base/metrics/sample_map.h

   1 // Copyright (c) 2012 The Chromium 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.
   4
   5 // SampleMap implements HistogramSamples interface. It is used by the
   6 // SparseHistogram class to store samples.
   7
   8 #ifndef BASE_METRICS_SAMPLE_MAP_H_
   9 #define BASE_METRICS_SAMPLE_MAP_H_
  10
  11 #include <map>
  12
  13 #include "base/compiler_specific.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "base/metrics/histogram_base.h"
  16 #include "base/metrics/histogram_samples.h"
  17
  18 namespace base {
  19
  20 class BASE_EXPORT_PRIVATE SampleMap : public HistogramSamples {
  21  public:
  22   SampleMap();
  23   ~SampleMap() override;
  24
  25   // HistogramSamples implementation:
  26   void Accumulate(HistogramBase::Sample value,
  27                   HistogramBase::Count count) override;
  28   HistogramBase::Count GetCount(HistogramBase::Sample value) const override;
  29   HistogramBase::Count TotalCount() const override;
  30   scoped_ptr<SampleCountIterator> Iterator() const override;
  31
  32  protected:
  33   bool AddSubtractImpl(
  34       SampleCountIterator* iter,
  35       HistogramSamples::Operator op) override;  // |op| is ADD or SUBTRACT.
  36
  37  private:
  38   std::map<HistogramBase::Sample, HistogramBase::Count> sample_counts_;
  39
  40   DISALLOW_COPY_AND_ASSIGN(SampleMap);
  41 };
  42
  43 class BASE_EXPORT_PRIVATE SampleMapIterator : public SampleCountIterator {
  44  public:
  45   typedef std::map<HistogramBase::Sample, HistogramBase::Count>
  46       SampleToCountMap;
  47
  48   explicit SampleMapIterator(const SampleToCountMap& sample_counts);
  49   ~SampleMapIterator() override;
  50
  51   // SampleCountIterator implementation:
  52   bool Done() const override;
  53   void Next() override;
  54   void Get(HistogramBase::Sample* min,
  55            HistogramBase::Sample* max,
  56            HistogramBase::Count* count) const override;
  57
  58  private:
  59   void SkipEmptyBuckets();
  60
  61   SampleToCountMap::const_iterator iter_;
  62   const SampleToCountMap::const_iterator end_;
  63 };
  64
  65 }  // namespace base
  66
  67 #endif  // BASE_METRICS_SAMPLE_MAP_H_