PBRT
/home/felix/UBC/projects/AdaptiveLightfieldSampling/pbrt_v2/src/3rdparty/ilmbase-1.0.2/IlmThreadSemaphore.h
00001 
00002 //
00003 // Copyright (c) 2005, Industrial Light & Magic, a division of Lucas
00004 // Digital Ltd. LLC
00005 // 
00006 // All rights reserved.
00007 // 
00008 // Redistribution and use in source and binary forms, with or without
00009 // modification, are permitted provided that the following conditions are
00010 // met:
00011 // *       Redistributions of source code must retain the above copyright
00012 // notice, this list of conditions and the following disclaimer.
00013 // *       Redistributions in binary form must reproduce the above
00014 // copyright notice, this list of conditions and the following disclaimer
00015 // in the documentation and/or other materials provided with the
00016 // distribution.
00017 // *       Neither the name of Industrial Light & Magic nor the names of
00018 // its contributors may be used to endorse or promote products derived
00019 // from this software without specific prior written permission. 
00020 // 
00021 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00022 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00023 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00024 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
00025 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
00026 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
00027 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
00028 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
00029 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
00030 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
00031 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00032 //
00034 
00035 #ifndef INCLUDED_ILM_THREAD_SEMAPHORE_H
00036 #define INCLUDED_ILM_THREAD_SEMAPHORE_H
00037 
00038 //-----------------------------------------------------------------------------
00039 //
00040 //      class Semaphore -- a wrapper class for
00041 //      system-dependent counting semaphores
00042 //
00043 //-----------------------------------------------------------------------------
00044 
00045 #include "IlmBaseConfig.h"
00046 
00047 #if defined _WIN32 || defined _WIN64
00048     #ifdef NOMINMAX
00049         #undef NOMINMAX
00050     #endif
00051     #define NOMINMAX
00052     #include <windows.h>
00053 #elif HAVE_PTHREAD && !HAVE_POSIX_SEMAPHORES
00054     #include <pthread.h>
00055 #elif HAVE_PTHREAD && HAVE_POSIX_SEMAPHORES
00056     #include <semaphore.h>
00057 #endif
00058 
00059 namespace IlmThread {
00060 
00061 
00062 class Semaphore
00063 {
00064   public:
00065 
00066     Semaphore (unsigned int value = 0);
00067     virtual ~Semaphore();
00068 
00069     void        wait();
00070     bool        tryWait();
00071     void        post();
00072     int         value() const;
00073 
00074   private:
00075 
00076     #if defined _WIN32 || defined _WIN64
00077 
00078         mutable HANDLE _semaphore;
00079 
00080     #elif HAVE_PTHREAD && !HAVE_POSIX_SEMAPHORES
00081 
00082         //
00083         // If the platform has Posix threads but no semapohores,
00084         // then we implement them ourselves using condition variables
00085         //
00086 
00087         struct sema_t
00088         {
00089             unsigned int count;
00090             unsigned long numWaiting;
00091             pthread_mutex_t mutex;
00092             pthread_cond_t nonZero;
00093         };
00094 
00095         mutable sema_t _semaphore;
00096 
00097     #elif HAVE_PTHREAD && HAVE_POSIX_SEMAPHORES
00098 
00099         mutable sem_t _semaphore;
00100 
00101     #endif
00102 
00103     void operator = (const Semaphore& s);       // not implemented
00104     Semaphore (const Semaphore& s);             // not implemented
00105 };
00106 
00107 
00108 } // namespace IlmThread
00109 
00110 #endif