KIWAD Archives
The "KingsIsle Where's All the Data?" format (name guessed) is a custom file format used by the
game to bundle all kinds of game assets in archives. The format presumably draws inspiration from
the original Doom WAD format and similarly uses .wad as
file extension.
Archives consist of a header, followed by the file table, and lastly the encoded file data as described in the table. All data is assumed to be encoded in little-endian byteorder unless stated otherwise.
Header
The header may consume 13 or 14 bytes in size and outlines the amount of files to expect in the archive:
| Offset | Type | Description |
|---|---|---|
| 0x0 | string | "KIWAD" as an ASCII string |
| 0x5 | uint32 | The KIWAD version that is used |
| 0x9 | uint32 | An integer holding the amount of files in the archive |
| 0xD | uint8 | optional; WAD Flags if version >= 2 |
Flags
On file format versions >= 2, the header encodes a mask of configuration bits which should be
treated as implementation-defined for the most parts; KIWAD implementations can safely ignore
these bit flags and always write 0.
This is how the official client uses them:
| Bit | Name |
|---|---|
| 0 | Memory-maps the file view |
| 1 | Prefetches the file handle |
File table
This table consists of n repetitions of the file structure, where n is the number
of archived files as encoded in the header.
File
This structure denotes the metadata of an encoded file, needed for extraction and validation:
| Offset | Type | Description |
|---|---|---|
| 0x0 | uint32 | The start offset of the file data in the archive |
| 0x4 | uint32 | The size of the uncompressed file in bytes |
| 0x8 | int32 | The size of the compressed file in bytes |
| 0xC | bool | Whether the encoded file data is compressed |
| 0xD | uint32 | The checksum of the file data |
| 0x11 | uint32 | The length of the file's path in the archive in bytes |
| 0x15 | char[] | The archive file name as a null-terminated string |
Compression
If a file is compressed, the corresponding file table entry encodes its uncompressed size and the compressed size and the data will run through zlib.
If a file is stored uncompressed, -1 (or 0xFFFF_FFFF) will be written for its
compressed size.
Notably, only .mp3 and .ogg files are shipped uncompressed in official archives
by KingsIsle.
Checksums
The checksum of a file is calculated by CRC32 using the polynomial 0x4C11DB7 and
reversed input and output values:
import crcengine
crc32 = crcengine.create(0x04C11DB7, 32, 0, xor_out=0)
assert crc32(b"KIWAD") == 4265429514