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Re: Emacs 23 character code space
From: |
Kenichi Handa |
Subject: |
Re: Emacs 23 character code space |
Date: |
Fri, 07 Nov 2008 20:52:37 +0900 |
In article <address@hidden>, Eli Zaretskii <address@hidden> writes:
> Thanks. But I'm still a bit in the dark, as for how to describe this
> correctly and concisely. Do we actually use the range of codes
> between 0x110000 and 0x3FFF7F? If so, for what characters? If we do
> not use them now, are there some plans for using them in the future?
I wrote about the usage of that area in the thread "size of
emacs executable after unicode merge" as below.
> (0) At first, Emacs assigns a unique linear character code
> space in upper Unicode area (#x110000-) to each big
> character set (e.g. GB, JIS, KSC) (*see the note at the
> tail). The decoding of a character of a specific
> charset into this area is quite fast (done just by a few
> steps of arithmetic calculation). Encoding is the same
> too.
[...]
> *Note:
>
> The reason Emacs assigns those linear area is because such
> big charsets tend to have their own private use area, and we
> must keep a unique characte code for them. Those private
> characters are decoded and encoded without being mapped to
> Unicode are.
For example, the charset `japanese-jisx0208' is defined as
below.
(define-charset 'japanese-jisx0208
"JISX0208.1983/1990 Japanese Kanji: ISO-IR-87"
:short-name "JISX0208"
:long-name "JISX0208.1983/1990 (Japanese): ISO-IR-87"
:iso-final-char ?B
:emacs-mule-id 146
:code-space [33 126 33 126]
:code-offset #x140000
:unify-map "JISX0208")
So, for that charset, the code space for 8836 (=94x94)
characters are preserved in that upper area linearly from
#x140000. Then, most of the characters are mapped into
Unicode area by the map "JISX0208". The remaining
characters stay in this upper area.
---
Kenichi Handa
address@hidden
- Re: Emacs 23 character code space, (continued)
- Re: Emacs 23 character code space, Eli Zaretskii, 2008/11/23
- Re: Emacs 23 character code space, Kenichi Handa, 2008/11/25
- Re: Emacs 23 character code space, Ulrich Mueller, 2008/11/23
- Re: Emacs 23 character code space, Eli Zaretskii, 2008/11/23
- Re: Emacs 23 character code space, Ulrich Mueller, 2008/11/23
- Re: Emacs 23 character code space, Stefan Monnier, 2008/11/23
- Re: Emacs 23 character code space, Kenichi Handa, 2008/11/25
- New function: what-file-line, used when writing gdb script, richardeng, 2008/11/22
Re: Emacs 23 character code space, Kenichi Handa, 2008/11/07