学步园

邓工写的一段 c# 串口接收数据的代码,感觉非常的经典,故写了注释,在此标记.

void _sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            int len, retry = 0;
            byte[] rcvData = new byte[2048];
            // 数据超过或等于包的长度
            while (_sp.BytesToRead >= 6)
            {
                //读取一个字节,即包起始字节 0xFE
                while (_sp.BytesToRead > 0)
                {
                    if (Global.Head == _sp.ReadByte())
                    {
                        rcvData[0] = Global.Head;
                        break;
                    }
                }
                if (_sp.BytesToRead < 2)
                {
                    return;
                }
                //读出包长度数据
                _sp.Read(rcvData, 1, 2);
                len = (rcvData[1] << 8) + rcvData[2];
                //包太长
                if (len > 2000)
                {
                    return;
                }
                //如果数据太短,等待1s,以便确定是否数据尚未接收到
                for (; retry < 100 && _sp.BytesToRead < len; retry++)
                {
                    Thread.Sleep(10);
                }
                //数据太短 返回
                if (_sp.BytesToRead < len)
                {
                    return;
                }
                //读取数据
                _sp.Read(rcvData, 3, len);
                //校验数据 处理数据
                if (CheckData(rcvData, len + 3))
                {
                    rcvData[len + 2] = 0;
                    HandelReceivedData(rcvData);
                }
            }
        }

对比先前我写的代码，有好几个优点，更加健壮了

 

        //Serial Received Data
        void _sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            int n = _sp.BytesToRead;
            byte[] buf = new byte[n];
            _sp.Read(buf, 0, n);
            buffer.AddRange(buf);
            while(buffer.Count > 5)
            {
                if(0xFE == buf[0])
                {
                    int len = (buf[1] << 8) + buf[2];
                    //数据区尚未接收完整
                    if (buffer.Count < len) 
                    {
                        break;
                    }
                    byte[] ReceiveBytes = new byte[len];
                    buffer.CopyTo(0, ReceiveBytes, 0, len);
                    if(CheckData(ReceiveBytes))
                    {
                        HandelReceivedData(ReceiveBytes);
                    }
                    buffer.RemoveRange(0, len);
                }
                else
                {
                    buffer.RemoveAt(0);
                }
            }
        }