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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 // SampleVector implements HistogramSamples interface. It is used by all
6 // Histogram based classes to store samples.
7 
8 #ifndef BASE_METRICS_SAMPLE_VECTOR_H_
9 #define BASE_METRICS_SAMPLE_VECTOR_H_
10 
11 #include <vector>
12 
13 #include "base/compiler_specific.h"
14 #include "base/gtest_prod_util.h"
15 #include "base/memory/scoped_ptr.h"
16 #include "base/metrics/histogram_base.h"
17 #include "base/metrics/histogram_samples.h"
18 
19 namespace base {
20 
21 class BucketRanges;
22 
23 class BASE_EXPORT_PRIVATE SampleVector : public HistogramSamples {
24  public:
25   explicit SampleVector(const BucketRanges* bucket_ranges);
26   virtual ~SampleVector();
27 
28   // HistogramSamples implementation:
29   virtual void Accumulate(HistogramBase::Sample value,
30                           HistogramBase::Count count) OVERRIDE;
31   virtual HistogramBase::Count GetCount(
32       HistogramBase::Sample value) const OVERRIDE;
33   virtual HistogramBase::Count TotalCount() const OVERRIDE;
34   virtual scoped_ptr<SampleCountIterator> Iterator() const OVERRIDE;
35 
36   // Get count of a specific bucket.
37   HistogramBase::Count GetCountAtIndex(size_t bucket_index) const;
38 
39  protected:
40   virtual bool AddSubtractImpl(
41       SampleCountIterator* iter,
42       HistogramSamples::Operator op) OVERRIDE;  // |op| is ADD or SUBTRACT.
43 
44   virtual size_t GetBucketIndex(HistogramBase::Sample value) const;
45 
46  private:
47   FRIEND_TEST_ALL_PREFIXES(HistogramTest, CorruptSampleCounts);
48 
49   std::vector<HistogramBase::Count> counts_;
50 
51   // Shares the same BucketRanges with Histogram object.
52   const BucketRanges* const bucket_ranges_;
53 
54   DISALLOW_COPY_AND_ASSIGN(SampleVector);
55 };
56 
57 class BASE_EXPORT_PRIVATE SampleVectorIterator : public SampleCountIterator {
58  public:
59   SampleVectorIterator(const std::vector<HistogramBase::Count>* counts,
60                        const BucketRanges* bucket_ranges);
61   virtual ~SampleVectorIterator();
62 
63   // SampleCountIterator implementation:
64   virtual bool Done() const OVERRIDE;
65   virtual void Next() OVERRIDE;
66   virtual void Get(HistogramBase::Sample* min,
67                    HistogramBase::Sample* max,
68                    HistogramBase::Count* count) const OVERRIDE;
69 
70   // SampleVector uses predefined buckets, so iterator can return bucket index.
71   virtual bool GetBucketIndex(size_t* index) const OVERRIDE;
72 
73  private:
74   void SkipEmptyBuckets();
75 
76   const std::vector<HistogramBase::Count>* counts_;
77   const BucketRanges* bucket_ranges_;
78 
79   size_t index_;
80 };
81 
82 }  // namespace base
83 
84 #endif  // BASE_METRICS_SAMPLE_VECTOR_H_
85