BUN file
BUN files (short for Bundle files) are a Binary Large Object (BLOB) archive format used in Pikmin 1. ANM files (likely short for Animation Folder) use the structure of BUN files as well. With minimal metadata, the bundle archive was likely used to reduce load time by packing several files into one[unsure]. The purpose they serve is different from the ARC+DIR file pair system, however, as all of the files within a bundle are unpacked into RAM as soon as they one is loaded, as shown by the OpenGl / Dolphin System.
File Structure
The bundle file is very simple. There is a header, followed by a repeating struct for every file contained within the BUN. Each struct has a subheader and file contained within it.
Here is root\dataDir\bosses\mizu\mizu.anm annotated for reference.
| Offset | Size | Purpose |
|---|---|---|
| 0x00 | 4 | Number of structs |
| Offset | Size | Purpose |
|---|---|---|
| 0x00 | 4 | File Content Indicator |
| 0x04 | 4 | Enclosed File Size |
| 0x08 | 4 | Mock-Directory String Length |
| 0x0c | 0x08 value | Mock-Directory Path |
| 0x0c + 0x08 value | 0x04 value | Enclosed File |
Mock-Directory
Similar to the ARC+DIR file pair system, the bundle archive emulates a folder path. When the file is unpacked in-game, it is assumed that whatever code is responsible treats the contents of the bundle files as if they were in the folder path described, starting from the root of the disc.
File Content Indicator
The file content indicator is a seemingly vestigial function. However, it has been observed that it always is set to specific values that reflect the type of file contained within the struct.
