Re: like/ilike improvements
От | Andrew Dunstan |
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Тема | Re: like/ilike improvements |
Дата | |
Msg-id | 4656C0A4.1040500@dunslane.net обсуждение исходный текст |
Ответ на | Re: like/ilike improvements ("Zeugswetter Andreas ADI SD" <ZeugswetterA@spardat.at>) |
Ответы |
Re: like/ilike improvements
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Список | pgsql-hackers |
Zeugswetter Andreas ADI SD wrote: > >> You have to be on a first byte before you can meaningfully >> apply NextChar, and you have to use NextChar or else you >> don't count characters correctly (eg "__" must match 2 chars >> not 2 bytes). >> > > Well, for utf8 NextChar could advance to the next char even if the > current byte > position is in the middle of a multibyte char (skip over all 10xxxxxx). > > > It doesn't matter - we are satisfied that it won't happen. However, this might well be a useful optimisation of NextChar() for the UTF8 case as something like do { (t)++; (tlen)--} while ((*(t) & 0xC0) == 0x80 && tlen > 0) In fact, I'm wondering if that might make the other UTF8 stuff redundant - the whole point of what we're doing is to avoid expensive calls to NextChar; cheers andrew
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