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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "remoting/protocol/message_decoder.h"
#include <stdint.h>
#include "base/check_op.h"
#include "net/base/io_buffer.h"
#include "remoting/base/compound_buffer.h"
#include "remoting/proto/internal.pb.h"
#include "third_party/webrtc/rtc_base/byte_order.h"
namespace remoting::protocol {
MessageDecoder::MessageDecoder() = default;
MessageDecoder::~MessageDecoder() = default;
void MessageDecoder::AddData(scoped_refptr<net::IOBuffer> data, int data_size) {
buffer_.Append(std::move(data), data_size);
}
CompoundBuffer* MessageDecoder::GetNextMessage() {
// Determine the payload size. If we already know it then skip this part.
// We may not have enough data to determine the payload size so use a
// utility function to find out.
int next_payload = -1;
if (!next_payload_known_ && GetPayloadSize(&next_payload)) {
DCHECK_NE(-1, next_payload);
next_payload_ = next_payload;
next_payload_known_ = true;
}
// If the next payload size is still not known or we don't have enough
// data for parsing then exit.
if (!next_payload_known_ || buffer_.total_bytes() < next_payload_) {
return nullptr;
}
CompoundBuffer* message_buffer = new CompoundBuffer();
message_buffer->CopyFrom(buffer_, 0, next_payload_);
message_buffer->Lock();
buffer_.CropFront(next_payload_);
next_payload_known_ = false;
return message_buffer;
}
bool MessageDecoder::GetPayloadSize(int* size) {
// The header has a size of 4 bytes.
const int kHeaderSize = sizeof(int32_t);
if (buffer_.total_bytes() < kHeaderSize) {
return false;
}
CompoundBuffer header_buffer;
char header[kHeaderSize];
header_buffer.CopyFrom(buffer_, 0, kHeaderSize);
header_buffer.CopyTo(header, kHeaderSize);
*size = webrtc::GetBE32(header);
buffer_.CropFront(kHeaderSize);
return true;
}
} // namespace remoting::protocol
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