3 ms·
Which characters are not available in UTF-8 that warrant using WTF-8?
by RedShift1 2y ago
Which characters are not available in UTF-8 that warrant using WTF-8?
- chrismorgan 2y agoJust read the abstract: > WTF-8 (Wobbly Transformation Format − 8-bit) is a superset of UTF-8 that encodes surrogate code points if they are not in a pair. It represents, in a way compatible with UTF-8, text from systems such as JavaScript and Windows that use UTF-16 internally but don’t enforce the well-formedness invariant that surrogates must be paired.
- RedShift1 2y agoOk, but in practice, what does this mean for the characters? Are there certain characters unavailable?
- chrismorgan 2y agoIt’s the unpaired surrogate code points. That’s the whole thing. It’s about encoding ill-formed UTF-16, which is distressingly common in the real world.
- numpad0 2y agobroken emojis? There apparently are known issues that some frameworks break Unicode at wrong boundaries, maybe the author saw it regularize into a deeper mess
- masklinn 2y agoIt’s not just broken emoji, it’s straight up broken content: UTF-8 can not represent unpaired surrogates. WTF-8 is necessary for Rust’s compatibility with Windows filesystems (it underlines OsString on Windows) as e.g. file names are sequences of UTF-16 code units (and thus may contain unpaired surrogates).
- badmintonbaseba 2y agoInvalid UTF-16 with unpaired surrogates. Or rather WTF-8 is an alternate encoding of UCS-2. The subset of UCS-2 that is valid UTF-16 encodes to valid UTF-8 when encoded with WTF-8. The encoding is invertible, valid UTF-8 decodes to valid UTF-16, otherwise any byte sequence decodes to UCS-2.