tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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pli.cc (2628B)

      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 #include "modules/rtp_rtcp/source/rtcp_packet/pli.h"
     12 
     13 #include <cstddef>
     14 #include <cstdint>
     15 
     16 #include "modules/rtp_rtcp/source/rtcp_packet/common_header.h"
     17 #include "rtc_base/checks.h"
     18 #include "rtc_base/logging.h"
     19 
     20 namespace webrtc {
     21 namespace rtcp {
     22 // RFC 4585: Feedback format.
     23 //
     24 // Common packet format:
     25 //
     26 //   0                   1                   2                   3
     27 //   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     28 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     29 //  |V=2|P|   FMT   |       PT      |          length               |
     30 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     31 //  |                  SSRC of packet sender                        |
     32 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     33 //  |                  SSRC of media source                         |
     34 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     35 //  :            Feedback Control Information (FCI)                 :
     36 //  :                                                               :
     37 
     38 Pli::Pli() = default;
     39 
     40 Pli::Pli(const Pli& pli) = default;
     41 
     42 Pli::~Pli() = default;
     43 
     44 //
     45 // Picture loss indication (PLI) (RFC 4585).
     46 // FCI: no feedback control information.
     47 bool Pli::Parse(const CommonHeader& packet) {
     48  RTC_DCHECK_EQ(packet.type(), kPacketType);
     49  RTC_DCHECK_EQ(packet.fmt(), kFeedbackMessageType);
     50 
     51  if (packet.payload_size_bytes() < kCommonFeedbackLength) {
     52    RTC_LOG(LS_WARNING) << "Packet is too small to be a valid PLI packet";
     53    return false;
     54  }
     55 
     56  ParseCommonFeedback(packet.payload());
     57  return true;
     58 }
     59 
     60 size_t Pli::BlockLength() const {
     61  return kHeaderLength + kCommonFeedbackLength;
     62 }
     63 
     64 bool Pli::Create(uint8_t* packet,
     65                 size_t* index,
     66                 size_t max_length,
     67                 PacketReadyCallback callback) const {
     68  while (*index + BlockLength() > max_length) {
     69    if (!OnBufferFull(packet, index, callback))
     70      return false;
     71  }
     72 
     73  CreateHeader(kFeedbackMessageType, kPacketType, HeaderLength(), packet,
     74               index);
     75  CreateCommonFeedback(packet + *index);
     76  *index += kCommonFeedbackLength;
     77  return true;
     78 }
     79 
     80 }  // namespace rtcp
     81 }  // namespace webrtc