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/*
* 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/dlrr.h"
#include <cstddef>
#include <cstdint>
#include "modules/rtp_rtcp/source/byte_io.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/safe_conversions.h"
namespace webrtc {
namespace rtcp {
// DLRR Report Block (RFC 3611).
//
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | BT=5 | reserved | block length |
// +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
// | SSRC_1 (SSRC of first receiver) | sub-
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
// | last RR (LRR) | 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | delay since last RR (DLRR) |
// +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
// | SSRC_2 (SSRC of second receiver) | sub-
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
// : ... : 2
Dlrr::Dlrr() = default;
Dlrr::Dlrr(const Dlrr& other) = default;
Dlrr::~Dlrr() = default;
bool Dlrr::Parse(const uint8_t* buffer, uint16_t block_length_32bits) {
RTC_DCHECK(buffer[0] == kBlockType);
// kReserved = buffer[1];
RTC_DCHECK_EQ(block_length_32bits,
ByteReader<uint16_t>::ReadBigEndian(&buffer[2]));
if (block_length_32bits % 3 != 0) {
RTC_LOG(LS_WARNING) << "Invalid size for dlrr block.";
return false;
}
size_t blocks_count = block_length_32bits / 3;
const uint8_t* read_at = buffer + kBlockHeaderLength;
sub_blocks_.resize(blocks_count);
for (ReceiveTimeInfo& sub_block : sub_blocks_) {
sub_block.ssrc = ByteReader<uint32_t>::ReadBigEndian(&read_at[0]);
sub_block.last_rr = ByteReader<uint32_t>::ReadBigEndian(&read_at[4]);
sub_block.delay_since_last_rr =
ByteReader<uint32_t>::ReadBigEndian(&read_at[8]);
read_at += kSubBlockLength;
}
return true;
}
size_t Dlrr::BlockLength() const {
if (sub_blocks_.empty())
return 0;
return kBlockHeaderLength + kSubBlockLength * sub_blocks_.size();
}
void Dlrr::Create(uint8_t* buffer) const {
if (sub_blocks_.empty()) // No subblocks, no need to write header either.
return;
// Create block header.
const uint8_t kReserved = 0;
buffer[0] = kBlockType;
buffer[1] = kReserved;
ByteWriter<uint16_t>::WriteBigEndian(
&buffer[2], dchecked_cast<uint16_t>(3 * sub_blocks_.size()));
// Create sub blocks.
uint8_t* write_at = buffer + kBlockHeaderLength;
for (const ReceiveTimeInfo& sub_block : sub_blocks_) {
ByteWriter<uint32_t>::WriteBigEndian(&write_at[0], sub_block.ssrc);
ByteWriter<uint32_t>::WriteBigEndian(&write_at[4], sub_block.last_rr);
ByteWriter<uint32_t>::WriteBigEndian(&write_at[8],
sub_block.delay_since_last_rr);
write_at += kSubBlockLength;
}
RTC_DCHECK_EQ(buffer + BlockLength(), write_at);
}
} // namespace rtcp
} // namespace webrtc
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