extrait de la doc de Shrink92 par David Kühling (auteur de Pk92lib et Shrnklib):
Shrink92 is a compression tool that is designed to reduce the size of Fargo programs by making it possible to compress
binary data on your PC and uncompressing them on a TI-92 by the Fargo library shrnklib. It may also be used by other
PC programs for text compressions and similar purposes. When you've allready used other compression libraries such as
hufflib, lzsslib or pk92lib you won't have any problems with that library. In fact Shrink92 is superior to all those
compression algorithms. It took me over a week to design the Shrink compression. It is a combination of an optimized
LZSS, RLE and Huffman compression. As you will see compression is quite slow. But therefore uncompression runs very
fast and compression ratios are sometimes almost Winzip - like. In case you already worked with Packer92, please don't
judge my programing skills by that program. Packer92 was the first thing I programed for Fargo, it's more than a year ago, I
was quite an amateur in these times. To convince you of Shrink92's power, here is a comparison of the most common
algorithms, used by TI-92 programmers: (ratio specifies the difference of the original file to the compressed file, thus a greater
ratio represents a better compression)
Filename
Size (bytes)
Huffman
LZSS
Packer92
Shrink92
traps.txt
5403
3390 (ratio:
37.26
2665 (ratio:
50.68
2201 (ratio:
59.26
2141 (ratio:
60.37
fargo.txt
47152
29220 (ratio:
38.03
21410 (ratio:
54.59
18080 (ratio:
61.66
16286 (ratio:
65.46
fpl.92p
2035
1902 (ratio: 6.54
1759 (ratio:
13.56
1859 (ratio: 8.65
1774 (ratio:
12.83
db92.92p
12882
10232 (ratio:
20.57
9534 (ratio:
25.99
8882 (ratio:
31.05
8408 (ratio:
34.73
bd.92p
14773
10736 (ratio:
27.33
9636 (ratio:
34.77
8465 (ratio:
42.70
8157 (ratio:
44.78
some 3 plane picture
11520
6812 (ratio:
40.87
7440 (ratio:
35.42
6944 (ratio:
39.72
6370 (ratio:
44.70
As you can see, small files (about 2K) aren't compressed very efficent. This can be compensated by putting many small files
into one archive. The structure of Shrink92 archives allows single files to be uncompressed without scanning through the rest
of the archive, although different files in one archive partially use same compression data, thus optimize the total compression
ratio. Shrink92 is also capable of creating an include file that will help you to access the archive.
