init

net/packet/packet.go

@@ -0,0 +1,141 @@
+package packet
+
+import (
+	"bytes"
+	"compress/zlib"
+	"fmt"
+	"io"
+)
+
+// Packet define a net data package
+type Packet struct {
+	ID   byte
+	Data []byte
+}
+
+//Marshal generate Packet with the ID and Fields
+func Marshal(ID byte, fields ...FieldEncoder) (pk Packet) {
+	pk.ID = ID
+
+	for _, v := range fields {
+		pk.Data = append(pk.Data, v.Encode()...)
+	}
+
+	return
+}
+
+//Scan decode the packet and fill data into fields
+func (p Packet) Scan(fields ...FieldDecoder) error {
+	r := bytes.NewReader(p.Data)
+	for _, v := range fields {
+		err := v.Decode(r)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Pack 打包一个数据包
+func (p *Packet) Pack(threshold int) (pack []byte) {
+	data := []byte{p.ID}           //data
+	data = append(data, p.Data...) //data
+
+	if threshold > 0 { //是否启用了压缩
+		if len(data) > threshold { //是否需要压缩
+			Len := len(data)
+			VarLen := VarInt(Len).Encode()
+			data = Compress(data)
+
+			pack = append(pack, VarInt(len(VarLen)+len(data)).Encode()...)
+			pack = append(pack, VarLen...)
+			pack = append(pack, data...)
+		} else {
+			pack = append(pack, VarInt(int32(len(data)+1)).Encode()...)
+			pack = append(pack, 0x00)
+			pack = append(pack, data...)
+		}
+	} else {
+		pack = append(pack, VarInt(int32(len(data))).Encode()...) //len
+		pack = append(pack, data...)
+	}
+
+	return
+}
+
+// RecvPacket recive a packet from server
+func RecvPacket(r io.ByteReader, useZlib bool) (*Packet, error) {
+	var len int
+	for i := 0; i < 5; i++ { //读数据前的长度标记
+		b, err := r.ReadByte()
+		if err != nil {
+			return nil, fmt.Errorf("read len of packet fail: %v", err)
+		}
+		len |= (int(b&0x7F) << uint(7*i))
+		if b&0x80 == 0 {
+			break
+		}
+	}
+
+	if len < 1 {
+		return nil, fmt.Errorf("packet length too short")
+	}
+
+	data := make([]byte, len) //读包内容
+	var err error
+	for i := 0; i < len; i++ {
+		data[i], err = r.ReadByte()
+		if err != nil {
+			return nil, fmt.Errorf("read content of packet fail: %v", err)
+		}
+	}
+
+	//解压数据
+	if useZlib {
+		return UnCompress(data)
+	}
+
+	return &Packet{
+		ID:   data[0],
+		Data: data[1:],
+	}, nil
+}
+
+// UnCompress 读取一个压缩的包
+func UnCompress(data []byte) (*Packet, error) {
+	reader := bytes.NewReader(data)
+
+	var sizeUncompressed VarInt
+	if err := sizeUncompressed.Decode(reader); err != nil {
+		return nil, err
+	}
+
+	uncompressData := make([]byte, sizeUncompressed)
+	if sizeUncompressed != 0 { // != 0 means compressed, let's decompress
+		r, err := zlib.NewReader(reader)
+
+		if err != nil {
+			return nil, fmt.Errorf("decompress fail: %v", err)
+		}
+		_, err = io.ReadFull(r, uncompressData)
+		if err != nil {
+			return nil, fmt.Errorf("decompress fail: %v", err)
+		}
+		r.Close()
+	} else {
+		uncompressData = data[1:]
+	}
+	return &Packet{
+		ID:   uncompressData[0],
+		Data: uncompressData[1:],
+	}, nil
+}
+
+// Compress 压缩数据
+func Compress(data []byte) []byte {
+	var b bytes.Buffer
+	w := zlib.NewWriter(&b)
+	w.Write(data)
+	w.Close()
+	return b.Bytes()
+}