.h"

//-----------------------------------------------------------------------------

//

//	Threading support for the IlmImf library

//

//	The IlmImf library uses threads to perform reading and writing

//	of OpenEXR files in parallel.  The thread that calls the library

//	always performs the actual file IO (this is usually the main

//	application thread) whereas a several worker threads perform

//	data compression and decompression.  The number of worker

//	threads can be any non-negative value (a value of zero reverts

//	to single-threaded operation).  As long as there is at least

//	one worker thread, file IO and compression can potentially be

//	done concurrently through pinelining.  If there are two or more

//	worker threads, then pipelining as well as concurrent compression

//	of multiple blocks can be performed.

// 

//	Threading in the Imf library is controllable at two granularities:

//

//	* The functions in this file query and control the total number

//	  of worker threads, which will be created globally for the whole

//	  library.  Regardless of how many input or output files are

//	  opened simultaneously, the library will use at most this number

//	  of worker threads to perform all work.  The default number of

//	  global worker threads is zero (i.e. single-threaded operation;

//	  everything happens in the thread that calls the library).

//

//	* Furthermore, it is possible to set the number of threads that

//	  each input or output file should keep busy.  This number can

//	  be explicitly set for each file.  The default behavior is for

//	  each file to try to occupy all worker threads in the library's

//	  thread pool.

//

//-----------------------------------------------------------------------------

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER

//-----------------------------------------------------------------------------

// Return the number of Imf-global worker threads used for parallel

// compression and decompression of OpenEXR files.

//-----------------------------------------------------------------------------

IMF_EXPORT int     globalThreadCount ();

//-----------------------------------------------------------------------------

// Change the number of Imf-global worker threads

//-----------------------------------------------------------------------------

IMF_EXPORT void    setGlobalThreadCount (int count);

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT

#endif