c++

137 Articles

Here’s A Plain C/C++ Implementation Of AI Speech Recognition, So Get Hackin’

November 27, 2022 by 19 Comments

[Georgi Gerganov] recently shared a great resource for running high-quality AI-driven speech recognition in a plain C/C++ implementation on a variety of platforms. The automatic speech recognition (ASR) model is fully implemented using only two source files and requires no dependencies. As a result, the high-quality speech recognition doesn’t involve calling remote APIs, and can run locally on different devices in a fairly straightforward manner. The image above shows it running locally on an iPhone 13, but it can do more than that.

Implementing a robust speech transcription that runs locally on a variety of devices is much easier with [Georgi]’s port of OpenAI’s Whisper.
[Georgi]’s work is a port of OpenAI’s Whisper model, a remarkably-robust piece of software that does a truly impressive job of turning human speech into text. Whisper is easy to set up and play with, but this port makes it easier to get the system working in other ways. Having such a lightweight implementation of the model means it can be more easily integrated over a variety of different platforms and projects.

The usual way that OpenAI’s Whisper works is to feed it an audio file, and it spits out a transcription. But [Georgi] shows off something else that might start giving hackers ideas: a simple real-time audio input example.

By using a tool to stream audio and feed it to the system every half-second, one can obtain pretty good (sort of) real-time results! This of course isn’t an ideal method, but the robustness and accuracy of Whisper is such that the results look pretty great nevertheless.

You can watch a quick demo of that in the video just under the page break. If it gives you some ideas, head over to the project’s GitHub repository and get hackin’!

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The demo toot screenshot, showing a text-only message sent from the ESP32 using the library.

Moved Off Twitter? Make Your ESP32 Toot

November 9, 2022 by 75 Comments

Since Twitter was officially taken over by Elon Musk a few days ago, there’s been significant staff cuts, a stream of questionable decisions, and uncertainty about the social media platform’s future. So it’s little surprise that a notable number of people, those in the tech and hacker scenes in particular, have decided to move over to (or at least bridge their accounts with) the distributed and open source Mastodon service.

Of course, the hacks would follow closely, and [Toby] shares a simple ESP32-based Mastodon client library for us to start with. Instead of “tweets”, messages on Mastodon instances are called “toots”, in line with the platform’s mammoth-like mascot. The library, called Luyba, is able to send toots and includes a demo firmware. Built using C++ and with support for Platform.IO, it should fit into quite a few projects out there, letting you easily send toots to whichever instance you find your home, as the library-aided demo toot shows.

What could you do with such a library on your MCU? Turns out, quite a few fun things – a home automation interface, a critter trap, an online BBC Basic interpreter, or, given image support, a camera that tweets whatever it’s pointed at. There’s quite a bit of fun hackers can have given a micro-blogging service API access and a bit of code that works with it. That said, for all the good that Twitter brought us over the years, there’s a lot that Mastodon can easily do better, between easily game-able “Trending” sidebar, bias found in auto-cropping algorithms and disarrayed internal security policies.

C23 Programming For Everyone

September 13, 2022 by 29 Comments

Here’s a history quiz: What architecture did the first C++ compiler target? Of course, it is a trick question. The original C++ — known then as C with classes — compiler wrote out standard C code that you then compiled for whatever your target was. This has a lot of advantages since C compilers are everywhere. Now we are seeing a similar approach to bring C23 to the world with Cake. Cake can translate C23 or other versions to C99 which you can then compile with normal compilers.

While the old C++ compiler, cfront, needed special steps to compile (since it was built using C++), you can build cake for Windows or Linux easily. However, it can also be built with emscripten and you can try it yourself in your web browser.

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Arduino Drum Platform Is Fast

June 28, 2022 by 53 Comments

Drums are an exciting instrument to learn to play, but often prohibitive if there are housemates or close neighbors involved. For that problem there are still electronic drums which can be played much more quietly, but then the problem becomes one of price. To solve at least part of that one, [Jeremy] turned to using an Arduino to build a drum module on his own, but he still had to solve yet a third problem: how to make the Arduino fast enough for the drums to sound natural.

Playing music in real life requires precise timing, so the choice of C++ as a language poses some problems as it’s not typically as fast as lower-level languages. It is much easier to work with though, and [Jeremy] explains this in great detail over a series of blog posts detailing his drum kit’s design. Some of the solutions to the software timing are made up for with the hardware on the specific Arduino he chose to use, including an even system, a speedy EEPROM, hardware timers, and an ADC that can sample at 150k samples per second.

With that being said, the hardware isn’t the only thing standing out on this build. [Jeremy] has released the source code on his GitHub page for those curious about the build, and is planning on releasing several more blog posts about the drum kit build in the near future as well. This isn’t the only path to electronic drums, though, as we’ve seen with this build which converts an analog drumset into a digital one.

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Building Faster Rsync From Scratch In Go

June 1, 2022 by 53 Comments

For a quick file transfer between two computers, SCP is a fine program to use. For more complex, large, or regular backups, however, the go-to tool is rsync. It’s faster, more efficient, and usable in a wider range of circumstances. For all its perks, [Michael Stapelberg] felt that it had one major weakness: it is a tool written in C. [Michael] is philosophically opposed to programs written in C, so he set out to implement rsync from scratch in Go instead.

[Michael]’s path to deciding to tackle this project is a complicated one. His ISP upgraded his internet connection to 25 Gbit/s recently, which means that his custom router was the bottleneck in his network. To solve that problem he migrated his router to a PC with several 25 Gbit/s network cards. To take full advantage of the speed now theoretically available, he began using a tool called gokrazy, which turns applications written in Go into their own appliance. That means that instead of installing a full Linux distribution to handle specific tasks (like a router, for example), the only thing loaded on the computer is essentially the Linux kernel, the Go compiler and libraries, and then the Go application itself.

With a new router with hardware capable of supporting these fast speeds and only running software written in Go, the last step was finally to build rsync to support his tasks on his network. This meant that rsync itself needed to be built from scratch in Go. Once [Michael] completed this final task, he found that his implementation of rsync is actually much faster than the version built in C, thanks to the modernization found in the Go language and the fact that his router isn’t running all of the cruft associated with a standard Linux distribution.

For a software project of this scope, we find [Michael]’s step-by-step process worth taking note of for any problem any of us attempt to tackle. Not only that, refactoring a foundational tool like rsync is an involved task on its own, let alone its creation simply to increase network speeds beyond what most of us would already consider blazingly fast. We’re leaving out a ton of details on this build so we definitely recommend checking out his talk in the video below.

Thanks to [sarinkhan] for the tip!

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AI Attempts Converting Python Code To C++

May 28, 2022 by 31 Comments

[Alexander] created codex_py2cpp as a way of experimenting with Codex, an AI intended to translate natural language into code. [Alexander] had slightly different ideas, however, and created codex_py2cpp as a way to play with the idea of automagically converting Python into C++. It’s not really intended to create robust code conversions, but as far as experiments go, it’s pretty neat.

The program works by reading a Python script as an input file, setting up a few parameters, then making a request to OpenAI’s Codex API for the conversion. It then attempts to compile the result. If compilation is successful, then hopefully the resulting executable actually works the same way the input file did. If not? Well, learning is fun, too. If you give it a shot, maybe start simple and don’t throw it too many curveballs.

Codex is an interesting idea, and this isn’t the first experiment we’ve seen that plays with the concept of using machine learning in this way. We’ve seen a project that generates Linux commands based on a verbal description, and our own [Maya Posch] took a close look at GitHub Copilot, a project high on promise and concept, but — at least at the time — considerably less so when it came to actual practicality or usefulness.

Things Are Getting Rusty In Kernel Land

May 17, 2022 by 163 Comments

There is gathering momentum around the idea of adding Rust to the Linux kernel. Why exactly is that a big deal, and what does this mean for the rest of us? The Linux kernel has been just C and assembly for its entire lifetime. A big project like the kernel has a great deal of shared tooling around making its languages work, so adding another one is quite an undertaking. There’s also the project culture developed around the language choice. So why exactly are the grey-beards of kernel development even entertaining the idea of adding Rust? To answer in a single line, it’s because C was designed in 1971, to run on the minicomputers at Bell Labs. If you want to shoot yourself in the foot, C will hand you the loaded firearm.

On the other hand, if you want to write a kernel, C is a great language for doing low-level coding. Direct memory access? Yep. Inline assembly? Sure. Runs directly on the metal, with no garbage collection or virtual machines in the way? Absolutely. But all the things that make C great for kernel programming also make C dangerous for kernel programming.

Now I hear your collective keyboards clacking in consternation: “It’s possible to write safe C code!” Yes, yes it is possible. It’s just very easy to mess up, and when you mess up in a kernel, you have security vulnerabilities. There’s also some things that are objectively terrible about C, like undefined behavior. C compilers do their best to do the right thing with cursed code like i++ + i++; or a[i] = i++;. But that’s almost certainly not going to do what you want it to, and even worse, it may sometimes do the right thing.

Rust seems to be gaining popularity. There are some ambitious projects out there, like rewriting coreutils in Rust. Many other standard applications are getting a Rust rewrite. It’s fairly inevitable that the collection of Rust developers started to ask, could we invade the kernel next? This was pitched for a Linux Plumbers Conference, and the mailing list response was cautiously optimistic. If Rust could be added without breaking things, and without losing the very things that makes Rust useful, then yes it would be interesting. Continue reading “Things Are Getting Rusty In Kernel Land” →