3 Encode::Supported -- Supported encodings by Encode
9 Encoding names are case insensitive. White space in names
10 is ignored. In addition an encoding may have aliases.
11 Each encoding has one "canonical" name. The "canonical"
12 name is chosen from the names of the encoding by picking
13 the first in the following sequence (with a few exceptions).
19 The name used by the perl community. That includes 'utf8' and 'ascii'.
20 Unlike aliases, canonical names directly reaches the method so such
21 frequently used words like 'utf8' should do without alias lookups.
25 The MIME name as defined in IETF RFCs This includes all "iso-"'s.
29 The name in the IANA registry.
33 The name used by the organization that defined it.
37 In case I<de jure> canonical names differ from that of the Encode
38 module, they are always aliased if it ever be implemented. So you can
39 safely tell if a given encoding is implemented or not just by passing
42 Because of all the alias issues, and because in the general case
43 encodings have state, "Encode" uses the encoding object internally
44 once an operation is in progress.
46 =head1 Supported Encodings
48 As of Perl 5.8.0, at least the following encodings are recognized.
49 Note that unless otherwise specified, they are all case insensitive
50 (via alias) and all occurrance of spaces are replaced with '-'. In
51 other words, "ISO 8859 1" and "iso-8859-1" are identical.
53 Encodings are categorized and implemented in several different modules
54 but you don't have to C<use Encode::XX> to make them available for
55 most cases. Encode.pm will automatically load those modules in need.
57 =head2 Built-in Encodings
59 The following encodings are always available.
61 Canonical Aliases Comments & References
62 ----------------------------------------------------------------
64 iso-8859-1 latin1 [ISO]
66 UCS-2BE UCS-2, iso-10646-1 [IANA, UC]
74 ----------------------------------------------------------------
76 To find how those (UCS-2|UTF-(16|32))(LE|BE)? differ to one another,
77 see L<Encode::Unicode>.
79 =head2 Encode::Byte -- Extended ASCII
81 Encode::Byte implements most of single-byte encodings except for
82 Symbols and EBCDIC. The following encodings are based single-byte
83 encoding implemented as extended ASCII. For most cases it uses
84 \x80-\xff (upper half) to map non-ASCII characters.
88 =item ISO-8859 and corresponding vendor mappings
90 Since there are so many, They are presented in table format with
91 Languages and corresponding encoding names by vendors. Note the table
92 is sorted in order of ISO-8859 and the corresponding vendor mappings
93 are slightly different from that of ISO. See
94 L<http://czyborra.com/charsets/iso8859.html> for details.
96 Lang/Regions ISO/Other Std. DOS Windows Macintosh Others
97 ----------------------------------------------------------------
98 N. America (ASCII) cp437 AdobeStandardEncoding
100 W. Europe (iso-8859-1) cp850 cp1252 MacRoman nextstep
102 cp860 (DOSPortuguese)
103 CE. Europe iso-8859-2 cp852 cp1250 MacCentralEurRoman
107 Latin3(*3) iso-8859-3
108 Latin4(*4) iso-8859-4
109 Cyrillics iso-8859-5 cp855 cp1251 MacCyrillic
110 (Also see next section) cp866 MacUkrainian
111 Arabic iso-8859-6 cp864 cp1256 MacArabic
113 Greek iso-8859-7 cp737 cp1253 MacGreek
115 Hebrew iso-8859-8 cp862 cp1255 MacHebrew
116 Turkish iso-8859-9 cp857 cp1254 MacTurkish
117 Nordics iso-8859-10 cp865
120 Thai iso-8859-11 cp874 MacThai
121 (iso-8859-12 is nonexistent. Reserved for Indics?)
122 Baltics iso-8859-13 cp775 cp1257
124 Latin9(*15) iso-8859-15
126 Vietnamese viscii cp1258 MacVietnamese
127 ----------------------------------------------------------------
129 (*3) Esperanto, Maltese, and Turkish. Turkish is now on 8859-5
130 (*4) Baltics. Now on 8859-10
131 (*9) Nicknamed Latin0; Euro sign as well as French and Finnish
132 letters that are missing from 8859-1 are added.
134 All cp* are also available as ibm-*, ms-*, and windows-* . See also
135 L<http://czyborra.com/charsets/codepages.html>.
137 Macintosh encodings don't seem to be registered in such entities as
138 IANA. "Canonical" names in Encode are based upon Apple's Tech Note
139 1150. See L<http://developer.apple.com/technotes/tn/tn1150.html>
142 =item KOI8 - De Facto Standard for Cyrillic world
144 Though ISO-8859 does have ISO-8859, KOI8 series is far more popular
145 in the Net. L<Encode> comes with the following KOI charsets. for
146 gory details, See <http://czyborra.com/charsets/cyrillic.html> for
149 ----------------------------------------------------------------
151 koi8-r cp878 [RFC1489]
154 =item gsm0338 - Hentai Latin 1
156 GSM0338 is for GSM handsets. Though it shares alpanumerals with ASCII,
157 control character ranges and other parts are mapped very differently,
158 presumablly to store Greek and Cyrillic alphabets. This one is also
159 covered in Encode::Byte even thought this one does not comply extended
164 =head2 The CJK: Chinese, Japanese, Korean (Multibyte)
166 Note Vietnamese is listed above. Also read "Encoding vs Charset"
167 below. Also note these are implemented in distinct module by
168 languages, due the the size concerns. Please also refer to their
169 respective document pages.
173 =item Encode::CN -- Continental China
175 Standard DOS/Win Macintosh Comment/Reference
176 ----------------------------------------------------------------
177 euc-cn(*1) MacChineseSimp
179 gb12345-raw { GB12345 without CES }
180 gb2312-raw { GB2312 without CES }
183 ----------------------------------------------------------------
185 (*1) GB2312 is aliased to this. see L<Microsoft-related naming mess>
186 (*2) gbk is aliased to this. see L<Microsoft-related naming mess>
188 =item Encode::JP -- Japan
190 Standard DOS/Win Macintosh Comment/Reference
191 ----------------------------------------------------------------
193 shiftjis cp932 macJapanese
196 iso-2022-jp [RFC1468]
197 iso-2022-jp-1 [RFC2237]
198 jis0201-raw { JIS X 0201 (roman + halfwidth kana) without CES }
199 jis0208-raw { JIS X 0208 (Kanji + fullwidth kana) without CES }
200 jis0212-raw { JIS X 0212 (Extended Kanji) without CES }
201 ----------------------------------------------------------------
203 =item Encode::KR -- Korea
205 Standard DOS/Win Macintosh Comment/Reference
206 ----------------------------------------------------------------
207 euc-kr MacKorean [RFC1557]
209 iso-2022-kr [RFC1557]
210 johab [KS X 1001:1998, Annex 3]
211 ksc5601-raw { KSC5601 without CES }
212 ----------------------------------------------------------------
214 (*) ks_c_5601-1987, (x-)?windows-949, and uhc are aliased to
218 =item Encode::TW -- Taiwan
220 Standard DOS/Win Macintosh Comment/Reference
221 ----------------------------------------------------------------
222 big5 cp950 MacChineseTrad
224 ----------------------------------------------------------------
226 =item Encode::HanExtra -- More Chinese via CPAN
228 Due to size concerns, additional Chinese encodings below are
229 distributed separately on CPAN, under the name Encode::HanExtra.
231 Standard DOS/Win Macintosh Comment/Reference
232 ----------------------------------------------------------------
236 ----------------------------------------------------------------
240 =head2 Miscellaneous encodings
246 See L<perlebcdic> for details.
248 ----------------------------------------------------------------
255 ----------------------------------------------------------------
257 =item Encode::Symbols
259 For symbols and dingbats.
261 ----------------------------------------------------------------
267 ----------------------------------------------------------------
271 =head1 Unsupported encodings
273 The following are not supported as yet. Some because they are rarely
274 usede, some because of technical difficulty. They may be supported by
275 external modules via CPAN in future, however.
279 =item ISO-2022-JP-2 [RFC1554]
281 Not very popular yet. Needs Unicode Database or equivalent to
282 implement encode() (Because it includes JIS X 0208/0212, KSC5601, and
283 GB2312 sumulteniously, which code points in unicode overlap. So you
284 need to lookup the database to determine what character set a given
285 Unicode character should belong).
287 =item ISO-2022-CN [RFC1922]
289 Not very popular. Needs CNS 11643-1 and 2 which are not available in
290 this module. CNS 11643 is supported (via euc-tw) in
291 Encode::HanExtra. Autrijus may add support for this encoding in his
294 =item various UP-UX encodings
296 The following are unsoported due to the lack of mapping data.
298 '8' - arabic8, greek8, hebrew8, kana8, thai8, and turkish8
299 '15' - japanese15, korean15, and roi15
301 =item Cyrillic encoding ISO-IR-111
303 Anton doubts its usefulness.
305 =item ISO-8859-8-1 [Hebrew]
307 None of the Encode team knows Hebrew enough (ISO-8859-8, cp1255 and
308 MacHebrew are supported because and just because there were mappings
309 available at L<http://www.unicode.org/>). Contribution welcome.
311 =item Thai encoding TCVN
315 =item Vietnamese encodings VPS
317 Though Jungshik has reported that mozilla supports this encoding, It was too late for us to add one. In future via a separate module. See
318 L<http://lxr.mozilla.org/seamonkey/source/intl/uconv/ucvlatin/vps.uf> and
319 L<http://lxr.mozilla.org/seamonkey/source/intl/uconv/ucvlatin/vps.ut>
320 if you are interested in helping us.
322 =item various Mac encodings
324 The following are unsoported due to the lack of mapping data.
326 MacArmenian, MacBengali, MacBurmese, MacEthiopic
327 MacExtArabic, MacGeorgian, MacKannada, MacKhmer
328 MacLaotian, MacMalayalam, MacMongolian, MacOriya
329 MacSinhalese, MacTamil, MacTelugu, MacTibetan
332 The rest of which already available are based upon the vendor mappings at
333 L<http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/> .
335 =item (Mac) Indic encodings
337 The maps for the following is available at L<http://www.unicode.org/>
338 but remains unsupport because those encordigs need algorithmical
339 approach, unsupported by F<enc2xs>
345 For details, please see C<Unicode mapping issues and notes:> at
346 L<http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/DEVANAGA.TXT> .
348 I believe this issue is prevalent not only for Mac Indics but also in
349 other Indic encodings but those mentions were the only Indic encodings
350 maps that I could find at L<http://www.unicode.org/> .
354 =head1 Encoding vs. Charset -- terminology
356 We are used to using the term (character) I<encoding> and I<character set>
357 interchangeably. But just as using the term byte and character is
358 dangerous and should be differenciated when needed, we need to
359 differenciate I<encoding> and I<character set>.
361 To understand that, it's follow how we make computers grok our characters.
367 First we start with which characters to include. We call this
368 collection of characters I<character repertoire>.
372 Then we have to give each character a unique ID so your computer can
373 tell the differnce from 'a' to 'A'. This itemized character
374 repartoire is now a I<character set>.
378 If your computer can grow the character set without further
379 proccessing, you can go ahead use it. This is called a I<coded
380 character set> (CCS) or I<raw character encoding>. ASCII is used this
385 But in many cases especially multi-byte CJK encodings, you have to
386 tweak a little more. Your network connection may not accept any data
387 with the Most Significant Bit set, Your computer may not be able to
388 tell if a given byte is a whole character or just half of it. So you
389 have to I<encode> the character set to use it.
391 A I<character encoding scheme> (CES) determines how to encode a given
392 character set, or a set of multiple character sets. 7bit ISO-2022 is
393 an example of CES. You switch between character sets via I<escape
398 Technically, or Mathematically speaking, a character set encoded in
399 such a CES that maps character by character may form a CCS. EUC is such
400 an example. CES of EUC is as follows;
410 Map such a character set that consists of 94 or 96 powered by N
411 members by adding 0x80 to each byte.
415 You can also use 0x8e and 0x8f to tell the following sequence of
416 characters belong to yet another character set. each following byte
421 By carefully looking at at the encoded byte sequence, you may find the
422 byte sequence conforms a unique number. In that sense EUC is a CCS
423 generated by a CES above from up to four CCS (complicated?). UTF-8
424 falls into this category. See L<perlunicode/"UTF-8"> to find how
425 UTF-8 maps Unicode to a byte sequence.
427 You may also find by now why 7bit ISO-2022 cannot conform a CCS. If
428 you look at a byte sequence \x21\x21, you can't tell if it is two !'s
429 or IDEOGRAPHIC SPACE. EUC maps the latter to \xA1\xA1 so you have no
430 trouble between "!!". and " "
432 =head1 Encoding Classification (by Anton Tagunov and Dan Kogai)
434 This section tries to classify the supported encodings by their
435 applicability for information exchange over the Internet and to
436 choose the most suitable aliases to name them in the context of
443 To (en|de) code Encodings marked as C<(**)>, You need
444 C<Encode::HanExtra>, available from CPAN.
450 US-ASCII UTF-8 ISO-8859-* KOI8-R
451 Shift_JIS EUC-JP ISO-2022-JP ISO-2022-JP-1
454 are registered to IANA as preferred MIME names and may probably
455 be used over the Internet.
457 C<Shift_JIS> has been officialized by JIS X 0208-1997.
458 L<Microsoft-related naming mess> gives details.
460 C<GB2312> is the IANA name for C<EUC-CN>.
461 See L<Microsoft-related naming mess> for details.
463 C<GB_2312-80> I<raw> encoding is available as C<gb2312-raw>
464 with Encode. See L<Encode::CN> for details.
469 have not been registered with IANA (as of March 2002) but
470 seem to be supported by major web browsers.
471 IANA name for C<EUC-CN> is C<GB2312>.
476 See L<Microsoft-related naming mess> for details.
478 C<KS_C_5601-1987> I<raw> encoding is available as C<kcs5601-raw>
479 with Encode. See L<Encode::KR> for details.
481 UTF-16 UTF-16BE UTF-16LE
483 are a IANA-registered C<charset>s. See [RFC 2781] for details.
484 Jungshik Shin reports that UTF-16 with a BOM is well accepted
485 by MS IE 5/6 and NS 4/6. Beware however that
491 C<UTF-16> support in any software you're going to be
492 using/interoperating with has probably been less tested
493 then C<UTF-8> support
497 data coded with C<UTF-8> seamlessly passes traditional
498 command piping (C<cat>, C<more>, etc.) while UTF-16 coded
499 data is likely to cause confusion (with it's zero bytes,
504 it is beyond the power of words to describe the way HTML browsers
505 encode non-C<ASCII> form data. To get a general impression refer to
506 L<http://ppewww.ph.gla.ac.uk/~flavell/charset/form-i18n.html>.
507 While encoding of form data has stabilzed for C<UTF-8> coded pages
508 (at least IE 5/6, NS 6, Opera 6 behave consitently), be sure to
509 expect fun (and cross-browser discrepancies) with C<UTF-16> coded
514 The rule of thumb is to use C<UTF-8> unless you know what
515 you're doing and unless you really need from using C<UTF-16>.
522 GB 18030 (**) (see links bellow)
525 are totally valid encodings but not registered at IANA.
526 The names under which they are listed here are probably the
527 most widely-known names for these encodings and are recommended
532 is a bit proprietary name.
534 =head2 Microsoft-related naming mess
536 Microsoft products misuse the following names:
542 Microsoft extension to C<EUC-KR>.
544 Proper name: C<CP949>.
546 See L<http://lists.w3.org/Archives/Public/ietf-charsets/2001AprJun/0033.html>
549 Encode aliases C<KS_C_5601-1987> to C<cp949> to reflect this common
550 misusage. I<Raw> C<KS_C_5601-1987> encoding is available as
553 See L<Encode::KR> for details.
557 Microsoft extension to C<EUC-CN>.
559 Proper names: C<CP936>, C<GBK>.
561 C<GB2312> has been registered in the C<EUC-CN> meaning at
562 IANA. This has partially repaired the situation: Microsoft's
563 C<GB2312> has become a superset of the official C<GB2312>.
565 Encode aliases C<GB2312> to C<euc-cn> in full agreement with
566 IANA registration. C<cp936> is supported separately.
567 I<Raw> C<GB_2312-80> encoding is available as C<gb2312-raw>.
569 See L<Encode::CN> for details.
573 Microsoft extension to C<Big5>.
575 Proper name: C<CP950>.
577 Encode separately supports C<Big5> and C<cp950>.
581 Microsoft's understanding of C<Shift_JIS>.
583 JIS has not endorsed the full Microsoft standard however.
584 The official C<Shift_JIS> includes only JIS X 0201 and JIS X 0208
585 subsets, while Microsoft has always been meaning C<Shift_JIS> to
586 encode a wider character repertoire.
588 As a historical predecessor Microsoft's variant
589 probably has more rights for the name, albeit it may be objected
590 that Microsoft shouldn't have used JIS as part of the name
593 Unabiguous name: C<CP932>.
595 Encode separately supports C<Shift_JIS> and C<cp932>.
603 =item character repertoire
605 A collection of unique characters. A I<character> set in the most
606 strict sense. At this stage characters are not numberd.
608 =item coded character set (CCS)
610 A character set that is mapped in a way computers can use directly.
611 Many character encodings including EUC falls in this category.
613 =item character encoding scheme (CES)
615 An algorithm to map a character set to a byte sequence. You don't
616 have to be able to tell which character set a given byte sequence
617 belongs. 7-bit ISO-2022 is a CES but it cannot be a CCS. EUC is an
618 example of being both a CCS and CES.
620 =item charset (in MIME context)
622 has long been used in the meaning of C<encoding>, CES.
624 While C<character set> word combination has lost this meaning
625 in MIME context since [RFC 2130], C<charset> abbreviation has
626 retained it. This is how [RFC 2277], [RFC 2278] bless C<charset>:
629 This document uses the term "charset" to mean a set of rules for
630 mapping from a sequence of octets to a sequence of characters, such
631 as the combination of a coded character set and a character encoding
632 scheme; this is also what is used as an identifier in MIME "charset="
633 parameters, and registered in the IANA charset registry ... (Note
634 that this is NOT a term used by other standards bodies, such as ISO).
639 Extended Unix Character. See ISO-2022
643 A CES that was carefully designed to coexist with ASCII. There are 7
644 bit version and 8 bit version.
646 7 bit version switches character set via escape sequence so this
647 cannot form a CCS. Since this is more difficult to handle in programs
648 than the 8 bit version, 7 bit version is not very popular except for
649 iso-2022-jp, the de facto standard CES for e-mails.
651 8 bit version can conform a CCS. EUC and ISO-8859 are two examples
652 thereof. pre-5.6 perl could use them as string literals.
656 Short for I<Universal Character Set>. When you say just UCS, it means
661 ISO/IEC 10646 encoding form: Universal Character Set coded in two
666 A Character Set that aims to include all character repertoire of the
667 world. Many character sets in various national as well as industorial
668 standards have become, in a way, just subsets of Unicode.
672 Short for I<Unicode Transformation Format>. Determines how to map a
673 unicode character into byte sequnece.
677 A UTF in 16-bit encoding. Can either be in big endian or little
678 endian. Big endian version is called UTF-16BE (equals to UCS-2 +
679 Surrogate Support) and little endian version is UTF-16LE.
687 L<Encode::CN>, L<Encode::JP>, L<Encode::KR>, L<Encode::TW>,
688 L<Encode::EBCDIC>, L<Encode::Symbol>
696 European Computer Manufacturers Association
697 L<http://www.ecma.ch>
701 =item EMCA-035 (eq C<ISO-2022>)
703 L<http://www.ecma.ch/ecma1/STAND/ECMA-035.HTM>
705 The very dspecification of ISO-2022 is available from the link above.
711 Internet Assigned Numbers Authority
712 L<http://www.iana.org/>
716 =item Assigned Charset Names by IANA
718 L<http://www.iana.org/assignments/character-sets>
720 Most of the C<canonical names> in Encode derive from this list
721 so you can directly apply the string you have extracted from MIME
722 header of mails and we pages.
728 International Organization for Standardization
729 L<http://www.iso.ch/>
733 Request For Comment -- need I say more?
734 L<http://www.rfc.net/>, L<http://www.faqs.org/rfcs/>
739 L<http://www.unicode.org/>
743 =item Unicode Glossary
745 L<http://www.unicode.org/glossary/>
747 The glossary of this document is based opon this site.
753 =head2 Other Notable Sites
759 L<http://czyborra.com/>
761 Contains a a lot of useful information, especially gory details of ISO
766 L<http://www.oreilly.com/people/authors/lunde/cjk_inf.html>
768 Somewhat obsolete (last update in 1996), but still useful. Also try
770 L<ftp://ftp.oreilly.com/pub/examples/nutshell/cjkv/pdf/GB18030_Summary.pdf>
772 You will find brief info on C<EUC-CN>, C<GBK> and mostly on C<GB 18030>
774 =item Jungshik Shin's Hangul FAQ
776 L<http://jshin.net/faq>
778 And especially it's subject 8
780 L<http://jshin.net/faq/qa8.html>
782 a comprehensive overview of the Korean (C<KS *>) standards.
786 =head2 Offline sources
790 =item C<CJKV Information Processing> by Ken Lunde
792 CJKV Information Processing
793 1999 O'Reilly & Associates, ISBN : 1-56592-224-7
795 The modern successor of the C<CJK.inf>.
797 Features a comprehensive coverage on CJKV character sets and
798 encodings along with many other issues faced by anyone trying
799 to better support CJKV languages/scripts in all the areas of
800 information processing.
802 To purchase this book visit
803 L<http://www.oreilly.com/catalog/cjkvinfo/>
809 I could not find this page because the hostname doesn't resolve!
811 Brief description for most of the mentioned CJK encodings
812 L<http://www.debian.org.ru/doc/manuals/intro-i18n/ch-codes.html>