barrier.h

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/*
* Barrier
* (C) 2016 Joel Low
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
 
#ifndef BOTAN_UTIL_BARRIER_H_
#define BOTAN_UTIL_BARRIER_H_
 
#include <condition_variable>
#include <mutex>
 
namespace Botan {
 
/**
Barrier implements a barrier synchronization primitive. wait() will
indicate how many threads to synchronize; each thread needing
synchronization should call sync(). When sync() returns, the barrier
is reset to zero, and the m_syncs counter is incremented. m_syncs is a
counter to ensure that wait() can be called after a sync() even if the
previously sleeping threads have not awoken.)
*/
class Barrier final {
   public:
      explicit Barrier(int value = 0) : m_value(value), m_syncs(0) {}
 
      void wait(size_t delta);
 
      void sync();
 
   private:
      size_t m_value;
      size_t m_syncs;
      std::mutex m_mutex;
      std::condition_variable m_cond;
};
 
}  // namespace Botan
 
#endif