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 "webrtc/modules/rtp_rtcp/source/rtcp_packet/psfb.h"
12
13#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
14
15namespace webrtc {
16namespace rtcp {
17
18// RFC 4585: Feedback format.
19//
20// Common packet format:
21//
22//    0                   1                   2                   3
23//    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
24//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
25//   |V=2|P|   FMT   |       PT      |          length               |
26//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
27// 0 |                  SSRC of packet sender                        |
28//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
29// 4 |                  SSRC of media source                         |
30//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
31//   :            Feedback Control Information (FCI)                 :
32//   :                                                               :
33
34void Psfb::ParseCommonFeedback(const uint8_t* payload) {
35  sender_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(&payload[0]);
36  media_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(&payload[4]);
37}
38
39void Psfb::CreateCommonFeedback(uint8_t* payload) const {
40  ByteWriter<uint32_t>::WriteBigEndian(&payload[0], sender_ssrc_);
41  ByteWriter<uint32_t>::WriteBigEndian(&payload[4], media_ssrc_);
42}
43
44}  // namespace rtcp
45}  // namespace webrtc
46