Editing Paired ARC+DIR file

'''ARC''' files (likely short for '''Archive''') and '''DIR''' files (technically short for '''Bundle''', though '''Directory''' makes more sense and avoids conflict with [[BUN file|'''BUN''' files]]) are two peas in a pod, together representing one of the many Binary Large Object (BLOB) archive formats used in ''[[Pikmin]]''.  Together, they will henceforth be referred to as the ''paired ARC+DIR file'' archive.

With minimal metadata, {{unsure|the paired ARC+DIR file archive was likely used to reduce load time by packing several files into one}}.  The purpose it serves is different from the [[BUN file|bundle]] archive, however, {{unsure|as standalone files within the archive can be unpacked independently of the files before it}}.  This makes the paired ARC+DIR file useful for archiving large directories with varied purposes.

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== File structure ==
As mentioned before, the paired ARC+DIR file archive consists of two files: the mock-directory (DIR) and the BLOB archive (ARC).  Think of the mock-directory as a map to navigate through the BLOB archive.

=== DIR ===
DIR files consist of a header followed by a repeating struct for each mock-filepath.

Here is <code>/dataDir/archives/pelletsbin.dir</code> annotated for reference.

[[File:DIR_file_documentation.png]][[File:Minty_Meeo_Documentation_Legend.png]]

{| class="wikitable" 
|+ Header
! Offset	|| Size		|| Purpose
|-
| 0x00		|| 4 		|| Size of DIR file	
|-
| 0x04		|| 4 		|| Number of structs	
|-
|}

{| class="wikitable" 
|+ Mock-directory struct
! Offset	|| Size		|| Purpose
|-
| 0x00		|| 4 		|| Offset of file in ARC	
|-
| 0x04		|| 4 		|| Size of file in ARC		
|-
| 0x08		|| 4	 	|| Mock-directory string length	
|-
| 0x0C		|| 0x08 value 	|| Mock-directory path		
|-
|}

==== Mock-directory ====
The DIR file emulates filepaths.  When a file is unpacked in-game, it is assumed that whatever code is responsible treats the entry in the DIR file as a legitimate filepath on the disc, starting from the root.

=== ARC ===
Here is <code>/dataDir/archives/pelletsbin.arc</code> annotated to demonstrate searching the BLOB archive.  Without the DIR file as a guide, the only way you could possibly differentiate between files would be with the <code>0xCC</code> padding between files.

[[File:ARC_file_documentation.png]][[File:Minty_Meeo_Documentation_Legend.png]]

==== <code>0xCC</code> padding ====
Files in the ARC are always padded out to have an amount of bytes that is a multiple of 32.  These bytes are not included in the file size recorded in the DIR for each file. It's like this because its an optimisation for loading data into the Gamecubes data registers.

== Extra information ==
Every paired ARC+DIR file archive has an uncompressed copy elsewhere on the disc.
* In <code>/dataDir/tekis</code> and <code>/dataDir/bosses</code>, a file named <code>arc_all.ini</code> can be found.  These INI files holds nothing, but give us a hint at how the developer's archiving tool functioned.
* It is unknown if every file in the archives is identical to its uncompressed sister file.
In the [[OpenGL / Dolphin System]], many files are not read from the paired ARC+DIR file archives like they are in the final game, and are instead read from the un-archived versions.  

Paired ARC+DIR file archives that have "bin" in their filename curiously only contain the '''BIN''' files from their respective directory.

The <code>log.txt</code> files left in the root of [[Pikmin|''Pikmin'' versions USA Demo, USA v1.00, and JPN v1.02]] detail the plugin "[[OpenGL / Dolphin System|plugTexConv]]" creating a paired ARC+DIR file archive.

{{Credits|[[User:Minty_Meeo|Minty_Meeo]]}}

[[Category:Pikmin]]
[[Category:File formats]]