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
Say you want to send a list of consumer records to another microservice over network via JSON. There are three concepts at play in this process: A logical value, which is how we humans treat the data. In this example, this would be “a...
Suppose that you’re writing a static analyzer and you want to write a diagnostic for match arms with equal bodies: match number { 1 => { // <-- let x = 1; f(x) } 2 => f(g(h())), 3 => "", 4 => { // <-- let x = 1; f(x) } _ =>...
Some time ago, I played around with decompiling Java class files in a more efficient manner than traditional solutions like Vineflower allow. Eventually, I wrote an article on my approach to decompiling control flow, which was a great...
A few days ago, I stumbled upon a Hacker News discussion about the expression problem – a conundrum that occasionally arises in software design. Some of the commenters noted that Rust completely avoids this problem thanks to trait...
Fenwick trees and interval trees are well-known data structures in computer science. Interval trees in particular are commonly used in bioinformatics and computational geometry, and Fenwick trees are useful for keeping statistics. This...
Here, read the intro of the Wikipedia page for Command pattern with me: In object-oriented programming, the command pattern is a behavioral design pattern in which an object is used to encapsulate all information needed to perform an...
In contemporary “AI” discourse, people often make a point that LLM output cannot be trusted, since it contains hallucinations, often doesn’t handle edge cases properly, causes vulnerabilities, and so on. This is seen as an argument to...
This is a tech phenomenon that I keep getting blindsided by no matter how much I try to anticipate it. Physical work feels difficult. You can look at someone and realize you don’t have nearly as much stamina, and even if you did, it...
I’m making progress on the Java decompiler I’ve mentioned in a previous post, and I want to share the next couple of tricks I’m using to speed it up. Java bytecode is a stack-based language, and so data flow is a bit cursed, especially...
This post is about a popular but niche technique I can never find a succinct reference for. I didn’t invent it, I just need a page I can link when giving optimization advice. Integer ↔ float casts that utilize specialized processor...
I’m working on a Java decompiler because I’m not satisfied with the performance of other solutions. I’ve always heard that decompiling JVM bytecode is a solved problem, but I’ve concluded that the decompilation methods used by CFR and...
I’m not talking about skill, knowledge, or convincing a world focused on radical acceleration that optimization is necessary. Performance optimization is hard because it’s fundamentally a brute-force task, and there’s nothing you can do...
Null pointers look simple on the surface, and that’s why they’re so dangerous. As compiler optimizations, intuitive but incorrect simplifications, and platform-specific quirks have piled on, the odds of making a wrong assumption have...
The RAM myth is a belief that modern computer memory resembles perfect random-access memory. Cache is seen as an optimization for small data: if it fits in L2, it’s going to be processed faster; if it doesn’t, there’s nothing we can do....
In languages like Python, Java, or C++, values are hashed by calling a “hash me” method on them, implemented by the type author. This fixed-hash size is then immediately used by the hash table or what have you. This design suffers from...