encode::supported.3

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

\&\*(L"Microsoft-related naming mess\*(R" gives details.
.PP
\&\f(CW\*(C`GB2312\*(C'\fR is the \s-1IANA\s0 name for \f(CW\*(C`EUC\-CN\*(C'\fR.
See \*(L"Microsoft-related naming mess\*(R" for details.
.PP
\&\f(CW\*(C`GB_2312\-80\*(C'\fR \fIraw\fR encoding is available as \f(CW\*(C`gb2312\-raw\*(C'\fR
with Encode. See Encode::CN for details.
.PP
.Vb 2
\&  EUC\-CN
\&  KOI8\-U        [RFC2319]
.Ve
.PP
have not been registered with \s-1IANA\s0 (as of March 2002) but
seem to be supported by major web browsers. 
The \s-1IANA\s0 name for \f(CW\*(C`EUC\-CN\*(C'\fR is \f(CW\*(C`GB2312\*(C'\fR.
.PP
.Vb 1
\&  KS_C_5601\-1987
.Ve
.PP
is heavily misused.
See \*(L"Microsoft-related naming mess\*(R" for details.
.PP
\&\f(CW\*(C`KS_C_5601\-1987\*(C'\fR \fIraw\fR encoding is available as \f(CW\*(C`kcs5601\-raw\*(C'\fR
with Encode. See Encode::KR for details.
.PP
.Vb 1
\&  UTF\-16 UTF\-16BE UTF\-16LE
.Ve
.PP
are IANA-registered \f(CW\*(C`charset\*(C'\fRs. See [\s-1RFC\s0 2781] for details.
Jungshik Shin reports that \s-1UTF\-16\s0 with a \s-1BOM\s0 is well accepted
by \s-1MS\s0 \s-1IE\s0 5/6 and \s-1NS\s0 4/6. Beware however that
.IP "\(bu" 2
\&\f(CW\*(C`UTF\-16\*(C'\fR support in any software you're going to be
using/interoperating with has probably been less tested
then \f(CW\*(C`UTF\-8\*(C'\fR support
.IP "\(bu" 2
\&\f(CW\*(C`UTF\-8\*(C'\fR coded data seamlessly passes traditional
command piping (\f(CW\*(C`cat\*(C'\fR, \f(CW\*(C`more\*(C'\fR, etc.) while \f(CW\*(C`UTF\-16\*(C'\fR coded
data is likely to cause confusion (with its zero bytes,
for example)
.IP "\(bu" 2
it is beyond the power of words to describe the way \s-1HTML\s0 browsers
encode non\-\f(CW\*(C`ASCII\*(C'\fR form data. To get a general impression, visit
<http://ppewww.ph.gla.ac.uk/~flavell/charset/form\-i18n.html>.
While encoding of form data has stabilized for \f(CW\*(C`UTF\-8\*(C'\fR encoded pages
(at least \s-1IE\s0 5/6, \s-1NS\s0 6, and Opera 6 behave consistently), be sure to
expect fun (and cross-browser discrepancies) with \f(CW\*(C`UTF\-16\*(C'\fR encoded
pages!
.PP
The rule of thumb is to use \f(CW\*(C`UTF\-8\*(C'\fR unless you know what
you're doing and unless you really benefit from using \f(CW\*(C`UTF\-16\*(C'\fR.
.PP
.Vb 5
\&  ISO\-IR\-165    [RFC1345]
\&  VISCII
\&  GB 12345
\&  GB 18030 (**)  (see links bellow)
\&  EUC\-TW   (**)
.Ve
.PP
are totally valid encodings but not registered at \s-1IANA\s0.
The names under which they are listed here are probably the
most widely-known names for these encodings and are recommended
names.
.PP
.Vb 1
\&  BIG5PLUS (**)
.Ve
.PP
is a proprietary name.
.Sh "Microsoft-related naming mess"
.IX Subsection "Microsoft-related naming mess"
Microsoft products misuse the following names:
.IP "\s-1KS_C_5601\-1987\s0" 2
.IX Item "KS_C_5601-1987"
Microsoft extension to \f(CW\*(C`EUC\-KR\*(C'\fR.
.Sp
Proper names: \f(CW\*(C`CP949\*(C'\fR, \f(CW\*(C`UHC\*(C'\fR, \f(CW\*(C`x\-windows\-949\*(C'\fR (as used by Mozilla).
.Sp
See <http://lists.w3.org/Archives/Public/ietf\-charsets/2001AprJun/0033.html>
for details.
.Sp
Encode aliases \f(CW\*(C`KS_C_5601\-1987\*(C'\fR to \f(CW\*(C`cp949\*(C'\fR to reflect this common
misusage. \fIRaw\fR \f(CW\*(C`KS_C_5601\-1987\*(C'\fR encoding is available as
\&\f(CW\*(C`kcs5601\-raw\*(C'\fR.
.Sp
See Encode::KR for details.
.IP "\s-1GB2312\s0" 2
.IX Item "GB2312"
Microsoft extension to \f(CW\*(C`EUC\-CN\*(C'\fR.
.Sp
Proper names: \f(CW\*(C`CP936\*(C'\fR, \f(CW\*(C`GBK\*(C'\fR.
.Sp
\&\f(CW\*(C`GB2312\*(C'\fR has been registered in the \f(CW\*(C`EUC\-CN\*(C'\fR meaning at
\&\s-1IANA\s0. This has partially repaired the situation: Microsoft's 
\&\f(CW\*(C`GB2312\*(C'\fR has become a superset of the official \f(CW\*(C`GB2312\*(C'\fR.
.Sp
Encode aliases \f(CW\*(C`GB2312\*(C'\fR to \f(CW\*(C`euc\-cn\*(C'\fR in full agreement with
\&\s-1IANA\s0 registration. \f(CW\*(C`cp936\*(C'\fR is supported separately.
\&\fIRaw\fR \f(CW\*(C`GB_2312\-80\*(C'\fR encoding is available as \f(CW\*(C`gb2312\-raw\*(C'\fR.
.Sp
See Encode::CN for details.
.IP "Big5" 2
.IX Item "Big5"
Microsoft extension to \f(CW\*(C`Big5\*(C'\fR.
.Sp
Proper name: \f(CW\*(C`CP950\*(C'\fR.
.Sp
Encode separately supports \f(CW\*(C`Big5\*(C'\fR and \f(CW\*(C`cp950\*(C'\fR.
.IP "Shift_JIS" 2
.IX Item "Shift_JIS"
Microsoft's understanding of \f(CW\*(C`Shift_JIS\*(C'\fR.
.Sp
\&\s-1JIS\s0 has not endorsed the full Microsoft standard however.
The official \f(CW\*(C`Shift_JIS\*(C'\fR includes only \s-1JIS\s0 X 0201 and \s-1JIS\s0 X 0208
character sets, while Microsoft has always used \f(CW\*(C`Shift_JIS\*(C'\fR
to encode a wider character repertoire. See \f(CW\*(C`IANA\*(C'\fR registration for
\&\f(CW\*(C`Windows\-31J\*(C'\fR.
.Sp
As a historical predecessor, Microsoft's variant
probably has more rights for the name, though it may be objected
that Microsoft shouldn't have used \s-1JIS\s0 as part of the name
in the first place.
.Sp
Unambiguous name: \f(CW\*(C`CP932\*(C'\fR. \f(CW\*(C`IANA\*(C'\fR name (also used by Mozilla, and
provided as an alias by Encode): \f(CW\*(C`Windows\-31J\*(C'\fR.
.Sp
Encode separately supports \f(CW\*(C`Shift_JIS\*(C'\fR and \f(CW\*(C`cp932\*(C'\fR.
.SH "Glossary"
.IX Header "Glossary"
.IP "character repertoire" 2
.IX Item "character repertoire"
A collection of unique characters.  A \fIcharacter\fR set in the strictest
sense. At this stage, characters are not numbered.
.IP "coded character set (\s-1CCS\s0)" 2
.IX Item "coded character set (CCS)"
A character set that is mapped in a way computers can use directly.
Many character encodings, including \s-1EUC\s0, fall in this category.
.IP "character encoding scheme (\s-1CES\s0)" 2
.IX Item "character encoding scheme (CES)"
An algorithm to map a character set to a byte sequence.  You don't
have to be able to tell which character set a given byte sequence
belongs.  7\-bit \s-1ISO\-2022\s0 is a \s-1CES\s0 but it cannot be a \s-1CCS\s0.  \s-1EUC\s0 is an
example of being both a \s-1CCS\s0 and \s-1CES\s0.
.IP "charset (in \s-1MIME\s0 context)" 2
.IX Item "charset (in MIME context)"
has long been used in the meaning of \f(CW\*(C`encoding\*(C'\fR, \s-1CES\s0.
.Sp
While the word combination \f(CW\*(C`character set\*(C'\fR has lost this meaning
in \s-1MIME\s0 context since [\s-1RFC\s0 2130], the \f(CW\*(C`charset\*(C'\fR abbreviation has
retained it. This is how [\s-1RFC\s0 2277] and [\s-1RFC\s0 2278] bless \f(CW\*(C`charset\*(C'\fR:
.Sp
.Vb 7
\& This document uses the term "charset" to mean a set of rules for
\& mapping from a sequence of octets to a sequence of characters, such
\& as the combination of a coded character set and a character encoding
\& scheme; this is also what is used as an identifier in MIME "charset="
\& parameters, and registered in the IANA charset registry ...  (Note
\& that this is NOT a term used by other standards bodies, such as ISO).
\& [RFC 2277]
.Ve
.IP "\s-1EUC\s0" 2
.IX Item "EUC"
Extended Unix Character.  See \s-1ISO\-2022\s0.
.IP "\s-1ISO\-2022\s0" 2
.IX Item "ISO-2022"
A \s-1CES\s0 that was carefully designed to coexist with \s-1ASCII\s0.  There are a 7
bit version and an 8 bit version.
.Sp
The 7 bit version switches character set via escape sequence so it
cannot form a \s-1CCS\s0.  Since this is more difficult to handle in programs
than the 8 bit version, the 7 bit version is not very popular except for
iso\-2022\-jp, the \fIde facto\fR standard \s-1CES\s0 for e\-mails.
.Sp
The 8 bit version can form a \s-1CCS\s0.  \s-1EUC\s0 and \s-1ISO\-8859\s0 are two examples
thereof.  Pre\-5.6 perl could use them as string literals.
.IP "\s-1UCS\s0" 2
.IX Item "UCS"
Short for \fIUniversal Character Set\fR.  When you say just \s-1UCS\s0, it means
\&\fIUnicode\fR.
.IP "\s-1UCS\-2\s0" 2
.IX Item "UCS-2"
\&\s-1ISO/IEC\s0 10646 encoding form: Universal Character Set coded in two
octets.
.IP "Unicode" 2
.IX Item "Unicode"
A character set that aims to include all character repertoires of the
world.  Many character sets in various national as well as industrial
standards have become, in a way, just subsets of Unicode.
.IP "\s-1UTF\s0" 2
.IX Item "UTF"
Short for \fIUnicode Transformation Format\fR.  Determines how to map a
Unicode character into a byte sequence.
.IP "\s-1UTF\-16\s0" 2
.IX Item "UTF-16"
A \s-1UTF\s0 in 16\-bit encoding.  Can either be in big endian or little
endian.  The big endian version is called \s-1UTF\-16BE\s0 (equal to \s-1UCS\-2\s0 + 
surrogate support) and the little endian version is called \s-1UTF\-16LE\s0.
.SH "See Also"
.IX Header "See Also"
Encode, 
Encode::Byte, 
Encode::CN, Encode::JP, Encode::KR, Encode::TW,
Encode::EBCDIC, Encode::Symbol
Encode::MIME::Header, Encode::Guess
.SH "References"
.IX Header "References"
.IP "\s-1ECMA\s0" 2
.IX Item "ECMA"
European Computer Manufacturers Association
<http://www.ecma.ch>
.RS 2
.ie n .IP "\s-1ECMA\-035\s0 (eq ""ISO\-2022"")" 2
.el .IP "\s-1ECMA\-035\s0 (eq \f(CWISO\-2022\fR)" 2
.IX Item "ECMA-035 (eq ISO-2022)"
<http://www.ecma.ch/ecma1/STAND/ECMA\-035.HTM>
.Sp
The specification of \s-1ISO\-2022\s0 is available from the link above.
.RE
.RS 2
.RE
.IP "\s-1IANA\s0" 2
.IX Item "IANA"
Internet Assigned Numbers Authority
<http://www.iana.org/>
.RS 2
.IP "Assigned Charset Names by \s-1IANA\s0" 2
.IX Item "Assigned Charset Names by IANA"
<http://www.iana.org/assignments/character\-sets>
.Sp
Most of the \f(CW\*(C`canonical names\*(C'\fR in Encode derive from this list
so you can directly apply the string you have extracted from \s-1MIME\s0
header of mails and web pages.
.RE
.RS 2
.RE
.IP "\s-1ISO\s0" 2
.IX Item "ISO"
International Organization for Standardization
<http://www.iso.ch/>
.IP "\s-1RFC\s0" 2
.IX Item "RFC"
Request For Comments \*(-- need I say more?
<http://www.rfc\-editor.org/>, <http://www.rfc.net/>,
<http://www.faqs.org/rfcs/>
.IP "\s-1UC\s0" 2
.IX Item "UC"
Unicode Consortium
<http://www.unicode.org/>
.RS 2
.IP "Unicode Glossary" 2
.IX Item "Unicode Glossary"
<http://www.unicode.org/glossary/>
.Sp
The glossary of this document is based upon this site.
.RE
.RS 2
.RE
.Sh "Other Notable Sites"
.IX Subsection "Other Notable Sites"
.IP "czyborra.com" 2
.IX Item "czyborra.com"
<http://czyborra.com/>
.Sp
Contains a lot of useful information, especially gory details of \s-1ISO\s0
vs. vendor mappings.
.IP "\s-1CJK\s0.inf" 2
.IX Item "CJK.inf"
<http://www.oreilly.com/people/authors/lunde/cjk_inf.html>
.Sp
Somewhat obsolete (last update in 1996), but still useful.  Also try
.Sp
<ftp://ftp.oreilly.com/pub/examples/nutshell/cjkv/pdf/GB18030_Summary.pdf>
.Sp
You will find brief info on \f(CW\*(C`EUC\-CN\*(C'\fR, \f(CW\*(C`GBK\*(C'\fR and mostly on \f(CW\*(C`GB 18030\*(C'\fR.
.IP "Jungshik Shin's Hangul \s-1FAQ\s0" 2
.IX Item "Jungshik Shin's Hangul FAQ"
<http://jshin.net/faq>
.Sp
And especially its subject 8.
.Sp
<http://jshin.net/faq/qa8.html>
.Sp
A comprehensive overview of the Korean (\f(CW\*(C`KS *\*(C'\fR) standards.
.ie n .IP "debian.org: ""Introduction to i18n""" 2
.el .IP "debian.org: ``Introduction to i18n''" 2
.IX Item "debian.org: Introduction to i18n"
A brief description for most of the mentioned \s-1CJK\s0 encodings is
contained in
<http://www.debian.org/doc/manuals/intro\-i18n/ch\-codes.en.html>
.Sh "Offline sources"
.IX Subsection "Offline sources"
.ie n .IP """CJKV Information Processing"" by Ken Lunde" 2
.el .IP "\f(CWCJKV Information Processing\fR by Ken Lunde" 2
.IX Item "CJKV Information Processing by Ken Lunde"
\&\s-1CJKV\s0 Information Processing
1999 O'Reilly & Associates, \s-1ISBN\s0 : 1\-56592\-224\-7
.Sp
The modern successor of \f(CW\*(C`CJK.inf\*(C'\fR.
.Sp
Features a comprehensive coverage of \s-1CJKV\s0 character sets and
encodings along with many other issues faced by anyone trying
to better support \s-1CJKV\s0 languages/scripts in all the areas of
information processing.
.Sp
To purchase this book, visit
<http://www.oreilly.com/catalog/cjkvinfo/>
or your favourite bookstore.