rrtr.cc (2020B)
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/rrtr.h" 12 13 #include <cstdint> 14 15 #include "modules/rtp_rtcp/source/byte_io.h" 16 #include "rtc_base/checks.h" 17 18 namespace webrtc { 19 namespace rtcp { 20 // Receiver Reference Time Report Block (RFC 3611). 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 // | BT=4 | reserved | block length = 2 | 26 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 27 // | NTP timestamp, most significant word | 28 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 29 // | NTP timestamp, least significant word | 30 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 31 32 void Rrtr::Parse(const uint8_t* buffer) { 33 RTC_DCHECK(buffer[0] == kBlockType); 34 // reserved = buffer[1]; 35 RTC_DCHECK(ByteReader<uint16_t>::ReadBigEndian(&buffer[2]) == kBlockLength); 36 uint32_t seconds = ByteReader<uint32_t>::ReadBigEndian(&buffer[4]); 37 uint32_t fraction = ByteReader<uint32_t>::ReadBigEndian(&buffer[8]); 38 ntp_.Set(seconds, fraction); 39 } 40 41 void Rrtr::Create(uint8_t* buffer) const { 42 const uint8_t kReserved = 0; 43 buffer[0] = kBlockType; 44 buffer[1] = kReserved; 45 ByteWriter<uint16_t>::WriteBigEndian(&buffer[2], kBlockLength); 46 ByteWriter<uint32_t>::WriteBigEndian(&buffer[4], ntp_.seconds()); 47 ByteWriter<uint32_t>::WriteBigEndian(&buffer[8], ntp_.fractions()); 48 } 49 50 } // namespace rtcp 51 } // namespace webrtc