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Date: Thu, 10 Jun 1999 10:14:10 +0800 (CST)
From: Michael Robinson <robinson@netrinsics.com>
Message-Id: <199906100214.KAA11420@netrinsics.com>
To: pgsql-hackers@hub.org
Subject: Re: [HACKERS] Postgres 6.5 beta2 and beta3 problem 

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