Re: [PATCHES] unknownin/out patch (was PQescapeBytea is

I'm about to commit your patches with a small fix.
--
Tatsuo Ishii

From: Joe Conway <mail@joeconway.com>
Subject: Re: [PATCHES] unknownin/out patch (was [HACKERS] PQescapeBytea is
Date: Mon, 08 Apr 2002 22:57:47 -0700
Message-ID: <3CB282DB.4050708@joeconway.com>

> Joe Conway wrote:
> > Tatsuo Ishii wrote:
> >  >>> Tatsuo Ishii wrote:
> >  >>>
> >  >>>>
> >  >>>> Try a multibyte encoding database. For example,
> >  >>>>
> >  >>>> $ createdb -E EUC_JP test $ psql -c 'SELECT
> >  >>>> SUBSTRING('1234567890' FROM 3)' test substring ----------- 3456
> >  >>>>
> >
> >  >>>> (1 row)
> >  >>>>
> >  >>>> Apparently this is wrong. -- Tatsuo Ishii
> >  >>>
> >  >>> This problem exists in CVS tip *without* the unknownin/out
> >  >>> patch:
> >  >>
> >  >> Sure. That has been broken for a while.
> >  >
> >  >
> >  > I guess this actually happened in 1.79 of varlena.c:
> >  >
> > Yes, I was just looking at that also. It doesn't consider the case of n
> > = -1 for MB. See the lines:
> >
> > #ifdef MULTIBYTE
> >    eml = pg_database_encoding_max_length ();
> >
> >    if (eml > 1)
> >    {
> >       sm = 0;
> >       sn = (m + n) * eml + 3;
> >    }
> > #endif
> >
> > When n = -1 this does the wrong thing. And also a few lines later:
> >
> > #ifdef MULTIBYTE
> >    len = pg_mbstrlen_with_len (VARDATA (string), sn - 3);
> >
> > I think both places need to test for n = -1. Do you agree?
> >
> >
> > Joe
> >
>
> The attached patch should fix the bug reported by Tatsuo.
>
> # psql -U postgres testjp
> Welcome to psql, the PostgreSQL interactive terminal.
>
> Type:  \copyright for distribution terms
>         \h for help with SQL commands
>         \? for help on internal slash commands
>         \g or terminate with semicolon to execute query
>         \q to quit
>
> testjp=# SELECT SUBSTRING('1234567890' FROM 3);
>   substring
> ------------
>   34567890
> (1 row)
>
> Joe