initial commit

1 files changed, 243 insertions, 0 deletions

diff --git a/classic/packets.go b/classic/packets.go
new file mode 100644
index 0000000..c1f650e
--- /dev/null
+++ b/classic/packets.go
@@ -0,0 +1,243 @@
+package classic
+
+import (
+	"io"
+	"fmt"
+	"bytes"
+	"bufio"
+	"encoding/binary"
+)
+
+type FByte int8
+type FShort int16
+type String [64]byte
+type LevelData [1024]byte
+
+type Packet interface {
+	PacketId() byte
+}
+
+const (
+	NonOpUser = 0x00
+	OpUser = 0x64
+)
+
+type PlayerId struct {
+	Version byte
+	Username String
+	VerificationKey String
+	Ext byte
+}
+func (p *PlayerId) PacketId() byte {
+	return 0x00
+}
+
+type ServerId struct {
+	Version byte
+	ServerName String
+	Motd String
+	UserType byte
+}
+func (p *ServerId) PacketId() byte {
+	return 0x00
+}
+
+type Ping struct {}
+func (p *Ping) PacketId() byte {
+	return 0x01
+}
+
+type LevelInit struct {}
+func (p *LevelInit) PacketId() byte {
+	return 0x02
+}
+
+type LevelDataChunk struct {
+	Length int16
+	Data LevelData
+	PercentComplete byte
+}
+func (p *LevelDataChunk) PacketId() byte {
+	return 0x03
+}
+
+type LevelFinalize struct {
+	Width int16
+	Height int16
+	Length int16
+}
+func (p *LevelFinalize) PacketId() byte {
+	return 0x04
+}
+
+const (
+	BlockDestroyed = iota
+	BlockCreated 
+)
+type ClientSetBlock struct {
+	X, Y, Z int16
+	Mode byte
+	Block byte
+}
+func (p *ClientSetBlock) PacketId() byte {
+	return 0x05
+}
+
+type SetBlock struct {
+	X, Y, Z int16
+	Block byte
+}
+func (p *SetBlock) PacketId() byte {
+	return 0x06
+}
+
+type SpawnPlayer struct {
+	PlayerId int8
+	Username String
+	X, Y, Z FShort
+	Yaw, Pitch byte
+}
+func (p *SpawnPlayer) PacketId() byte {
+	return 0x07
+}
+
+type SetPosFacing struct {
+	PlayerId int8
+	X, Y, Z FShort
+	Yaw, Pitch byte
+}
+func (p *SetPosFacing) PacketId() byte {
+	return 0x08
+}
+
+type UpdatePosFacing struct {
+	UpdatePos
+	UpdateFacing
+}
+func (p *UpdatePosFacing) PacketId() byte {
+	return 0x09
+}
+
+type UpdatePos struct {
+	DeltaX, DeltaY, DeltaZ FByte
+}
+func (p *UpdatePos) PacketId() byte {
+	return 0x0a
+}
+
+type UpdateFacing struct {
+	Yaw, Pitch byte
+}
+func (p *UpdateFacing) PacketId() byte {
+	return 0x0b
+}
+
+type DespawnPlayer struct {
+	PlayerId int8
+}
+func (p *DespawnPlayer) PacketId() byte {
+	return 0x0c
+}
+
+type Message struct {
+	PlayerId int8
+	Message String
+}
+func (p *Message) PacketId() byte {
+	return 0x0d
+}
+
+type DisconnectPlayer struct {
+	Reason String
+}
+func (p *DisconnectPlayer) PacketId() byte {
+	return 0x0e
+}
+
+type UpdateUserType struct {
+	Type byte
+}
+func (p *UpdateUserType) PacketId() byte {
+	return 0x0f
+}
+
+func createPacketType(packetId byte, client bool) Packet {
+	switch packetId {
+	case 0x00:
+		if client {
+			return &ServerId {}
+		} else {
+			return &PlayerId {}
+		}
+	case 0x01: return &Ping {}
+	case 0x02: return &LevelInit {}
+	case 0x03: return &LevelDataChunk {}
+	case 0x04: return &LevelFinalize {}
+	case 0x05: return &ClientSetBlock {}
+	case 0x06: return &SetBlock {}
+	case 0x07: return &SpawnPlayer {}
+	case 0x08: return &SetPosFacing {}
+	case 0x09: return &UpdatePosFacing {}
+	case 0x0a: return &UpdatePos {}
+	case 0x0b: return &UpdateFacing {}
+	case 0x0c: return &DespawnPlayer {}
+	case 0x0d: return &Message {}
+	case 0x0e: return &DisconnectPlayer {}
+	case 0x0f: return &UpdateUserType {}
+	default: return nil
+	}
+}
+
+func readPacket(rd io.Reader, client bool) (Packet, error) {
+	var b [1]byte
+	_, err := io.ReadFull(rd, b[:])
+	if err != nil {
+		return nil, fmt.Errorf("Read packet: %w", err)
+	}
+	packetId := b[0]
+
+	packet := createPacketType(packetId, client)
+	if packet == nil {
+		return nil, fmt.Errorf("Unknown packet type: 0x%02x", packetId)
+	}
+	err = binary.Read(rd, binary.BigEndian, packet)
+	if err != nil {
+		return nil, fmt.Errorf("Read packet: %w", err)
+	}
+	return packet, nil
+}
+
+func SReadPacket(rd io.Reader) (Packet, error) {
+	return readPacket(rd, false)
+}
+
+func CReadPacket(rd io.Reader) (Packet, error) {
+	return readPacket(rd, true)
+}
+
+func WritePacket(wr io.Writer, packet Packet) error {
+	bw := bufio.NewWriter(wr)
+	bw.WriteByte(packet.PacketId())
+	err := binary.Write(bw, binary.BigEndian, packet)
+	if err != nil {
+		return fmt.Errorf("Write packet: %w", err)
+	}
+	return bw.Flush()
+}
+
+func PadString(str string) String {
+	var pstr String
+	copy(pstr[:], []byte(str))
+	if len(str) < 64 {
+		copy(pstr[len(str):], bytes.Repeat([]byte(" "), 64 - len(str)))
+	}
+	return pstr
+}
+
+func UnpadString(pstr String) string {
+	return string(bytes.TrimRight(pstr[:], " "))
+}
+
+func (s String) String() string {
+	return UnpadString(s)
+}