add Go-style documentation header

msgpack.go

@@ -9,27 +9,38 @@ import (
 	"net"
 )
 
+// IMsgPack is an interface that defined a packager,
+// which carries HeadLen, and provides Pack() and Unpack() method.
 type IMsgPack interface {
+	// Get the head length of the message package.
 	GetHeadLen() uint32
+	// Pack returns bytes stream packed from a message.
 	Pack(Imessage) ([]byte, error)
+	// Unpack returns a message from bytes stream.
 	Unpack() (Imessage, error)
 }
 
+// MsgPack implements the interface IMsgPack,
+// carrying HeadLen and conn for Pack() and Unpack().
 type MsgPack struct {
 	HeadLen uint32
 	conn    net.Conn
 }
 
+// NewMsgPack returns a packager `*MsgPack`
 func NewMsgPack(headlen uint32, conn net.Conn) *MsgPack {
 	return &MsgPack{
 		HeadLen: headlen,
 		conn:    conn,
 	}
 }
 
+// GetHeadLen return HeadLen of the message.
 func (mp *MsgPack) GetHeadLen() uint32 {
 	return mp.HeadLen
 }
+
+// Pack packs a message to bytes stream.
 func (mp *MsgPack) Pack(msg Imessage) ([]byte, error) {
 	buffer := bytes.NewBuffer([]byte{})
 	if err := binary.Write(buffer, binary.LittleEndian, msg.GetDataLen()); err != nil {
@@ -43,6 +54,8 @@ func (mp *MsgPack) Pack(msg Imessage) ([]byte, error) {
 	}
 	return buffer.Bytes(), nil
 }
+
+// Unpack unpacks a certain length bytes stream to a message.
 func (mp *MsgPack) Unpack() (Imessage, error) {
 	headDate := make([]byte, mp.GetHeadLen())
 	_, err := io.ReadFull(mp.conn, headDate)