1 files changed, 77 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/agc2/clipping_predictor_level_buffer.cc b/third_party/libwebrtc/modules/audio_processing/agc2/clipping_predictor_level_buffer.cc
new file mode 100644
index 0000000000..fe4cf2a154
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/agc2/clipping_predictor_level_buffer.cc
@@ -0,0 +1,77 @@
+/*
+ *  Copyright (c) 2021 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/agc2/clipping_predictor_level_buffer.h"
+
+#include <algorithm>
+#include <cmath>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+
+bool ClippingPredictorLevelBuffer::Level::operator==(const Level& level) const {
+  constexpr float kEpsilon = 1e-6f;
+  return std::fabs(average - level.average) < kEpsilon &&
+         std::fabs(max - level.max) < kEpsilon;
+}
+
+ClippingPredictorLevelBuffer::ClippingPredictorLevelBuffer(int capacity)
+    : tail_(-1), size_(0), data_(std::max(1, capacity)) {
+  if (capacity > kMaxCapacity) {
+    RTC_LOG(LS_WARNING) << "[agc]: ClippingPredictorLevelBuffer exceeds the "
+                        << "maximum allowed capacity. Capacity: " << capacity;
+  }
+  RTC_DCHECK(!data_.empty());
+}
+
+void ClippingPredictorLevelBuffer::Reset() {
+  tail_ = -1;
+  size_ = 0;
+}
+
+void ClippingPredictorLevelBuffer::Push(Level level) {
+  ++tail_;
+  if (tail_ == Capacity()) {
+    tail_ = 0;
+  }
+  if (size_ < Capacity()) {
+    size_++;
+  }
+  data_[tail_] = level;
+}
+
+// TODO(bugs.webrtc.org/12774): Optimize partial computation for long buffers.
+absl::optional<ClippingPredictorLevelBuffer::Level>
+ClippingPredictorLevelBuffer::ComputePartialMetrics(int delay,
+                                                    int num_items) const {
+  RTC_DCHECK_GE(delay, 0);
+  RTC_DCHECK_LT(delay, Capacity());
+  RTC_DCHECK_GT(num_items, 0);
+  RTC_DCHECK_LE(num_items, Capacity());
+  RTC_DCHECK_LE(delay + num_items, Capacity());
+  if (delay + num_items > Size()) {
+    return absl::nullopt;
+  }
+  float sum = 0.0f;
+  float max = 0.0f;
+  for (int i = 0; i < num_items && i < Size(); ++i) {
+    int idx = tail_ - delay - i;
+    if (idx < 0) {
+      idx += Capacity();
+    }
+    sum += data_[idx].average;
+    max = std::fmax(data_[idx].max, max);
+  }
+  return absl::optional<Level>({sum / static_cast<float>(num_items), max});
+}
+
+}  // namespace webrtc