SharedCounter.h

#ifndef DASH__SHARED_COUNTER_H_
#define DASH__SHARED_COUNTER_H_

#include <dash/Array.h>

namespace dash {

template<typename ValueType = int>
class SharedCounter {
private:
  typedef SharedCounter<ValueType> self_t;

public:
  SharedCounter()
  : _num_units(dash::Team::All().size()),
    _myid(dash::Team::All().myid()),
    _local_counts(_num_units)
  {
    _local_counts.local[0] = 0;
    _local_counts.barrier();
  }

  SharedCounter(dash::Team& team)
  : _num_units(team.size()),
    _myid(team.myid()),
    _local_counts(_num_units, team)
  {
    _local_counts.local[0] = 0;
    _local_counts.barrier();
  }

  void inc(
    ValueType increment)
  {
    _local_counts[_myid] += increment;
  }

  void dec(
    ValueType increment)
  {
    _local_counts[_myid] -= increment;
  }

  ValueType get() const
  {
    ValueType acc = 0;
    for (team_unit_t i{0}; i < _num_units; ++i) {
      // use local access on own counter value:
      acc += (i == _myid
                ? _local_counts.local[0]
                : _local_counts[i]);
    }
    return acc;
  }

private:
  size_t                 _num_units;
  team_unit_t            _myid;
  dash::Array<ValueType> _local_counts;
};

} // namespace dash

#endif // DASH__SHARED_COUNTER_H_