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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 #include "base/metrics/sample_map.h"
      6 
      7 #include "base/logging.h"
      8 
      9 namespace base {
     10 
     11 typedef HistogramBase::Count Count;
     12 typedef HistogramBase::Sample Sample;
     13 
     14 SampleMap::SampleMap() : SampleMap(0) {}
     15 
     16 SampleMap::SampleMap(uint64_t id) : HistogramSamples(id) {}
     17 
     18 SampleMap::~SampleMap() {}
     19 
     20 void SampleMap::Accumulate(Sample value, Count count) {
     21   sample_counts_[value] += count;
     22   IncreaseSum(count * value);
     23   IncreaseRedundantCount(count);
     24 }
     25 
     26 Count SampleMap::GetCount(Sample value) const {
     27   std::map<Sample, Count>::const_iterator it = sample_counts_.find(value);
     28   if (it == sample_counts_.end())
     29     return 0;
     30   return it->second;
     31 }
     32 
     33 Count SampleMap::TotalCount() const {
     34   Count count = 0;
     35   for (const auto& entry : sample_counts_) {
     36     count += entry.second;
     37   }
     38   return count;
     39 }
     40 
     41 scoped_ptr<SampleCountIterator> SampleMap::Iterator() const {
     42   return scoped_ptr<SampleCountIterator>(new SampleMapIterator(sample_counts_));
     43 }
     44 
     45 bool SampleMap::AddSubtractImpl(SampleCountIterator* iter,
     46                                 HistogramSamples::Operator op) {
     47   Sample min;
     48   Sample max;
     49   Count count;
     50   for (; !iter->Done(); iter->Next()) {
     51     iter->Get(&min, &max, &count);
     52     if (min + 1 != max)
     53       return false;  // SparseHistogram only supports bucket with size 1.
     54 
     55     sample_counts_[min] += (op == HistogramSamples::ADD) ? count : -count;
     56   }
     57   return true;
     58 }
     59 
     60 SampleMapIterator::SampleMapIterator(const SampleToCountMap& sample_counts)
     61     : iter_(sample_counts.begin()),
     62       end_(sample_counts.end()) {
     63   SkipEmptyBuckets();
     64 }
     65 
     66 SampleMapIterator::~SampleMapIterator() {}
     67 
     68 bool SampleMapIterator::Done() const {
     69   return iter_ == end_;
     70 }
     71 
     72 void SampleMapIterator::Next() {
     73   DCHECK(!Done());
     74   ++iter_;
     75   SkipEmptyBuckets();
     76 }
     77 
     78 void SampleMapIterator::Get(Sample* min, Sample* max, Count* count) const {
     79   DCHECK(!Done());
     80   if (min != NULL)
     81     *min = iter_->first;
     82   if (max != NULL)
     83     *max = iter_->first + 1;
     84   if (count != NULL)
     85     *count = iter_->second;
     86 }
     87 
     88 void SampleMapIterator::SkipEmptyBuckets() {
     89   while (!Done() && iter_->second == 0) {
     90     ++iter_;
     91   }
     92 }
     93 
     94 }  // namespace base
     95