SampleSet -> HistogramSamples (will be reused by SparseHistogram)

base/metrics/histogram_samples.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/metrics/histogram_samples.h"
+
+#include "base/compiler_specific.h"
+#include "base/pickle.h"
+
+namespace base {
+
+namespace {
+
+class SampleCountPickleIterator : public SampleCountIterator {
+ public:
+  SampleCountPickleIterator(PickleIterator* iter);
+
+  virtual bool Done() const OVERRIDE;
+  virtual void Next() OVERRIDE;
+  virtual void Get(HistogramBase::Sample* min,
+                   HistogramBase::Sample* max,
+                   HistogramBase::Count* count) const OVERRIDE;
+ private:
+  bool ReadNext();
+
+  PickleIterator* const iter_;
+
+  HistogramBase::Sample min_;
+  HistogramBase::Sample max_;
+  HistogramBase::Count count_;
+  bool is_done_;
+};
+
+SampleCountPickleIterator::SampleCountPickleIterator(PickleIterator* iter)
+    : iter_(iter),
+      is_done_(false) {
+  Next();
+}
+
+bool SampleCountPickleIterator::Done() const {
+  return is_done_;
+}
+
+void SampleCountPickleIterator::Next() {
+  CHECK(!Done());
+  if (!ReadNext())
+    is_done_ = true;
+}
+
+void SampleCountPickleIterator::Get(HistogramBase::Sample* min,
+                                    HistogramBase::Sample* max,
+                                    HistogramBase::Count* count) const {
+  CHECK(!Done());
+  *min = min_;
+  *max = max_;
+  *count = count_;
+}
+
+bool SampleCountPickleIterator::ReadNext() {

[Ilya Sherman, 2012/09/12 03:20:58]

Optional nit: This method is only used in one place -- is it worth decomposing?

[kaiwang, 2012/09/20 22:54:59]

Done.

+  return iter_->ReadInt(&min_) &&
+      iter_->ReadInt(&max_) &&
+      iter_->ReadInt(&count_);
+}
+
+}  // namespace
+
+HistogramSamples::HistogramSamples() : sum_(0), redundant_count_(0) {}
+
+HistogramSamples::~HistogramSamples() {}
+
+void HistogramSamples::Add(const HistogramSamples& other) {
+  sum_ += other.sum();
+  redundant_count_ += other.redundant_count();
+  CHECK(AddSubtractImpl(other.Iterator().get(), ADD));
+}
+
+bool HistogramSamples::AddFromPickle(PickleIterator* iter) {
+  int64 sum;
+  HistogramBase::Count redundant_count;
+
+  if (!iter->ReadInt64(&sum) || !iter->ReadInt(&redundant_count))
+    return false;
+  sum_ += sum;
+  redundant_count_ += redundant_count;
+
+  SampleCountPickleIterator pickle_iter(iter);
+  return AddSubtractImpl(&pickle_iter, ADD);
+}
+
+void HistogramSamples::Subtract(const HistogramSamples& other) {
+  sum_ -= other.sum();
+  redundant_count_ -= other.redundant_count();
+  CHECK(AddSubtractImpl(other.Iterator().get(), SUBTRACT));
+}
+
+bool HistogramSamples::Serialize(Pickle* pickle) const {
+  if (!pickle->WriteInt64(sum_) || !pickle->WriteInt(redundant_count_))
+    return false;
+
+  HistogramBase::Sample min;
+  HistogramBase::Sample max;
+  HistogramBase::Count count;
+  for (scoped_ptr<SampleCountIterator> it = Iterator();
+       !it->Done();
+       it->Next()) {
+    it->Get(&min, &max, &count);
+    if (!pickle->WriteInt(min) ||
+        !pickle->WriteInt(max) ||
+        !pickle->WriteInt(count))
+      return false;
+  }
+  return true;
+}
+
+void HistogramSamples::IncreaseSum(int64 diff) {
+  sum_ += diff;
+}
+
+void HistogramSamples::IncreaseRedundantCount(HistogramBase::Count diff) {
+  redundant_count_ += diff;
+}
+
+SampleCountIterator::~SampleCountIterator() {}
+
+bool SampleCountIterator::GetBucketIndex(size_t* index) const {
+  CHECK(!Done());

[Ilya Sherman, 2012/09/12 03:20:58]

nit: DCHECK

+  return false;
+}
+
+}  // namespace base