Re: UCS-2BE

[Kenichi Handa <handa@m17n.org>]

Thank you for the info! 

In article <wl3bbbvn71.wl%mituharu@math.s.chiba-u.ac.jp>, YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp> writes:

> "Unicode Technical Report #17, Character Encoding Model"
> (http://www.unicode.org/reports/tr17/index.html) says:
[...]
>   Examples of Unicode Character Encoding Schemes:
[...]
>     Unicode 1.1 had three character encoding schemes: UTF-8, UCS-2BE,
>     and UCS-2LE, although the latter two were not named that way at
>     the time.

Ah!  So here we can see the term "UCS-2BE" as CES.  But how
it was defined? (I don't have Unicode 1.1)

> I suspect "UCS-2BE" is just a customary name and not explicitly
> defined even in ISO/IEC 10646.

> "UTF-8 and Unicode FAQ" (http://www.cl.cam.ac.uk/~mgk25/unicode.html)
> says:

>   No endianess is implied by the encoding names UCS-2, UCS-4, UTF-16,
>   and UTF-32, though ISO 10646-1 says that Bigendian should be
>   preferred unless otherwise agreed.  It has become customary to
>   append the letters "BE" (Bigendian, high-byte first) and "LE"
>   (Littleendian, low-byte first) to the encoding names in order to
>   explicitly specify a byte order.

I don't know how much authorized this page is, but it also
says:

    A full featured character encoding converter will have
    to provide the following 13 encoding variants of Unicode
    and UCS:

	UCS-2, UCS-2BE, UCS-2LE, UCS-4, UCS-4LE, UCS-4BE,
	UTF-8, UTF-16, UTF-16BE, UTF-16LE, UTF-32, UTF-32BE,
	UTF-32LE

It seems that UCS-2BE is not a mis-label of UTF-16BE, then,
it seems that treating it as a subset (not using surrogate
pair) of UTF-16BE (as done in iconv) is the right thing.
I'll try to implement it (and others) in emacs-unicode-2.

By the way, why do people want such many variants... sigh...

---
Kenichi Handa
handa@m17n.org