Line data    Source code

       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             : 
      20             : namespace webrtc {
      21             : 
      22             : struct DtmfEvent {
      23             :   uint32_t timestamp;
      24             :   int event_no;
      25             :   int volume;
      26             :   int duration;
      27             :   bool end_bit;
      28             : 
      29             :   // Constructors
      30           0 :   DtmfEvent()
      31           0 :       : timestamp(0),
      32             :         event_no(0),
      33             :         volume(0),
      34             :         duration(0),
      35           0 :         end_bit(false) {
      36           0 :   }
      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.
      47           0 : class 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_