Refactoring of the farend buffering scheme inside the AEC

webrtc/modules/audio_processing/aec/aec_core.h

Index: webrtc/modules/audio_processing/aec/aec_core.h
diff --git a/webrtc/modules/audio_processing/aec/aec_core.h b/webrtc/modules/audio_processing/aec/aec_core.h
index 4f2db63108fc99f20286e32b4656cf111a4a05e1..1f3077c87983d514aa411bd31c97feadf1eeea59 100644
--- a/webrtc/modules/audio_processing/aec/aec_core.h
+++ b/webrtc/modules/audio_processing/aec/aec_core.h
@@ -83,6 +83,21 @@ typedef struct PowerLevel {
   float minlevel;
 } PowerLevel;
 
+class BlockBuffer {
+ public:
+  BlockBuffer();
+  ~BlockBuffer();
+  void ReInit();
+  void Insert(const float block[PART_LEN]);
+  void ExtractExtendedBlock(float extended_block[PART_LEN]);
+  int AdjustSize(int buffer_size_decrease);
+  size_t Size();
+  size_t AvaliableSpace();
+
+ private:
+  RingBuffer* buffer_;
+};
+
 class DivergentFilterFraction {
  public:
   DivergentFilterFraction();
@@ -168,7 +183,7 @@ struct AecCore {
 
   int xfBufBlockPos;
 
-  RingBuffer* far_time_buf;
+  BlockBuffer farend_block_buffer_;
 
   int system_delay;  // Current system delay buffered in AEC.
 
@@ -246,7 +261,7 @@ void WebRtcAec_InitAec_mips(void);
 void WebRtcAec_InitAec_neon(void);
 #endif
 
-void WebRtcAec_BufferFarendPartition(AecCore* aec, const float* farend);
+void WebRtcAec_BufferFarendBlock(AecCore* aec, const float* farend);
 void WebRtcAec_ProcessFrames(AecCore* aec,
                              const float* const* nearend,
                              size_t num_bands,
@@ -254,10 +269,11 @@ void WebRtcAec_ProcessFrames(AecCore* aec,
                              int knownDelay,
                              float* const* out);
 
-// A helper function to call WebRtc_MoveReadPtr() for all far-end buffers.
-// Returns the number of elements moved, and adjusts |system_delay| by the
-// corresponding amount in ms.
-int WebRtcAec_MoveFarReadPtr(AecCore* aec, int elements);
+// A helper function to call adjust the farend buffer size.
+// Returns the number of elements the size was decreased with, and adjusts
+// |system_delay| by the corresponding amount in ms.
+int WebRtcAec_AdjustFarendBufferSizeAndSystemDelay(AecCore* aec,
+                                                   int size_decrease);
 
 // Calculates the median, standard deviation and amount of poor values among the
 // delay estimates aggregated up to the first call to the function. After that