Re: Unicode width data inconsistent/outdated

[Thomas Wolff <towo@towo.net>]

Hi Brian,

Am 07.08.2017 um 21:07 schrieb Brian Inglis:
> ...
> Implementation considerations for handling the Unicode tables described in
> 	http://www.unicode.org/versions/Unicode10.0.0/ch05.pdf
> and implemented in
> 	https://www.strchr.com/multi-stage_tables
>
> ICU icu4[cj] uses a folded trie of the properties, where the unique property
> combinations are indexed, strings of those indices are generated for fixed size
> groups of character codes, unique values of those strings are then indexed, and
> those indices assigned to each character code group. The result is a multi-level
> indexing operation that returns the required property combination for each
> character.
>
> https://slidegur.com/doc/4172411/folded-trie--efficient-data-structure-for-all-of-unicode
>
> The FOX Toolkit uses a similar approach, splitting the 21 bit character code
> into 7 bit groups, with two higher levels of 7 bit indices, and more tweaks to
> eliminate redundancy.
>
> ftp://ftp.fox-toolkit.org/pub/FOX_Unicode_Tables.pdf
>
Thanks for the interesting links, I'll chech them out.
But such multi-level tables don't really help without a given procedure 
how to update them (that's only available for the lowest level, not for 
the code-embedded levels).
Also, as I've demonstrated, my more straight-forward and more efficient 
approach will even use less total space than the multi-level approach if 
packed table entries are used.
Thomas

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple