nigeltao

8 ms·

1.
by nigeltao 2mo ago
Hi, author here. Thanks for the "check your HTML" bug report.
2.
by nigeltao 2mo ago
Handsum is intrinsically 16x16. Decoding to 32x32 is a two step process: 1. Decode to 16x16. This is done by the Handsum library. 2. Upscale 2x. This is done by the caller of the Handsum library (or, for the Wasm demo, by the HTML renderer)
3.
Show HN: Handsum: An LQIP Image File Format(nigeltao.github.io)
11 points by nigeltao 2mo ago|0 comments
4.
by nigeltao 8mo ago
> Russ Cox should make a C version of his code. https://github.com/rsc/fpfmt/blob/main/bench/uscalec/ftoa.c
5.
by nigeltao 11mo ago
It's a great idea. Chromium uses Wuffs to parse GIF data from the untrusted network. There's also a "wget some JSON and pipe that to what Wuffs calls example/jsonptr" example at https://nigeltao.github.io
6.
by nigeltao 11mo ago
The top-level README has a link called "Getting Started".
7.
by nigeltao 11mo ago
See https://github.com/google/wuffs/blob/main/doc/related-work.m... > Kaitai Struct is in a similar space, generating safe parsers for multiple target programming languages from one declarative s
8.
by nigeltao 1y ago
I like my colleague Simon Morris's observation about software complexity: > Software has a Peter Principle. If a piece of code is comprehensible, someone will extend it, so they can apply it to their own problem. If it’s incomprehen
9.
by nigeltao 1y ago
> Compressing QOI with something like LZ4 would generally outperform PNG. https://github.com/nigeltao/qoir has some numbers comparing QOIR (which is QOI-inspired-with-LZ4) vs PNG. QOIR has better decode speed and co
10.
by nigeltao 1y ago
For Wuffs, top level declarations start with either pub or pri (and both keywords have the same width, in a monospace font). pub status "#blah" pub struct foo(etc etc) pri func foo.bar(etc etc) Since code is also
11.
by nigeltao 2y ago
Might be relevant to your interests: https://nigeltao.github.io/blog/2022/gamma-aware-ordered-dit...
12.
by nigeltao 2y ago
You might like JWCC, which literally stands for JSON With Commas and Comments. https://nigeltao.github.io/blog/2021/json-with-commas-commen...
13.
by nigeltao 2y ago
JWCC literally stands for JSON With Commas and Comments. JWCC is also what Tailscale call HuJSON, as in "JSON for Humans", which as amusingly also what json5 claims to be. https://github.com/tailscale/hujson
14.
by nigeltao 2y ago
> I believe the standard does not specify what the intermediate progressive renderings should look like. This is possibly getting too academic, but IIUC for a progressive JPEG, e.g. encoded by cjpeg to have 10 0xDA Start Of Scan markers,
15.
by nigeltao 2y ago
> all decoders will render the same pixels Not true. Even just within libjpeg, there are three different IDCT implementations (jidctflt.c, jidctfst.c, jidctint.c) and they produce different pixels (it's a classic speed vs quality tr
16.
by nigeltao 2y ago
You're right that Wuffs' memory-safety isn't relevant for this attack. Still, Wuffs doesn't use autotools, and if you're pulling the library from the https://github.com/google/wuffs-mirror-relea
17.
by nigeltao 2y ago
Yeah, it's just a coincidence (†), but I started working on Wuffs' LZMA and XZ decoders last December. It works well enough to decode the Linux source code tarball correctly (producing the same output as /usr/bin/xz
18.
by nigeltao 2y ago
Encoding is definitely in Wuffs' long term objectives (it's issue #2 and literally in its doc/roadmap.md file). It's just that decoding has been a higher priority. It's also a simpler problem. There's often onl
19.
by nigeltao 2y ago
Yeah, you're right. It's not as easy to write Wuffs code during the research phase, since you don't just have to write the code, you also have to help the compiler prove that the code is safe, and sometimes refactor the code
20.
by nigeltao 2y ago
When I wrote my jsonptr tool a few years ago, I noticed that some JSON libraries (in both C++ and Rust) don't even do "parse a string of decimal digits as a float64" properly. I don't mean that in the "0.3 isn'
21.
by nigeltao 3y ago
If you want commas and comments, another term to search for is JWCC, which literally stands for "JSON With Commas and Comments". HuJSON is another name for it.
22.
by nigeltao 3y ago
> Isn't it fixed during the decoding process though? For Wuffs' image decoding, it's flexible up until decode_image_config returns. It's fixed afterwards. In practice, that works fine for BMP, GIF, JPEG and PNG (and I
23.
by nigeltao 3y ago
1024 is a loose but correct bound. That's what enough.c (or script/print-deflate-huff-table-size.go) says. Stepping back, I'm not sure if I understand what you're saying. Perhaps we're just disagreeing on how &quo
24.
by nigeltao 3y ago
The logo is no longer shown because I think the tweet-screenshot is a more compelling introduction for people new to Wuffs.
25.
by nigeltao 3y ago
I've written a WebP Lossy decoder in Go and I'm confident that I can write one in Wuffs too.
26.
by nigeltao 3y ago
As an intellectual 'puzzle', I'd be curious to see what that sort of trace-guided verification could look like, if that's even feasible. My recollection of enough.c is that, algorithmically, it's sufficiently compli
27.
by nigeltao 3y ago
If you want some code to study, https://github.com/golang/image/tree/master/vp8l is a WebP-Lossless decoder in under 1200 lines of code.
28.
by nigeltao 3y ago
Wuffs author here. It's not full-blown formal verification but it doesn't have to be. Unlike most formal verification projects that I've seen, the proof part of Wuffs isn't about correctness (proving that "this im
29.
by nigeltao 3y ago
Wuffs and SkWuffsCodec.cpp author here. Wuffs' GIF decoder has shipped in Google Chrome since July 2021 (milestone M93). A fair chunk out of that 1000 lines of glue code is adapting Wuffs' API to Skia's API. (Skia is the 2-D
30.
by nigeltao 3y ago
Thanks for the feedback. I'll add better build instructions. If you just want the jsonptr program, instead of everything in the repo (the Wuffs compiler (written in Go), the Wuffs standard library (written in Wuffs), tests and benchm

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