包名重构

protocol/bt/peer/message/message.go

@@ -0,0 +1,96 @@
+package message
+
+import (
+	"encoding/binary"
+)
+
+// message ID
+type ID byte
+
+const (
+	IdChoke ID = iota
+	IdUnchoke
+	IdInterested
+	IdNotinterested
+	IdHave
+	IdBitfield
+	IdRequest
+	IdPiece
+	IdCancel
+)
+
+/*type Message struct {
+	Length  uint32
+	ID      MessageID
+	Payload []byte
+}*/
+type Message struct {
+	Length uint32
+	ID     ID
+}
+
+func (msg *Message) Encode() []byte {
+	buf := make([]byte, 5)
+	binary.BigEndian.PutUint32(buf, msg.Length)
+	buf[4] = byte(msg.ID)
+	return buf
+}
+
+func (msg *Message) Decode(buf []byte) {
+	msg.Length = binary.BigEndian.Uint32(buf)
+	msg.ID = ID(buf[4])
+}
+
+type Serialize interface {
+	Encode() []byte
+	Decode(buf []byte) Serialize
+}
+
+/*func NewMessage(id MessageID, payload []byte) *Message {
+	message := &Message{ID: id, Payload: payload}
+	if id == Keepalive {
+		message.Length = 0
+	} else {
+		message.Length = uint32(len(payload) + 1)
+	}
+	return message
+}
+
+func (msg *Message) Encode() []byte {
+	if msg.ID == Keepalive {
+		return make([]byte, 4)
+	} else {
+		buf := make([]byte, 5+len(msg.Payload))
+		binary.BigEndian.PutUint32(buf, msg.Length)
+		buf[4] = byte(msg.ID)
+		copy(buf[5:], msg.Payload[:])
+		return buf
+	}
+}
+
+func (msg *Message) Decode(buf []byte) {
+	msg.Length = binary.BigEndian.Uint32(buf)
+	if msg.Length == 0 {
+		msg.ID = -1
+	} else {
+		msg.ID = MessageID(buf[4])
+		if msg.Length > 4 {
+			msg.Payload = buf[5:]
+		}
+	}
+}*/
+
+// Message protocol
+// Length prefix| message ID | Payload
+// 4-byte       | 1-byte     | remaining bytes
+// 100          | 5          | 99-bytes
+// https://wiki.theory.org/index.php/BitTorrentSpecification#Messages
+func SplitMessage(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if !atEOF && len(data) > 4 {
+		length := int(binary.BigEndian.Uint32(data))
+		if len(data)-4 >= length {
+			return length + 4, data[:length+4], nil
+		}
+	}
+	return
+}