1 /*
2  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 #ifndef WEBRTC_COMMON_AUDIO_AUDIO_RING_BUFFER_H_
11 #define WEBRTC_COMMON_AUDIO_AUDIO_RING_BUFFER_H_
12 
13 #include <stddef.h>
14 #include <vector>
15 
16 struct RingBuffer;
17 
18 namespace webrtc {
19 
20 // A ring buffer tailored for float deinterleaved audio. Any operation that
21 // cannot be performed as requested will cause a crash (e.g. insufficient data
22 // in the buffer to fulfill a read request.)
23 class AudioRingBuffer final {
24  public:
25   // Specify the number of channels and maximum number of frames the buffer will
26   // contain.
27   AudioRingBuffer(size_t channels, size_t max_frames);
28   ~AudioRingBuffer();
29 
30   // Copies |data| to the buffer and advances the write pointer. |channels| must
31   // be the same as at creation time.
32   void Write(const float* const* data, size_t channels, size_t frames);
33 
34   // Copies from the buffer to |data| and advances the read pointer. |channels|
35   // must be the same as at creation time.
36   void Read(float* const* data, size_t channels, size_t frames);
37 
38   size_t ReadFramesAvailable() const;
39   size_t WriteFramesAvailable() const;
40 
41   // Moves the read position. The forward version advances the read pointer
42   // towards the write pointer and the backward verison withdraws the read
43   // pointer away from the write pointer (i.e. flushing and stuffing the buffer
44   // respectively.)
45   void MoveReadPositionForward(size_t frames);
46   void MoveReadPositionBackward(size_t frames);
47 
48  private:
49   // We don't use a ScopedVector because it doesn't support a specialized
50   // deleter (like scoped_ptr for instance.)
51   std::vector<RingBuffer*> buffers_;
52 };
53 
54 }  // namespace webrtc
55 
56 #endif  // WEBRTC_COMMON_AUDIO_AUDIO_RING_BUFFER_H_
57