Add beast_basics module

modules/beast_basics/threads/beast_ParallelFor.cpp

@@ -0,0 +1,76 @@
+/*============================================================================*/
+/*
+  VFLib: https://github.com/vinniefalco/VFLib
+
+  Copyright (C) 2008 by Vinnie Falco <vinnie.falco@gmail.com>
+
+  This library contains portions of other open source products covered by
+  separate licenses. Please see the corresponding source files for specific
+  terms.
+
+  VFLib is provided under the terms of The MIT License (MIT):
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+  IN THE SOFTWARE.
+*/
+/*============================================================================*/
+
+ParallelFor::ParallelFor (ThreadGroup& pool)
+    : m_pool (pool)
+    , m_finishedEvent (false) // auto-reset
+{
+}
+
+int ParallelFor::getNumberOfThreads () const
+{
+    return m_pool.getNumberOfThreads ();
+}
+
+void ParallelFor::doLoop (int numberOfIterations, Iteration& iteration)
+{
+    if (numberOfIterations > 1)
+    {
+        int const numberOfThreads = m_pool.getNumberOfThreads ();
+
+        // The largest number of pool threads we need is one less than the number
+        // of iterations, because we also run the loop body on the caller's thread.
+        //
+        int const maxThreads = numberOfIterations - 1;
+
+        // Calculate the number of parallel instances as the smaller of the number
+        // of threads available (including the caller's) and the number of iterations.
+        //
+        int const numberOfParallelInstances = std::min (
+                numberOfThreads + 1, numberOfIterations);
+
+        LoopState* loopState (new (m_pool.getAllocator ()) LoopState (
+                                  iteration, m_finishedEvent, numberOfIterations, numberOfParallelInstances));
+
+        m_pool.call (maxThreads, &LoopState::forLoopBody, loopState);
+
+        // Also use the caller's thread to run the loop body.
+        loopState->forLoopBody ();
+
+        m_finishedEvent.wait ();
+    }
+    else if (numberOfIterations == 1)
+    {
+        // Just one iteration, so do it.
+        iteration (0);
+    }
+}