1 files changed, 59 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/agc2/saturation_protector_buffer.h b/third_party/libwebrtc/modules/audio_processing/agc2/saturation_protector_buffer.h
new file mode 100644
index 0000000000..e17d0998c4
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/agc2/saturation_protector_buffer.h
@@ -0,0 +1,59 @@
+/*
+ *  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.
+ */
+
+#ifndef MODULES_AUDIO_PROCESSING_AGC2_SATURATION_PROTECTOR_BUFFER_H_
+#define MODULES_AUDIO_PROCESSING_AGC2_SATURATION_PROTECTOR_BUFFER_H_
+
+#include <array>
+
+#include "absl/types/optional.h"
+#include "modules/audio_processing/agc2/agc2_common.h"
+
+namespace webrtc {
+
+// Ring buffer for the saturation protector which only supports (i) push back
+// and (ii) read oldest item.
+class SaturationProtectorBuffer {
+ public:
+  SaturationProtectorBuffer();
+  ~SaturationProtectorBuffer();
+
+  bool operator==(const SaturationProtectorBuffer& b) const;
+  inline bool operator!=(const SaturationProtectorBuffer& b) const {
+    return !(*this == b);
+  }
+
+  // Maximum number of values that the buffer can contain.
+  int Capacity() const;
+
+  // Number of values in the buffer.
+  int Size() const;
+
+  void Reset();
+
+  // Pushes back `v`. If the buffer is full, the oldest value is replaced.
+  void PushBack(float v);
+
+  // Returns the oldest item in the buffer. Returns an empty value if the
+  // buffer is empty.
+  absl::optional<float> Front() const;
+
+ private:
+  int FrontIndex() const;
+  // `buffer_` has `size_` elements (up to the size of `buffer_`) and `next_` is
+  // the position where the next new value is written in `buffer_`.
+  std::array<float, kSaturationProtectorBufferSize> buffer_;
+  int next_ = 0;
+  int size_ = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AGC2_SATURATION_PROTECTOR_BUFFER_H_