1/*
2 *  Copyright (c) 2012 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
11#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_BUFFER_H_
12#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_BUFFER_H_
13
14#include <list>
15#include <string>  // size_t
16
17#include "webrtc/base/constructormagic.h"
18#include "webrtc/typedefs.h"
19
20namespace webrtc {
21
22struct DtmfEvent {
23  uint32_t timestamp;
24  int event_no;
25  int volume;
26  int duration;
27  bool end_bit;
28
29  // Constructors
30  DtmfEvent()
31      : timestamp(0),
32        event_no(0),
33        volume(0),
34        duration(0),
35        end_bit(false) {
36  }
37  DtmfEvent(uint32_t ts, int ev, int vol, int dur, bool end)
38      : timestamp(ts),
39        event_no(ev),
40        volume(vol),
41        duration(dur),
42        end_bit(end) {
43  }
44};
45
46// This is the buffer holding DTMF events while waiting for them to be played.
47class DtmfBuffer {
48 public:
49  enum BufferReturnCodes {
50    kOK = 0,
51    kInvalidPointer,
52    kPayloadTooShort,
53    kInvalidEventParameters,
54    kInvalidSampleRate
55  };
56
57  // Set up the buffer for use at sample rate |fs_hz|.
58  explicit DtmfBuffer(int fs_hz);
59
60  virtual ~DtmfBuffer();
61
62  // Flushes the buffer.
63  virtual void Flush();
64
65  // Static method to parse 4 bytes from |payload| as a DTMF event (RFC 4733)
66  // and write the parsed information into the struct |event|. Input variable
67  // |rtp_timestamp| is simply copied into the struct.
68  static int ParseEvent(uint32_t rtp_timestamp,
69                        const uint8_t* payload,
70                        size_t payload_length_bytes,
71                        DtmfEvent* event);
72
73  // Inserts |event| into the buffer. The method looks for a matching event and
74  // merges the two if a match is found.
75  virtual int InsertEvent(const DtmfEvent& event);
76
77  // Checks if a DTMF event should be played at time |current_timestamp|. If so,
78  // the method returns true; otherwise false. The parameters of the event to
79  // play will be written to |event|.
80  virtual bool GetEvent(uint32_t current_timestamp, DtmfEvent* event);
81
82  // Number of events in the buffer.
83  virtual size_t Length() const;
84
85  virtual bool Empty() const;
86
87  // Set a new sample rate.
88  virtual int SetSampleRate(int fs_hz);
89
90 private:
91  typedef std::list<DtmfEvent> DtmfList;
92
93  int max_extrapolation_samples_;
94  int frame_len_samples_;  // TODO(hlundin): Remove this later.
95
96  // Compares two events and returns true if they are the same.
97  static bool SameEvent(const DtmfEvent& a, const DtmfEvent& b);
98
99  // Merges |event| to the event pointed out by |it|. The method checks that
100  // the two events are the same (using the SameEvent method), and merges them
101  // if that was the case, returning true. If the events are not the same, false
102  // is returned.
103  bool MergeEvents(DtmfList::iterator it, const DtmfEvent& event);
104
105  // Method used by the sort algorithm to rank events in the buffer.
106  static bool CompareEvents(const DtmfEvent& a, const DtmfEvent& b);
107
108  DtmfList buffer_;
109
110  RTC_DISALLOW_COPY_AND_ASSIGN(DtmfBuffer);
111};
112
113}  // namespace webrtc
114#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_BUFFER_H_
115