Feedback on the proposal to change U+FFFD generation when decoding ill-formed UTF-8

Jonathan Coxhead via Unicode unicode at
Tue May 23 01:10:09 CDT 2017

On 18/05/2017 1:58 am, Alastair Houghton via Unicode wrote:
> On 18 May 2017, at 07:18, Henri Sivonen via Unicode <unicode at> wrote:
>> the decision complicates U+FFFD generation when validating UTF-8 by state machine.
> It *really* doesn’t.  Even if you’re hell bent on using a pure state machine approach, you need to add maybe two additional error states (two-trailing-bytes-to-eat-then-fffd and one-trailing-byte-to-eat-then-fffd) on top of the states you already have.  The implementation complexity argument is a *total* red herring.

    Heh. A state machine with N+2 states is, /a fortiori/, more complex 
than one with N states. So I think your argument is self-contradictory.
> Alastair.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Unicode mailing list