===========
RARC Format
===========

``RARC`` (Revolution Archive) is a proprietary archive file format primarily used in Nintendo GameCube and Wii games.
It acts like a mini file system or a .zip file without compression, storing a hierarchy of directories (Nodes) and files (Entries) along with their actual binary data

Structure
---------

A RARC file is divided into several contiguous sections. Offsets for the internal structures (Nodes, Entries, String Table) are usually relative to the Info Block (which starts at ``0x20``), while the file data offsets are relative to the Data Block starting address

..  figure::    images/rarc/structure.png
    :align:     center
    :height:    700px

    Structure information of a RARC file

Detailed section
----------------

Header & info block
^^^^^^^^^^^^^^^^^^^

The file starts with a ``0x20`` byte header, immediately followed by a ``0x20`` byte info block

* **Header:** Defines the file as a RARC and tells where the data are (and its length)
* **Info block:** Provides the counts and offsets for the arrays (Nodes and Entries) and the string table

Nodes - ``0x10`` bytes
^^^^^^^^^^^^^^^^^^^^^^

A node represents a folder with this structure:

* **Type:** A 4-char string (padded with spaces if less)
* **Name Offset:** Pointer to the directory's name in the String Table
* **Name Hash:** A hash of the name
* **Entry Count:** How many nodes are inside this node
* **First Entry Index:** Offset of the first node

File - ``0x14`` bytes
^^^^^^^^^^^^^^^^^^^^^

A file represents a file or a directory:

- **File ID:** An ID for the file. ``0xFFFF`` if it's a directory
- **Hash**
- Attributes (Type & Name Offset):
    - 8 bits as flags: The entry Type (0x02 for directory, 0x01 for file)
    - Lower 16 bits: The offset to the file name in the String Table
- Data Offset or Index: 
    - If it's a File: This is the offset to the file data (relative to the data block)
    - If it's a Subdirectory: This is the index of the child Node
- Data Size: The size of the file in bytes

Reading
-------

..  figure:: images/rarc/reading.png
    :align: center
    :height: 700px

    Reading process

Writing
-------

..  figure:: images/rarc/writing.png
    :align: center

    Writing process

References
----------

* `Pikmin Technical Knowledge Base`_
* `Custom Mario kart Wiiki`_
* `Luma's Workshop`_
* `Amnoid.de`_



.. _Pikmin Technical Knowledge Base: https://pikmintkb.com/wiki/RARC_file
.. _Custom Mario kart Wiiki: https://wiki.tockdom.com/wiki/RARC_(File_Format)
.. _Luma's Workshop: https://www.lumasworkshop.com/wiki/RARC_(File_Format)
.. _Amnoid.de: http://www.amnoid.de/gc/Rarc.txt