Commit | Line | Data |
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1 | =head1 NAME |
2 | |
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3 | Encode::Supported -- Encodings supported by Encode |
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4 | |
5 | =head1 DESCRIPTION |
6 | |
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7 | =head2 Encoding Names |
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8 | |
9 | Encoding names are case insensitive. White space in names |
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10 | is ignored. In addition, an encoding may have aliases. |
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11 | Each encoding has one "canonical" name. The "canonical" |
12 | name is chosen from the names of the encoding by picking |
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13 | the first in the following sequence (with a few exceptions). |
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14 | |
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15 | =over 4 |
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16 | |
17 | =item * |
18 | |
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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. |
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22 | |
23 | =item * |
24 | |
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25 | The MIME name as defined in IETF RFCs. This includes all "iso-"s. |
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26 | |
27 | =item * |
28 | |
29 | The name in the IANA registry. |
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30 | |
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31 | =item * |
32 | |
33 | The name used by the organization that defined it. |
34 | |
35 | =back |
36 | |
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 |
40 | the canonical name. |
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41 | |
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42 | Because of all the alias issues, and because in the general case |
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43 | encodings have state, "Encode" uses an encoding object internally |
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44 | once an operation is in progress. |
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45 | |
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46 | =head1 Supported Encodings |
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47 | |
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 |
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50 | (via alias) and all occurrence of spaces are replaced with '-'. |
51 | In other words, "ISO 8859 1" and "iso-8859-1" are identical. |
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52 | |
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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 |
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55 | most cases. Encode.pm will automatically load those modules on demand. |
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56 | |
5129552c |
57 | =head2 Built-in Encodings |
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58 | |
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59 | The following encodings are always available. |
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60 | |
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61 | Canonical Aliases Comments & References |
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62 | ---------------------------------------------------------------- |
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63 | ascii US-ascii [ECMA] |
64 | iso-8859-1 latin1 [ISO] |
65 | utf8 UTF-8 [RFC2279] |
c731e18e |
66 | ---------------------------------------------------------------- |
67 | |
c731e18e |
68 | =head2 Encode::Unicode -- other Unicode encodings |
69 | |
70 | Unicode coding schemes other than native utf8 are supported by |
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71 | Encode::Unicode, which will be autoloaded on demand. |
c731e18e |
72 | |
73 | ---------------------------------------------------------------- |
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74 | UCS-2BE UCS-2, iso-10646-1 [IANA, UC] |
75 | UCS-2LE [UC] |
76 | UTF-16 [UC] |
77 | UTF-16BE [UC] |
78 | UTF-16LE [UC] |
79 | UTF-32 [UC] |
80 | UTF-32BE [UC] |
81 | UTF-32LE [UC] |
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82 | ---------------------------------------------------------------- |
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83 | |
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84 | To find how (UCS-2|UTF-(16|32))(LE|BE)? differ from one another, |
f2a2953c |
85 | see L<Encode::Unicode>. |
86 | |
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87 | =head2 Encode::Byte -- Extended ASCII |
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88 | |
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89 | Encode::Byte implements most single-byte encodings except for |
90 | Symbols and EBCDIC. The following encodings are based on single-byte |
91 | encodings implemented as extended ASCII. Most of them map |
92 | \x80-\xff (upper half) to non-ASCII characters. |
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93 | |
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94 | =over 4 |
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95 | |
96 | =item ISO-8859 and corresponding vendor mappings |
97 | |
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98 | Since there are so many, they are presented in table format with |
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99 | languages and corresponding encoding names by vendors. Note that |
100 | the table is sorted in order of ISO-8859 and the corresponding vendor |
101 | mappings are slightly different from that of ISO. See |
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102 | L<http://czyborra.com/charsets/iso8859.html> for details. |
103 | |
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104 | Lang/Regions ISO/Other Std. DOS Windows Macintosh Others |
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105 | ---------------------------------------------------------------- |
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106 | N. America (ASCII) cp437 AdobeStandardEncoding |
107 | cp863 (DOSCanadaF) |
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108 | W. Europe iso-8859-1 cp850 cp1252 MacRoman nextstep |
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109 | hp-roman8 |
110 | cp860 (DOSPortuguese) |
111 | Cntrl. Europe iso-8859-2 cp852 cp1250 MacCentralEurRoman |
112 | MacCroatian |
113 | MacRomanian |
114 | MacRumanian |
115 | Latin3 [1] iso-8859-3 |
116 | Latin4 [2] iso-8859-4 |
117 | Cyrillics iso-8859-5 cp855 cp1251 MacCyrillic |
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118 | (See also next section) cp866 MacUkrainian |
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119 | Arabic iso-8859-6 cp864 cp1256 MacArabic |
120 | cp1006 MacFarsi |
121 | Greek iso-8859-7 cp737 cp1253 MacGreek |
122 | cp869 (DOSGreek2) |
123 | Hebrew iso-8859-8 cp862 cp1255 MacHebrew |
124 | Turkish iso-8859-9 cp857 cp1254 MacTurkish |
125 | Nordics iso-8859-10 cp865 |
126 | cp861 MacIcelandic |
127 | MacSami |
128 | Thai iso-8859-11 [3] cp874 MacThai |
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129 | (iso-8859-12 is nonexistent. Reserved for Indics?) |
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130 | Baltics iso-8859-13 cp775 cp1257 |
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131 | Celtics iso-8859-14 |
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132 | Latin9 [4] iso-8859-15 |
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133 | Latin10 iso-8859-16 |
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134 | Vietnamese viscii cp1258 MacVietnamese |
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135 | ---------------------------------------------------------------- |
136 | |
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137 | [1] Esperanto, Maltese, and Turkish. Turkish is now on 8859-9. |
138 | [2] Baltics. Now on 8859-10, except for Latvian. |
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139 | [3] Also know as TIS 620. |
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140 | [4] Nicknamed Latin0; the Euro sign as well as French and Finnish |
141 | letters that are missing from 8859-1 were added. |
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142 | |
143 | All cp* are also available as ibm-*, ms-*, and windows-* . See also |
144 | L<http://czyborra.com/charsets/codepages.html>. |
145 | |
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> |
0ab8f81e |
149 | for details. |
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150 | |
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151 | =item KOI8 - De Facto Standard for the Cyrillic world |
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152 | |
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153 | Though ISO-8859 does have ISO-8859-5, the KOI8 series is far more |
154 | popular in the Net. L<Encode> comes with the following KOI charsets. |
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155 | For gory details, see L<http://czyborra.com/charsets/cyrillic.html> |
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156 | |
67d7b5ef |
157 | ---------------------------------------------------------------- |
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158 | koi8-f |
159 | koi8-r cp878 [RFC1489] |
160 | koi8-u [RFC2319] |
85982a32 |
161 | ---------------------------------------------------------------- |
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162 | |
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163 | =item gsm0338 - Hentai Latin 1 |
164 | |
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165 | GSM0338 is for GSM handsets. Though it shares alphanumerals with |
166 | ASCII, control character ranges and other parts are mapped very |
167 | differently, presumably to store Greek and Cyrillic alphabets. |
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168 | This is also covered in Encode::Byte even though it is not an |
169 | "extended ASCII" encoding. |
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170 | |
171 | =back |
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172 | |
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173 | =head2 CJK: Chinese, Japanese, Korean (Multibyte) |
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174 | |
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175 | Note that Vietnamese is listed above. Also read "Encoding vs Charset" |
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176 | below. Also note that these are implemented in distinct modules by |
177 | countries, due the the size concerns (simplified Chinese is mapped |
178 | to 'CN', continental China, while traditional Chinese is mapped to |
179 | 'TW', Taiwan). Please refer to their respective documentataion pages. |
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180 | |
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181 | =over 4 |
182 | |
183 | =item Encode::CN -- Continental China |
184 | |
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185 | Standard DOS/Win Macintosh Comment/Reference |
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186 | ---------------------------------------------------------------- |
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187 | euc-cn [1] MacChineseSimp |
188 | (gbk) cp936 [2] |
189 | gb12345-raw { GB12345 without CES } |
190 | gb2312-raw { GB2312 without CES } |
5129552c |
191 | hz |
192 | iso-ir-165 |
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193 | ---------------------------------------------------------------- |
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194 | |
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195 | [1] GB2312 is aliased to this. See L<Microsoft-related naming mess> |
196 | [2] gbk is aliased to this. See L<Microsoft-related naming mess> |
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197 | |
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198 | =item Encode::JP -- Japan |
199 | |
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200 | Standard DOS/Win Macintosh Comment/Reference |
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201 | ---------------------------------------------------------------- |
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202 | euc-jp |
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203 | shiftjis cp932 macJapanese |
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204 | 7bit-jis |
205 | euc-jp |
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206 | iso-2022-jp [RFC1468] |
207 | iso-2022-jp-1 [RFC2237] |
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208 | jis0201-raw { JIS X 0201 (roman + halfwidth kana) without CES } |
209 | jis0208-raw { JIS X 0208 (Kanji + fullwidth kana) without CES } |
210 | jis0212-raw { JIS X 0212 (Extended Kanji) without CES } |
67d7b5ef |
211 | ---------------------------------------------------------------- |
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212 | |
213 | =item Encode::KR -- Korea |
214 | |
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215 | Standard DOS/Win Macintosh Comment/Reference |
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216 | ---------------------------------------------------------------- |
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217 | euc-kr MacKorean [RFC1557] |
218 | cp949 [1] |
219 | iso-2022-kr [RFC1557] |
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220 | johab [KS X 1001:1998, Annex 3] |
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221 | ksc5601-raw { KSC5601 without CES } |
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222 | ---------------------------------------------------------------- |
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223 | |
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224 | [1] ks_c_5601-1987, (x-)?windows-949, and uhc are aliased to this. |
225 | See below. |
226 | |
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227 | =item Encode::TW -- Taiwan |
228 | |
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229 | Standard DOS/Win Macintosh Comment/Reference |
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230 | ---------------------------------------------------------------- |
b0b300a3 |
231 | big5-eten cp950 MacChineseTrad {big5 aliased to big5-eten} |
232 | big5-hkscs |
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233 | ---------------------------------------------------------------- |
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234 | |
235 | =item Encode::HanExtra -- More Chinese via CPAN |
236 | |
237 | Due to size concerns, additional Chinese encodings below are |
238 | distributed separately on CPAN, under the name Encode::HanExtra. |
239 | |
962111ca |
240 | Standard DOS/Win Macintosh Comment/Reference |
67d7b5ef |
241 | ---------------------------------------------------------------- |
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242 | gb18030 |
243 | euc-tw |
244 | big5plus |
67d7b5ef |
245 | ---------------------------------------------------------------- |
5129552c |
246 | |
247 | =back |
248 | |
249 | =head2 Miscellaneous encodings |
250 | |
251 | =over 4 |
252 | |
253 | =item Encode::EBCDIC |
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254 | |
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255 | See L<perlebcdic> for details. |
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256 | |
67d7b5ef |
257 | ---------------------------------------------------------------- |
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258 | cp37 |
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259 | cp500 |
260 | cp875 |
261 | cp1026 |
262 | cp1047 |
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263 | posix-bc |
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264 | ---------------------------------------------------------------- |
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265 | |
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266 | =item Encode::Symbols |
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267 | |
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268 | For symbols and dingbats. |
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269 | |
67d7b5ef |
270 | ---------------------------------------------------------------- |
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271 | symbol |
272 | dingbats |
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273 | MacDingbats |
274 | AdobeZdingbat |
275 | AdobeSymbol |
67d7b5ef |
276 | ---------------------------------------------------------------- |
277 | |
278 | =back |
279 | |
280 | =head1 Unsupported encodings |
281 | |
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282 | The following encodings are not supported as yet; some because they |
283 | are rarely used, some because of technical difficulties. They may |
284 | be supported by external modules via CPAN in the future, however. |
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285 | |
286 | =over 4 |
287 | |
288 | =item ISO-2022-JP-2 [RFC1554] |
289 | |
290 | Not very popular yet. Needs Unicode Database or equivalent to |
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291 | implement encode() (because it includes JIS X 0208/0212, KSC5601, and |
292 | GB2312 simultaneously, whose code points in Unicode overlap. So you |
293 | need to lookup the database to determine to what character set a given |
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294 | Unicode character should belong). |
295 | |
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296 | =item ISO-2022-CN [RFC1922] |
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297 | |
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298 | Not very popular. Needs CNS 11643-1 and -2 which are not available in |
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299 | this module. CNS 11643 is supported (via euc-tw) in Encode::HanExtra. |
0ab8f81e |
300 | Autrijus Tang may add support for this encoding in his module in future. |
67d7b5ef |
301 | |
0ab8f81e |
302 | =item Various HP-UX encodings |
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303 | |
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304 | The following are unsupported due to the lack of mapping data. |
305 | |
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306 | '8' - arabic8, greek8, hebrew8, kana8, thai8, and turkish8 |
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307 | '15' - japanese15, korean15, and roi15 |
67d7b5ef |
308 | |
309 | =item Cyrillic encoding ISO-IR-111 |
310 | |
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311 | Anton Tagunov doubts its usefulness. |
67d7b5ef |
312 | |
313 | =item ISO-8859-8-1 [Hebrew] |
314 | |
a999c27c |
315 | None of the Encode team knows Hebrew enough (ISO-8859-8, cp1255 and |
316 | MacHebrew are supported because and just because there were mappings |
962111ca |
317 | available at L<http://www.unicode.org/>). Contributions welcome. |
318 | |
319 | =item ISIRI 3342, Iran System, ISIRI 2900 [Farsi] |
320 | |
321 | Ditto. |
67d7b5ef |
322 | |
323 | =item Thai encoding TCVN |
324 | |
325 | Ditto. |
326 | |
327 | =item Vietnamese encodings VPS |
328 | |
0ab8f81e |
329 | Though Jungshik Shin has reported that Mozilla supports this encoding, |
330 | it was too late before 5.8.0 for us to add it. In the future, it |
331 | may be available via a separate module. See |
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332 | L<http://lxr.mozilla.org/seamonkey/source/intl/uconv/ucvlatin/vps.uf> |
333 | and |
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334 | L<http://lxr.mozilla.org/seamonkey/source/intl/uconv/ucvlatin/vps.ut> |
335 | if you are interested in helping us. |
67d7b5ef |
336 | |
962111ca |
337 | =item Various Mac encodings |
67d7b5ef |
338 | |
962111ca |
339 | The following are unsupported due to the lack of mapping data. |
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340 | |
341 | MacArmenian, MacBengali, MacBurmese, MacEthiopic |
342 | MacExtArabic, MacGeorgian, MacKannada, MacKhmer |
343 | MacLaotian, MacMalayalam, MacMongolian, MacOriya |
344 | MacSinhalese, MacTamil, MacTelugu, MacTibetan |
345 | MacVietnamese |
346 | |
0ab8f81e |
347 | The rest which are already available are based upon the vendor mappings |
962111ca |
348 | at L<http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/> . |
a999c27c |
349 | |
350 | =item (Mac) Indic encodings |
351 | |
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352 | The maps for the following are available at L<http://www.unicode.org/> |
353 | but remain unsupport because those encodings need algorithmical |
354 | approach, currently unsupported by F<enc2xs>: |
67d7b5ef |
355 | |
a999c27c |
356 | MacDevanagari |
357 | MacGurmukhi |
358 | MacGujarati |
67d7b5ef |
359 | |
a999c27c |
360 | For details, please see C<Unicode mapping issues and notes:> at |
361 | L<http://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/DEVANAGA.TXT> . |
362 | |
363 | I believe this issue is prevalent not only for Mac Indics but also in |
962111ca |
364 | other Indic encodings, but the above were the only Indic encodings |
a999c27c |
365 | maps that I could find at L<http://www.unicode.org/> . |
5129552c |
366 | |
367 | =back |
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368 | |
a999c27c |
369 | =head1 Encoding vs. Charset -- terminology |
5d030b67 |
370 | |
0ab8f81e |
371 | We are used to using the term (character) I<encoding> and I<character |
372 | set> interchangeably. But just as confusing the terms byte and |
373 | character is dangerous and the terms should be differentiated when |
374 | needed, we need to differentiate I<encoding> and I<character set>. |
5d030b67 |
375 | |
0ab8f81e |
376 | To understand that, here is a description of how we make computers |
377 | grok our characters. |
a999c27c |
378 | |
379 | =over 4 |
380 | |
381 | =item * |
67d7b5ef |
382 | |
a999c27c |
383 | First we start with which characters to include. We call this |
384 | collection of characters I<character repertoire>. |
5d030b67 |
385 | |
a999c27c |
386 | =item * |
5d030b67 |
387 | |
a999c27c |
388 | Then we have to give each character a unique ID so your computer can |
0ab8f81e |
389 | tell the difference between 'a' and 'A'. This itemized character |
962111ca |
390 | repertoire is now a I<character set>. |
a63c962f |
391 | |
a999c27c |
392 | =item * |
393 | |
394 | If your computer can grow the character set without further |
0ab8f81e |
395 | processing, you can go ahead and use it. This is called a I<coded |
a999c27c |
396 | character set> (CCS) or I<raw character encoding>. ASCII is used this |
397 | way for most cases. |
398 | |
399 | =item * |
400 | |
0ab8f81e |
401 | But in many cases, especially multi-byte CJK encodings, you have to |
a999c27c |
402 | tweak a little more. Your network connection may not accept any data |
0ab8f81e |
403 | with the Most Significant Bit set, and your computer may not be able to |
a999c27c |
404 | tell if a given byte is a whole character or just half of it. So you |
405 | have to I<encode> the character set to use it. |
406 | |
407 | A I<character encoding scheme> (CES) determines how to encode a given |
408 | character set, or a set of multiple character sets. 7bit ISO-2022 is |
0ab8f81e |
409 | an example of a CES. You switch between character sets via I<escape |
410 | sequences>. |
67d7b5ef |
411 | |
412 | =back |
413 | |
0ab8f81e |
414 | Technically, or mathematically, speaking, a character set encoded in |
a999c27c |
415 | such a CES that maps character by character may form a CCS. EUC is such |
0ab8f81e |
416 | an example. The CES of EUC is as follows: |
67d7b5ef |
417 | |
a999c27c |
418 | =over 4 |
5d030b67 |
419 | |
a999c27c |
420 | =item * |
5d030b67 |
421 | |
a999c27c |
422 | Map ASCII unchanged. |
423 | |
424 | =item * |
425 | |
426 | Map such a character set that consists of 94 or 96 powered by N |
427 | members by adding 0x80 to each byte. |
428 | |
429 | =item * |
430 | |
0ab8f81e |
431 | You can also use 0x8e and 0x8f to indicate that the following sequence of |
432 | characters belongs to yet another character set. To each following byte |
433 | is added the value 0x80. |
a999c27c |
434 | |
435 | =back |
436 | |
0ab8f81e |
437 | By carefully looking at the encoded byte sequence, you can find that the |
438 | byte sequence conforms a unique number. In that sense, EUC is a CCS |
a999c27c |
439 | generated by a CES above from up to four CCS (complicated?). UTF-8 |
0ab8f81e |
440 | falls into this category. See L<perlUnicode/"UTF-8"> to find out how |
a999c27c |
441 | UTF-8 maps Unicode to a byte sequence. |
442 | |
0ab8f81e |
443 | You may also have found out by now why 7bit ISO-2022 cannot comprise |
444 | a CCS. If you look at a byte sequence \x21\x21, you can't tell if |
445 | it is two !'s or IDEOGRAPHIC SPACE. EUC maps the latter to \xA1\xA1 |
446 | so you have no trouble differentiating between "!!". and S<" ">. |
67d7b5ef |
447 | |
a63c962f |
448 | =head1 Encoding Classification (by Anton Tagunov and Dan Kogai) |
449 | |
450 | This section tries to classify the supported encodings by their |
451 | applicability for information exchange over the Internet and to |
452 | choose the most suitable aliases to name them in the context of |
453 | such communication. |
454 | |
0ab8f81e |
455 | =over 4 |
67d7b5ef |
456 | |
457 | =item * |
458 | |
0ab8f81e |
459 | To (en|de)code encodings marked by C<(**)>, you need |
a999c27c |
460 | C<Encode::HanExtra>, available from CPAN. |
67d7b5ef |
461 | |
462 | =back |
463 | |
a63c962f |
464 | Encoding names |
5d030b67 |
465 | |
f2a2953c |
466 | US-ASCII UTF-8 ISO-8859-* KOI8-R |
467 | Shift_JIS EUC-JP ISO-2022-JP ISO-2022-JP-1 |
468 | EUC-KR Big5 GB2312 |
a999c27c |
469 | |
0ab8f81e |
470 | are registered with IANA as preferred MIME names and may |
a999c27c |
471 | be used over the Internet. |
5d030b67 |
472 | |
c731e18e |
473 | C<Shift_JIS> has been officialized by JIS X 0208:1997. |
a999c27c |
474 | L<Microsoft-related naming mess> gives details. |
5d030b67 |
475 | |
a999c27c |
476 | C<GB2312> is the IANA name for C<EUC-CN>. |
477 | See L<Microsoft-related naming mess> for details. |
478 | |
479 | C<GB_2312-80> I<raw> encoding is available as C<gb2312-raw> |
f2a2953c |
480 | with Encode. See L<Encode::CN> for details. |
5d030b67 |
481 | |
a63c962f |
482 | EUC-CN |
f2a2953c |
483 | KOI8-U [RFC2319] |
5d030b67 |
484 | |
a999c27c |
485 | have not been registered with IANA (as of March 2002) but |
486 | seem to be supported by major web browsers. |
0ab8f81e |
487 | The IANA name for C<EUC-CN> is C<GB2312>. |
67d7b5ef |
488 | |
489 | KS_C_5601-1987 |
490 | |
a999c27c |
491 | is heavily misused. |
492 | See L<Microsoft-related naming mess> for details. |
493 | |
494 | C<KS_C_5601-1987> I<raw> encoding is available as C<kcs5601-raw> |
f2a2953c |
495 | with Encode. See L<Encode::KR> for details. |
496 | |
497 | UTF-16 UTF-16BE UTF-16LE |
498 | |
448e90bb |
499 | are IANA-registered C<charset>s. See [RFC 2781] for details. |
f2a2953c |
500 | Jungshik Shin reports that UTF-16 with a BOM is well accepted |
501 | by MS IE 5/6 and NS 4/6. Beware however that |
502 | |
0ab8f81e |
503 | =over 4 |
f2a2953c |
504 | |
505 | =item * |
5d030b67 |
506 | |
f2a2953c |
507 | C<UTF-16> support in any software you're going to be |
508 | using/interoperating with has probably been less tested |
509 | then C<UTF-8> support |
5d030b67 |
510 | |
f2a2953c |
511 | =item * |
512 | |
c731e18e |
513 | C<UTF-8> coded data seamlessly passes traditional |
514 | command piping (C<cat>, C<more>, etc.) while C<UTF-16> coded |
0ab8f81e |
515 | data is likely to cause confusion (with its zero bytes, |
f2a2953c |
516 | for example) |
517 | |
518 | =item * |
519 | |
520 | it is beyond the power of words to describe the way HTML browsers |
0ab8f81e |
521 | encode non-C<ASCII> form data. To get a general impression, visit |
f2a2953c |
522 | L<http://ppewww.ph.gla.ac.uk/~flavell/charset/form-i18n.html>. |
0ab8f81e |
523 | While encoding of form data has stabilized for C<UTF-8> encoded pages |
524 | (at least IE 5/6, NS 6, and Opera 6 behave consistently), be sure to |
525 | expect fun (and cross-browser discrepancies) with C<UTF-16> encoded |
f2a2953c |
526 | pages! |
527 | |
528 | =back |
529 | |
530 | The rule of thumb is to use C<UTF-8> unless you know what |
c731e18e |
531 | you're doing and unless you really benefit from using C<UTF-16>. |
a999c27c |
532 | |
5d030b67 |
533 | |
f2a2953c |
534 | ISO-IR-165 [RFC1345] |
5d030b67 |
535 | VISCII |
a63c962f |
536 | GB 12345 |
f2a2953c |
537 | GB 18030 (**) (see links bellow) |
538 | EUC-TW (**) |
5d030b67 |
539 | |
540 | are totally valid encodings but not registered at IANA. |
a63c962f |
541 | The names under which they are listed here are probably the |
542 | most widely-known names for these encodings and are recommended |
543 | names. |
544 | |
f2a2953c |
545 | BIG5PLUS (**) |
a63c962f |
546 | |
0ab8f81e |
547 | is a proprietary name. |
5d030b67 |
548 | |
a999c27c |
549 | =head2 Microsoft-related naming mess |
550 | |
551 | Microsoft products misuse the following names: |
5d030b67 |
552 | |
0ab8f81e |
553 | =over 4 |
a63c962f |
554 | |
a999c27c |
555 | =item KS_C_5601-1987 |
5d030b67 |
556 | |
a999c27c |
557 | Microsoft extension to C<EUC-KR>. |
5d030b67 |
558 | |
c731e18e |
559 | Proper names: C<CP949>, C<UHC>, C<x-windows-949> (as used by Mozilla). |
67d7b5ef |
560 | |
f2a2953c |
561 | See L<http://lists.w3.org/Archives/Public/ietf-charsets/2001AprJun/0033.html> |
a999c27c |
562 | for details. |
5d030b67 |
563 | |
f2a2953c |
564 | Encode aliases C<KS_C_5601-1987> to C<cp949> to reflect this common |
565 | misusage. I<Raw> C<KS_C_5601-1987> encoding is available as |
566 | C<kcs5601-raw>. |
5d030b67 |
567 | |
f2a2953c |
568 | See L<Encode::KR> for details. |
67d7b5ef |
569 | |
a999c27c |
570 | =item GB2312 |
67d7b5ef |
571 | |
a999c27c |
572 | Microsoft extension to C<EUC-CN>. |
a63c962f |
573 | |
a999c27c |
574 | Proper names: C<CP936>, C<GBK>. |
a63c962f |
575 | |
a999c27c |
576 | C<GB2312> has been registered in the C<EUC-CN> meaning at |
577 | IANA. This has partially repaired the situation: Microsoft's |
578 | C<GB2312> has become a superset of the official C<GB2312>. |
67d7b5ef |
579 | |
a999c27c |
580 | Encode aliases C<GB2312> to C<euc-cn> in full agreement with |
581 | IANA registration. C<cp936> is supported separately. |
f2a2953c |
582 | I<Raw> C<GB_2312-80> encoding is available as C<gb2312-raw>. |
a999c27c |
583 | |
f2a2953c |
584 | See L<Encode::CN> for details. |
a999c27c |
585 | |
586 | =item Big5 |
587 | |
588 | Microsoft extension to C<Big5>. |
589 | |
590 | Proper name: C<CP950>. |
591 | |
592 | Encode separately supports C<Big5> and C<cp950>. |
593 | |
594 | =item Shift_JIS |
595 | |
596 | Microsoft's understanding of C<Shift_JIS>. |
597 | |
598 | JIS has not endorsed the full Microsoft standard however. |
599 | The official C<Shift_JIS> includes only JIS X 0201 and JIS X 0208 |
0ab8f81e |
600 | character sets, while Microsoft has always used C<Shift_JIS> |
85982a32 |
601 | to encode a wider character repertoire. See C<IANA> registration for |
c731e18e |
602 | C<Windows-31J>. |
a999c27c |
603 | |
0ab8f81e |
604 | As a historical predecessor, Microsoft's variant |
605 | probably has more rights for the name, though it may be objected |
a999c27c |
606 | that Microsoft shouldn't have used JIS as part of the name |
607 | in the first place. |
608 | |
fcb875d4 |
609 | Unambiguous name: C<CP932>. C<IANA> name (not used?): C<Windows-31J>. |
a999c27c |
610 | |
611 | Encode separately supports C<Shift_JIS> and C<cp932>. |
612 | |
613 | =back |
614 | |
615 | =head1 Glossary |
616 | |
0ab8f81e |
617 | =over 4 |
a999c27c |
618 | |
619 | =item character repertoire |
620 | |
0ab8f81e |
621 | A collection of unique characters. A I<character> set in the strictest |
622 | sense. At this stage, characters are not numbered. |
a999c27c |
623 | |
624 | =item coded character set (CCS) |
625 | |
626 | A character set that is mapped in a way computers can use directly. |
0ab8f81e |
627 | Many character encodings, including EUC, fall in this category. |
a999c27c |
628 | |
629 | =item character encoding scheme (CES) |
630 | |
631 | An algorithm to map a character set to a byte sequence. You don't |
632 | have to be able to tell which character set a given byte sequence |
633 | belongs. 7-bit ISO-2022 is a CES but it cannot be a CCS. EUC is an |
634 | example of being both a CCS and CES. |
635 | |
f2a2953c |
636 | =item charset (in MIME context) |
637 | |
638 | has long been used in the meaning of C<encoding>, CES. |
639 | |
0ab8f81e |
640 | While the word combination C<character set> has lost this meaning |
641 | in MIME context since [RFC 2130], the C<charset> abbreviation has |
642 | retained it. This is how [RFC 2277] and [RFC 2278] bless C<charset>: |
f2a2953c |
643 | |
644 | This document uses the term "charset" to mean a set of rules for |
645 | mapping from a sequence of octets to a sequence of characters, such |
646 | as the combination of a coded character set and a character encoding |
647 | scheme; this is also what is used as an identifier in MIME "charset=" |
648 | parameters, and registered in the IANA charset registry ... (Note |
649 | that this is NOT a term used by other standards bodies, such as ISO). |
650 | [RFC 2277] |
651 | |
a999c27c |
652 | =item EUC |
653 | |
0ab8f81e |
654 | Extended Unix Character. See ISO-2022. |
a999c27c |
655 | |
656 | =item ISO-2022 |
657 | |
0ab8f81e |
658 | A CES that was carefully designed to coexist with ASCII. There are a 7 |
659 | bit version and an 8 bit version. |
f2a2953c |
660 | |
0ab8f81e |
661 | The 7 bit version switches character set via escape sequence so it |
f2a2953c |
662 | cannot form a CCS. Since this is more difficult to handle in programs |
0ab8f81e |
663 | than the 8 bit version, the 7 bit version is not very popular except for |
664 | iso-2022-jp, the I<de facto> standard CES for e-mails. |
f2a2953c |
665 | |
0ab8f81e |
666 | The 8 bit version can form a CCS. EUC and ISO-8859 are two examples |
962111ca |
667 | thereof. Pre-5.6 perl could use them as string literals. |
a999c27c |
668 | |
669 | =item UCS |
670 | |
671 | Short for I<Universal Character Set>. When you say just UCS, it means |
0ab8f81e |
672 | I<Unicode>. |
a999c27c |
673 | |
674 | =item UCS-2 |
675 | |
676 | ISO/IEC 10646 encoding form: Universal Character Set coded in two |
677 | octets. |
678 | |
679 | =item Unicode |
680 | |
0ab8f81e |
681 | A character set that aims to include all character repertoires of the |
962111ca |
682 | world. Many character sets in various national as well as industrial |
f2a2953c |
683 | standards have become, in a way, just subsets of Unicode. |
a999c27c |
684 | |
685 | =item UTF |
686 | |
f2a2953c |
687 | Short for I<Unicode Transformation Format>. Determines how to map a |
0ab8f81e |
688 | Unicode character into a byte sequence. |
a999c27c |
689 | |
690 | =item UTF-16 |
691 | |
692 | A UTF in 16-bit encoding. Can either be in big endian or little |
0ab8f81e |
693 | endian. The big endian version is called UTF-16BE (equal to UCS-2 + |
694 | surrogate support) and the little endian version is called UTF-16LE. |
67d7b5ef |
695 | |
696 | =back |
5d030b67 |
697 | |
698 | =head1 See Also |
699 | |
5129552c |
700 | L<Encode>, |
701 | L<Encode::Byte>, |
a63c962f |
702 | L<Encode::CN>, L<Encode::JP>, L<Encode::KR>, L<Encode::TW>, |
5129552c |
703 | L<Encode::EBCDIC>, L<Encode::Symbol> |
5d030b67 |
704 | |
a999c27c |
705 | =head1 References |
706 | |
0ab8f81e |
707 | =over 4 |
a999c27c |
708 | |
709 | =item ECMA |
710 | |
711 | European Computer Manufacturers Association |
712 | L<http://www.ecma.ch> |
713 | |
0ab8f81e |
714 | =over 4 |
a999c27c |
715 | |
0ab8f81e |
716 | =item ECMA-035 (eq C<ISO-2022>) |
a999c27c |
717 | |
718 | L<http://www.ecma.ch/ecma1/STAND/ECMA-035.HTM> |
719 | |
0ab8f81e |
720 | The specification of ISO-2022 is available from the link above. |
a999c27c |
721 | |
722 | =back |
723 | |
724 | =item IANA |
725 | |
726 | Internet Assigned Numbers Authority |
727 | L<http://www.iana.org/> |
728 | |
0ab8f81e |
729 | =over 4 |
a999c27c |
730 | |
731 | =item Assigned Charset Names by IANA |
732 | |
733 | L<http://www.iana.org/assignments/character-sets> |
734 | |
735 | Most of the C<canonical names> in Encode derive from this list |
736 | so you can directly apply the string you have extracted from MIME |
448e90bb |
737 | header of mails and web pages. |
a999c27c |
738 | |
739 | =back |
740 | |
741 | =item ISO |
742 | |
743 | International Organization for Standardization |
744 | L<http://www.iso.ch/> |
745 | |
746 | =item RFC |
747 | |
962111ca |
748 | Request For Comments -- need I say more? |
0ab8f81e |
749 | L<http://www.rfc-editor.org/>, L<http://www.rfc.net/>, |
750 | L<http://www.faqs.org/rfcs/> |
a999c27c |
751 | |
752 | =item UC |
753 | |
754 | Unicode Consortium |
755 | L<http://www.unicode.org/> |
756 | |
0ab8f81e |
757 | =over 4 |
a999c27c |
758 | |
759 | =item Unicode Glossary |
760 | |
761 | L<http://www.unicode.org/glossary/> |
762 | |
962111ca |
763 | The glossary of this document is based upon this site. |
a999c27c |
764 | |
765 | =back |
766 | |
767 | =back |
768 | |
769 | =head2 Other Notable Sites |
770 | |
0ab8f81e |
771 | =over 4 |
a999c27c |
772 | |
773 | =item czyborra.com |
774 | |
f2a2953c |
775 | L<http://czyborra.com/> |
a999c27c |
776 | |
777 | Contains a a lot of useful information, especially gory details of ISO |
778 | vs. vendor mappings. |
779 | |
780 | =item CJK.inf |
781 | |
782 | L<http://www.oreilly.com/people/authors/lunde/cjk_inf.html> |
783 | |
784 | Somewhat obsolete (last update in 1996), but still useful. Also try |
785 | |
786 | L<ftp://ftp.oreilly.com/pub/examples/nutshell/cjkv/pdf/GB18030_Summary.pdf> |
787 | |
0ab8f81e |
788 | You will find brief info on C<EUC-CN>, C<GBK> and mostly on C<GB 18030>. |
a999c27c |
789 | |
f2a2953c |
790 | =item Jungshik Shin's Hangul FAQ |
791 | |
792 | L<http://jshin.net/faq> |
793 | |
0ab8f81e |
794 | And especially its subject 8. |
f2a2953c |
795 | |
796 | L<http://jshin.net/faq/qa8.html> |
797 | |
962111ca |
798 | A comprehensive overview of the Korean (C<KS *>) standards. |
f2a2953c |
799 | |
0ab8f81e |
800 | =item debian.org: "Introduction to i18n" |
801 | |
802 | A brief description for most of the mentioned CJK encodings is |
803 | contained in |
804 | L<http://www.debian.org/doc/manuals/intro-i18n/ch-codes.en.html> |
805 | |
f2a2953c |
806 | =back |
807 | |
808 | =head2 Offline sources |
809 | |
0ab8f81e |
810 | =over 4 |
f2a2953c |
811 | |
812 | =item C<CJKV Information Processing> by Ken Lunde |
813 | |
814 | CJKV Information Processing |
815 | 1999 O'Reilly & Associates, ISBN : 1-56592-224-7 |
816 | |
0ab8f81e |
817 | The modern successor of C<CJK.inf>. |
f2a2953c |
818 | |
0ab8f81e |
819 | Features a comprehensive coverage of CJKV character sets and |
f2a2953c |
820 | encodings along with many other issues faced by anyone trying |
821 | to better support CJKV languages/scripts in all the areas of |
822 | information processing. |
823 | |
0ab8f81e |
824 | To purchase this book, visit |
f2a2953c |
825 | L<http://www.oreilly.com/catalog/cjkvinfo/> |
0ab8f81e |
826 | or your favourite bookstore. |
f2a2953c |
827 | |
a999c27c |
828 | =back |
829 | |
5d030b67 |
830 | =cut |