Date: Fri, 06 Dec 2024 14:21:30 +0900 (JST)
Message-Id: <20241206.142130.1661155698933375612.ishii@postgresql.org>
To: tgl@sss.pgh.pa.us
Cc: koichi.dbms@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18735: Specific multibyte character in psql file path
 command parameter for Windows
From: Tatsuo Ishii <ishii@postgresql.org>
In-Reply-To: <2572359.1733424649@sss.pgh.pa.us>
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	<2572359.1733424649@sss.pgh.pa.us>
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> I don't believe Shift-JIS uses '/' as part of multibyte characters,

Correct.

> so it should be sufficient to consider '\'.

Agreed.

> BTW, according to wikipedia[1], backslash is not even part of the
> Shift-JIS character set:
> 
>     The single-byte characters 0x00 to 0x7F match the ASCII encoding,
>     except for a yen sign (U+00A5) at 0x5C and an overline (U+203E) at
>     0x7E in place of the ASCII character set's backslash and tilde
>     respectively (these deviations from ASCII align with JIS X
>     0201). The single-byte characters from 0xA1 to 0xDF map to the
>     half-width katakana characters found in JIS X 0201.
> 
>     For double-byte characters, the first byte is always in the range
>     0x81 to 0x9F or the range 0xE0 to 0xEF (these ranges are
>     unassigned in JIS X 0201). If the first byte is odd, the second
>     byte must be in the range 0x40 to 0x9E (but cannot be 0x7F); if
>     the first byte is even, the second byte must in the range 0x9F to
>     0xFC.
> 
> This might mean that it'd be okay to just skip the backslash-to-slash
> conversion loops altogether if we think the encoding is Shift-JIS.

I suggest to not do so because majority of Shift-JIS users treat 0x5C
as a backslash. They understand that a 0x5C means a backslash in
Shift-JIS files if the files are for programming (source code) or for
the technical documentations and so on.

Best reagards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp