同步代码

decoder/decode_omc.go

@@ -0,0 +1,88 @@
+package decoder
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/hex"
+	"github.com/aceld/zinx/ziface"
+	"github.com/aceld/zinx/zlog"
+	"math"
+)
+
+//ffff 01 00999999 000a 68656c6c6f2074657374
+// +---------------+---------------+--------------------+----------------+-------------------
+// |    开始标志     |     type       |     秒时间戳       |  长度           |     消息体
+// | 0xffff(2byte) |  uint8(1byte)  |     uint32(4byte) |  uint16(2byte) |    bytes(N byte)
+// +---------------+---------------+--------------------+----------------+-------------------
+
+const OmcMsgHeaderSize = 9 //表示OMC空包长度
+
+type OmcDecoder struct {
+	StartSign uint16
+	MsgType   uint8
+	TimeStamp uint32
+	LenOfBody uint16
+	Value     []byte
+}
+
+func NewOmcDecoder() ziface.IDecoder {
+	return &OmcDecoder{}
+}
+
+func (omc *OmcDecoder) GetLengthField() *ziface.LengthField {
+	return &ziface.LengthField{
+		MaxFrameLength:      math.MaxUint16 + 9,
+		LengthFieldOffset:   7,
+		LengthFieldLength:   2,
+		LengthAdjustment:    0,
+		InitialBytesToStrip: 0,
+		//注意现在默认是大端，使用小端需要指定编码方式
+		Order: binary.BigEndian,
+	}
+}
+
+func (omc *OmcDecoder) decode(data []byte) *OmcDecoder {
+	ltvData := OmcDecoder{}
+	ltvData.StartSign = binary.BigEndian.Uint16(data[0:2])
+	ltvData.MsgType = data[2]
+	ltvData.TimeStamp = binary.BigEndian.Uint32(data[3:7])
+	ltvData.LenOfBody = binary.BigEndian.Uint16(data[7:9])
+	//Determine the length of V. (确定V的长度)
+	ltvData.Value = make([]byte, ltvData.LenOfBody)
+
+	//5. Get V
+	binary.Read(bytes.NewBuffer(data[OmcMsgHeaderSize:OmcMsgHeaderSize+ltvData.LenOfBody]), binary.BigEndian, ltvData.Value)
+
+	return &ltvData
+}
+
+func (omc *OmcDecoder) Intercept(chain ziface.IChain) ziface.IcResp {
+	//1. Get the IMessage of zinx
+	iMessage := chain.GetIMessage()
+	if iMessage == nil {
+		// Go to the next layer in the chain of responsibility
+		return chain.ProceedWithIMessage(iMessage, nil)
+	}
+
+	//2. Get Data
+	data := iMessage.GetData()
+	zlog.Ins().DebugF("omc-RawData size:%d data:%s\n", len(data), hex.EncodeToString(data))
+
+	// (读取的数据不超过包头，直接进入下一层)
+	if len(data) < OmcMsgHeaderSize {
+		return chain.ProceedWithIMessage(iMessage, nil)
+	}
+
+	//4.  Decode
+	ltvData := omc.decode(data)
+	zlog.Ins().DebugF("omc-decode  %v", ltvData)
+
+	// (将解码后的数据重新设置到IMessage中, Zinx的Router需要MsgID来寻址)
+	iMessage.SetDataLen(uint32(ltvData.LenOfBody))
+	iMessage.SetMsgID(uint32(ltvData.MsgType))
+	iMessage.SetData(ltvData.Value)
+
+	//6. Pass the decoded data to the next layer.
+	// (将解码后的数据进入下一层)
+	return chain.ProceedWithIMessage(iMessage, *ltvData)
+}