Index: media/base/moving_average.cc |
diff --git a/media/base/moving_average.cc b/media/base/moving_average.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..c8ca7dda08d3fe879d882a773d32f648e773528b |
--- /dev/null |
+++ b/media/base/moving_average.cc |
@@ -0,0 +1,41 @@ |
+// Copyright 2015 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 "media/base/moving_average.h" |
+ |
+#include <algorithm> |
+ |
+namespace media { |
+ |
+MovingAverage::MovingAverage(size_t depth) |
+ : depth_(depth), count_(0), samples_(depth_) { |
+} |
+ |
+MovingAverage::~MovingAverage() { |
+} |
+ |
+void MovingAverage::AddSample(base::TimeDelta sample) { |
+ // |samples_| is zero-initialized, so |oldest| is also zero before |count_| |
+ // exceeds |depth_|. |
+ base::TimeDelta& oldest = samples_[count_++ % depth_]; |
+ total_ += sample - oldest; |
+ oldest = sample; |
+} |
+ |
+base::TimeDelta MovingAverage::Average() const { |
+ DCHECK_GT(count_, 0u); |
+ |
+ // TODO(dalecurtis): Consider limiting |depth| to powers of two so that we can |
+ // replace the integer divide with a bit shift operation. |
+ |
+ return total_ / std::min(depth_, count_); |
+} |
+ |
+void MovingAverage::Reset() { |
+ count_ = 0; |
+ total_ = base::TimeDelta(); |
+ std::fill(samples_.begin(), samples_.end(), base::TimeDelta()); |
+} |
+ |
+} // namespace media |