Koei Decompress

Koei Decompress
V1.1

by darkmoon2321

Readme.txt

This program was intended to decompress/compress data from several Koei games for the SNES.
This program has been confirmed to work with Romance of the Three Kingdoms III and IV, 
Gemfire, Uncharted Waters: New Horizons, and Genghis Khan II.  It should work with any
other Koei game that uses the same compression format.

To use this program, place ROMs or other data that you wish to process in the same folder as 
the program.  When you run the program, you will be given the option to compress or 
decompress data, and you will be prompted to enter the filename containing your starting 
data.  If you are decompressing data, you will be given a few options.

Option 1: Filters decompressed results for graphical data.  Only decompressed data that 
appears to be in tile format will appear in the output.
Option 2: Filters decompressed results for text.  Searches for data that contains a large 
proportion of alpha-numeric characters.  So far, only Romance of the Three Kingdoms 4 has 
been known to compress text using this algorithm.
Option 3: Decompress a single sequence of data from the ROM or file, given an offset for the 
start point.  You may either enter the offset in decimal or hexadecimal.  To enter the 
offset in hexadecimal, prefix the offset with '0x'.  The decompression will stop after a 
single sequence is completed.  If a valid sequence is not found, an error message will be shown.
Option 4: Decompress everything.  This will output all potentially valid decompression 
sequences to a file.  This will include graphical data, text, and binary data that happens 
to be compressed.

Results of the decompression will be stored in a file with the extension .kdf (Koei 
decompressed file).  Results of the compression will be stored in a file with the extension 
.kcf (Koei compressed file).  In addition to these file types, running a decompression will 
also generate a file with a .dat extension.  This file holds information regarding the hex 
offsets of compressed data in the ROM, corresponding locations in the .kdf file, and also 
the size of the sequence in bytes both compressed and uncompressed.  Once the data is
decompressed, graphics data can be easily viewed using a different tool, such as
TileLayerPro.

Run times vary, with decompression of the entire ROM taking sometimes over a minute to
handle, depending on your computer.  Re-compressing individual sequences should no longer
take a long time in V1.1.  The largest individual sequences I have found in Koei games are
about 20kB when decompressed.  Compressing anything significantly larger than this could take
awhile, as compression is much slower than decompression.

The source code for this program is included to allow for user modifications or extension.  
I am not a professional programmer, so be fore-warned about poor commenting and not 
following ISO guidelines.  I apologize in advance if you are trying to read my code :)

Release History:
10/20/14 V1.0 Initial Release
11/3/14  V1.1 Fixed a problem with readControl that would cause errors at the end of a
              compression sequence.  Also made improvements to the efficiency of the
              compression algorithm, making it run significantly faster.