/
packet_writer.go
99 lines (82 loc) · 1.84 KB
/
packet_writer.go
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package packets
import (
"bytes"
"compress/zlib"
"github.com/mkorman9/go-minecraft-server/types"
"io"
)
type PacketWriter struct {
writer io.Writer
compressionThreshold int
}
func NewPacketWriter(writer io.Writer) *PacketWriter {
return &PacketWriter{
writer: writer,
compressionThreshold: -1,
}
}
func (pw *PacketWriter) SetCompression(threshold int) {
pw.compressionThreshold = threshold
}
func (pw *PacketWriter) SetEncryption(cipherStream *CipherStream) {
pw.writer = cipherStream.WrapWriter(pw.writer)
}
func (pw *PacketWriter) Write(packet *PacketData) error {
var packetData bytes.Buffer
_, err := packet.WriteTo(&packetData)
if err != nil {
return err
}
switch pw.compressionThreshold {
case -1:
// no compression
err = types.WriteVarInt(pw.writer, packetData.Len())
if err != nil {
return err
}
_, err = pw.writer.Write(packetData.Bytes())
if err != nil {
return err
}
default:
// compression
if packetData.Len() >= pw.compressionThreshold {
var zlibBuffer bytes.Buffer
zlibWriter := zlib.NewWriter(&zlibBuffer)
_, err = zlibWriter.Write(packetData.Bytes())
if err != nil {
return err
}
err = zlibWriter.Close()
if err != nil {
return err
}
err = types.WriteVarInt(pw.writer, types.GetVarIntSize(packetData.Len())+zlibBuffer.Len())
if err != nil {
return err
}
err = types.WriteVarInt(pw.writer, packetData.Len())
if err != nil {
return err
}
_, err := pw.writer.Write(zlibBuffer.Bytes())
if err != nil {
return err
}
} else {
err = types.WriteVarInt(pw.writer, packetData.Len()+1)
if err != nil {
return err
}
err = types.WriteVarInt(pw.writer, 0)
if err != nil {
return err
}
_, err := pw.writer.Write(packetData.Bytes())
if err != nil {
return err
}
}
}
return nil
}