Le 21/09/2013 16:38, Olivier Renaud a écrit :
I'd expect this offset to be absolute. After all, the only thing that the
programmer can do with this information at this point is to report it to the
user ; if the programmer wanted to handle the error, he could have done it by
using a trap. A relative offset has no meaning outside of the processing loop,
whereas an absolute offset can still be useful even outside of the program (if
the source of the stream is a file, then an absolute offset will give the exact
location of the error in the file).
A counter is super cheap, I would'nt worry about its cost. Actually, it just
has to be incremented once for each call to 'feed'.
Well to get the position inside a given chunk of input you still have to
count individual bytes. (Maybe with Iterator::enumerate?) Unless maybe
we do dirty pointer arithmetic…
If possible, I’d rather find a way to not have to pay that cost in the
common case where the error handling is *not* abort and DecodeError is
never used.
This is also a bit annoying as each implementation will have to repeat
the counting logic, but maybe it’s still worth it.
Note : for the encoder, you will have to specify wether the offset is a 'code
point' count or a 'code unit' count.
Yes. I don’t know yet. If we do [1] and make the input generic it will
probably have to be code points.
[1] https://mail.mozilla.org/pipermail/rust-dev/2013-September/005662.html
Otherwise, it may be preferable to match Str::slice and count UTF-8
bytes. (Which I suppose is what you call code units?)
--
Simon Sapin
_______________________________________________
Rust-dev mailing list
[email protected]
https://mail.mozilla.org/listinfo/rust-dev
