93 lines
4.1 KiB
C++
93 lines
4.1 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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#ifndef INCLUDED_IMF_THREADING_H
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#define INCLUDED_IMF_THREADING_H
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//-----------------------------------------------------------------------------
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//
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// Threading support for the IlmImf library
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//
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// The IlmImf library uses threads to perform reading and writing
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// of OpenEXR files in parallel. The thread that calls the library
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// always performs the actual file IO (this is usually the main
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// application thread) whereas a several worker threads perform
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// data compression and decompression. The number of worker
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// threads can be any non-negative value (a value of zero reverts
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// to single-threaded operation). As long as there is at least
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// one worker thread, file IO and compression can potentially be
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// done concurrently through pinelining. If there are two or more
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// worker threads, then pipelining as well as concurrent compression
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// of multiple blocks can be performed.
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//
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// Threading in the Imf library is controllable at two granularities:
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//
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// * The functions in this file query and control the total number
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// of worker threads, which will be created globally for the whole
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// library. Regardless of how many input or output files are
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// opened simultaneously, the library will use at most this number
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// of worker threads to perform all work. The default number of
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// global worker threads is zero (i.e. single-threaded operation;
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// everything happens in the thread that calls the library).
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//
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// * Furthermore, it is possible to set the number of threads that
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// each input or output file should keep busy. This number can
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// be explicitly set for each file. The default behavior is for
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// each file to try to occupy all worker threads in the library's
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// thread pool.
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//
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//-----------------------------------------------------------------------------
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namespace Imf {
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//-----------------------------------------------------------------------------
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// Return the number of Imf-global worker threads used for parallel
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// compression and decompression of OpenEXR files.
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//-----------------------------------------------------------------------------
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int globalThreadCount ();
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//-----------------------------------------------------------------------------
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// Change the number of Imf-global worker threads
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//-----------------------------------------------------------------------------
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void setGlobalThreadCount (int count);
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} // namespace Imf
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#endif
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