CLI & Packet System

CLI Architecture

The cli module is the user-facing entry point, built with picocli.

Command Structure

• Main — creates a CommandLine instance and executes.
• ExtractCommand — parent command (extract), defines --help and --version. No logic, just routes to subcommands.
• ExtractResourceCommand — the primary subcommand (resource). Handles file/directory traversal, deserialization, and output.
• ExtractPacketCommand — secondary subcommand (packet). Handles network packet file deserialization ( experimental).

Resource Extraction Arguments

Argument	Flag	Type	Default	Description
Client root folder	(positional 0)	Path	required	DDON installation root (e.g., D:\DDON_03040008)
Translation file	(positional 1)	Path	required	GMD translation CSV file
Input path	(positional 2)	Path	required	File or directory to process
Output format	-f, --format	SerializationFormat	json	json or yaml
Write to file	-o	boolean	false	Output to file instead of console
Meta information	-m, --meta-information	boolean	false	Enrich output with resolved names/translations
Unpack archives	-u, --unpack-archives	boolean	false	Decompress and decrypt .arc files
Archives only	-x, --unpack-archives-exclusively	boolean	false	Only process .arc files, skip others
Parallel	-p, --parallel	boolean	true	Run file processing in parallel
Export textures	-t, --export-textures	boolean	false	Export .tex files as .dds
Ignore extensions	-i, --ignore-extensions	Set<String>	empty	Comma-separated extensions to skip

Version Detection Flow

File Processing Pipeline

Utility Classes

Class	Purpose
ArchiveUnpacker	Extracts files from deserialized Archive objects to disk, creating the directory structure.
FileChangeDetector	Tracks file checksums to detect changes and avoid redundant reprocessing.
ResourceFileFilter	Filters files by supported extensions (ClientResourceFileExtension.getSupportedFileExtensions()), respects the ignore list.
TextureExporter	Converts deserialized Texture objects to DDS format using DirectDrawSurfaceSerializer and writes them to disk.

Native Packaging

The cli module's build.gradle configures JLink + jpackage:

jlink options: --strip-debug, --compress zip-6, --no-header-files, --no-man-pages
jpackage:      --win-console, skipInstaller = true
Application:   mainModule = org.sehkah.ddon.tools.extractor.cli
               mainClass  = org.sehkah.ddon.tools.extractor.cli.Main

This produces a self-contained executable (ddon-extractor.exe on Windows) with an embedded JRE — no system Java installation required.

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Packet System

The packet system mirrors the resource deserialization architecture but operates on captured network traffic instead of client files. It is experimental and currently only supports Season 3 with 2 packet types.

Architecture

Packet Naming Convention

DDON uses a directional naming convention:

Prefix	Direction	Meaning
C2L	Client → Login Server	Login-phase packets
L2C	Login Server → Client	Login-phase responses
C2S	Client → Game Server	Gameplay packets
S2C	Game Server → Client	Gameplay responses

Registered Packets (Season 3)

Identifier	Group	ID	SubID	Source	Deserializer
C2L_LOGIN_REQ	0	1	1	0x00	C2LLoginReqBufferDeserializer
L2C_LOGIN_RES	0	1	2	0x34	L2CLoginResBufferDeserializer

Packet vs. Resource Differences

Aspect	Resources	Packets
Byte order	Little-endian	Big-endian
Header	Magic string + version	Group + ID + SubID + source
Lookup key	Pair<Extension, FileHeader>	PacketHeader
Manager	ClientResourceFileManager	PacketManager
Base class	Resource	Packet
Season support	All three	Season 3 only
Deserializer instantiation	Direct constructor	Reflection via Class.getConstructor(GamePacket.class).newInstance(this)

Packet Extraction Arguments

Argument	Flag	Type	Default	Description
Client root folder	(positional 0)	Path	required	DDON client resource path
Input path	(positional 1)	Path	required	Packet file or directory
Output format	-f, --format	SerializationFormat	json	json or yaml
Write to file	-o	boolean	false	Output to file
Meta information	-m, --meta-information	boolean	false	Enrich output
Parallel	-p, --parallel	boolean	true	Parallel processing

MetaInformation on Packets

The PacketHeader class uses @MetaInformation annotations on enriched fields:

@MetaInformation
private final PacketGroup packetGroup;      // resolved group name
@MetaInformation
private final PacketSubType packetSubType;  // resolved sub-type
@MetaInformation
private final PacketType packetType;        // resolved type name
@MetaInformation
private PacketIdentifier identifier;        // human-readable enum name

Similarly, Packet.size and Packet.dataSize are marked @MetaInformation as they are wire-level metadata not part of the logical packet payload.