grpc/test/cpp/qps/histogram.h

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#ifndef TEST_QPS_HISTOGRAM_H
#define TEST_QPS_HISTOGRAM_H

#include <grpc/support/histogram.h>
#include "test/proto/benchmarks/stats.grpc.pb.h"

namespace grpc {
namespace testing {

class Histogram {
 public:
  // TODO: look into making histogram params not hardcoded for C++
  Histogram() : impl_(gpr_histogram_create(default_resolution(),
                                           default_max_possible())) {}
  ~Histogram() {
    if (impl_) gpr_histogram_destroy(impl_);
  }
  Histogram(Histogram&& other) : impl_(other.impl_) { other.impl_ = nullptr; }

  void Merge(const Histogram& h) { gpr_histogram_merge(impl_, h.impl_); }
  void Add(double value) { gpr_histogram_add(impl_, value); }
  double Percentile(double pctile) const {
    return gpr_histogram_percentile(impl_, pctile);
  }
  double Count() const { return gpr_histogram_count(impl_); }
  void Swap(Histogram* other) { std::swap(impl_, other->impl_); }
  void FillProto(HistogramData* p) {
    size_t n;
    const auto* data = gpr_histogram_get_contents(impl_, &n);
    for (size_t i = 0; i < n; i++) {
      p->add_bucket(data[i]);
    }
    p->set_min_seen(gpr_histogram_minimum(impl_));
    p->set_max_seen(gpr_histogram_maximum(impl_));
    p->set_sum(gpr_histogram_sum(impl_));
    p->set_sum_of_squares(gpr_histogram_sum_of_squares(impl_));
    p->set_count(gpr_histogram_count(impl_));
  }
  void MergeProto(const HistogramData& p) {
    gpr_histogram_merge_contents(impl_, &*p.bucket().begin(), p.bucket_size(),
                                 p.min_seen(), p.max_seen(), p.sum(),
                                 p.sum_of_squares(), p.count());
  }

  static double default_resolution() { return 0.01; }
  static double default_max_possible() { return 60e9; }

 private:
  Histogram(const Histogram&);
  Histogram& operator=(const Histogram&);

  gpr_histogram* impl_;
};
}
}

#endif /* TEST_QPS_HISTOGRAM_H */