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 ----------------------------------------------------------------
69 =head2 Encode::Unicode -- other Unicode encodings
71 Unicode coding schemes other than native utf8 are supported by
72 Encode::Unicode which will be autoloaded on demand.
74 ----------------------------------------------------------------
75 UCS-2BE UCS-2, iso-10646-1 [IANA, UC]
83 ----------------------------------------------------------------
85 To find how those (UCS-2|UTF-(16|32))(LE|BE)? differ to one another,
86 see L<Encode::Unicode>.
88 =head2 Encode::Byte -- Extended ASCII
90 Encode::Byte implements most of single-byte encodings except for
91 Symbols and EBCDIC. The following encodings are based single-byte
92 encoding implemented as extended ASCII. For most cases it uses
93 \x80-\xff (upper half) to map non-ASCII characters.
97 =item ISO-8859 and corresponding vendor mappings
99 Since there are so many, They are presented in table format with
100 Languages and corresponding encoding names by vendors. Note the table
101 is sorted in order of ISO-8859 and the corresponding vendor mappings
102 are slightly different from that of ISO. See
103 L<http://czyborra.com/charsets/iso8859.html> for details.
105 Lang/Regions ISO/Other Std. DOS Windows Macintosh Others
106 ----------------------------------------------------------------
107 N. America (ASCII) cp437 AdobeStandardEncoding
109 W. Europe (iso-8859-1) cp850 cp1252 MacRoman nextstep
111 cp860 (DOSPortuguese)
112 CE. Europe iso-8859-2 cp852 cp1250 MacCentralEurRoman
116 Latin3(*3) iso-8859-3
117 Latin4(*4) iso-8859-4
118 Cyrillics iso-8859-5 cp855 cp1251 MacCyrillic
119 (Also see next section) cp866 MacUkrainian
120 Arabic iso-8859-6 cp864 cp1256 MacArabic
122 Greek iso-8859-7 cp737 cp1253 MacGreek
124 Hebrew iso-8859-8 cp862 cp1255 MacHebrew
125 Turkish iso-8859-9 cp857 cp1254 MacTurkish
126 Nordics iso-8859-10 cp865
129 Thai iso-8859-11 cp874 MacThai
130 (iso-8859-12 is nonexistent. Reserved for Indics?)
131 Baltics iso-8859-13 cp775 cp1257
133 Latin9(*15) iso-8859-15
135 Vietnamese viscii cp1258 MacVietnamese
136 ----------------------------------------------------------------
138 (*3) Esperanto, Maltese, and Turkish. Turkish is now on 8859-5
139 (*4) Baltics. Now on 8859-10
140 (*9) Nicknamed Latin0; Euro sign as well as French and Finnish
141 letters that are missing from 8859-1 are added.
143 All cp* are also available as ibm-*, ms-*, and windows-* . See also
144 L<http://czyborra.com/charsets/codepages.html>.
146 Macintosh encodings don't seem to be registered in such entities as
147 IANA. "Canonical" names in Encode are based upon Apple's Tech Note
148 1150. See L<http://developer.apple.com/technotes/tn/tn1150.html>
151 =item KOI8 - De Facto Standard for Cyrillic world
153 Though ISO-8859 does have ISO-8859, KOI8 series is far more popular
154 in the Net. L<Encode> comes with the following KOI charsets. for
155 gory details, See <http://czyborra.com/charsets/cyrillic.html> for
158 ----------------------------------------------------------------
160 koi8-r cp878 [RFC1489]
163 =item gsm0338 - Hentai Latin 1
165 GSM0338 is for GSM handsets. Though it shares alpanumerals with ASCII,
166 control character ranges and other parts are mapped very differently,
167 presumablly to store Greek and Cyrillic alphabets. This one is also
168 covered in Encode::Byte even thought this one does not comply extended
173 =head2 The CJK: Chinese, Japanese, Korean (Multibyte)
175 Note Vietnamese is listed above. Also read "Encoding vs Charset"
176 below. Also note these are implemented in distinct module by
177 languages, due the the size concerns. Please also refer to their
178 respective document pages.
182 =item Encode::CN -- Continental China
184 Standard DOS/Win Macintosh Comment/Reference
185 ----------------------------------------------------------------
186 euc-cn(*1) MacChineseSimp
188 gb12345-raw { GB12345 without CES }
189 gb2312-raw { GB2312 without CES }
192 ----------------------------------------------------------------
194 (*1) GB2312 is aliased to this. see L<Microsoft-related naming mess>
195 (*2) gbk is aliased to this. see L<Microsoft-related naming mess>
197 =item Encode::JP -- Japan
199 Standard DOS/Win Macintosh Comment/Reference
200 ----------------------------------------------------------------
202 shiftjis cp932 macJapanese
205 iso-2022-jp [RFC1468]
206 iso-2022-jp-1 [RFC2237]
207 jis0201-raw { JIS X 0201 (roman + halfwidth kana) without CES }
208 jis0208-raw { JIS X 0208 (Kanji + fullwidth kana) without CES }
209 jis0212-raw { JIS X 0212 (Extended Kanji) without CES }
210 ----------------------------------------------------------------
212 =item Encode::KR -- Korea
214 Standard DOS/Win Macintosh Comment/Reference
215 ----------------------------------------------------------------
216 euc-kr MacKorean [RFC1557]
218 iso-2022-kr [RFC1557]
219 johab [KS X 1001:1998, Annex 3]
220 ksc5601-raw { KSC5601 without CES }
221 ----------------------------------------------------------------
223 (*) ks_c_5601-1987, (x-)?windows-949, and uhc are aliased to
227 =item Encode::TW -- Taiwan
229 Standard DOS/Win Macintosh Comment/Reference
230 ----------------------------------------------------------------
231 big5 cp950 MacChineseTrad
233 ----------------------------------------------------------------
235 =item Encode::HanExtra -- More Chinese via CPAN
237 Due to size concerns, additional Chinese encodings below are
238 distributed separately on CPAN, under the name Encode::HanExtra.
240 Standard DOS/Win Macintosh Comment/Reference
241 ----------------------------------------------------------------
245 ----------------------------------------------------------------
249 =head2 Miscellaneous encodings
255 See L<perlebcdic> for details.
257 ----------------------------------------------------------------
264 ----------------------------------------------------------------
266 =item Encode::Symbols
268 For symbols and dingbats.
270 ----------------------------------------------------------------
276 ----------------------------------------------------------------
280 =head1 Unsupported encodings
282 The following are not supported as yet. Some because they are rarely
283 usede, some because of technical difficulty. They may be supported by
284 external modules via CPAN in future, however.
288 =item ISO-2022-JP-2 [RFC1554]
290 Not very popular yet. Needs Unicode Database or equivalent to
291 implement encode() (Because it includes JIS X 0208/0212, KSC5601, and
292 GB2312 sumulteniously, which code points in unicode overlap. So you
293 need to lookup the database to determine what character set a given
294 Unicode character should belong).
296 =item ISO-2022-CN [RFC1922]
298 Not very popular. Needs CNS 11643-1 and 2 which are not available in
299 this module. CNS 11643 is supported (via euc-tw) in
300 Encode::HanExtra. Autrijus may add support for this encoding in his
303 =item various UP-UX encodings
305 The following are unsoported due to the lack of mapping data.
307 '8' - arabic8, greek8, hebrew8, kana8, thai8, and turkish8
308 '15' - japanese15, korean15, and roi15
310 =item Cyrillic encoding ISO-IR-111
312 Anton doubts its usefulness.
314 =item ISO-8859-8-1 [Hebrew]
316 None of the Encode team knows Hebrew enough (ISO-8859-8, cp1255 and
317 MacHebrew are supported because and just because there were mappings
318 available at L<http://www.unicode.org/>). Contribution welcome.
320 =item Thai encoding TCVN
324 =item Vietnamese encodings VPS
326 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
327 L<http://lxr.mozilla.org/seamonkey/source/intl/uconv/ucvlatin/vps.uf> and
328 L<http://lxr.mozilla.org/seamonkey/source/intl/uconv/ucvlatin/vps.ut>
329 if you are interested in helping us.
331 =item various Mac encodings
333 The following are unsoported due to the lack of mapping data.
335 MacArmenian, MacBengali, MacBurmese, MacEthiopic
336 MacExtArabic, MacGeorgian, MacKannada, MacKhmer
337 MacLaotian, MacMalayalam, MacMongolian, MacOriya
338 MacSinhalese, MacTamil, MacTelugu, MacTibetan
341 The rest of which already available are based upon the vendor mappings at
342 L<http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/> .
344 =item (Mac) Indic encodings
346 The maps for the following is available at L<http://www.unicode.org/>
347 but remains unsupport because those encordigs need algorithmical
348 approach, unsupported by F<enc2xs>
354 For details, please see C<Unicode mapping issues and notes:> at
355 L<http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/DEVANAGA.TXT> .
357 I believe this issue is prevalent not only for Mac Indics but also in
358 other Indic encodings but those mentions were the only Indic encodings
359 maps that I could find at L<http://www.unicode.org/> .
363 =head1 Encoding vs. Charset -- terminology
365 We are used to using the term (character) I<encoding> and I<character set>
366 interchangeably. But just as using the term byte and character is
367 dangerous and should be differenciated when needed, we need to
368 differenciate I<encoding> and I<character set>.
370 To understand that, it's follow how we make computers grok our characters.
376 First we start with which characters to include. We call this
377 collection of characters I<character repertoire>.
381 Then we have to give each character a unique ID so your computer can
382 tell the differnce from 'a' to 'A'. This itemized character
383 repartoire is now a I<character set>.
387 If your computer can grow the character set without further
388 proccessing, you can go ahead use it. This is called a I<coded
389 character set> (CCS) or I<raw character encoding>. ASCII is used this
394 But in many cases especially multi-byte CJK encodings, you have to
395 tweak a little more. Your network connection may not accept any data
396 with the Most Significant Bit set, Your computer may not be able to
397 tell if a given byte is a whole character or just half of it. So you
398 have to I<encode> the character set to use it.
400 A I<character encoding scheme> (CES) determines how to encode a given
401 character set, or a set of multiple character sets. 7bit ISO-2022 is
402 an example of CES. You switch between character sets via I<escape
407 Technically, or Mathematically speaking, a character set encoded in
408 such a CES that maps character by character may form a CCS. EUC is such
409 an example. CES of EUC is as follows;
419 Map such a character set that consists of 94 or 96 powered by N
420 members by adding 0x80 to each byte.
424 You can also use 0x8e and 0x8f to tell the following sequence of
425 characters belong to yet another character set. each following byte
430 By carefully looking at at the encoded byte sequence, you may find the
431 byte sequence conforms a unique number. In that sense EUC is a CCS
432 generated by a CES above from up to four CCS (complicated?). UTF-8
433 falls into this category. See L<perlunicode/"UTF-8"> to find how
434 UTF-8 maps Unicode to a byte sequence.
436 You may also find by now why 7bit ISO-2022 cannot conform a CCS. If
437 you look at a byte sequence \x21\x21, you can't tell if it is two !'s
438 or IDEOGRAPHIC SPACE. EUC maps the latter to \xA1\xA1 so you have no
439 trouble between "!!". and " "
441 =head1 Encoding Classification (by Anton Tagunov and Dan Kogai)
443 This section tries to classify the supported encodings by their
444 applicability for information exchange over the Internet and to
445 choose the most suitable aliases to name them in the context of
452 To (en|de) code Encodings marked as C<(**)>, You need
453 C<Encode::HanExtra>, available from CPAN.
459 US-ASCII UTF-8 ISO-8859-* KOI8-R
460 Shift_JIS EUC-JP ISO-2022-JP ISO-2022-JP-1
463 are registered to IANA as preferred MIME names and may probably
464 be used over the Internet.
466 C<Shift_JIS> has been officialized by JIS X 0208:1997.
467 L<Microsoft-related naming mess> gives details.
469 C<GB2312> is the IANA name for C<EUC-CN>.
470 See L<Microsoft-related naming mess> for details.
472 C<GB_2312-80> I<raw> encoding is available as C<gb2312-raw>
473 with Encode. See L<Encode::CN> for details.
478 have not been registered with IANA (as of March 2002) but
479 seem to be supported by major web browsers.
480 IANA name for C<EUC-CN> is C<GB2312>.
485 See L<Microsoft-related naming mess> for details.
487 C<KS_C_5601-1987> I<raw> encoding is available as C<kcs5601-raw>
488 with Encode. See L<Encode::KR> for details.
490 UTF-16 UTF-16BE UTF-16LE
492 are a IANA-registered C<charset>s. See [RFC 2781] for details.
493 Jungshik Shin reports that UTF-16 with a BOM is well accepted
494 by MS IE 5/6 and NS 4/6. Beware however that
500 C<UTF-16> support in any software you're going to be
501 using/interoperating with has probably been less tested
502 then C<UTF-8> support
506 C<UTF-8> coded data seamlessly passes traditional
507 command piping (C<cat>, C<more>, etc.) while C<UTF-16> coded
508 data is likely to cause confusion (with it's zero bytes,
513 it is beyond the power of words to describe the way HTML browsers
514 encode non-C<ASCII> form data. To get a general impression visit
515 L<http://ppewww.ph.gla.ac.uk/~flavell/charset/form-i18n.html>.
516 While encoding of form data has stabilized for C<UTF-8> coded pages
517 (at least IE 5/6, NS 6, Opera 6 behave consitently), be sure to
518 expect fun (and cross-browser discrepancies) with C<UTF-16> coded
523 The rule of thumb is to use C<UTF-8> unless you know what
524 you're doing and unless you really benefit from using C<UTF-16>.
531 GB 18030 (**) (see links bellow)
534 are totally valid encodings but not registered at IANA.
535 The names under which they are listed here are probably the
536 most widely-known names for these encodings and are recommended
541 is a bit proprietary name.
543 =head2 Microsoft-related naming mess
545 Microsoft products misuse the following names:
551 Microsoft extension to C<EUC-KR>.
553 Proper names: C<CP949>, C<UHC>, C<x-windows-949> (as used by Mozilla).
555 See L<http://lists.w3.org/Archives/Public/ietf-charsets/2001AprJun/0033.html>
558 Encode aliases C<KS_C_5601-1987> to C<cp949> to reflect this common
559 misusage. I<Raw> C<KS_C_5601-1987> encoding is available as
562 See L<Encode::KR> for details.
566 Microsoft extension to C<EUC-CN>.
568 Proper names: C<CP936>, C<GBK>.
570 C<GB2312> has been registered in the C<EUC-CN> meaning at
571 IANA. This has partially repaired the situation: Microsoft's
572 C<GB2312> has become a superset of the official C<GB2312>.
574 Encode aliases C<GB2312> to C<euc-cn> in full agreement with
575 IANA registration. C<cp936> is supported separately.
576 I<Raw> C<GB_2312-80> encoding is available as C<gb2312-raw>.
578 See L<Encode::CN> for details.
582 Microsoft extension to C<Big5>.
584 Proper name: C<CP950>.
586 Encode separately supports C<Big5> and C<cp950>.
590 Microsoft's understanding of C<Shift_JIS>.
592 JIS has not endorsed the full Microsoft standard however.
593 The official C<Shift_JIS> includes only JIS X 0201 and JIS X 0208
594 subsets, while Microsoft has always been meaning C<Shift_JIS> to
595 encode a wider character repertoire. See C<IANA> registration for
598 As a historical predecessor Microsoft's variant
599 probably has more rights for the name, albeit it may be objected
600 that Microsoft shouldn't have used JIS as part of the name
603 Unambiguous name: C<CP932>. C<IANA> name (not used?): C<Windows-31J>.
605 Encode separately supports C<Shift_JIS> and C<cp932>.
613 =item character repertoire
615 A collection of unique characters. A I<character> set in the most
616 strict sense. At this stage characters are not numberd.
618 =item coded character set (CCS)
620 A character set that is mapped in a way computers can use directly.
621 Many character encodings including EUC falls in this category.
623 =item character encoding scheme (CES)
625 An algorithm to map a character set to a byte sequence. You don't
626 have to be able to tell which character set a given byte sequence
627 belongs. 7-bit ISO-2022 is a CES but it cannot be a CCS. EUC is an
628 example of being both a CCS and CES.
630 =item charset (in MIME context)
632 has long been used in the meaning of C<encoding>, CES.
634 While C<character set> word combination has lost this meaning
635 in MIME context since [RFC 2130], C<charset> abbreviation has
636 retained it. This is how [RFC 2277], [RFC 2278] bless C<charset>:
639 This document uses the term "charset" to mean a set of rules for
640 mapping from a sequence of octets to a sequence of characters, such
641 as the combination of a coded character set and a character encoding
642 scheme; this is also what is used as an identifier in MIME "charset="
643 parameters, and registered in the IANA charset registry ... (Note
644 that this is NOT a term used by other standards bodies, such as ISO).
649 Extended Unix Character. See ISO-2022
653 A CES that was carefully designed to coexist with ASCII. There are 7
654 bit version and 8 bit version.
656 7 bit version switches character set via escape sequence so this
657 cannot form a CCS. Since this is more difficult to handle in programs
658 than the 8 bit version, 7 bit version is not very popular except for
659 iso-2022-jp, the de facto standard CES for e-mails.
661 8 bit version can conform a CCS. EUC and ISO-8859 are two examples
662 thereof. pre-5.6 perl could use them as string literals.
666 Short for I<Universal Character Set>. When you say just UCS, it means
671 ISO/IEC 10646 encoding form: Universal Character Set coded in two
676 A Character Set that aims to include all character repertoire of the
677 world. Many character sets in various national as well as industorial
678 standards have become, in a way, just subsets of Unicode.
682 Short for I<Unicode Transformation Format>. Determines how to map a
683 unicode character into byte sequnece.
687 A UTF in 16-bit encoding. Can either be in big endian or little
688 endian. Big endian version is called UTF-16BE (equals to UCS-2 +
689 Surrogate Support) and little endian version is UTF-16LE.
697 L<Encode::CN>, L<Encode::JP>, L<Encode::KR>, L<Encode::TW>,
698 L<Encode::EBCDIC>, L<Encode::Symbol>
706 European Computer Manufacturers Association
707 L<http://www.ecma.ch>
711 =item EMCA-035 (eq C<ISO-2022>)
713 L<http://www.ecma.ch/ecma1/STAND/ECMA-035.HTM>
715 The very dspecification of ISO-2022 is available from the link above.
721 Internet Assigned Numbers Authority
722 L<http://www.iana.org/>
726 =item Assigned Charset Names by IANA
728 L<http://www.iana.org/assignments/character-sets>
730 Most of the C<canonical names> in Encode derive from this list
731 so you can directly apply the string you have extracted from MIME
732 header of mails and we pages.
738 International Organization for Standardization
739 L<http://www.iso.ch/>
743 Request For Comment -- need I say more?
744 L<http://www.rfc.net/>, L<http://www.faqs.org/rfcs/>
749 L<http://www.unicode.org/>
753 =item Unicode Glossary
755 L<http://www.unicode.org/glossary/>
757 The glossary of this document is based opon this site.
763 =head2 Other Notable Sites
769 L<http://czyborra.com/>
771 Contains a a lot of useful information, especially gory details of ISO
776 L<http://www.oreilly.com/people/authors/lunde/cjk_inf.html>
778 Somewhat obsolete (last update in 1996), but still useful. Also try
780 L<ftp://ftp.oreilly.com/pub/examples/nutshell/cjkv/pdf/GB18030_Summary.pdf>
782 You will find brief info on C<EUC-CN>, C<GBK> and mostly on C<GB 18030>
784 =item Jungshik Shin's Hangul FAQ
786 L<http://jshin.net/faq>
788 And especially it's subject 8
790 L<http://jshin.net/faq/qa8.html>
792 a comprehensive overview of the Korean (C<KS *>) standards.
796 =head2 Offline sources
800 =item C<CJKV Information Processing> by Ken Lunde
802 CJKV Information Processing
803 1999 O'Reilly & Associates, ISBN : 1-56592-224-7
805 The modern successor of the C<CJK.inf>.
807 Features a comprehensive coverage on CJKV character sets and
808 encodings along with many other issues faced by anyone trying
809 to better support CJKV languages/scripts in all the areas of
810 information processing.
812 To purchase this book visit
813 L<http://www.oreilly.com/catalog/cjkvinfo/>
819 I could not find this page because the hostname doesn't resolve!
821 Brief description for most of the mentioned CJK encodings
822 L<http://www.debian.org.ru/doc/manuals/intro-i18n/ch-codes.html>