New module for the adaptive level controlling functionality in the audio processing module

webrtc/modules/audio_processing/level_controller/gain_selector.h

Index: webrtc/modules/audio_processing/level_controller/gain_selector.h
diff --git a/webrtc/modules/audio_processing/level_controller/gain_selector.h b/webrtc/modules/audio_processing/level_controller/gain_selector.h
new file mode 100644
index 0000000000000000000000000000000000000000..3d00499652d66b8b3442ad21f6ccec122620d72d
--- /dev/null
+++ b/webrtc/modules/audio_processing/level_controller/gain_selector.h
@@ -0,0 +1,39 @@
+/*
+ *  Copyright (c) 2016 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 WEBRTC_MODULES_AUDIO_PROCESSING_LEVEL_CONTROLLER_GAIN_SELECTOR_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_LEVEL_CONTROLLER_GAIN_SELECTOR_H_
+
+#include "webrtc/base/constructormagic.h"
+
+#include "webrtc/modules/audio_processing/level_controller/signal_classifier.h"
+
+namespace webrtc {
+
+class GainSelector {
+ public:
+  GainSelector();
+  void Initialize(int sample_rate_hz);
+  float GetNewGain(float peak_level,
+                   float noise_energy,
+                   float saturating_gain,
+                   SignalClassifier::SignalType signal_type);
+
+ private:
+  float gain_;
+  size_t frame_length_;
+  int highly_nonstationary_signal_hold_counter_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(GainSelector);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_LEVEL_CONTROLLER_GAIN_SELECTOR_H_