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
10namespace leveldb {
11
12class 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 enum { kNumBuckets = 154 };
25
26 double Median() const;
27 double Percentile(double p) const;
28 double Average() const;
29 double StandardDeviation() const;
30
31 static const double kBucketLimit[kNumBuckets];
32
33 double min_;
34 double max_;
35 double num_;
36 double sum_;
37 double sum_squares_;
38
39 double buckets_[kNumBuckets];
40};
41
42} // namespace leveldb
43
44#endif // STORAGE_LEVELDB_UTIL_HISTOGRAM_H_
45