'''''U8 Archive''''' is a hierarchical archive format developed by Nintendo during the GameCube era and was predominantly used on the Wii.

== Titles using U8 Archive ==
{| class="wikitable"
|+
!Game
!Usage
!Platforms
!Year
|-
|Sonic Heroes
| rowspan="2" |Used as the packed file system.
|PlayStation 2
|2003
|-
|[[Sonic the Hedgehog (2006)]]
|Xbox 360, PlayStation 3
|2006
|-
|Sonic and the Secret Rings
| rowspan="2" |Used for operating system only.
| rowspan="3" |Wii
|2007
|-
|Sonic and the Black Knight
|2009
|-
|[[Sonic Colors]]
|Used as the packed file system.
|2010
|-
|Sonic Colors: Ultimate
|Used as the packed file system for data not covered by Godot.
|Windows, Xbox One, PlayStation 4, Switch
|2021
|}

== Specification ==
=== Header ===
The header consists of the following data structure:
{| class="wikitable"
|+Length: 0x20
!Offset
!Type
!Name
!Description
|-
|0x00
|UInt32
|Signature
|Always 0x55AA382D (big-endian) or 0x2D38AA55 (little-endian).
|-
|0x04
|UInt32
|FSTableOffset
|The offset of the file system table.
|-
|0x08
|UInt32
|FSTableLength
|The length of the file system table (including the string pool).
|-
|0x0C
|UInt32
|DataOffset
|The offset of the file data.
|-
|0x10
|UInt32[4]
|Reserved
|These fields appear to be populated in archives for '''Sonic the Hedgehog (2006)''', but this is bogus data from uninitialised memory and should be ignored. For the sake of tooling heuristics, writing <code>0xE4F91300</code> (big-endian) to index 0 and <code>0x78013800</code> (big-endian) to index 3 would be ideal for detecting whether an archive is from that game specifically.
|}

=== File System ===
The file system consists of an array of the following data structure:
{| class="wikitable"
|+Length: 0x0C (or 0x10 for Sonic the Hedgehog (2006))
!Offset
!Type
!Name
!Description
|-
|0x00
|Boolean (UInt8)
|IsDirectory
|Determines whether this node is a directory.
|-
|0x01
|UInt24
|NameOffset
|The offset of this node's name in the string pool. If root, always zero.
|-
|0x04
|Union (UInt32, UInt32)
|DataOffset, ParentIndex
|
{| class="wikitable"
|+
|File
|The offset of this file's data.
|-
|Directory
|The index of the parent node for this directory. If root, always zero.
|}
|-
|0x08
|Union (UInt32, UInt32)
|Length, NodeCount
|
{| class="wikitable"
|+
|File
|The length of this file's data.
|-
|Directory
|The total number of nodes in this directory. If root, the total number of nodes in this archive.
|}
|-
|0x0C
|UInt32
|UncompressedLength
|This field is unique to archives for '''Sonic the Hedgehog (2006)'''.
{| class="wikitable"
|+
|File
|The uncompressed length of this file's data. This field can be set to zero to disable compression for this file, allowing its data to be stored uncompressed.
|-
|Directory
|Undefined. Much like the reserved bytes in the header, this field will appear to be populated, but again, this is bogus data from uninitialised memory.
|}
|}
The total number of nodes to read is determined by the root node's <code>NodeCount</code> field. As this is a hierarchical file system, nodes should be read recursively to build the file system correctly.

The first node '''must''' be a root node defined as a directory, with the <code>NodeCount</code> field set to the total number of nodes in the archive. This is necessary for determining the length of the file system table.

=== String Pool ===
The string pool offset can be calculated after reading the root node and using the following expression:<syntaxhighlight lang="text">
FSTableOffset + (Root.NodeCount * FSNodeSize) // FSNodeSize = 0x0C (or 0x10 for Sonic the Hedgehog (2006))
</syntaxhighlight>Each string in the pool is ASCII-encoded and null-terminated, the offsets to which are relative to the start of the pool.

The string pool '''must''' have a single null terminator at the beginning for the root node, as it does not have a name.

=== File Data ===
Files are aligned by 32 bytes per file after the string pool.

In '''Sonic the Hedgehog (2006)''', files may be compressed using [[wikipedia:Zlib|zlib]]. This compression is optional, and files can be stored uncompressed so long as <code>UncompressedLength</code> is set to zero.
[[Category:File Formats]]

Sonic the Hedgehog (2006)

2026-05-03T18:55:20Z

Hyper:

== Guides ==
=== Level Editing ===
* [[How To Use Sonic GLvl with Sonic '06|Sonic GLvl]]

== Documentation ==
=== General ===
* [[Sonic the Hedgehog (2006) File System|File System]]

=== Graphics ===
* [[Sonic the Hedgehog (2006) Shaders|Shaders]]
* [[Texture Tags]]

=== Player ===
* [[Player State IDs]]
* [[Player State Maps]]

=== Script ===
* [[Sonic the Hedgehog (2006) Script Functions|Script Functions]]
* [[Mission Parameters]]
* [[Player Parameters]]
* [[Scene Parameters]]

=== Stage ===
* [[Section IDs]]

== Formats ==

=== Acroarts ===
* [[Acroarts Resource]] (*.mab)
* [[DirectDraw Map]] (*.ddm)

=== Archive ===
* [[U8 Archive|Arc File]] (*.arc)

=== Audio ===
* [[Sound Bank]] (*.sbk)

=== Event ===
* [[Event Playbook]] (*.epb)
* [[Time Event]] (*.tev)

=== Kynapse ===
* [[Kynapse Big File]] (*.kbf)
* [[Kynogon A* Data]] (*.adl)
* [[Kynogon Find Nearest Data]] (*.fdl)
* [[Kynogon Path Cost Data]] (*.cdl)
* [[Kynogon Path Way]] (*.pwl)
* [[Kynogon Spatial Graph]] (*.pdl)

=== Mesh ===
* [[Land Collision]] (collision.bin)
* [[Reflection Area]] (*.rab)
* [[Spline Path]] (*.path)
* [[Spline Path (Old)]] (*.bin)

=== [[NN Chunk Format|Ninja]] ===
* Camera (*.xnc, *.xnd)
* Camera Motion (*.xnd)
* Effect List (*.xne)
* Light (*.xni, *.xnl)
* Light Motion (*.xni)
* Material Motion (*.xnv)
* Morph Motion (*.xnf)
* Morph Target (*.xng)
* Node Motion (*.xnm)
* Node Name (*.xna)
* Object (*.xno)
* Texture List (*.xnt)

=== Parameter ===
* [[Enemy Parameter List]] (ScriptParameter.bin)
* [[Enemy Shot Parameter List]] (ShotParameter.bin)
* [[Object Explosion Parameter List]] (Explosion.bin)
* [[Object Physics Parameter List]] (Common.bin)
* [[Package]] (*.pkg)
* [[Path Object Parameter List]] (PathObj.bin)

=== Particle ===
* [[Particle Container]] (*.plc)
* [[Particle Effect Bank]] (*.peb)
* [[Particle Global Settings]] (*.pgs)
* [[Particle Texture Bank]] (*.ptb)

=== Placement ===
* [[Prop Library]] (*.prop)
* [[Stage Set]] (*.set)

=== Save ===
* [[Save Data]] (SonicNextSaveData.bin)

=== Script ===
* [[Lua Binary]] (*.lub)

=== Text ===
* [[Text Book]] (*.mst)
* [[Text Font Map]] (*.ftm)
* [[Text Font Picture]] (*.pft)
* [[Text Font Proportion]] (*.pfi)

Hyper:

{{Notice|type=warn|content=This page is unfinished.}}{{ToolInfobox|title=PackCpk|author=Skyth|website=https://github.com/blueskythlikesclouds/SkythTools|download=https://github.com/blueskythlikesclouds/SkythTools/tree/master/Common}}

'''PackCpk''' is a SkythTools tool designed to extract and pack CPK files.
[[Category:Tools]]