purplesyringa's blog
purplesyringa's blog
Alisa Sireneva
Hi! đź‘‹ I'm Alisa Sireneva (she/her), a software developer and blogger from Moscow. I specialize in performance optimization and systems programming. I also have experience with security, compression, and decentralized systems. My primary goal as a writer is to teach the concepts I regularly apply through accessible content.
Latest Posts
This post assumes basic familiarity with arithmetic coding. I’ve written an arithmetic coder, like, three times in my life, so the mistake I want to highlight is likely amateurish. But since I didn’t have a clue that my understanding was...
Everyone knows Wasm is a stack machine. Wikipedia says so, the official Wasm design specification says so, you get it. I thought so too. That is, until I started writing Wasm code – not compiling for Wasm, but writing the instructions by...
I needed to convert file status flags between operating systems yesterday. They are the values you pass as the second argument to open – O_NONBLOCK, O_NOATIME, O_SYNC, O_DSYNC, and so on: int open(const char *path, int flags, /* mode_t...
The appearance of Mythos – a private LLM allegedly capable of finding a multitude of 0-days – has made people concerned about being denied powerful tools. This seems to be a turning point in the mainstream discourse, and it motivated me...
In case you’re unaware, I’m not a developer. I’m actually an autistic catgirl annoyed by suboptimal use of computing power, and fixing that happens to involve programming. Crucially, it also includes discussing foundational technology...
What came to your mind when you read “hash functions” in the title? If you’re pragmatic, you probably remembered SHA-256 or MD5. Those are cryptographic hash functions, and they work fast and well for arbitrary inputs, even if they are...
This is a rant about how broken everything Web is based on is. You know, the usual. No offence intended towards framework developers, I’m glad this technology exists, but I’m sure you know this feeling. It gets too much sometimes. I’ve...
Minecraft generates a bedrock floor at the bottom of the world from a random noise. Since it’s random, it can contain naturally generated unescapable regions – prisons. While small prisons are common, larger ones are hard to find – a...
Two years ago, I was pondering ways to enhance borrowck with proof-based analysis. At the time, I was only aware of formal verification tools for functional languages, while Rust is impure. For the purposes of borrow checking, though, we...
The story goes like this. ComputerCraft is a mod that adds programming to Minecraft. You write Lua code that gets executed by a bespoke interpreter with access to world APIs, and now you’re writing code instead of having fun. Computers...
Last year, Lemire wrote about an optimized variation of the Euclidean algorithm for computing the greatest common divisor of two numbers, called binary Euclidean algorithm or Stein’s algorithm. It’s a best-of-class implementation, though...
Functions in binary files need to have unique names, so Rust needs to decide what to call its functions and statics. This format needs to be standardized so that debuggers and profilers can recover the full names (e.g. alloc::vec::Vec...
This article is a technical counterpart of my previous post Finding duplicated code with tools from your CS course. It is deliberately written in a terse manner, and I’m not going to hold your hand. Consider reading the previous post...
Recently I was scrolling through brson’s Rust quote database and stumbled upon a link to the official Rust tutorial from the very beginning of 2013. It says Rust 0.6 in the corner, but it lists many things that were removed in 0.6, so...