JavaScriptCore-903.tar.gz

[apple/javascriptcore.git] / wtf / ParallelJobsLibdispatch.h

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+/*
+ * Copyright (C) 2011 University of Szeged
+ * Copyright (C) 2011 Gabor Loki <loki@webkit.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY UNIVERSITY OF SZEGED ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL UNIVERSITY OF SZEGED OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef ParallelJobsLibdispatch_h
+#define ParallelJobsLibdispatch_h
+
+#if ENABLE(THREADING_LIBDISPATCH)
+
+#include <dispatch/dispatch.h>
+
+namespace WTF {
+
+static const int maxParallelThreads = 2;
+
+class ParallelEnvironment {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    typedef void (*ThreadFunction)(void*);
+
+    ParallelEnvironment(ThreadFunction threadFunction, size_t sizeOfParameter, int requestedJobNumber) :
+        m_threadFunction(threadFunction),
+        m_sizeOfParameter(sizeOfParameter)
+    {
+        if (!requestedJobNumber || requestedJobNumber > maxParallelThreads)
+            requestedJobNumber = maxParallelThreads;
+
+        ASSERT(requestedJobNumber > 0);
+
+        m_numberOfJobs = requestedJobNumber;
+    }
+
+    int numberOfJobs()
+    {
+        return m_numberOfJobs;
+    }
+
+    void execute(unsigned char* parameters)
+    {
+        // libdispatch is NOT supported inside a template
+        dispatch_queue_t parallelJobsQueue = dispatch_queue_create("ParallelJobs", 0);
+
+        for (int i = 0; i < m_numberOfJobs - 1; ++i) {
+            dispatch_async(parallelJobsQueue, ^{(*m_threadFunction)(parameters);});
+            parameters += m_sizeOfParameter;
+        }
+
+        // The work for the main thread. Wait until all jobs are done.
+        dispatch_sync(parallelJobsQueue, ^{(*m_threadFunction)(parameters);});
+    }
+
+private:
+    ThreadFunction m_threadFunction;
+    size_t m_sizeOfParameter;
+    int m_numberOfJobs;
+};
+
+} // namespace WTF
+
+#endif // ENABLE(THREADING_LIBDISPATCH)
+
+#endif // ParallelJobsLibdispatch_h