# QDA Package Format #

The QDA package format is used by BUSTER in all his Windows games,
including *Guardian of Paradise* and *Akuji the Demon*.

Like Fastfile, it condenses a directory full of images down to one
package to be used as a mini-filesystem by the game.


## File Format ##

The format begins with a 0x100 byte header, then begins a pattern
where it repeats 268 byte chunks. Its maximum storable filename is
255 bytes. All values are stored in little endian ordering:

<pre>Null [4 bytes, long]
ID Tag: 'QDA0' [4 bytes, string]
File count [4 bytes, long]
(pad up to 0x100)
(file loop)
  File offset [4 bytes, long]
  File size [4 bytes, long]
  Repeat file size [4 bytes, long (unconfirmed)
  File name [256 bytes, string]
(end loop)</pre>

Despite not being certain about the repeated file size, I was able to
successfully rebuild QDA packages from scratch and have them work in
BUSTER's game by copying the file size to both offsets.

## Proof of Concept ##

A proof of concept extractor is shown below:

<pre class="line-numbers"><code class="language-php">$fd = fopen('bmp.qda', 'rb');
fseek($fd, 0x4, SEEK_SET);
if(fread($fd, 4)!="QDA0") die;
list($junk, $count) = unpack('l*', fread($fd, 4));
$offset = array();
$filesize = array();
$unknown = array();
$name = array();
for($i=0; $i< $count; $i++) {
  list($junk, $offset[$i]) = unpack('l*', fread($fd, 4));
  list($junk, $filesize[$i]) = unpack('l*', fread($fd, 4));
  list($junk, $unknown[$i]) = unpack('l*', fread($fd, 4));
  $filename[$i] = rtrim(fread($fd, 256));
}
for($i=0; $i<$count; $i++) {
  $fo = fopen($filename[$i], 'w');
  fseek($fd, $offset[$i], SEEK_SET);
  fputs($fo, fread($fd, $filesize[$i]));
  fclose($fo);
}
fclose($fd);</code></pre>


Copyright (c) 2005 Derrick Sobodash. Some Rights Reserved.

This work is licensed under a CC Attribution-ShareAlike 4.0 International
License (http://creativecommons.org/licenses/by-sa/4.0/).