Writing a competitive BZip2 encoder in Ada from scratch in a few days – part 3

https://gautiersblog.blogspot.com/2025/09/writing-competitive-bzip2-encoder-in.html

by etrez • 10 months ago

97 9 10 months ago

gautiersblog.blogspot.com

ohyoutravel• 10 months ago

What is up with the absolutely terrible and obtrusive ads on this page? They take up 80% of my phone screen space, then I tried to scroll down and they pop up again. Awful, I can’t even read this post (and it sounded interesting). Yuck.

I’ll read it when I get back to my home network with my pihole. Websites like this remind me why I block all ads.

stefanos82• 10 months ago

Now you understand why people have no other choice than to use ad blockers...for this exact reason you have just shared with us!

sevg• 10 months ago

This is off-topic but I highly recommend NextDNS, plus either Firefox Focus on iOS or Firefox with uBlock Origin on Android.

I get basically no ads on any website on iOS.

rustybolt• 10 months ago

Not sure what's happening but I don't see a single ad and I don't have an ad blocker.

quietbritishjim• 10 months ago

Yep same for me (Chrome on Android): no ads

zerr• 10 months ago

Didn't expect somebody on HN without an ad blocker. Even FBI urges using it.

Dwedit• 10 months ago

BZip3 is a thing now.

whartung• 10 months ago

I groused about this before, when part 1 rolled out, and I looked at part 2, and now 3.

But, still, these are treatises on the BZip2 algorithm. These posts have pretty much nothing to do with Ada.

No "how would one approach this with Ada", "here's the naive simple Ada", "here's how I made it faster with more clever Ada", "see, Ada, can write fast code too".

Anything like that, but there's nothing there.

There's links to code, but I just felt that with the title, that this would be about Ada implementing BZip2, not about BZip2 and, "oh, here's some source that just happens to be Ada".

etrez• 10 months ago

The "Ada" topic is (only) for the last part. It precisely because with such a good tool, you focus on the important things: the algorithms.

Precisely, there is no such a thing as the BZip2 algorithm: there are multiple ways of programming it, and more importantly, there is a near infinity of possible encodings of the same inputs in the BZip2 format. The compression ratio depends on the choices made in that area. That point is addressed in part 3.

Writing a competitive BZip2 encoder in Ada from scratch in a few days – part 3

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