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 reach the method so such
21 frequently used words like 'utf8' don't need to do 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 an 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 occurrence of spaces are replaced with '-'.
51 In 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 on demand.
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 ----------------------------------------------------------------
68 =head2 Encode::Unicode -- other Unicode encodings
70 Unicode coding schemes other than native utf8 are supported by
71 Encode::Unicode which will be autoloaded on demand.
73 ----------------------------------------------------------------
74 UCS-2BE UCS-2, iso-10646-1 [IANA, UC]
82 ----------------------------------------------------------------
84 To find how those (UCS-2|UTF-(16|32))(LE|BE)? differ to one another,
85 see L<Encode::Unicode>.
87 =head2 Encode::Byte -- Extended ASCII
89 Encode::Byte implements most of single-byte encodings except for
90 Symbols and EBCDIC. The following encodings are based single-byte
91 encoding implemented as extended ASCII. For most cases it uses
92 \x80-\xff (upper half) to map non-ASCII characters.
96 =item ISO-8859 and corresponding vendor mappings
98 Since there are so many, they are presented in table format with
99 languages and corresponding encoding names by vendors. Note the table
100 is sorted in order of ISO-8859 and the corresponding vendor mappings
101 are slightly different from that of ISO. See
102 L<http://czyborra.com/charsets/iso8859.html> for details.
104 Lang/Regions ISO/Other Std. DOS Windows Macintosh Others
105 ----------------------------------------------------------------
106 N. America (ASCII) cp437 AdobeStandardEncoding
108 W. Europe iso-8859-1 cp850 cp1252 MacRoman nextstep
110 cp860 (DOSPortuguese)
111 Cntrl. Europe iso-8859-2 cp852 cp1250 MacCentralEurRoman
115 Latin3 [1] iso-8859-3
116 Latin4 [2] iso-8859-4
117 Cyrillics iso-8859-5 cp855 cp1251 MacCyrillic
118 (Also see next section) cp866 MacUkrainian
119 Arabic iso-8859-6 cp864 cp1256 MacArabic
121 Greek iso-8859-7 cp737 cp1253 MacGreek
123 Hebrew iso-8859-8 cp862 cp1255 MacHebrew
124 Turkish iso-8859-9 cp857 cp1254 MacTurkish
125 Nordics iso-8859-10 cp865
128 Thai iso-8859-11 [3] cp874 MacThai
129 (iso-8859-12 is nonexistent. Reserved for Indics?)
130 Baltics iso-8859-13 cp775 cp1257
132 Latin9 [4] iso-8859-15
134 Vietnamese viscii cp1258 MacVietnamese
135 ----------------------------------------------------------------
137 [1] Esperanto, Maltese, and Turkish. Turkish is now on 8859-5.
138 [2] Baltics. Now on 8859-10.
139 [3] Also know as TIS 620.
140 [4] 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.
155 For gory details, see L<http://czyborra.com/charsets/cyrillic.html>
157 ----------------------------------------------------------------
159 koi8-r cp878 [RFC1489]
162 =item gsm0338 - Hentai Latin 1
164 GSM0338 is for GSM handsets. Though it shares alphanumerals with
165 ASCII, control character ranges and other parts are mapped very
166 differently, presumably to store Greek and Cyrillic alphabets.
167 This is also covered in Encode::Byte even though it does not
168 comply to extended ASCII.
172 =head2 The CJK: Chinese, Japanese, Korean (Multibyte)
174 Note that Vietnamese is listed above. Also read "Encoding vs Charset"
175 below. Also note these are implemented in distinct module by
176 languages, due the the size concerns. Please refer to their
177 respective document pages.
181 =item Encode::CN -- Continental China
183 Standard DOS/Win Macintosh Comment/Reference
184 ----------------------------------------------------------------
185 euc-cn [1] MacChineseSimp
187 gb12345-raw { GB12345 without CES }
188 gb2312-raw { GB2312 without CES }
191 ----------------------------------------------------------------
193 [1] GB2312 is aliased to this. see L<Microsoft-related naming mess>
194 [2] gbk is aliased to this. see L<Microsoft-related naming mess>
196 =item Encode::JP -- Japan
198 Standard DOS/Win Macintosh Comment/Reference
199 ----------------------------------------------------------------
201 shiftjis cp932 macJapanese
204 iso-2022-jp [RFC1468]
205 iso-2022-jp-1 [RFC2237]
206 jis0201-raw { JIS X 0201 (roman + halfwidth kana) without CES }
207 jis0208-raw { JIS X 0208 (Kanji + fullwidth kana) without CES }
208 jis0212-raw { JIS X 0212 (Extended Kanji) without CES }
209 ----------------------------------------------------------------
211 =item Encode::KR -- Korea
213 Standard DOS/Win Macintosh Comment/Reference
214 ----------------------------------------------------------------
215 euc-kr MacKorean [RFC1557]
217 iso-2022-kr [RFC1557]
218 johab [KS X 1001:1998, Annex 3]
219 ksc5601-raw { KSC5601 without CES }
220 ----------------------------------------------------------------
222 [1] ks_c_5601-1987, (x-)?windows-949, and uhc are aliased to this.
225 =item Encode::TW -- Taiwan
227 Standard DOS/Win Macintosh Comment/Reference
228 ----------------------------------------------------------------
229 big5 cp950 MacChineseTrad
231 ----------------------------------------------------------------
233 =item Encode::HanExtra -- More Chinese via CPAN
235 Due to size concerns, additional Chinese encodings below are
236 distributed separately on CPAN, under the name Encode::HanExtra.
238 Standard DOS/Win Macintosh Comment/Reference
239 ----------------------------------------------------------------
243 ----------------------------------------------------------------
247 =head2 Miscellaneous encodings
253 See L<perlebcdic> for details.
255 ----------------------------------------------------------------
262 ----------------------------------------------------------------
264 =item Encode::Symbols
266 For symbols and dingbats.
268 ----------------------------------------------------------------
274 ----------------------------------------------------------------
278 =head1 Unsupported encodings
280 The following are not supported as yet. Some because they are rarely
281 used, some because of technical difficulties. They may be supported by
282 external modules via CPAN in future, however.
286 =item ISO-2022-JP-2 [RFC1554]
288 Not very popular yet. Needs Unicode Database or equivalent to
289 implement encode() (Because it includes JIS X 0208/0212, KSC5601, and
290 GB2312 simultaneously, which code points in Unicode overlap. So you
291 need to lookup the database to determine what character set a given
292 Unicode character should belong).
294 =item ISO-2022-CN [RFC1922]
296 Not very popular. Needs CNS 11643-1 and 2 which are not available in
297 this module. CNS 11643 is supported (via euc-tw) in Encode::HanExtra.
298 Autrijus may add support for this encoding in his module in future.
300 =item various UP-UX encodings
302 The following are unsupported due to the lack of mapping data.
304 '8' - arabic8, greek8, hebrew8, kana8, thai8, and turkish8
305 '15' - japanese15, korean15, and roi15
307 =item Cyrillic encoding ISO-IR-111
309 Anton doubts its usefulness.
311 =item ISO-8859-8-1 [Hebrew]
313 None of the Encode team knows Hebrew enough (ISO-8859-8, cp1255 and
314 MacHebrew are supported because and just because there were mappings
315 available at L<http://www.unicode.org/>). Contributions welcome.
317 =item ISIRI 3342, Iran System, ISIRI 2900 [Farsi]
321 =item Thai encoding TCVN
325 =item Vietnamese encodings VPS
327 Though Jungshik has reported that Mozilla supports this encoding it
328 was too late before 5.8.0 for us to add one. In future via a separate
330 L<http://lxr.mozilla.org/seamonkey/source/intl/uconv/ucvlatin/vps.uf>
332 L<http://lxr.mozilla.org/seamonkey/source/intl/uconv/ucvlatin/vps.ut>
333 if you are interested in helping us.
335 =item Various Mac encodings
337 The following are unsupported due to the lack of mapping data.
339 MacArmenian, MacBengali, MacBurmese, MacEthiopic
340 MacExtArabic, MacGeorgian, MacKannada, MacKhmer
341 MacLaotian, MacMalayalam, MacMongolian, MacOriya
342 MacSinhalese, MacTamil, MacTelugu, MacTibetan
345 The rest of which already available are based upon the vendor mappings
346 at L<http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/> .
348 =item (Mac) Indic encodings
350 The maps for the following is available at L<http://www.unicode.org/>
351 but remains unsupport because those encodings need algorithmical
352 approach, currently unsupported by F<enc2xs>
358 For details, please see C<Unicode mapping issues and notes:> at
359 L<http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/DEVANAGA.TXT> .
361 I believe this issue is prevalent not only for Mac Indics but also in
362 other Indic encodings, but the above were the only Indic encodings
363 maps that I could find at L<http://www.unicode.org/> .
367 =head1 Encoding vs. Charset -- terminology
369 We are used to using the term (character) I<encoding> and I<character set>
370 interchangeably. But just as using the term byte and character is
371 dangerous and should be differentiated when needed, we need to
372 differentiate I<encoding> and I<character set>.
374 To understand that, it's follow how we make computers grok our characters.
380 First we start with which characters to include. We call this
381 collection of characters I<character repertoire>.
385 Then we have to give each character a unique ID so your computer can
386 tell the difference from 'a' to 'A'. This itemized character
387 repertoire is now a I<character set>.
391 If your computer can grow the character set without further
392 processing, you can go ahead use it. This is called a I<coded
393 character set> (CCS) or I<raw character encoding>. ASCII is used this
398 But in many cases especially multi-byte CJK encodings, you have to
399 tweak a little more. Your network connection may not accept any data
400 with the Most Significant Bit set, Your computer may not be able to
401 tell if a given byte is a whole character or just half of it. So you
402 have to I<encode> the character set to use it.
404 A I<character encoding scheme> (CES) determines how to encode a given
405 character set, or a set of multiple character sets. 7bit ISO-2022 is
406 an example of CES. You switch between character sets via I<escape
411 Technically, or Mathematically speaking, a character set encoded in
412 such a CES that maps character by character may form a CCS. EUC is such
413 an example. CES of EUC is as follows;
423 Map such a character set that consists of 94 or 96 powered by N
424 members by adding 0x80 to each byte.
428 You can also use 0x8e and 0x8f to tell the following sequence of
429 characters belong to yet another character set. each following byte
434 By carefully looking at at the encoded byte sequence, you may find the
435 byte sequence conforms a unique number. In that sense EUC is a CCS
436 generated by a CES above from up to four CCS (complicated?). UTF-8
437 falls into this category. See L<perlUnicode/"UTF-8"> to find how
438 UTF-8 maps Unicode to a byte sequence.
440 You may also find by now why 7bit ISO-2022 cannot conform a CCS. If
441 you look at a byte sequence \x21\x21, you can't tell if it is two !'s
442 or IDEOGRAPHIC SPACE. EUC maps the latter to \xA1\xA1 so you have no
443 trouble between "!!". and " "
445 =head1 Encoding Classification (by Anton Tagunov and Dan Kogai)
447 This section tries to classify the supported encodings by their
448 applicability for information exchange over the Internet and to
449 choose the most suitable aliases to name them in the context of
456 To (en|de) code Encodings marked as C<(**)>, You need
457 C<Encode::HanExtra>, available from CPAN.
463 US-ASCII UTF-8 ISO-8859-* KOI8-R
464 Shift_JIS EUC-JP ISO-2022-JP ISO-2022-JP-1
467 are registered to IANA as preferred MIME names and may probably
468 be used over the Internet.
470 C<Shift_JIS> has been officialized by JIS X 0208:1997.
471 L<Microsoft-related naming mess> gives details.
473 C<GB2312> is the IANA name for C<EUC-CN>.
474 See L<Microsoft-related naming mess> for details.
476 C<GB_2312-80> I<raw> encoding is available as C<gb2312-raw>
477 with Encode. See L<Encode::CN> for details.
482 have not been registered with IANA (as of March 2002) but
483 seem to be supported by major web browsers.
484 IANA name for C<EUC-CN> is C<GB2312>.
489 See L<Microsoft-related naming mess> for details.
491 C<KS_C_5601-1987> I<raw> encoding is available as C<kcs5601-raw>
492 with Encode. See L<Encode::KR> for details.
494 UTF-16 UTF-16BE UTF-16LE
496 are IANA-registered C<charset>s. See [RFC 2781] for details.
497 Jungshik Shin reports that UTF-16 with a BOM is well accepted
498 by MS IE 5/6 and NS 4/6. Beware however that
504 C<UTF-16> support in any software you're going to be
505 using/interoperating with has probably been less tested
506 then C<UTF-8> support
510 C<UTF-8> coded data seamlessly passes traditional
511 command piping (C<cat>, C<more>, etc.) while C<UTF-16> coded
512 data is likely to cause confusion (with it's zero bytes,
517 it is beyond the power of words to describe the way HTML browsers
518 encode non-C<ASCII> form data. To get a general impression visit
519 L<http://ppewww.ph.gla.ac.uk/~flavell/charset/form-i18n.html>.
520 While encoding of form data has stabilized for C<UTF-8> coded pages
521 (at least IE 5/6, NS 6, Opera 6 behave consistently), be sure to
522 expect fun (and cross-browser discrepancies) with C<UTF-16> coded
527 The rule of thumb is to use C<UTF-8> unless you know what
528 you're doing and unless you really benefit from using C<UTF-16>.
534 GB 18030 (**) (see links bellow)
537 are totally valid encodings but not registered at IANA.
538 The names under which they are listed here are probably the
539 most widely-known names for these encodings and are recommended
544 is a bit proprietary name.
546 =head2 Microsoft-related naming mess
548 Microsoft products misuse the following names:
554 Microsoft extension to C<EUC-KR>.
556 Proper names: C<CP949>, C<UHC>, C<x-windows-949> (as used by Mozilla).
558 See L<http://lists.w3.org/Archives/Public/ietf-charsets/2001AprJun/0033.html>
561 Encode aliases C<KS_C_5601-1987> to C<cp949> to reflect this common
562 misusage. I<Raw> C<KS_C_5601-1987> encoding is available as
565 See L<Encode::KR> for details.
569 Microsoft extension to C<EUC-CN>.
571 Proper names: C<CP936>, C<GBK>.
573 C<GB2312> has been registered in the C<EUC-CN> meaning at
574 IANA. This has partially repaired the situation: Microsoft's
575 C<GB2312> has become a superset of the official C<GB2312>.
577 Encode aliases C<GB2312> to C<euc-cn> in full agreement with
578 IANA registration. C<cp936> is supported separately.
579 I<Raw> C<GB_2312-80> encoding is available as C<gb2312-raw>.
581 See L<Encode::CN> for details.
585 Microsoft extension to C<Big5>.
587 Proper name: C<CP950>.
589 Encode separately supports C<Big5> and C<cp950>.
593 Microsoft's understanding of C<Shift_JIS>.
595 JIS has not endorsed the full Microsoft standard however.
596 The official C<Shift_JIS> includes only JIS X 0201 and JIS X 0208
597 subsets, while Microsoft has always been meaning C<Shift_JIS> to
598 encode a wider character repertoire. See C<IANA> registration for
601 As a historical predecessor Microsoft's variant
602 probably has more rights for the name, albeit it may be objected
603 that Microsoft shouldn't have used JIS as part of the name
606 Unambiguous name: C<CP932>. C<IANA> name (not used?): C<Windows-31J>.
608 Encode separately supports C<Shift_JIS> and C<cp932>.
616 =item character repertoire
618 A collection of unique characters. A I<character> set in the most
619 strict sense. At this stage characters are not numbered.
621 =item coded character set (CCS)
623 A character set that is mapped in a way computers can use directly.
624 Many character encodings including EUC falls in this category.
626 =item character encoding scheme (CES)
628 An algorithm to map a character set to a byte sequence. You don't
629 have to be able to tell which character set a given byte sequence
630 belongs. 7-bit ISO-2022 is a CES but it cannot be a CCS. EUC is an
631 example of being both a CCS and CES.
633 =item charset (in MIME context)
635 has long been used in the meaning of C<encoding>, CES.
637 While C<character set> word combination has lost this meaning
638 in MIME context since [RFC 2130], C<charset> abbreviation has
639 retained it. This is how [RFC 2277], [RFC 2278] bless C<charset>:
642 This document uses the term "charset" to mean a set of rules for
643 mapping from a sequence of octets to a sequence of characters, such
644 as the combination of a coded character set and a character encoding
645 scheme; this is also what is used as an identifier in MIME "charset="
646 parameters, and registered in the IANA charset registry ... (Note
647 that this is NOT a term used by other standards bodies, such as ISO).
652 Extended Unix Character. See ISO-2022
656 A CES that was carefully designed to coexist with ASCII. There are 7
657 bit version and 8 bit version.
659 7 bit version switches character set via escape sequence so this
660 cannot form a CCS. Since this is more difficult to handle in programs
661 than the 8 bit version, 7 bit version is not very popular except for
662 iso-2022-jp, the de facto standard CES for e-mails.
664 8 bit version can conform a CCS. EUC and ISO-8859 are two examples
665 thereof. Pre-5.6 perl could use them as string literals.
669 Short for I<Universal Character Set>. When you say just UCS, it means
674 ISO/IEC 10646 encoding form: Universal Character Set coded in two
679 A Character Set that aims to include all character repertoire of the
680 world. Many character sets in various national as well as industrial
681 standards have become, in a way, just subsets of Unicode.
685 Short for I<Unicode Transformation Format>. Determines how to map a
686 Unicode character into byte sequence.
690 A UTF in 16-bit encoding. Can either be in big endian or little
691 endian. Big endian version is called UTF-16BE (equals to UCS-2 +
692 Surrogate Support) and little endian version is UTF-16LE.
700 L<Encode::CN>, L<Encode::JP>, L<Encode::KR>, L<Encode::TW>,
701 L<Encode::EBCDIC>, L<Encode::Symbol>
709 European Computer Manufacturers Association
710 L<http://www.ecma.ch>
714 =item EMCA-035 (eq C<ISO-2022>)
716 L<http://www.ecma.ch/ecma1/STAND/ECMA-035.HTM>
718 The very specification of ISO-2022 is available from the link above.
724 Internet Assigned Numbers Authority
725 L<http://www.iana.org/>
729 =item Assigned Charset Names by IANA
731 L<http://www.iana.org/assignments/character-sets>
733 Most of the C<canonical names> in Encode derive from this list
734 so you can directly apply the string you have extracted from MIME
735 header of mails and web pages.
741 International Organization for Standardization
742 L<http://www.iso.ch/>
746 Request For Comments -- need I say more?
747 L<http://www.rfc.net/>, L<http://www.faqs.org/rfcs/>
752 L<http://www.unicode.org/>
756 =item Unicode Glossary
758 L<http://www.unicode.org/glossary/>
760 The glossary of this document is based upon this site.
766 =head2 Other Notable Sites
772 L<http://czyborra.com/>
774 Contains a a lot of useful information, especially gory details of ISO
779 L<http://www.oreilly.com/people/authors/lunde/cjk_inf.html>
781 Somewhat obsolete (last update in 1996), but still useful. Also try
783 L<ftp://ftp.oreilly.com/pub/examples/nutshell/cjkv/pdf/GB18030_Summary.pdf>
785 You will find brief info on C<EUC-CN>, C<GBK> and mostly on C<GB 18030>
787 =item Jungshik Shin's Hangul FAQ
789 L<http://jshin.net/faq>
791 And especially it's subject 8.
793 L<http://jshin.net/faq/qa8.html>
795 A comprehensive overview of the Korean (C<KS *>) standards.
799 =head2 Offline sources
803 =item C<CJKV Information Processing> by Ken Lunde
805 CJKV Information Processing
806 1999 O'Reilly & Associates, ISBN : 1-56592-224-7
808 The modern successor of the C<CJK.inf>.
810 Features a comprehensive coverage on CJKV character sets and
811 encodings along with many other issues faced by anyone trying
812 to better support CJKV languages/scripts in all the areas of
813 information processing.
815 To purchase this book visit
816 L<http://www.oreilly.com/catalog/cjkvinfo/>
822 I could not find this page because the hostname doesn't resolve!
824 Brief description for most of the mentioned CJK encodings
825 L<http://www.debian.org.ru/doc/manuals/intro-i18n/ch-codes.html>