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 #include "base/metrics/sample_map.h"
6
7 #include "base/logging.h"
8 #include "base/memory/ptr_util.h"
9 #include "base/stl_util.h"
10
11 namespace base {
12
13 typedef HistogramBase::Count Count;
14 typedef HistogramBase::Sample Sample;
15
16 namespace {
17
18 // An iterator for going through a SampleMap. The logic here is identical
19 // to that of PersistentSampleMapIterator but with different data structures.
20 // Changes here likely need to be duplicated there.
21 class SampleMapIterator : public SampleCountIterator {
22 public:
23 typedef std::map<HistogramBase::Sample, HistogramBase::Count>
24 SampleToCountMap;
25
26 explicit SampleMapIterator(const SampleToCountMap& sample_counts);
27 ~SampleMapIterator() override;
28
29 // SampleCountIterator:
30 bool Done() const override;
31 void Next() override;
32 void Get(HistogramBase::Sample* min,
33 HistogramBase::Sample* max,
34 HistogramBase::Count* count) const override;
35
36 private:
37 void SkipEmptyBuckets();
38
39 SampleToCountMap::const_iterator iter_;
40 const SampleToCountMap::const_iterator end_;
41 };
42
SampleMapIterator(const SampleToCountMap & sample_counts)43 SampleMapIterator::SampleMapIterator(const SampleToCountMap& sample_counts)
44 : iter_(sample_counts.begin()),
45 end_(sample_counts.end()) {
46 SkipEmptyBuckets();
47 }
48
~SampleMapIterator()49 SampleMapIterator::~SampleMapIterator() {}
50
Done() const51 bool SampleMapIterator::Done() const {
52 return iter_ == end_;
53 }
54
Next()55 void SampleMapIterator::Next() {
56 DCHECK(!Done());
57 ++iter_;
58 SkipEmptyBuckets();
59 }
60
Get(Sample * min,Sample * max,Count * count) const61 void SampleMapIterator::Get(Sample* min, Sample* max, Count* count) const {
62 DCHECK(!Done());
63 if (min)
64 *min = iter_->first;
65 if (max)
66 *max = iter_->first + 1;
67 if (count)
68 *count = iter_->second;
69 }
70
SkipEmptyBuckets()71 void SampleMapIterator::SkipEmptyBuckets() {
72 while (!Done() && iter_->second == 0) {
73 ++iter_;
74 }
75 }
76
77 } // namespace
78
SampleMap()79 SampleMap::SampleMap() : SampleMap(0) {}
80
SampleMap(uint64_t id)81 SampleMap::SampleMap(uint64_t id) : HistogramSamples(id) {}
82
~SampleMap()83 SampleMap::~SampleMap() {}
84
Accumulate(Sample value,Count count)85 void SampleMap::Accumulate(Sample value, Count count) {
86 sample_counts_[value] += count;
87 IncreaseSum(static_cast<int64_t>(count) * value);
88 IncreaseRedundantCount(count);
89 }
90
GetCount(Sample value) const91 Count SampleMap::GetCount(Sample value) const {
92 std::map<Sample, Count>::const_iterator it = sample_counts_.find(value);
93 if (it == sample_counts_.end())
94 return 0;
95 return it->second;
96 }
97
TotalCount() const98 Count SampleMap::TotalCount() const {
99 Count count = 0;
100 for (const auto& entry : sample_counts_) {
101 count += entry.second;
102 }
103 return count;
104 }
105
Iterator() const106 std::unique_ptr<SampleCountIterator> SampleMap::Iterator() const {
107 return WrapUnique(new SampleMapIterator(sample_counts_));
108 }
109
AddSubtractImpl(SampleCountIterator * iter,Operator op)110 bool SampleMap::AddSubtractImpl(SampleCountIterator* iter, Operator op) {
111 Sample min;
112 Sample max;
113 Count count;
114 for (; !iter->Done(); iter->Next()) {
115 iter->Get(&min, &max, &count);
116 if (min + 1 != max)
117 return false; // SparseHistogram only supports bucket with size 1.
118
119 sample_counts_[min] += (op == HistogramSamples::ADD) ? count : -count;
120 }
121 return true;
122 }
123
124 } // namespace base
125