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Re: normalization filters?

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Leon Timmermans
January 16, 2012 05:04
Re: normalization filters?
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On Wed, Jul 20, 2011 at 11:58 PM, Eric Brine <> wrote:
> I started writing one pure Perl version (using PerlIO::via) a while back.
> Should be easy right? ha!
> It lead to improvements to Unicode::Normalize (addition of
> C<normalize_partial> and some doc improvements), but I stalled when I found
> that PerlIO::via didn't provide access to a crucial facility available to XS
> PerlIO layers. Specifically, PerlIO::via doesn't provide the ability to peek
> into the buffer of the previous layer. IIRC, without that facility,
> PerlIO::via layers cannot process input as it comes in and must wait for
> EOF. I never got around to adding the functionality to PerlIO::via.
> I'll dig up what I have tonight.

What it really needs is not so much a peek ability, but a
read-and-give-up ability. Currently in PerlIO, when you try to
PerlIO_read X bytes, it will loop reading until you have X
bytes/characters, instead of returning what it has an letting the rest
be. Peeking into the buffer is currently the only way to implement the
latter, but it shouldn't be IMHO.


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