Re: Q: something like autoload for coding-systems?

[Kenichi Handa]

Richard Stallman <address@hidden> writes:
>                 I've just checked how big the interval list
>     will be for GB2312 charset.  I tried to make a vector of the
>     forms [ (FROM-CHAR . TO-CHAR) ... ], and to optimize, if
>     FROM-CHAR == TO-CHAR, put FROM-CHAR in a element instead of
>     cons.  Provided that each number consumes one word, and each
>     cons consumes three words, the vector roughly consumes 6300
>     words.  It's about 25K-byte.  It is surely smaller than the
>     whole mapping table.

> Can these codes fit in 16 bits?

No.

> Depending on the patterns of coverage, other data types such as
> bitmaps and run-length-encodings of bitmaps could provide more dense
> representations, especially if they can be used for just parts of the
> code space.

It uses less space, but, isn't it time-consuming to check if
a specific character is included or not with such an format?

> Another idea: instead of one table for each coding system, have a
> common table for characters covered by all the Chinese coding systems,
> and then a table of extra characters for each one.  Maybe this
> would save further space.

No.  I checked it for Big5, GB2312, and CNS.  Less than 10%
of chinese characters belongs to all of them, even if we
take care only BMP of Unicode.

---
Ken'ichi HANDA
address@hidden