In my previous article, I said I needed to stop thinking of Rust generics as Java generics, because in Rust, generic types are erased.

Someone gently pointed out that they are also erased in Java, the difference was elsewhere. And so, let’s learn the difference together.

Java generics

I learned Java first (a long, long time ago), and their approach to generics made sense to me at the time.

Welcome back and thanks for joining us for the reads notes… the thirteenth installment of our series on ELF files, what they are, what they can do, what does the dynamic linker do to them, and how can we do it ourselves.

I’ve been pretty successfully avoiding talking about TLS so far (no, not that one) but I guess we’ve reached a point where it cannot be delayed any further, so.

Part 1

In the day 2 challenge, we’re playing Rock Papers Scissors.

We’re given a strategy guide like so:

A Y B X C Z

Left column is “their move”: A means Rock, B means Paper, C means Scissors. Right column is “our move”: X means Rock, Y means Paper, Z means Scissors.

Each line corresponds to a turn, and we must calculate the total score we get. Picking “Rock” gives 1 point, “Paper” gives 2 points, and “Scissors” gives 3. Losing the round gives 0 points, drawing gives 3, winning it gives 6.

Alright. ALRIGHT. I know, we’re all excited, but let’s think about what we’re doing again.

So we’ve managed to look at real network traffic and parse it completely. We’ve also taken some ICMP packets, parsed them, and then serialized them right back and we got the exact same result.

So I know what you’re thinking - let’s just move our way down the stack again - stuff that ICMP packet in an IP packet, then in an Ethernet frame, and then serialize the whole thing.

A little while ago, I wrote an article on things that can go wrong when downloading, it listed a series of reasons, from network problems to invalid content to imperfect hardware that may occur when initially installing a game.

This article discusses what methods we can use to upgrade a game to a later version, when an older version has been successfully installed.

It’s time for Day 4 of the Advent of Code 2020!

Now, I’ve already had a look at the problem statement, at least for part 1, and I’m not particularly excited.

But it will allow me to underline some of the points I’ve recently been *trying to make about types and correctness.

The problem is to parse passports, with fields like these:

Hey everyone!

This article is brought to you by a shameless nerd snipe, courtesy of Pascal.

In case you’ve blocked Twitter for your own good, this reads:

There should be a post explaining and comparing smolstr and smartstring (and maybe others, like smallstr)

Well, I took the bait.

But, since this is me writing, I get to set the rules:

• There will be no “maybe others” - we’ll review just the first two

It took a hot minute.

Try several weeks.

Well, yeah. I got to contribute to a bunch of open-source projects in the meantime though, so I’m fairly pleased with it!

• libffi (for static linking)
• cairo (more static linking!)
• proxy-libintl (more static linking!)
• expat (static linking strikes again)
• poppler (for file descriptor stuff not properly gated on Windows, closed in favor of a similar MR)

Advent of Code gets harder and harder, and I’m not getting any smarter. Or any more free time. So, in order to close out this series anyway, I’m going to try and port other people’s solutions from “language X” to Rust. That way, they already figured out the hard stuff, and we can just focus on the Rust bits!

Sounds good? Good. Let’s proceed.