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Here's an analogy that may help when thinking about probability tables: Many types of standard codes like Morse code are like Huffman coding, where you give different variable length codes for each letter.. In Morse E and T are both a single dot and a dash respectively but X and Z get four.

You can view this Huffman Table or Morse codebook as a probability distribution on the likely letters to follow. A symbol with a small number of bits == high probability. A symbol needing large number of bits == low probability.

The only innovation with Arithmetic coding and ANS is that they allow for "fractional bits:" you don't need a whole dot for a very likely next-letter. But the idea is the same: you are taking your understanding of the probability distribution table and using it to come up with codes for the following letters.

One caveat is that instead of agreeing to a fixed code upfront, you agree to an algorithm to dynamically estimate the future probability tables as you read through the file.


Makes sense. Thanks!


There's privateer remake https://sourceforge.net/projects/privateer/files/ (supposed to have a homepage here: http://privateer.sourceforge.net/ )

Disclaimer: Ages ago I coded the GPL Vega Strike http://vegastrike.sourceforge.net/ engine on which the privateer remake operates -- you might need to run in xp compat mode unless you checkout the data dir


It seems like use-after-free is still a potential issue, even with those guard rails. Rust deals with those through named lifetimes --would those ideas be useful in D as well?


I like the one called priority matrix -- it syncs between all my devices. The mobile version is free https://sync.appfluence.com/manage/downloads/ It has a high priority/low priority urgent/nonurgent split


How does this compare to packpnm http://packjpg.encode.ru/?page_id=73


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