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 
11 #ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_NACK_H_
12 #define WEBRTC_MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_NACK_H_
13 
14 #include <vector>
15 
16 #include "webrtc/base/basictypes.h"
17 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.h"
18 #include "webrtc/modules/rtp_rtcp/source/rtcp_utility.h"
19 
20 namespace webrtc {
21 namespace rtcp {
22 
23 class Nack : public Rtpfb {
24  public:
25   const uint8_t kFeedbackMessageType = 1;
Nack()26   Nack() {}
27 
~Nack()28   virtual ~Nack() {}
29 
30   // Parse assumes header is already parsed and validated.
31   bool Parse(const RTCPUtility::RtcpCommonHeader& header,
32              const uint8_t* payload);  // Size of the payload is in the header.
33 
34   void WithList(const uint16_t* nack_list, size_t length);
packet_ids()35   const std::vector<uint16_t>& packet_ids() const { return packet_ids_; }
36 
37  protected:
38   bool Create(uint8_t* packet,
39               size_t* index,
40               size_t max_length,
41               RtcpPacket::PacketReadyCallback* callback) const override;
42 
43   size_t BlockLength() const override;
44 
45  private:
46   const size_t kNackItemLength = 4;
47   struct PackedNack {
48     uint16_t first_pid;
49     uint16_t bitmask;
50   };
51 
52   void Pack();    // Fills packed_ using packed_ids_. (used in WithList).
53   void Unpack();  // Fills packet_ids_ using packed_. (used in Parse).
54 
55   std::vector<PackedNack> packed_;
56   std::vector<uint16_t> packet_ids_;
57 
58   RTC_DISALLOW_COPY_AND_ASSIGN(Nack);
59 };
60 
61 }  // namespace rtcp
62 }  // namespace webrtc
63 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_NACK_H_
64