flzp_ac2 (flzp + an order-2 arithmetic coder)

[inikep]

On the basis of flzp (http://cs.fit.edu/~mmahoney/compression/flzp.zip) and coders6b (http://compression.ru/sh/coders6b.rar) I've created a simple LZP compressor (attached).

In opposite to flzp it's one pass, it codes matches of length 3 or more as
a match flag (257-th symbol in alphabet) and a match length. Match lengths and literals are encoded using an order-2 arithmetic coder (separate models for lengths and literals).

Przemyslaw Skibinski

[LovePimple]

Thanks Przemyslaw!

[LovePimple]

Some timings for ENWIK8 from my AMD Sempron 2400+, Windows XP SP2 machine.


FLZP

Compressed Size: 54.7 MB (57,366,279 bytes)

Compression Time: 21.97 Seconds



FLZP_AC2

Compressed Size: 28.4 MB (29,827,613 bytes)

Compression Time: 66.70 Seconds

[LovePimple]

MC SFC test...


FLZP

A10.jpg > 892,834
AcroRd32.exe > 2,585,643
english.dic > 1,715,463
FlashMX.pdf > 4,197,230
FP.LOG > 1,311,552
MSO97.DLL > 3,024,554
ohs.doc > 1,201,473
rafale.bmp > 2,608,919
vcfiu.hlp > 1,409,727
world95.txt > 1,251,473

Total = 20,198,868 bytes



FLZP_AC2

A10.jpg > 900,318
AcroRd32.exe > 1,840,394
english.dic > 1,027,555
FlashMX.pdf > 3,992,042
FP.LOG > 841,390
MSO97.DLL > 2,144,333
ohs.doc > 910,138
rafale.bmp > 1,234,679
vcfiu.hlp > 825,173
world95.txt > 672,206

Total = 14,388,228 bytes

[inikep]

Thanks for testing.