noxnet: Support xfer message decoding.

noxnet/msg_xfer.go

@@ -0,0 +1,228 @@
+package noxnet
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+func init() {
+	RegisterMessage(&MsgXfer{})
+}
+
+type XferCode byte
+
+const (
+	XferStart  = XferCode(0)
+	XferAccept = XferCode(1)
+	XferData   = XferCode(2)
+	XferAck    = XferCode(3)
+	XferClose  = XferCode(4)
+	XferCode5  = XferCode(5)
+	XferCode6  = XferCode(6)
+)
+
+type SubXfer interface {
+	XferOp() XferCode
+	EncodeSize() int
+	Encode(data []byte) (int, error)
+	Decode(data []byte) (int, error)
+}
+
+type MsgXferStart struct {
+	Act   byte
+	Unk1  byte
+	Size  uint32
+	Type  string
+	Token byte
+	Unk5  [3]byte
+}
+
+func (*MsgXferStart) XferOp() XferCode {
+	return XferStart
+}
+
+func (*MsgXferStart) EncodeSize() int {
+	return 138
+}
+
+func (m *MsgXferStart) Encode(data []byte) (int, error) {
+	panic("TODO")
+}
+
+func (m *MsgXferStart) Decode(data []byte) (int, error) {
+	if len(data) < 138 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	m.Act = data[0]
+	m.Unk1 = data[1]
+	m.Size = binary.LittleEndian.Uint32(data[2:6])
+	m.Type = cString(data[6:134])
+	m.Token = data[134]
+	copy(m.Unk5[:], data[135:138])
+	return 138, nil
+}
+
+type MsgXferState struct {
+	Code   XferCode
+	Stream byte
+	Token  byte
+}
+
+func (m *MsgXferState) XferOp() XferCode {
+	return m.Code
+}
+
+func (*MsgXferState) EncodeSize() int {
+	return 2
+}
+
+func (m *MsgXferState) Encode(data []byte) (int, error) {
+	panic("TODO")
+}
+
+func (m *MsgXferState) Decode(data []byte) (int, error) {
+	if len(data) < 2 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	m.Stream = data[0]
+	m.Token = data[1]
+	return 2, nil
+}
+
+type MsgXferData struct {
+	Stream byte
+	Token  byte
+	Chunk  uint16
+	Data   []byte
+}
+
+func (*MsgXferData) XferOp() XferCode {
+	return XferData
+}
+
+func (m *MsgXferData) EncodeSize() int {
+	return 6 + len(m.Data)
+}
+
+func (m *MsgXferData) Encode(data []byte) (int, error) {
+	panic("TODO")
+}
+
+func (m *MsgXferData) Decode(data []byte) (int, error) {
+	if len(data) < 6 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	m.Stream = data[0]
+	m.Token = data[1]
+	m.Chunk = binary.LittleEndian.Uint16(data[2:4])
+	sz := int(binary.LittleEndian.Uint16(data[4:6]))
+	if sz < 0 || sz > len(data[6:]) {
+		return 0, io.ErrUnexpectedEOF
+	}
+	m.Data = make([]byte, sz)
+	copy(m.Data, data[6:6+sz])
+	return 6 + sz, nil
+}
+
+type MsgXferAck struct {
+	Stream byte
+	Token  byte
+	Chunk  uint16
+}
+
+func (*MsgXferAck) XferOp() XferCode {
+	return XferAck
+}
+
+func (*MsgXferAck) EncodeSize() int {
+	return 4
+}
+
+func (m *MsgXferAck) Encode(data []byte) (int, error) {
+	panic("TODO")
+}
+
+func (m *MsgXferAck) Decode(data []byte) (int, error) {
+	if len(data) < 4 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	m.Stream = data[0]
+	m.Token = data[1]
+	m.Chunk = binary.LittleEndian.Uint16(data[2:4])
+	return 4, nil
+}
+
+type MsgXferClose struct {
+	Stream byte
+}
+
+func (*MsgXferClose) XferOp() XferCode {
+	return XferClose
+}
+
+func (*MsgXferClose) EncodeSize() int {
+	return 1
+}
+
+func (m *MsgXferClose) Encode(data []byte) (int, error) {
+	panic("TODO")
+}
+
+func (m *MsgXferClose) Decode(data []byte) (int, error) {
+	if len(data) < 1 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	m.Stream = data[0]
+	return 1, nil
+}
+
+type MsgXfer struct {
+	Msg SubXfer
+}
+
+func (*MsgXfer) NetOp() Op {
+	return MSG_XFER_MSG
+}
+
+func (m *MsgXfer) EncodeSize() int {
+	return 1 + m.Msg.EncodeSize()
+}
+
+func (m *MsgXfer) Encode(data []byte) (int, error) {
+	if len(data) < m.EncodeSize() {
+		return 0, io.ErrShortBuffer
+	}
+	data[0] = byte(m.Msg.XferOp())
+	n, err := m.Msg.Encode(data[1:])
+	if err != nil {
+		return 0, err
+	}
+	return 1 + n, nil
+}
+
+func (m *MsgXfer) Decode(data []byte) (int, error) {
+	if len(data) < 1 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	typ := XferCode(data[0])
+	switch typ {
+	case XferStart:
+		m.Msg = &MsgXferStart{}
+	case XferAccept, XferCode5, XferCode6:
+		m.Msg = &MsgXferState{Code: typ}
+	case XferData:
+		m.Msg = &MsgXferData{}
+	case XferAck:
+		m.Msg = &MsgXferAck{}
+	case XferClose:
+		m.Msg = &MsgXferClose{}
+	default:
+		return 0, fmt.Errorf("unexpected xfer message subtype: 0x%x", typ)
+	}
+	n, err := m.Msg.Decode(data[1:])
+	if err != nil {
+		return 0, err
+	}
+	return 1 + n, nil
+}