Pull the Voice Activity Detector out from the AGC

webrtc/modules/audio_processing/vad/vad_circular_buffer.h

 /*
  *  Copyright (c) 2012 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_AGC_CIRCULAR_BUFFER_H_
-#define WEBRTC_MODULES_AUDIO_PROCESSING_AGC_CIRCULAR_BUFFER_H_
+#ifndef WEBRTC_MODULES_AUDIO_PROCESSING_VAD_VAD_CIRCULAR_BUFFER_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_VAD_VAD_CIRCULAR_BUFFER_H_
 
 #include "webrtc/base/scoped_ptr.h"
 
 namespace webrtc {
 
 // A circular buffer tailored to the need of this project. It stores last
 // K samples of the input, and keeps track of the mean of the last samples.
 //
 // It is used in class "PitchBasedActivity" to keep track of posterior
 // probabilities in the past few seconds. The posterior probabilities are used
 // to recursively update prior probabilities.
-class AgcCircularBuffer {
+class VadCircularBuffer {
  public:
-  static AgcCircularBuffer* Create(int buffer_size);
-  ~AgcCircularBuffer();
+  static VadCircularBuffer* Create(int buffer_size);
+  ~VadCircularBuffer();
 
   // If buffer is wrapped around.
   bool is_full() const { return is_full_; }
   // Get the oldest entry in the buffer.
   double Oldest() const;
   // Insert new value into the buffer.
   void Insert(double value);
   // Reset buffer, forget the past, start fresh.
   void Reset();
 
   // The mean value of the elements in the buffer. The return value is zero if
   // buffer is empty, i.e. no value is inserted.
   double Mean();
   // Remove transients. If the values exceed |val_threshold| for a period
   // shorter then or equal to |width_threshold|, then that period is considered
   // transient and set to zero.
   int RemoveTransient(int width_threshold, double val_threshold);
 
  private:
-  explicit AgcCircularBuffer(int buffer_size);
+  explicit VadCircularBuffer(int buffer_size);
   // Get previous values. |index = 0| corresponds to the most recent
   // insertion. |index = 1| is the one before the most recent insertion, and
   // so on.
   int Get(int index, double* value) const;
   // Set a given position to |value|. |index| is interpreted as above.
   int Set(int index, double value);
   // Return the number of valid elements in the buffer.
   int BufferLevel();
 
   // Convert an index with the interpretation as get() method to the
   // corresponding linear index.
   int ConvertToLinearIndex(int* index) const;
 
   rtc::scoped_ptr<double[]> buffer_;
   bool is_full_;
   int index_;
   int buffer_size_;
   double sum_;
 };
 
 }  // namespace webrtc
-#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AGC_CIRCULAR_BUFFER_H_
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_VAD_VAD_CIRCULAR_BUFFER_H_