/*
 *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "modules/rtp_rtcp/source/rtcp_packet/psfb.h"

#include "modules/rtp_rtcp/source/byte_io.h"

namespace webrtc {
namespace rtcp {
constexpr uint8_t Psfb::kPacketType;
constexpr size_t Psfb::kCommonFeedbackLength;
// RFC 4585: Feedback format.
//
// Common packet format:
//
//    0                   1                   2                   3
//    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
//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//   |V=2|P|   FMT   |       PT      |          length               |
//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 0 |                  SSRC of packet sender                        |
//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 4 |                  SSRC of media source                         |
//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//   :            Feedback Control Information (FCI)                 :
//   :                                                               :

void Psfb::ParseCommonFeedback(const uint8_t* payload) {
  sender_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(&payload[0]);
  media_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(&payload[4]);
}

void Psfb::CreateCommonFeedback(uint8_t* payload) const {
  ByteWriter<uint32_t>::WriteBigEndian(&payload[0], sender_ssrc_);
  ByteWriter<uint32_t>::WriteBigEndian(&payload[4], media_ssrc_);
}

}  // namespace rtcp
}  // namespace webrtc