include/EventCache.h

#ifndef EVENTCACHE_H_
#define EVENTCACHE_H_

#include <TTreeReader.h>


class EventCache {
 public:
  EventCache(TTreeReader const &reader);

  bool IsUpdated() const;

 private:
  TTreeReader const &reader_;

  mutable long long latestEntry_;
};


inline EventCache::EventCache(TTreeReader const &reader)
    : reader_{reader}, latestEntry_{-1} {}


inline bool EventCache::IsUpdated() const {
  long long curEntry = reader_.GetCurrentEntry();

  if (curEntry == latestEntry_)
    return false;
  else {
    latestEntry_ = curEntry;
    return true;
  }
}


#endif  // EVENTCACHE_H_

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