src/leveldb/util/histogram.h

   1 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file. See the AUTHORS file for names of contributors.
   4
   5 #ifndef STORAGE_LEVELDB_UTIL_HISTOGRAM_H_
   6 #define STORAGE_LEVELDB_UTIL_HISTOGRAM_H_
   7
   8 #include <string>
   9
  10 namespace leveldb {
  11
  12 class Histogram {
  13  public:
  14   Histogram() { }
  15   ~Histogram() { }
  16
  17   void Clear();
  18   void Add(double value);
  19   void Merge(const Histogram& other);
  20
  21   std::string ToString() const;
  22
  23  private:
  24   double min_;
  25   double max_;
  26   double num_;
  27   double sum_;
  28   double sum_squares_;
  29
  30   enum { kNumBuckets = 154 };
  31   static const double kBucketLimit[kNumBuckets];
  32   double buckets_[kNumBuckets];
  33
  34   double Median() const;
  35   double Percentile(double p) const;
  36   double Average() const;
  37   double StandardDeviation() const;
  38 };
  39
  40 }  // namespace leveldb
  41
  42 #endif  // STORAGE_LEVELDB_UTIL_HISTOGRAM_H_