Keep only base/extractor.[cc|h].

common/progress_sampler.h

-// Copyright 2011 Google Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-// ========================================================================
-
-#ifndef OMAHA_COMMON_PROGRESS_SAMPLER_H_
-#define OMAHA_COMMON_PROGRESS_SAMPLER_H_
-
-#include <windows.h>
-#include <algorithm>
-#include <queue>
-#include "omaha/base/debug.h"
-#include "omaha/base/time.h"
-
-namespace omaha {
-
-// This class keeps track of the input data (samples) and helps to calculate
-// the average progress based on that.
-//
-// Example usage:
-//   // Create a sampler that keep samples within last 500ms and calculates
-//   // average progress only if minimum time range 100ms is reached.
-//   ProgressSampler<int> progress_sampler(500, 100);
-//   ASSERT1(!progress_sampler.HasEnoughSamples());
-//
-//   progress_sampler.AddSample(0, 100);
-//   ASSERT1(!progress_sampler.HasEnoughSamples());
-//
-//   progress_sampler.AddSample(20, 200);
-//   // Minimum time range 100ms has not been reached yet.
-//   ASSERT1(!progress_sampler.HasEnoughSamples());
-//
-//   progress_sampler.AddSample(200, 300);
-//   ASSERT1(progress_sampler.HasEnoughSamples());
-//   // Samples in queue: [(0, 100), (20, 200), (200, 300)].
-//   // Average speed: (300-100) / (200-0) = 1.
-//   ASSERT1(1 == progress_sampler.GetAverageProgressPerMs());
-//
-//   progress_sampler.AddSample(520, 450);
-//   // The first sample value was added at timeline 0 is now out of
-//   // range (500ms) and thus discarded.
-//   // Samples in queue now: [(20, 200), (200, 300), [520, 450)].
-//   // Average speed: (520-20) / (450-200) = 2.
-//   ASSERT1(2 == progress_sampler.GetAverageProgressPerMs());
-template<typename T> class ProgressSampler {
- public:
-  ProgressSampler(int sample_time_range_ms, int minimum_range_required_ms)
-      : sample_time_range_ms_(sample_time_range_ms),
-        minimum_range_required_ms_(minimum_range_required_ms) {
-      ASSERT1(minimum_range_required_ms > 0);
-  }
-
-  void AddSampleWithCurrentTimeStamp(T sample_value) {
-    AddSample(GetCurrent100NSTime() / kMillisecsTo100ns, sample_value);
-  }
-
-  void AddSample(uint64 timestamp_in_ms, T sample_value) {
-    if (!samples_.empty() &&
-        (sample_value < samples_.back().value ||          // Value regression.
-         timestamp_in_ms < samples_.back().timestamp)) {  // Clock regression.
-      Reset();
-      return;
-    }
-
-    samples_.push(Sample(timestamp_in_ms, sample_value));
-
-    // Discard old data that is out of range.
-    while (samples_.back().timestamp - samples_.front().timestamp >
-           sample_time_range_ms_ && samples_.size() > 2) {
-      samples_.pop();
-    }
-  }
-
-  bool HasEnoughSamples() const {
-    if (samples_.size() < 2) {
-      return false;
-    }
-
-    ASSERT1(samples_.back().timestamp >= samples_.front().timestamp);
-    return (samples_.back().timestamp - samples_.front().timestamp >
-            minimum_range_required_ms_);
-  }
-
-  T GetAverageProgressPerMs() const {
-    if (!HasEnoughSamples()) {
-      return kUnknownProgressPerMs;
-    }
-
-    uint64 time_diff = samples_.back().timestamp - samples_.front().timestamp;
-    ASSERT1(time_diff > 0);
-    return (samples_.back().value - samples_.front().value) /
-            static_cast<T>(time_diff);
-  }
-
-  void Reset() {
-    std::queue<Sample> empty_queue;
-    std::swap(samples_, empty_queue);
-  }
-
-  static const T kUnknownProgressPerMs = static_cast<T>(-1);
-
- private:
-  const uint64 sample_time_range_ms_;
-  const uint64 minimum_range_required_ms_;
-
-  struct Sample {
-    Sample(uint64 local_timestamp, T local_value)
-        : timestamp(local_timestamp), value(local_value) {
-    }
-
-    uint64  timestamp;
-    T value;
-  };
-  std::queue<Sample> samples_;
-};
-
-}  // namespace omaha
-
-#endif  // OMAHA_COMMON_PROGRESS_SAMPLER_H_