From: Michael Robinson <robinson@netrinsics.com>
To: pgsql-hackers@hub.org
Subject: Re: [HACKERS] Postgres 6.5 beta2 and beta3 problem
Date: Thu, 10 Jun 1999 10:14:10 +0800 (CST)
Message-ID: <199906100214.KAA11420@netrinsics.com> (raw)
Hannu Krosing <hannu@trust.ee> writes:
>in single-byte locales it should be easy:
If you do it right, in double-byte locales as well.
>1. sort a char[256] array from 0-255 using the current locale settings,
> do it once, either at startup or when first needed.
Or, alternatively, maintain per-locale table files and mmap them.
>2. use binary search on that array to locate the last char before %
> in this sorted array:
Or, alternatively, maintain another table that maps char values to
lexicographic order (and a per-locale constant for maximum character
order value):
> if (it is not the last char in sorted array)
> then (replace that char with the one at index+1)
> else (
> if (it is not the first char in like string)
> then (discard the last char and goto 2.
> else (don't do the end restriction)
> )
if ( (nextindex = charorder[c]+1) <= maxchar ) {
nextchar = charmap[nextindex];
} else {
no nextchar, append charmap[maxchar] to LIKE base string
}
I don't see where the pain is, but I may be missing something.
-Michael Robinson
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To: pgsql-hackers@postgresql.org
Cc: robinson@netrinsics.com, pgsql-hackers@hub.org
Subject: Re: [HACKERS] Postgres 6.5 beta2 and beta3 problem
In-Reply-To: <199906100214.KAA11420@netrinsics.com>
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