Using ring buffer for AudioVector in NetEq.

webrtc/modules/audio_coding/neteq/audio_vector.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.
  */
 
@@ skipping 19 matching lines @@
   virtual ~AudioVector();
 
   // Deletes all values and make the vector empty.
   virtual void Clear();
 
   // Copies all values from this vector to |copy_to|. Any contents in |copy_to|
   // are deleted before the copy operation. After the operation is done,
   // |copy_to| will be an exact replica of this object.
   virtual void CopyTo(AudioVector* copy_to) const;
 
+  // Copies |length| values from |position| in this vector to |copy_to|.
+  virtual void CopyTo(size_t length, size_t position, int16_t* copy_to) const;
+
   // Prepends the contents of AudioVector |prepend_this| to this object. The
   // length of this object is increased with the length of |prepend_this|.
   virtual void PushFront(const AudioVector& prepend_this);
 
   // Same as above, but with an array |prepend_this| with |length| elements as
   // source.
   virtual void PushFront(const int16_t* prepend_this, size_t length);
 
   // Same as PushFront but will append to the end of this object.
   virtual void PushBack(const AudioVector& append_this);
 
+  // Appends a segment of |append_this| to the end of this object. The segment
+  // starts from |position| and has |length| samples.
+  virtual void PushBack(const AudioVector& append_this,
+                        size_t length,
+                        size_t position);
+
   // Same as PushFront but will append to the end of this object.
   virtual void PushBack(const int16_t* append_this, size_t length);
 
   // Removes |length| elements from the beginning of this object.
   virtual void PopFront(size_t length);
 
   // Removes |length| elements from the end of this object.
   virtual void PopBack(size_t length);
 
   // Extends this object with |extra_length| elements at the end. The new
   // elements are initialized to zero.
   virtual void Extend(size_t extra_length);
 
   // Inserts |length| elements taken from the array |insert_this| and insert
   // them at |position|. The length of the AudioVector is increased by |length|.
   // |position| = 0 means that the new values are prepended to the vector.
   // |position| = Size() means that the new values are appended to the vector.
   virtual void InsertAt(const int16_t* insert_this, size_t length,
                         size_t position);
 
   // Like InsertAt, but inserts |length| zero elements at |position|.
   virtual void InsertZerosAt(size_t length, size_t position);
 
+  // Overwrites |length| elements of this AudioVector starting from |position|
+  // with first values in |AudioVector|. The definition of |position|
+  // is the same as for InsertAt(). If |length| and |position| are selected
+  // such that the new data extends beyond the end of the current AudioVector,
+  // the vector is extended to accommodate the new data.
+  virtual void OverwriteAt(const AudioVector& insert_this,
+                           size_t length,
+                           size_t position);
+
   // Overwrites |length| elements of this AudioVector with values taken from the
   // array |insert_this|, starting at |position|. The definition of |position|
   // is the same as for InsertAt(). If |length| and |position| are selected
   // such that the new data extends beyond the end of the current AudioVector,
   // the vector is extended to accommodate the new data.
   virtual void OverwriteAt(const int16_t* insert_this,
                            size_t length,
                            size_t position);
 
   // Appends |append_this| to the end of the current vector. Lets the two
   // vectors overlap by |fade_length| samples, and cross-fade linearly in this
   // region.
   virtual void CrossFade(const AudioVector& append_this, size_t fade_length);
 
   // Returns the number of elements in this AudioVector.
   virtual size_t Size() const;
 
   // Returns true if this AudioVector is empty.
   virtual bool Empty() const;
 
   // Accesses and modifies an element of AudioVector.
   const int16_t& operator[](size_t index) const;
   int16_t& operator[](size_t index);
 
  private:
   static const size_t kDefaultInitialSize = 10;
 
   void Reserve(size_t n);
 
+  void InsertByPushBack(const int16_t* insert_this, size_t length,
+                        size_t position);
+
+  void InsertByPushFront(const int16_t* insert_this, size_t length,
+                         size_t position);
+
+  void InsertZerosByPushBack(size_t length, size_t position);
+
+  void InsertZerosByPushFront(size_t length, size_t position);
+
   std::unique_ptr<int16_t[]> array_;
-  size_t first_free_ix_;  // The first index after the last sample in array_.
-                          // Note that this index may point outside of array_.
+
   size_t capacity_;  // Allocated number of samples in the array.
 
+  // The index of the first sample in |array_|, except when
+  // |begin_index_ == end_index_|, which indicates an empty buffer.
+  size_t begin_index_;
+
+  // The index of the sample after the last sample in |array_|.
+  size_t end_index_;
+
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioVector);
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_AUDIO_VECTOR_H_