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( * );
 
                         size_t bytes_transferred = m_imp->m_sockPtr->read_some(boost::asio::buffer(tmpreadBuffer), ec);
 
                         std::cout << "Byte Transfered:" << bytes_transferred << "\n";
 
                         if (!ec)
                         {
 
                             if (bytes_transferred == )  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 << "\n";
 
                                     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