Обсуждение: Unicode restriction
In src/backend/utils/mb/wchar.c there is a check to exclude Unicode
characters above 0x10000. I can't see anything to explain this
restriction, except possibly this in the release notes for 7.2:
Reject invalid multibyte character sequences (Tatsuo)
It does not explain why part of the Unicode character range is invalid.
There is a Debian bug report from someone whose client is trying to
store characters in the excluded range. What would be needed to enable
support for it?
--
Oliver Elphick olly@lfix.co.uk
Isle of Wight http://www.lfix.co.uk/oliver
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> In src/backend/utils/mb/wchar.c there is a check to exclude Unicode > characters above 0x10000. I can't see anything to explain this > restriction, except possibly this in the release notes for 7.2: > > Reject invalid multibyte character sequences (Tatsuo) > > It does not explain why part of the Unicode character range is invalid. > There is a Debian bug report from someone whose client is trying to > store characters in the excluded range. What would be needed to enable > support for it? Before 7.4, to be handled by regex routines, UTF-8 are converted to ISO 10646. There was a limitaion in regex routines in that they cannot handle multibyte characters > 2bytes. In another word only 16bit UCS-2 are supported. That's why ISO 10646 > 0x10000 is rejected. I'm not sure if the regex routines include in 7.4 or later has this restrictions or not. If not, probably we could remove the check (with losing data compatibilty). -- Tatsuo Ishii
Tatsuo Ishii <t-ishii@sra.co.jp> writes:
> Before 7.4, to be handled by regex routines, UTF-8 are converted to
> ISO 10646. There was a limitaion in regex routines in that they cannot
> handle multibyte characters > 2bytes. In another word only 16bit UCS-2
> are supported. That's why ISO 10646 > 0x10000 is rejected.
> I'm not sure if the regex routines include in 7.4 or later has this
> restrictions or not. If not, probably we could remove the check (with
> losing data compatibilty).
It looks to me like the regex routines now use pg_wchar, so I don't
think we need the restriction any longer.
regards, tom lane