DRAFT: Initial working beta multiplexing. Version based routing, not hostname

mcproto/beta_decode.go

@@ -0,0 +1,56 @@
+package mcproto
+
+import (
+	"encoding/binary"
+	"io"
+	"unicode/utf16"
+)
+
+func VersionToProtocolVersion(versionClient string) int {
+	switch versionClient {
+	// b1.4_01 and prior require additional troubleshooting
+	case "b1.5", "b1.5_01":
+		return 11
+	case "b1.6", "b1.6.1", "b1.6.2", "b1.6.3", "b1.6.4", "b1.6.5", "b1.6.6":
+		return 13
+	case "b1.7", "b1.7.2", "b1.7.3":
+		return 14
+	case "b1.8.1", "b1.8":
+		return 17
+	case "1.0":
+		return 22
+	case "1.1":
+		return 23
+	case "1.2.1", "1.2.2", "1.2.3":
+		return 28
+	case "1.2.4", "1.2.5":
+		return 29
+	// 1.3.1 onwards require additional troubleshooting
+	default:
+		return -1
+	}
+}
+
+// readBetaString reads a legacy MC string: [Short Length] [UTF-16BE Chars...]
+func ReadBetaString(r io.Reader) (string, []byte, error) {
+	// Read Length (Short)
+	var length int16
+	if err := binary.Read(r, binary.BigEndian, &length); err != nil {
+		return "", nil, err
+	}
+
+	// Read Characters (Length * 2 bytes)
+	byteData := make([]byte, length*2)
+	if _, err := io.ReadFull(r, byteData); err != nil {
+		return "", nil, err
+	}
+
+	// Decode UTF-16BE to Go String
+	shorts := make([]uint16, length)
+	for i := 0; i < int(length); i++ {
+		shorts[i] = binary.BigEndian.Uint16(byteData[i*2 : i*2+2])
+	}
+
+	// Return both the string (for logic) and raw bytes (for replaying)
+	return string(utf16.Decode(shorts)), byteData, nil
+}