encode::supported(3)

NAME

Encode::Supported -- Encodings supported by Encode

DESCRIPTION

Encoding Names

Encoding names are case insensitive. White space in names
is ignored. In addition, an encoding may have aliases.
Each encoding has one "canonical" name. The "canonical"
name is chosen from the names of the encoding by picking
the first in the following sequence (with a few excep
tions).

� The name used by the Perl community. That includes: 'utf8' and 'ascii'. Unlike aliases, canonical names
directly reach the method so such frequently used
words like 'utf8' don't need to do alias lookups.
� The MIME name as defined in IETF RFCs. This includes: all "iso-"s.
� The name in the IANA registry.
� The name used by the organization that defined it.
In case de jure canonical names differ from that of the Encode module, they are always aliased if it ever be implemented. So you can safely tell if a given encoding is implemented or not just by passing the canonical name.
Because of all the alias issues, and because in the gen eral case encodings have state, "Encode" uses an encoding object internally once an operation is in progress.

Supported Encodings

As of Perl 5.8.0, at least the following encodings are
recognized. Note that unless otherwise specified, they
are all case insensitive (via alias) and all occurrence of
spaces are replaced with '-'. In other words, "ISO 8859
1" and "iso-8859-1" are identical.

Encodings are categorized and implemented in several dif
ferent modules but you don't have to "use Encode::XX" to
make them available for most cases. Encode.pm will auto
matically load those modules on demand.

Built-in Encodings

The following encodings are always available.: Canonical Aliases Comments &; References
---------------------------------------------------------------ascii US-ascii ISO-646-US; [ECMA]
ascii-ctrl Special; Encoding
iso-8859-1 latin1; [ISO]
null Special; Encoding
utf8 UTF-8; [RFC2279]
---------------------------------------------------------------
null and ascii-ctrl are special. "null" fails for all character so when you set fallback mode to PERLQQ, HTML CREF or XMLCREF, ALL CHARACTERS will fall back to character references. Ditto for "ascii-ctrl" except for control characters. For fallback modes, see Encode.
Encode::Unicode -- other Unicode encodings
Unicode coding schemes other than native utf8 are sup ported by Encode::Unicode, which will be autoloaded on demand.: ---------------------------------------------------------------UCS-2BE UCS-2, iso-10646-1; [IANA, UC]
UCS-2LE; [UC]
UTF-16; [UC]
UTF-16BE; [UC]
UTF-16LE; [UC]
UTF-32; [UC]
UTF-32BE UCS-4; [UC]
UTF-32LE; [UC]
---------------------------------------------------------------
To find how (UCS-2|UTF-(16|32))(LE|BE)? differ from one another, see Encode::Unicode.
Encode::Byte -- Extended ASCII
Encode::Byte implements most single-byte encodings except for Symbols and EBCDIC. The following encodings are based on single-byte encodings implemented as extended ASCII. Most of them map 0- (upper half) to non-ASCII char acters.
ISO-8859 and corresponding vendor mappings: Since there are so many, they are presented in table
format with languages and corresponding encoding names
by vendors. Note that the table is sorted in order of
ISO-8859 and the corresponding vendor mappings are
slightly different from that of ISO. See <http://czy
borra.com/charsets/iso8859.html> for details.

Lang/Regions ISO/Other Std. DOS Windows Macin

tosh Others
---------------------------------------------------------------N. America (ASCII) cp437 Adobe

StandardEncoding
cp863 (DOSCanadaF)

W. Europe iso-8859-1 cp850 cp1252 MacRo

man nextstep

hp

roman8

cp860 (DOSPortuguese); Cntrl. Europe iso-8859-2 cp852 cp1250 Mac; CentralEurRoman
Mac

Croatian
MacRo

manian
MacRu

manian; Latin3 [1] iso-8859-3
Latin4 [2] iso-8859-4
Cyrillics iso-8859-5 cp855 cp1251 Mac; Cyrillic
(See also next section) cp866

MacUkrainian; Arabic iso-8859-6 cp864 cp1256; MacArabic
cp1006 Mac

Farsi; Greek iso-8859-7 cp737 cp1253 Mac; Greek
cp869 (DOSGreek2); Hebrew iso-8859-8 cp862 cp1255 MacHe; brew
Turkish iso-8859-9 cp857 cp1254 Mac; Turkish
Nordics iso-8859-10 cp865
cp861 MacI

celandic
MacSa

mi

Thai iso-8859-11 [3] cp874 Mac

Thai
(iso-8859-12 is nonexistent. Reserved for Indics?)
Baltics iso-8859-13 cp775 cp1257
Celtics iso-8859-14
Latin9 [4] iso-8859-15
Latin10 iso-8859-16
Vietnamese viscii cp1258

MacVietnamese
---------------------------------------------------------------

[1] Esperanto, Maltese, and Turkish. Turkish is now

on 8859-9.
[2] Baltics. Now on 8859-10, except for Latvian.
[3] Also know as TIS 620.
[4] Nicknamed Latin0; the Euro sign as well as

French and Finnish

letters that are missing from 8859-1 were added.

All cp* are also available as ibm-*, ms-*, and win
dows-* . See also <http://czyborra.com/charsets/code
pages.html>.

Macintosh encodings don't seem to be registered in
such entities as IANA. "Canonical" names in Encode
are based upon Apple's Tech Note 1150. See
<http://developer.apple.com/technotes/tn/tn1150.html>
for details.; KOI8 - De Facto Standard for the Cyrillic world
Though ISO-8859 does have ISO-8859-5, the KOI8 series
is far more popular in the Net. Encode comes with
the following KOI charsets. For gory details, see
<http://czyborra.com/charsets/cyrillic.html>

---------------------------------------------------------------koi8-f
koi8-r cp878

[RFC1489]
koi8-u

[RFC2319]
---------------------------------------------------------------

gsm0338 - Hentai Latin 1

GSM0338 is for GSM handsets. Though it shares alphanu
merals with ASCII, control character ranges and other
parts are mapped very differently, presumably to store
Greek and Cyrillic alphabets. This is also covered in
Encode::Byte even though it is not an "extended ASCII"
encoding.

CJK: Chinese, Japanese, Korean (Multibyte)

Note that Vietnamese is listed above. Also read "Encoding
vs Charset" below. Also note that these are implemented
in distinct modules by countries, due the the size con
cerns (simplified Chinese is mapped to 'CN', continental
China, while traditional Chinese is mapped to 'TW', Tai
wan). Please refer to their respective documentataion
pages.

Encode::CN -- Continental China

Standard DOS/Win Macintosh Com

ment/Reference
---------------------------------------------------------------euc-cn [1] MacChineseSimp
(gbk) cp936 [2]
gb12345-raw { GB12345 without

CES }
gb2312-raw { GB2312 without

CES }
hz
iso-ir-165
---------------------------------------------------------------

[1] GB2312 is aliased to this. See L<Microsoft-re

lated naming mess>
[2] gbk is aliased to this. See L<Microsoft-related

naming mess>

Encode::JP -- Japan

Standard DOS/Win Macintosh Com

ment/Reference
---------------------------------------------------------------euc-jp
shiftjis cp932 macJapanese
7bit-jis
iso-2022-jp

[RFC1468]
iso-2022-jp-1

[RFC2237]
jis0201-raw { JIS X 0201 (roman + halfwidth kana)

without CES }
jis0208-raw { JIS X 0208 (Kanji + fullwidth kana)

without CES }
jis0212-raw { JIS X 0212 (Extended Kanji)

without CES }
---------------------------------------------------------------

Encode::KR -- Korea

Standard DOS/Win Macintosh Com

ment/Reference
---------------------------------------------------------------euc-kr MacKorean

[RFC1557]
cp949 [1]

iso-2022-kr

[RFC1557]
johab [KS X

1001:1998, Annex 3]
ksc5601-raw { KSC5601

without CES }
---------------------------------------------------------------

[1] ks_c_5601-1987, (x-)?windows-949, and uhc are

aliased to this.
See below.

Encode::TW -- Taiwan

Standard DOS/Win Macintosh Com

ment/Reference
---------------------------------------------------------------big5-eten cp950 MacChineseTrad {big5 aliased

to big5-eten}
big5-hkscs
---------------------------------------------------------------

Encode::HanExtra -- More Chinese via CPAN

Due to size concerns, additional Chinese encodings
below are distributed separately on CPAN, under the
name Encode::HanExtra.

Standard DOS/Win Macintosh Com

ment/Reference
---------------------------------------------------------------big5ext CMEX's

Big5e Extension
big5plus CMEX's

Big5+ Extension
cccii Chinese Character Code for Information

Interchange
euc-tw EUC (Extended

Unix Character)
gb18030 GBK with Tradition

al Characters
---------------------------------------------------------------

Encode::JIS2K -- JIS X 0213 encodings via CPAN

Due to size concerns, additional Japanese encodings
below are distributed separately on CPAN, under the
name Encode::JIS2K.

Standard DOS/Win Macintosh Com

ment/Reference
---------------------------------------------------------------euc-jisx0213
shiftjisx0123
iso-2022-jp-3
jis0213-1-raw
jis0213-2-raw
---------------------------------------------------------------

Miscellaneous encodings

Encode::EBCDIC

See perlebcdic for details.

---------------------------------------------------------------cp37
cp500
cp875
cp1026
cp1047
posix-bc
---------------------------------------------------------------

Encode::Symbols

For symbols and dingbats.

---------------------------------------------------------------symbol
dingbats
MacDingbats
AdobeZdingbat
AdobeSymbol
---------------------------------------------------------------

Encode::MIME::Header

Strictly speaking, MIME header encoding documented in
RFC 2047 is more of encapsulation than encoding. But
included anyway.

---------------------------------------------------------------MIME-Header

[RFC2047]
MIME-B

[RFC2047]
MIME-Q

[RFC2047]
---------------------------------------------------------------

Encode::Guess

This one is not a name of encoding but a utility that
lets you pick up the most appropriate encoding for a
data out of given suspects. See Encode::Guess for details.

Unsupported encodings

The following encodings are not supported as yet; some
because they are rarely used, some because of technical
difficulties. They may be supported by external modules
via CPAN in the future, however.

ISO-2022-JP-2 [RFC1554]: Not very popular yet. Needs Unicode Database or
equivalent to implement encode() (because it includes JIS X 0208/0212, KSC5601, and GB2312 simultaneously,
whose code points in Unicode overlap. So you need to
lookup the database to determine to what character set
a given Unicode character should belong).
ISO-2022-CN [RFC1922]: Not very popular. Needs CNS 11643-1 and -2 which are
not available in this module. CNS 11643 is supported
(via euc-tw) in Encode::HanExtra. Autrijus Tang may
add support for this encoding in his module in future.
Various HP-UX encodings: The following are unsupported due to the lack of map
ping data.

'8' - arabic8, greek8, hebrew8, kana8, thai8, and

turkish8
'15' - japanese15, korean15, and roi15; Cyrillic encoding ISO-IR-111
Anton Tagunov doubts its usefulness.; ISO-8859-8-1 [Hebrew]
None of the Encode team knows Hebrew enough
(ISO-8859-8, cp1255 and MacHebrew are supported
because and just because there were mappings available
at <http://www.unicode.org/>). Contributions welcome.; ISIRI 3342, Iran System, ISIRI 2900 [Farsi]
Ditto.; Thai encoding TCVN
Ditto.; Vietnamese encodings VPS
Though Jungshik Shin has reported that Mozilla sup
ports this encoding, it was too late before 5.8.0 for
us to add it. In the future, it may be available via
a separate module. See <http://lxr.mozilla.org/sea
monkey/source/intl/uconv/ucvlatin/vps.uf> and
<http://lxr.mozilla.org/seamon
key/source/intl/uconv/ucvlatin/vps.ut> if you are
interested in helping us.; Various Mac encodings
The following are unsupported due to the lack of map
ping data.

MacArmenian, MacBengali, MacBurmese,

MacEthiopic
MacExtArabic, MacGeorgian, MacKannada, MacKhmer
MacLaotian, MacMalayalam, MacMongolian, MacOriya
MacSinhalese, MacTamil, MacTelugu, MacTibetan
MacVietnamese

The rest which are already available are based upon
the vendor mappings at <http://www.unicode.org/Pub
lic/MAPPINGS/VENDORS/APPLE/> .; (Mac) Indic encodings
The maps for the following are available at
<http://www.unicode.org/> but remain unsupport because
those encodings need algorithmical approach, currently
unsupported by enc2xs:

MacDevanagari
MacGurmukhi
MacGujarati

For details, please see "Unicode mapping issues and
notes:" at <http://www.unicode.org/Public/MAP
PINGS/VENDORS/APPLE/DEVANAGA.TXT> .

I believe this issue is prevalent not only for Mac
Indics but also in other Indic encodings, but the
above were the only Indic encodings maps that I could
find at <http://www.unicode.org/> .

Encoding vs. Charset -- terminology

We are used to using the term (character) encoding and character set interchangeably. But just as confusing the terms byte and character is dangerous and the terms should
be differentiated when needed, we need to differentiate
encoding and character set.

To understand that, here is a description of how we make
computers grok our characters.

� First we start with which characters to include. We: call this collection of characters character reper_ toire.
� Then we have to give each character a unique ID so: your computer can tell the difference between 'a' and
'A'. This itemized character repertoire is now a
character set.
� If your computer can grow the character set without: further processing, you can go ahead and use it. This
is called a coded character set (CCS) or raw character encoding. ASCII is used this way for most cases.
� But in many cases, especially multi-byte CJK encod: ings, you have to tweak a little more. Your network
connection may not accept any data with the Most Sig
nificant Bit set, and your computer may not be able to
tell if a given byte is a whole character or just half
of it. So you have to encode the character set to use it.; A character encoding scheme (CES) determines how to encode a given character set, or a set of multiple
character sets. 7bit ISO-2022 is an example of a CES.
You switch between character sets via escape
sequences.
Technically, or mathematically, speaking, a character set encoded in such a CES that maps character by character may form a CCS. EUC is such an example. The CES of EUC is as follows:
� Map ASCII unchanged.
� Map such a character set that consists of 94 or 96: powered by N members by adding 0x80 to each byte.
� You can also use 0x8e and 0x8f to indicate that the: following sequence of characters belongs to yet
another character set. To each following byte is
added the value 0x80.
By carefully looking at the encoded byte sequence, you can find that the byte sequence conforms a unique number. In that sense, EUC is a CCS generated by a CES above from up to four CCS (complicated?). UTF-8 falls into this cate gory. See "UTF-8" in perlUnicode to find out how UTF-8 maps Unicode to a byte sequence.
You may also have found out by now why 7bit ISO-2022 can not comprise a CCS. If you look at a byte sequence 11, you can't tell if it is two !'s or IDEOGRAPHIC SPACE. EUC maps the latter to so you have no
trouble differentiating between "!!". and " ".

Encoding Classification (by Anton Tagunov and Dan Kogai)

This section tries to classify the supported encodings by
their applicability for information exchange over the
Internet and to choose the most suitable aliases to name
them in the context of such communication.

� To (en|de)code encodings marked by "(**)", you need: "Encode::HanExtra", available from CPAN.
Encoding names: US-ASCII UTF-8 ISO-8859-* KOI8-R
Shift_JIS EUC-JP ISO-2022-JP ISO-2022-JP-1
EUC-KR Big5 GB2312
are registered with IANA as preferred MIME names and may be used over the Internet.
"Shift_JIS" has been officialized by JIS X 0208:1997. "Microsoft-related naming mess" gives details.
"GB2312" is the IANA name for "EUC-CN". See "Microsoft-related naming mess" for details.
"GB_2312-80" raw encoding is available as "gb2312-raw" with Encode. See Encode::CN for details.: EUC-CN
KOI8-U [RFC2319]
have not been registered with IANA (as of March 2002) but seem to be supported by major web browsers. The IANA name for "EUC-CN" is "GB2312".: KS_C_5601-1987
is heavily misused. See "Microsoft-related naming mess" for details.
"KS_C_5601-1987" raw encoding is available as "kcs5601-raw" with Encode. See Encode::KR for details.: UTF-16 UTF-16BE UTF-16LE
are IANA-registered "charset"s. See [RFC 2781] for details. Jungshik Shin reports that UTF-16 with a BOM is well accepted by MS IE 5/6 and NS 4/6. Beware however that
� "UTF-16" support in any software you're going to be: using/interoperating with has probably been less
tested then "UTF-8" support
� "UTF-8" coded data seamlessly passes traditional com: mand piping ("cat", "more", etc.) while "UTF-16" coded
data is likely to cause confusion (with its zero
bytes, for example)
� it is beyond the power of words to describe the way: HTML browsers encode non-"ASCII" 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 "UTF-8"
encoded pages (at least IE 5/6, NS 6, and Opera 6
behave consistently), be sure to expect fun (and
cross-browser discrepancies) with "UTF-16" encoded
pages!
The rule of thumb is to use "UTF-8" unless you know what you're doing and unless you really benefit from using "UTF-16".: ISO-IR-165 [RFC1345]
VISCII
GB 12345
GB 18030 (**) (see links bellow)
EUC-TW (**)
are totally valid encodings but not registered at IANA. The names under which they are listed here are probably the most widely-known names for these encodings and are recommended names.: BIG5PLUS (**)
is a proprietary name.
Microsoft-related naming mess
Microsoft products misuse the following names:
KS_C_5601-1987: Microsoft extension to "EUC-KR".; Proper names: "CP949", "UHC", "x-windows-949" (as used
by Mozilla).; See <http://lists.w3.org/Archives/Pub
lic/ietf-charsets/2001AprJun/0033.html> for details.; Encode aliases "KS_C_5601-1987" to "cp949" to reflect
this common misusage. Raw "KS_C_5601-1987" encoding is
available as "kcs5601-raw".; See Encode::KR for details.
GB2312: Microsoft extension to "EUC-CN".; Proper names: "CP936", "GBK".; "GB2312" has been registered in the "EUC-CN" meaning
at IANA. This has partially repaired the situation:
Microsoft's "GB2312" has become a superset of the
official "GB2312".; Encode aliases "GB2312" to "euc-cn" in full agreement
with IANA registration. "cp936" is supported sepa
rately. Raw "GB_2312-80" encoding is available as
"gb2312-raw".; See Encode::CN for details.
Big5: Microsoft extension to "Big5".; Proper name: "CP950".; Encode separately supports "Big5" and "cp950".
Shift_JIS: Microsoft's understanding of "Shift_JIS".; JIS has not endorsed the full Microsoft standard how
ever. The official "Shift_JIS" includes only JIS X
0201 and JIS X 0208 character sets, while Microsoft
has always used "Shift_JIS" to encode a wider charac
ter repertoire. See "IANA" registration for "Win
dows-31J".; As a historical predecessor, Microsoft's variant prob
ably has more rights for the name, though it may be
objected that Microsoft shouldn't have used JIS as
part of the name in the first place.; Unambiguous name: "CP932". "IANA" name (not used?):
"Windows-31J".; Encode separately supports "Shift_JIS" and "cp932".

Glossary

character repertoire: A collection of unique characters. A character set in the strictest sense. At this stage, characters are not
numbered.
coded character set (CCS): A character set that is mapped in a way computers can
use directly. Many character encodings, including
EUC, fall in this category.
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
ISO-2022 is a CES but it cannot be a CCS. EUC is an
example of being both a CCS and CES.
charset (in MIME context): has long been used in the meaning of "encoding", CES.; While the word combination "character set" has lost
this meaning in MIME context since [RFC 2130], the
"charset" abbreviation has retained it. This is how
[RFC 2277] and [RFC 2278] bless "charset":

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 reg

istry ... (Note
that this is NOT a term used by other standards bod

ies, such as ISO).
[RFC

2277]
EUC Extended Unix Character. See ISO-2022.
ISO-2022: A CES that was carefully designed to coexist with
ASCII. There are a 7 bit version and an 8 bit ver
sion.; The 7 bit version switches character set via escape
sequence so it cannot form a CCS. Since this is more
difficult to handle in programs than the 8 bit ver
sion, the 7 bit version is not very popular except for
iso-2022-jp, the de facto standard CES for e-mails.; The 8 bit version can form a CCS. EUC and ISO-8859
are two examples thereof. Pre-5.6 perl could use them
as string literals.
UCS Short for Universal Character Set. When you say just: UCS, it means Unicode.
UCS-2: ISO/IEC 10646 encoding form: Universal Character Set
coded in two octets.
Unicode: A character set that aims to include all character
repertoires of the world. Many character sets in var
ious national as well as industrial standards have
become, in a way, just subsets of Unicode.
UTF Short for Unicode Transformation Format. Determines: how to map a Unicode character into a byte sequence.
UTF-16: A UTF in 16-bit encoding. Can either be in big endian
or little endian. The big endian version is called
UTF-16BE (equal to UCS-2 + surrogate support) and the
little endian version is called UTF-16LE.

References

ECMA: European Computer Manufacturers Association
<http://www.ecma.ch>; ECMA-035 (eq "ISO-2022")
<http://www.ecma.ch/ecma1/STAND/ECMA-035.HTM>

The specification of ISO-2022 is available from
the link above.
IANA: Internet Assigned Numbers Authority
<http://www.iana.org/>; Assigned Charset Names by IANA
<http://www.iana.org/assignments/character-sets>

Most of the "canonical names" in Encode derive
from this list so you can directly apply the
string you have extracted from MIME header of
mails and web pages.
ISO International Organization for Standardization: <http://www.iso.ch/>
RFC Request For Comments -- need I say more?: <http://www.rfc-editor.org/>, <http://www.rfc.net/>,
<http://www.faqs.org/rfcs/>
UC Unicode Consortium <http://www.unicode.org/>: Unicode Glossary
<http://www.unicode.org/glossary/>

The glossary of this document is based upon this
site.
Other Notable Sites
czyborra.com: <http://czyborra.com/>; Contains a a lot of useful information, especially
gory details of ISO vs. vendor mappings.
CJK.inf: <http://www.oreilly.com/peo
ple/authors/lunde/cjk_inf.html>; Somewhat obsolete (last update in 1996), but still
useful. Also try; <ftp://ftp.oreilly.com/pub/examples/nut
shell/cjkv/pdf/GB18030_Summary.pdf>; You will find brief info on "EUC-CN", "GBK" and mostly
on "GB 18030".
Jungshik Shin's Hangul FAQ: <http://jshin.net/faq>; And especially its subject 8.; <http://jshin.net/faq/qa8.html>; A comprehensive overview of the Korean ("KS *") stan
dards.
debian.org: "Introduction to i18n": A brief description for most of the mentioned CJK
encodings is contained in
<http://www.debian.org/doc/manu
als/intro-i18n/ch-codes.en.html>
Offline sources
"CJKV Information Processing" by Ken Lunde: CJKV Information Processing 1999 O'Reilly & Associ
ates, ISBN : 1-56592-224-7; The modern successor of "CJK.inf".; Features a comprehensive coverage of CJKV character
sets and encodings along with many other issues faced
by anyone trying to better support CJKV lan
guages/scripts in all the areas of information pro
cessing.; To purchase this book, visit
<http://www.oreilly.com/catalog/cjkvinfo/> or your
favourite bookstore.

docs.sk

comprehensive documentation repository

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