1 files changed, 60 insertions, 0 deletions
diff --git a/webrtc/modules/audio_processing/aec3/moving_average.cc b/webrtc/modules/audio_processing/aec3/moving_average.cc
new file mode 100644
index 0000000..7a81ee8
--- /dev/null
+++ b/webrtc/modules/audio_processing/aec3/moving_average.cc
@@ -0,0 +1,60 @@
+
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/audio_processing/aec3/moving_average.h"
+
+#include <algorithm>
+#include <functional>
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+namespace aec3 {
+
+MovingAverage::MovingAverage(size_t num_elem, size_t mem_len)
+    : num_elem_(num_elem),
+      mem_len_(mem_len - 1),
+      scaling_(1.0f / static_cast<float>(mem_len)),
+      memory_(num_elem * mem_len_, 0.f),
+      mem_index_(0) {
+  RTC_DCHECK(num_elem_ > 0);
+  RTC_DCHECK(mem_len > 0);
+}
+
+MovingAverage::~MovingAverage() = default;
+
+void MovingAverage::Average(rtc::ArrayView<const float> input,
+                            rtc::ArrayView<float> output) {
+  RTC_DCHECK(input.size() == num_elem_);
+  RTC_DCHECK(output.size() == num_elem_);
+
+  // Sum all contributions.
+  std::copy(input.begin(), input.end(), output.begin());
+  for (auto i = memory_.begin(); i < memory_.end(); i += num_elem_) {
+    std::transform(i, i + num_elem_, output.begin(), output.begin(),
+                   std::plus<float>());
+  }
+
+  // Divide by mem_len_.
+  for (float& o : output) {
+    o *= scaling_;
+  }
+
+  // Update memory.
+  if (mem_len_ > 0) {
+    std::copy(input.begin(), input.end(),
+              memory_.begin() + mem_index_ * num_elem_);
+    mem_index_ = (mem_index_ + 1) % mem_len_;
+  }
+}
+
+}  // namespace aec3
+}  // namespace webrtc