Re: Fwd: Initial Review: JSON contrib modul was: Re: Another swing at JSON - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Fwd: Initial Review: JSON contrib modul was: Re: Another swing at JSON
Date
Msg-id 201107200345.p6K3jMK04594@momjian.us
Whole thread Raw
In response to Fwd: Initial Review: JSON contrib modul was: Re: Another swing at JSON  (Joey Adams <joeyadams3.14159@gmail.com>)
Responses Re: Fwd: Initial Review: JSON contrib modul was: Re: Another swing at JSON
List pgsql-hackers
Joey Adams wrote:
> Forwarding because the mailing list rejected the original message.

Yes, I am seeing email failures to the 'core' email list.

---------------------------------------------------------------------------


> 
> ---------- Forwarded message ----------
> From: Joey Adams <joeyadams3.14159@gmail.com>
> Date: Tue, Jul 19, 2011 at 11:23 PM
> Subject: Re: Initial Review: JSON contrib modul was: Re: [HACKERS]
> Another swing at JSON
> To: Alvaro Herrera <alvherre@commandprompt.com>
> Cc: Florian Pflug <fgp@phlo.org>, Tom Lane <tgl@sss.pgh.pa.us>, Robert
> Haas <robertmhaas@gmail.com>, Bernd Helmle <mailings@oopsware.de>,
> Dimitri Fontaine <dimitri@2ndquadrant.fr>, David Fetter
> <david@fetter.org>, Josh Berkus <josh@agliodbs.com>, Pg Hackers
> <pgsql-hackers@postgresql.org>
> 
> 
> On Tue, Jul 19, 2011 at 10:01 PM, Alvaro Herrera
> <alvherre@commandprompt.com> wrote:
> > Would it work to have a separate entry point into mbutils.c that lets
> > you cache the conversion proc caller-side?
> 
> That sounds like a really good idea. ?There's still the overhead of
> calling the proc, but I imagine it's a lot less than looking it up.
> 
> > I think the main problem is
> > determining the byte length of each source character beforehand.
> 
> I'm not sure what you mean. ?The idea is to convert the \uXXXX escape
> to UTF-8 with unicode_to_utf8 (the length of the resulting UTF-8
> sequence is easy to compute), call the conversion proc to get the
> null-terminated database-encoded character, then append the result to
> whatever StringInfo the string is going into.
> 
> The only question mark is how big the destination buffer will need to
> be. ?The maximum number of bytes per char in any supported encoding is
> 4, but is it possible for one Unicode character to turn into multiple
> "character"s in the database encoding?
> 
> While we're at it, should we provide the same capability to the SQL
> parser? ?Namely, the ability to use \uXXXX escapes above U+007F when
> the server encoding is not UTF-8?
> 
> - Joey
> 
> -- 
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--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +


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