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Open Source Computer Vision Library
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141 lines
4.6 KiB
141 lines
4.6 KiB
/////////////////////////////////////////////////////////////////////////// |
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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_ILM_THREAD_H |
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#define INCLUDED_ILM_THREAD_H |
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//----------------------------------------------------------------------------- |
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// |
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// class Thread |
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// |
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// Class Thread is a portable interface to a system-dependent thread |
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// primitive. In order to make a thread actually do something useful, |
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// you must derive a subclass from class Thread and implement the |
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// run() function. If the operating system supports threading then |
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// the run() function will be executed int a new thread. |
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// |
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// The actual creation of the thread is done by the start() routine |
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// which then calls the run() function. In general the start() |
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// routine should be called from the constructor of the derived class. |
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// |
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// The base-class thread destructor will join/destroy the thread. |
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// |
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// IMPORTANT: Due to the mechanisms that encapsulate the low-level |
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// threading primitives in a C++ class there is a race condition |
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// with code resembling the following: |
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// |
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// { |
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// WorkerThread myThread; |
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// } // myThread goes out of scope, is destroyed |
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// // and the thread is joined |
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// |
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// The race is between the parent thread joining the child thread |
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// in the destructor of myThread, and the run() function in the |
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// child thread. If the destructor gets executed first then run() |
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// will be called with an invalid "this" pointer. |
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// |
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// This issue can be fixed by using a Semaphore to keep track of |
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// whether the run() function has already been called. You can |
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// include a Semaphore member variable within your derived class |
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// which you post() on in the run() function, and wait() on in the |
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// destructor before the thread is joined. Alternatively you could |
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// do something like this: |
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// |
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// Semaphore runStarted; |
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// |
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// void WorkerThread::run () |
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// { |
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// runStarted.post() |
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// // do some work |
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// ... |
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// } |
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// |
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// { |
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// WorkerThread myThread; |
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// runStarted.wait (); // ensure that we have started |
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// // the run function |
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// } // myThread goes out of scope, is destroyed |
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// // and the thread is joined |
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// |
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//----------------------------------------------------------------------------- |
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#include "OpenEXRConfig.h" |
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#if defined _WIN32 || defined _WIN64 |
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#ifdef NOMINMAX |
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#undef NOMINMAX |
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#endif |
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#define NOMINMAX |
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#include <windows.h> |
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#include <process.h> |
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#elif HAVE_PTHREAD |
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#include <pthread.h> |
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#endif |
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namespace IlmThread { |
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// |
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// Query function to determine if the current platform supports |
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// threads AND this library was compiled with threading enabled. |
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// |
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bool supportsThreads (); |
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class Thread |
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{ |
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public: |
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Thread (); |
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virtual ~Thread (); |
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void start (); |
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virtual void run () = 0; |
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private: |
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#if defined _WIN32 || defined _WIN64 |
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HANDLE _thread; |
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#elif HAVE_PTHREAD |
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pthread_t _thread; |
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#endif |
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void operator = (const Thread& t); // not implemented |
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Thread (const Thread& t); // not implemented |
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}; |
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} // namespace IlmThread |
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#endif
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