1 files changed, 65 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/agc2/rnn_vad/ring_buffer.h b/third_party/libwebrtc/modules/audio_processing/agc2/rnn_vad/ring_buffer.h
new file mode 100644
index 0000000000..a6f7fdd1a6
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+++ b/third_party/libwebrtc/modules/audio_processing/agc2/rnn_vad/ring_buffer.h
@@ -0,0 +1,65 @@
+/*
+ *  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.
+ */
+
+#ifndef MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_RING_BUFFER_H_
+#define MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_RING_BUFFER_H_
+
+#include <array>
+#include <cstring>
+#include <type_traits>
+
+#include "api/array_view.h"
+
+namespace webrtc {
+namespace rnn_vad {
+
+// Ring buffer for N arrays of type T each one with size S.
+template <typename T, int S, int N>
+class RingBuffer {
+  static_assert(S > 0, "");
+  static_assert(N > 0, "");
+  static_assert(std::is_arithmetic<T>::value,
+                "Integral or floating point required.");
+
+ public:
+  RingBuffer() : tail_(0) {}
+  RingBuffer(const RingBuffer&) = delete;
+  RingBuffer& operator=(const RingBuffer&) = delete;
+  ~RingBuffer() = default;
+  // Set the ring buffer values to zero.
+  void Reset() { buffer_.fill(0); }
+  // Replace the least recently pushed array in the buffer with `new_values`.
+  void Push(rtc::ArrayView<const T, S> new_values) {
+    std::memcpy(buffer_.data() + S * tail_, new_values.data(), S * sizeof(T));
+    tail_ += 1;
+    if (tail_ == N)
+      tail_ = 0;
+  }
+  // Return an array view onto the array with a given delay. A view on the last
+  // and least recently push array is returned when `delay` is 0 and N - 1
+  // respectively.
+  rtc::ArrayView<const T, S> GetArrayView(int delay) const {
+    RTC_DCHECK_LE(0, delay);
+    RTC_DCHECK_LT(delay, N);
+    int offset = tail_ - 1 - delay;
+    if (offset < 0)
+      offset += N;
+    return {buffer_.data() + S * offset, S};
+  }
+
+ private:
+  int tail_;  // Index of the least recently pushed sub-array.
+  std::array<T, S * N> buffer_{};
+};
+
+}  // namespace rnn_vad
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_RING_BUFFER_H_