83 lines
3.1 KiB
C++
83 lines
3.1 KiB
C++
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/*
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* Copyright (c) 2013 ARM Limited
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* All rights reserved
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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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: 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 copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* 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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* Authors: Ali Saidi
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*/
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#ifndef __BASE_BARRIER_HH__
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#define __BASE_BARRIER_HH__
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#include <condition_variable>
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class Barrier
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{
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private:
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/// Mutex to protect access to numLeft and generation
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std::mutex bMutex;
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/// Condition variable for waiting on barrier
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std::condition_variable bCond;
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/// Number of threads we should be waiting for before completing the barrier
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unsigned numWaiting;
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/// Generation of this barrier
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unsigned generation;
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/// Number of threads remaining for the current generation
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unsigned numLeft;
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public:
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Barrier(unsigned _numWaiting)
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: numWaiting(_numWaiting), generation(0), numLeft(_numWaiting)
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{}
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bool
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wait()
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{
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std::unique_lock<std::mutex> lock(bMutex);
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unsigned int gen = generation;
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if (--numLeft == 0) {
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generation++;
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numLeft = numWaiting;
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bCond.notify_all();
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return true;
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}
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while (gen == generation)
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bCond.wait(lock);
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return false;
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}
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};
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#endif // __BASE_BARRIER_HH__
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