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/*
* Copyright (c) 2022 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 "net/dcsctp/rx/reassembly_streams.h"
#include <cstddef>
#include <map>
#include <utility>
namespace dcsctp {
ReassembledMessage AssembleMessage(std::map<UnwrappedTSN, Data>::iterator start,
std::map<UnwrappedTSN, Data>::iterator end) {
size_t count = std::distance(start, end);
if (count == 1) {
// Fast path - zero-copy
Data& data = start->second;
return ReassembledMessage{
.tsns = {start->first},
.message = DcSctpMessage(data.stream_id, data.ppid,
std::move(start->second.payload)),
};
}
// Slow path - will need to concatenate the payload.
std::vector<UnwrappedTSN> tsns;
std::vector<uint8_t> payload;
size_t payload_size = std::accumulate(
start, end, 0,
[](size_t v, const auto& p) { return v + p.second.size(); });
tsns.reserve(count);
payload.reserve(payload_size);
for (auto it = start; it != end; ++it) {
Data& data = it->second;
tsns.push_back(it->first);
payload.insert(payload.end(), data.payload.begin(), data.payload.end());
}
return ReassembledMessage{
.tsns = std::move(tsns),
.message = DcSctpMessage(start->second.stream_id, start->second.ppid,
std::move(payload)),
};
}
} // namespace dcsctp
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