Andrew Dunstan <[EMAIL PROTECTED]> writes:
> OK, here is a patch that I think incorporates all the ideas discussed 
> (including part of Mark Mielke's suggestion about optimising %_). There 
> is now no special treatment of UTF8 other than its use of a faster 
> NextChar macro.

Looks mostly pretty good.  I would suggest replacing tests "tlen == 0"
and "plen == 0" with "<= 0", just so the code doesn't go completely
insane if presented with invalidly-encoded data that causes it to step
beyond the end of data.  Also, this comment is not really good enough:

> !             /*
> !              * It is safe to use NextByte instead of NextChar here, even for
> !              * multi-byte character sets, because we are not following 
> !              * immediately after a wildcard character.
> !              */
> !             NextByte(t, tlen);
> !             NextByte(p, plen);
>       }

I'd suggest adding something like "If we are in the middle of a
multibyte character, we must already have matched at least one byte of
the character from both text and pattern; so we cannot get out-of-sync
on character boundaries.  And we know that no backend-legal encoding
allows ASCII characters such as '%' to appear as non-first bytes of
characters, so we won't mistakenly detect a new wildcard."

                        regards, tom lane

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