TCP粘包的拆包处理

因为TCP是流式处理的，所以包没有边界，必须设计一个包头，里面表示包的长度（一般用字节表示），根据这个来逐个拆包。如果对于发送/接收频率不高的话，一般也就不做拆包处理了，因为不大可能有粘包现象。

以下是粘包和拆包的分析：

http://blog.csdn.net/zhangxinrun/article/details/6721495

用Qt的TCPSocket读出的数据来拆：

http://www.aiuxian.com/article/p-1732805.html

我是根据以上链接例子Qt的逻辑来实现的，用Boost的ASIO来读取，是同步的：

m_imp->m_thread = boost::make_shared<boost::thread>(
            [=]()
            {
                while (!boost::this_thread::interruption_requested())
                {
                    boost::this_thread::interruption_point();

                    try
                    {
                        boost::system::error_code ec;
                        std::vector<uint8_t> tmpreadBuffer(1024 * 500);
                        
                        size_t bytes_transferred = m_imp->m_sockPtr->read_some(boost::asio::buffer(tmpreadBuffer), ec);

                        std::cout << "Byte Transfered:" << bytes_transferred << "
";

                        if (!ec)
                        {
                            
                            if (bytes_transferred == 0)  continue;
                            
                            if (bytes_transferred < MSG_HEAD_SIZE)
                            {
                                m_imp->m_readBuffer.insert(m_imp->m_readBuffer.end(), tmpreadBuffer.begin(), tmpreadBuffer.begin() + bytes_transferred / sizeof(uint8_t));
                                continue;
                            }
                            else
                            {
                                m_imp->m_readBuffer.insert(m_imp->m_readBuffer.end(), tmpreadBuffer.begin(), tmpreadBuffer.begin() + bytes_transferred / sizeof(uint8_t));
                                
                                size_t totalSize = m_imp->m_readBuffer.size()*sizeof(uint8_t);

                                while (totalSize)
                                {
                                    size_t msgSize = m_imp->getMsgLen();
                                    std::cout << "Msg Size is:" << msgSize << "
";
                                    
                                    std::vector<uint8_t>::const_iterator first = m_imp->m_readBuffer.begin();
                                    std::vector<uint8_t>::const_iterator last = m_imp->m_readBuffer.begin() + msgSize / sizeof(uint8_t);
                                    std::vector<uint8_t> tmpMsg(first, last);

                                    m_imp->m_msgQueue.push_back(tmpMsg);

                                    m_imp->m_readBuffer.erase(first, last);

                                    totalSize = m_imp->m_readBuffer.size()*sizeof(uint8_t);

                                    
                                }

                            }
                            
                            

                           


                        }
                        else
                        {
                            std::cerr << "recv error : RAC module！" << ec.message() << std::endl;
                            m_imp->m_sockPtr->close();
                            break;
                        }
                    }
                    catch (std::exception& e)
                    {
                        std::cerr << e.what() << std::endl;
                        m_imp->m_sockPtr->close();
                        break;
                    }
                }
            }
            
            
            
            );

以下一个附带干货，以前一直不太理解Qt的TCPSocket，下面是底层原理：

http://blog.csdn.net/ying_593254979/article/details/17006507