Network Working Group HF. Zhu
Internet Draft: Chinese Character Encoding Tsinghua U
Document: internet-drafts/draft-apng-cc-encoding-03.8.txt DY. Hu
Tsinghua U
ZG. Wang
CITS
TC. Kao
III
WC. Chang
III
M. Crispin
U Washington
July 1995
Chinese Character Encoding for Internet Messages
Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
To learn the current status of any Internet-Draft, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
Directories on ds.internic.net (US East Coast), nic.nordu.net
(Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific
Rim).
This is a draft document of APNG-CC, the Chinese Character
sub-working group of the I18N/L10N (Internationalization and
Localization) working group of APNG (Asia-Pacific Networking Group).
A revised version of this draft document will be submitted to the RFC
editor as an Informational RFC for the Internet Community.
Discussion and suggestions for improvement are requested, and should
be sent to apng-cc@apng.org or zhf@net.edu.cn (the coordinator). This
document will expire before February 30, 1996. Distribution of this
memo is unlimited.
Abstract
This memo provides methods for transporting Chinese characters
through, but not limited to, electronic mail [RFC-822] and network
news [RFC-1036] in the Internet community.
Introduction
As the use of Internet covers more and more Chinese people in the
world, the need has increased for the ability to send documents
containing Chinese characters on the Internet. The methods
described in this document provide means of transporting existing
Chinese character sets as well as leaving sufficient space for future
extension.
This document describes three groups of encodings:
1. ISO-2022-CN and ISO-2022-CN-EXT
2. CN-GB and CN-Big5
3. ISO/IEC 10646/Unicode
The first group of encodings are designed with interoperability in
mind and are encouraged in this document; they are 7-bit, support
both simplified and traditional characters using both GB and CNS/Big5,
and do not impose any unusual quoting requirements on ASCII characters
The second group of encodings describes current common domestic
usage. The third group of encodings refers to the universal
multilingual character set defined by ISO.
Note: ISO/IEC 10646 [ISO-10646] defines a 32bit character space
with the intent to encode all characters in the world. Currently, only
the lowest 16bit plane of ISO 10646, the Basic Multilingual Plane (BMP),
is defined. The BMP is code-by-code identical to Unicode [Unicode 1.1].
Specification
1. 7bit Chinese encodings: ISO-2022-CN and ISO-2022-CN-EXT
1.1 Description
ISO-2022-CN is based upon ISO 2022 [ISO-2022], similar to earlier
work on ISO-2022-JP [RFC-1468] and ISO-2022-KR [RFC-1557] for Japanese
and Korean languages. It is 7-bit, and supports both simplified Chinese
characters using GB 2312-80 [GB-2312] and traditional Chinese characters
using the first two planes of CNS 11643 [CNS-11643], as well as ASCII
[ASCII] characters.
ISO-2022-CN-EXT is a superset of ISO-2022-CN that additionally
supports other GB character sets and planes of CNS 11643.
Since ISO-2022-CN and ISO-2022-CN-EXT are 7-bit encodings, they do
not require the 8-bit SMTP extensions. ISO-2022-CN supports almost
all the characters which appear in Big5 [BIG5] except for two duplicate
characters which were mistakes in defining Big5.
1.2 ISO-2022-CN
The starting code of ISO-2022-CN is ASCII. ASCII and Chinese characters
are distinguished by the use of designations (ESC sequences) and shift
functions.
Designations define the Chinese character sets used in the text.
There are three kinds of designations: SOdesignation, SS2designation
and SS3designation.
The SOdesignation is in the form ESC $ ) <F>, where <F> is the
"final character" assigned to the character set by ISO (refer to the
ISO registry [ISOREG] for more details). The SS2designation is in
the form ESC $ * <F>, and the SS3designation is in the form ESC $ +
<F> . A designation overrides any previous designation for
subsequent bytes in the text.
There are four kinds of shifts: SI, SO, SS2 and SS3.
The shift SI (one byte with hexadecimal value 0F) declares that
subsequent bytes are interpreted in ASCII.
The shift SO (one byte with hexadecimal value 0E) declares that
subsequent bytes are interpreted in the character set defined by
SOdesignation.
The shift SS2 (two bytes with hexadecimal values 1B 4E) declares
that the subsequent TWO bytes are interpreted in the character set
defined by SS2designation, after which the previous interpretation
(from SI or SO) is restored.
The shift SS3 (two bytes with hexadecimal values 1B 4F) declares
that the subsequent TWO bytes are interpreted in the character set
defined by SS3designation, after which the previous interpretation
(from SI or SO) is restored.
For example, the sequence:
ESC $ ) A SO c_char1 ... c_char1 ESC $ ) G c_char2 ... c_char2 SI
transfers mixed simplified Chinese and traditional Chinese text, in
which c_char1s are simplified Chinese characters from GB-2312 and
c_char2s are traditional Chinese characters from CNS-11643-plane 1.
The escape sequence, shift function and character set used in an
ISO-2022-CN text are as follows:
Character sets Shift in with
--------------------------------------------------------------------
ASCII SI
GB 2312, CNS 11643-plane-1 SO
CNS 11643-plane-2 SS2
ESC $ ) A Indicates the bytes following SO are Chinese characters
as defined in GB 2312-80, until another SOdesignation
appears
ESC $ ) G Indicates the bytes following SO are as defined in
CNS 11643-plane-1, until another SOdesignation appears
ESC $ * H Indicates the two bytes immediately following SS2 is a
Chinese character as defined in CNS 11643-plane-2, until
another SS2designation appears
If there are any GB or CNS characters on a line, a designation for
the corresponding character set should be used so that each line has
its own character set information and the text can be displayed
correctly when scroll back in a window. Also, there must be a shift
to ASCII (SI) before the end of the line (i.e., before the CRLF). In
other words, each line starts in ASCII, and ends in ASCII.
The name given to this character encoding is "ISO-2022-CN". This name
is intended to be used as the "charset" parameter in MIME [MIME-1,
MIME-2] messages.
Content-Type: text/plain; charset=iso-2022-cn
The ISO-2022-CN encoding is already in 7-bit form, so it is not
necessary to use a Content-Transfer-Encoding header.
Other restrictions are given in the "Formal Syntax of ISO-2022-CN
and ISO-2022-CN-EXT" part at the end of this document.
1.3 ISO-2022-CN-EXT
ISO-2022-CN-EXT supports all characters in existing GB, Big5 and CNS
11643 character sets.
The escape sequence, shift function and character set used in an
ISO-2022-CN-EXT text are as follows:
Character sets Shift in with
--------------------------------------------------------------------
ASCII SI
GB 2312, GB 12345, CNS 11643-plane-1, GB 2312+GB 8565 SO
GB 7589, GB 13131, CNS 11643-plane-2 SS2
GB 7590, GB 13132 or other new GBs,CNS 11643-plane-3 or SS3
higher planes of CNS 11643
Note: Currently, there are some GB sets that have not been
registered in ISO. Here <X7589>, <X7590>, <X12345>, <X13131>
and <X13132> represent the final character that will be assigned
by ISO for those sets.
ESC $ ) A Indicates the bytes following SO are Chinese characters
as defined in GB 2312-80, until another SOdesignation
appears
ESC $ * <X7589>
Indicates the two bytes immediately following SS2 is a
Chinese character as defined in GB 7589-87 [GB-7589],
until another SS2designation appears
ESC $ + <X7590>
Indicates the two bytes immediately following SS3 is a
Chinese character as defined in GB 7590-87 [GB-7590],
until another SS3designation appears
ESC $ ) <X12345>
Indicates the bytes following SO are as defined in
GB 12345-90 [GB-12345], until another SOdesignation
appears
ESC $ * <X13131>
Indicates the two bytes immediately following SS2 is a
Chinese character as defined in GB 13131-91 [GB-13131],
until another SS2designation appears
ESC $ + <X13132>
Indicates the two bytes immediately following SS3 is a
Chinese character as defined in GB 13132-91 [GB-13131],
until another SS3designation appears
ESC $ ) E Indicates the bytes following SO are as defined in GB 2312+
GB 8565 [GB-8565], until another SOdesignation appears
ESC $ ) G Indicates the bytes following SO are as defined in
CNS 11643-plane-1, until another SOdesignation appears
ESC $ * H Indicates the two bytes immediately following SS2 is a
Chinese character as defined in CNS 11643-plane-2, until
another SS2designation appears
ESC $ + I Indicates the immediate two bytes following SS3 is a
Chinese character as defined in CNS 11643-plane-3,
until another SS3designation appears
ESC $ + J Indicates the immediate two bytes following SS3 is a
Chinese character as defined in CNS 11643-plane-4,
until another SS3designation appears
ESC $ + K Indicates the immediate two bytes following SS3 is a
Chinese character as defined in CNS 11643-plane-5,
until another SS3designation appears
ESC $ + L Indicates the immediate two bytes following SS3 is a
Chinese character as defined in CNS 11643-plane-6,
until another SS3designation appears
ESC $ + M Indicates the immediate two bytes following SS3 is a
Chinese character as defined in CNS 11643-plane-7,
until another SS3designation appears
As in ISO-2022-CN, each line should start in ASCII, and end in ASCII,
and should have its own designation information before any Chinese
characters appear.
The name given to this character encoding is "ISO-2022-CN-EXT". This name
is intended to be used as the "charset" parameter in MIME messages.
Content-Type: text/plain; charset=ISO-2022-CN-EXT
The ISO-2022-CN-EXT encoding is also in 7-bit form, so it is not
necessary to use a Content-Transfer-Encoding header.
Other restrictions are given in the "Formal Syntax of ISO-2022-CN and
ISO-2022-CN-EXT" part at the end of this document.
1.4 How to Support Big5 or other internal codesets with ISO-2022-CN
and ISO-2022-CN-EXT
Since there are many different Chinese internal coding systems [CJK],
such as Big5, GB internal code, CCCII (an encoding for library systems
in Taiwan), XGB (the codepage for Microsoft simplified Chinese Windows
95) etc. ISO-2022-CN and ISO-2022-CN-EXT, which are 7bit and will not
lose information during communication among different codesets and thus
increase interoperability, are ideal interchange encodings for various
internal Chinese codesets in international communication.
For instance, ISO-2022-CN and ISO-2022-CN-EXT can be used to support
Big5, because CNS-11643-plane 1 and 2 incorporate all Chinese characters
in Big5 except two duplicate characters which was a mistake when defining
Big5.
Since the code sequence of Big5 and CNS-11643 is different, it needs a
conversion table for converting Big5 to and from CNS-11643. The
conversion table is attached as an appendix in this document.
Public domain software (either binary or source in C) is provided in
many places in the Internet too:
1) Beijing:
ftp://ftp.net.tsinghua.edu.cn/pub/Chinese/
(IP address: 166.111.1.11)
2) Taiwan:
ftp://tpdns.seed.net.tw/Pub/Chinese/DOS/code-convert/chcode.zip
(IP address: 139.175.1.12)
3) US:
ftp://ftp.ifcss.org/pub/software/unix/convert/BeTTY-1.534.tar.gz
(IP address: 128.123.1.55)
4) Japan:
ftp://etlport.etl.go.jp/pub/iso-2022-cn/
(IP address: 192.31.197.99)
2. 8bit Chinese encodings: CN-GB and CN-Big5
The CN-GB and CN-Big5 charset names are given below.
Among other things, these support current practice; specifically,
CN-GB reflects the current usage for simplified Chinese e-mail,
and CN-Big5 reflects the current usage for traditional Chinese e-mail.
Note: the use of 8-bit character sets requires the use of
either an 8-to-7 Content-Transfer-Encoding mechanism such as
"BASE64" or "QUOTED-PRINTABLE" if the network is not 8-bit clean,
or the 8-bit SMTP extensions [SMTPEXT] with the "8BIT"
Content-Transfer-Encoding on 8-bit clean networks. Otherwise,
an 8-bit message which passes through a 7-bit mailer is likely
to have the 8th bit truncated, resulting in an unreadable
message. Although "just send 8-bit data" has been common
practice in the past, it is incorrect according to the
Internet standards and causes interoperability problems.
2.1 CN-GB
E-mail using GB characters is sent in this way:
GB 2312-80 characters are used with ASCII characters,
not GB 1988-80 [GB-1988].
GB 2312-80 is also 7-bit, to avoid conflicting with ASCII. If the
character is from GB 2312-80, the MSB (bit-8) of each byte is set to
1, and therefore becomes a 8-bit character. Otherwise, the byte is
interpreted as ASCII. This constructs a character set named "GB
Internal Code".
This method is also adopted in the .gb files in the Internet.
To use this character scheme with MIME, CN-GB is used as the value
for the charset parameter:
Content-Type: text/plain; charset=cn-gb
GB-12345 is the traditional form of GB-2312, the charset name given
to this set is CN-GB-12345-90.
There is also a kind of dependent character set that can only be used
with one of the above sets. For example, if GB 8565 is used, it can
only be used with GB 2312 or GB 12345, in this case, "+" is permitted
to appear in the charset name, i.e. CN-GB-2312-80+GB-8565-88.
Similarly as CN-GB, CN-GB-12345-90 and CN-GB-2312-80+GB-8565-88 support
ASCII too, the MSB of Chinese characters should be set to 1, in order to
be distinguished from ASCII.
Note: There are some supplementary character sets in GB, i.e. GB 7589-87,
GB 7590-87, GB 13131-91 and GB 13132-91. Normally, they won't
be used independently without using GB-2312 or GB-12345, so they
are not necessarily be registered. Characters in these standards
could be support with ISO-2022-CN and ISO-2022-CN-EXT. If, in the
future, they do needed to be used with "charset" names in some cases,
it is the responsibility of any interested third party (the
standardization organization herself or anybody else) to write the
necessary documents and do the IANA registration for them. It is
greatly encouraged that their charset names should also take the form
of CN-GB-<number>-<edition> as CN-GB-12345-90. Here, <number> is the
GB standard number, and <edition> is the year of edition represented
with the last two digits of the year. They should be coded in 8-bit
as CN-GB.
To avoid hindering interoperability, CN-GB is encouraged to be used
whenever possible.
2.2 CN-Big5
Big5 is a character set of traditional Chinese characters, widely
used in Taiwan and overseas. E-mail using Big5 characters is
sent in this way:
Big5 characters are used with ASCII characters.
Big5 is a two-byte coding, in which the first byte is 7-bit, and
the second byte is 8-bit. If the character is from Big5, the MSB
(bit-8) of the first byte is set to 1, and therefore becomes an 8-bit
character. Otherwise, the byte is interpreted as ASCII. (Big5 uses
the code space: [0xa1-0xfe,0x40-0x7e] and [0xa1-0xfe,0xa1-0xfe], and
two other user areas with the first byte in the range of [0x81-0xa0].)
To use this character scheme with MIME, CN-Big5 is used as the value
for the charset parameter:
Content-Type: text/plain; charset=cn-big5
3. Universal Multilingual Character Set: ISO/IEC-10646/Unicode
ISO/IEC 10646's BMP (code-to-code identical to Unicode) contains
large repertoire of Chinese characters (it currently includes all
the characters of GB 2312-80, GB 12345-90, GB 8565-89, CNS 11643's
plane 1 and 2, and part of some other standards) and therefore can
be used to transporting Chinese characters in the Internet community.
This document does not give any details on how to do this, as this has
been done elsewhere. For details of using Unicode with MIME, refer to
RFC 1641 [RFC-1641], RFC 1642 [RFC-1642]. For assigned names for
10646 sets, refer to STD 2--"Assigned Numbers", which is RFC 1700
[RFC-1700] currently. For more up-to-date assigned numbers, please
check:
ftp://ftp.isi.edu/in-notes/iana/assignments/character-sets
A New MIME parameter -- "charset-variant"
Here, a new MIME parameter--"charset-variant" is defined as below:
This parameter is used after the MIME "charset" parameter mainly in
the form of <variant>-<version>, or any extension based on this form,
in which <variant> is the product name and <version> indicates its
version number. It is case-insensetive and optional, and any value
of this parameter should be registered in IANA.
For example:
Content-Type: text/plain; charset=CN-Big5; charset-variant=ETen-2.00.03-DOS
This may indicate Eten company's variant of Big5: ETen 2.00.03 for DOS.
The reason to define this parameter is that some implementation may
want to check the variants in order to deal with them in slightly different
methods to gain better operability. Although some features of certain
variant may bring problem of interoperability, however, variants will
still exist as they will go; moreover, certain variant may be so popular
that it becomes de facto industrial standard, therefore indicating its
name can improve the ability of communication implementation in handling
its messages.
Background Information
1. Writing systems and their encodings in Chinese-spoken nations and regions
The mainland provinces of China use simplified Chinese character in
daily life. GB is the standard electronic character set. It is the
main means for communications between people who share simplified
Chinese characters in the world.
Taiwan uses traditional Chinese characters in daily life. CNS-11643
is the formal character set for information interchange in Taiwan;
however, Big5, a widely-used character set of traditional Chinese
characters, is the de-facto industrial standard in Taiwan.
Hong Kong uses traditional Chinese characters in daily life, but uses
both GB and Big5 in electronic form, because Hong Kong people often
communicate with people in all of China's provinces.
Singapore seldom uses Chinese characters, and uses the simplified
form when Chinese characters are used. In electronic form, Unicode
is more popular, however GB is also used.
2. Miscellaneouses about Chinese character sets
The GB 1988-80 character set is identical to ISO 646 [ISO-646] except
for currency symbol and tilde. The currency symbol and the tilde are
replaced by the Yuan sign and the over line. This set is GB's variant
of ISO 646. This character set and CNS 5205 [CNS-5205] are not
encouraged for use in the Internet, since ASCII combined with GB 2312
or CNS 11643-plane 1 and plane 2 comprises all characters in them.
The GB 2312-80 character set consists of simplified Chinese
characters, digits, Latin, Greek and Russian alphabets, and some
other symbols; in all, 7445 characters. Each character is represented
with two bytes.
GB 13000-95 [GB-13000] is the GB's variant of ISO 10646. However, for
interoperability in the Internet, assigned names for ISO 10646 are
encouraged to be used.
3. Miscellaneous implementation information
For maximum interoperability, implementations SHOULD at least support
sending and receiving ISO-2022-CN. Supporting all registered character
sets in ISO-2022-CN-EXT is greatly encouraged.
It is also essential to be able to support CN-GB (the status quo for
simplified Chinese e-mail ) and CN-Big5 (the status quo for traditional
Chinese e-mail). But sending ISO-2022-CN message is always encouraged
whenever possible.
To the maximum extent possible, implementations should be capable of
receiving messages in any of the encodings introduced in this document,
even if they only transmit messages in one form. Preferably the
implementation should display the characters with glyphs appropriate
to the typographic tradition that is implied in the encoding of the
received text. Implementation may also translate these encodings
to the encoding that its platform supports.
The human user (not implementor) should try to keep lines within 80
display columns, or, preferably, within 75 (or so) columns, to allow
insertion of ">" at the beginning of each line in excerpts. Each
Chinese character takes up two columns, and the shift sequences do
not take up any columns. The implementor is reminded that Chinese
characters take up two bytes and should not be split in the middle to
break lines for displaying, etc.
Freely available fonts of Chinese characters:
Beijing:
ftp://ftp.net.tsinghua.edu.cn/pub/Chinese/fonts/
Taiwan:
ftp://ftp.edu.tw/Chinese/ifcss/software/fonts/
ftp://ftp.ntu.edu.tw/Chinese/ifcss/software/fonts/
HongKong:
ftp://ftp.cuhk.hk/pub/chinese/ifcss/software/fonts/
Singapore:
ftp://ftp.technet.sg:/pub/chinese/fonts/
US:
ftp://ftp.ifcss.org/pub/software/fonts/
http://ccic.ifcss.org/www/pub/software/fonts/
X.400 Considerations
X.400 has the ability of carrying different character sets in a
message by using the body part "GeneralText" defined by ISO/IEC-10021-7.
[ISO-10021].
The X.400 ASN.1 definition of the GeneralText body part is:
general-text-body-part EXTENDED-BODY-PART-TYPE
PARAMETERS GeneralTextParameters IDENTIFIED BY id-ep-general-text
DATA GeneralTextData
::= id-et-general-text
GeneralTextParameters ::= SET OF CharacterSetRegistration
CharacterSetRegistration ::= INTEGER (1..32767)
GeneralTextData ::= GeneralString
Therefore, to use ISO-2022-CN, set the "CharacterSetRegistration"
part as { 6 58 171 172 }, and add an ESC sequence of ESC ( B (three bytes,
hexadecimal values: 1B 28 42) before the beginning of ISO-2022-CN text.
Similarly, to use ISO-2022-CN-EXT, set the registered numbers of
all character sets in the "CharacterSetRegistration" part and add ESC
( B at the beginning. For the registered numbers, please refer to
ISO registry. In addition to the character sets supported by ISO-2022-CN,
currently registered numbers are:
GB 2312+GB 8565: 165
CNS 11643-plane 3: 183
CNS 11643-plane 4: 184
CNS 11643-plane 5: 185
CNS 11643-plane 6: 186
CNS 11643-plane 7: 187
176 is the registered number for the BASESET of ISO/IEC 10646-1:1993
UCS-2 with implementation level 3, Escape sequence of ESC % / E
(four bytes, hexadecimal values 1B 25 2F 45) indicates starting of
this codeset.
For CN-GB and CN-Big5 character sets, there currently are no formal
methods that could be used in X.400 yet.
For detail about X.400 use of character sets, please refer to
RFC 1502 [RFC-1502].
Formal Syntax of ISO-2022-CN and ISO-2022-CN-EXT
The notational conventions used here are identical to those used in
RFC 822.
1. Formal Syntax of ISO-2022-CN
body ::= * ( ascii_line / c_line )
ascii_line ::= *char CRLF
c_line ::= *char 1*(1*designation 1*(*char 1*c_text *char)) CRLF
designation ::= SOdesignation / SS2designation
SOdesignation ::= ESC "$" ")" finalchar_for_SO
SS2designation ::= ESC "$" "*" finalchar_for_SS2
finalchar_for_SO ::= "A" / "G"
finalchar_for_SS2 ::= "H"
c_text ::= 1* ( SO-SI-segment / SS2segment )
SO-SI-segment ::= SO 1*c_char *designation *( c_segment / SO-segment ) SI
c_segment ::= 1* ( c_char / SS2segment )
SO-segment ::= SO 1*c_char
SS2segment ::= SS2 c_char
c_char ::= one_of_94 one_of_94
; ( Octal, Decimal.)
ESC ::= <ISO-646 ESC, escape> ; ( 33, 27.)
SI ::= <ASCII SI, shift in> ; ( 17, 15.)
SO ::= <ASCII SO, shift out> ; ( 16, 14.)
SS2 ::= <ISO 2022 Single_shift two> ; ( 33 116, 27 78.)
SS3 ::= <ISO 2022 Single_shift three> ; ( 33 117, 27 79.)
one_of_94 ::= <any char in 94_char set> ; (41-176, 33-126.)
char ::= <any char in 96_char_set> ; (40-177, 30-127.)
2. Formal Syntax of ISO-2022-CN-EXT
body ::= * ( ascii_line / c_line )
ascii_line ::= *char CRLF
c_line ::= *char 1*(1*designation 1*(*char 1*c_text *char)) CRLF
designation ::= SOdesignation / SS2designation / SS3designation
SOdesignation ::= ESC "$" ")" finalchar_for_SO
SS2designation ::= ESC "$" "*" finalchar_for_SS2
SS3designation ::= ESC "$" "+" finalchar_for_SS3
finalchar_for_SO ::= "A" / <X12345> / "G" / "E"
finalchar_for_SS2 ::= <X7589> / <X13131> / "H"
finalchar_for_SS3 ::= <X7590> / <X13132> / "I" / "J" / "K" / "L" / "M"
c_text ::= 1* ( SO-SI-segment / SS2segment / SS3segment )
SO-SI-segment ::= SO 1*c_char *designation *( c_segment / SO-segment ) SI
c_segment ::= 1* ( c_char / SS2segment / SS3segment )
SO-segment ::= SO 1*c_char
SS2segment ::= SS2 c_char
SS3segment ::= SS3 c_char
c_char ::= one_of_94 one_of_94
; ( Octal, Decimal.)
ESC ::= <ISO-646 ESC, escape> ; ( 33, 27.)
SI ::= <ASCII SI, shift in> ; ( 17, 15.)
SO ::= <ASCII SO, shift out> ; ( 16, 14.)
SS2 ::= <ISO 2022 Single_shift two> ; ( 33 116, 27 78.)
SS3 ::= <ISO 2022 Single_shift three> ; ( 33 117, 27 79.)
one_of_94 ::= <any char in 94_char set> ; (41-176, 33-126.)
char ::= <any char in 96_char_set> ; (40-177, 30-127.)
Registration of New "charset"s and New MIME parameter
1. This document defines the following MIME "charset" names for Chinese
text:
ISO-2022-CN, ISO-2022-CN-EXT
CN-GB, CN-Big5
CN-GB-12345-90
CN-GB-2312-80+GB-8565-88
2. This document defines a new MIME parameter:
charset-variant
Acknowledgments
This document is the result of cooperation in the APNG-CC, the
Chinese Character sub-working group of the I18N/L10N
(Internationalization and Localization) working group of APNG
(Asia-Pacific Networking Group), coordinator Zhu Haifeng
<zhf@net.tsinghua.edu.cn>. The membership of APNG-CC consists
of individuals from both sides of the Taiwan Strait, HongKong,
and from Singapore and other countries. The authors wish to
thank all members of APNG-CC.
Prof.Yao Shiquan and Ms.Lin Ning of CITS (China Information Technology
Standardization Technical Committee), Prof. Zhao Jingrong, Prof. Li Xing,
and Mr.YouYue of Tsinghua University gave many help in the process
of the work.
Many thanks to Mr. C.J.Cherng and Mr. C.K.Fan of III (Institute for
Information Industry), and Mr. Chang JingShin from Tsinghua University
in Hsinchu, Taiwan.
In particular, Mr.Masataka Ohta, who is the coordinator of APNG-I18N,
contributed many efforts towards the work from the beginning of APNG-CC.
The authors also wish to thank the following people who contributed
in many ways towards this draft.
Martin J. Duerst Kenichi Handa
Zhang Ling Zhang ZhouCai
Zhu Bin Nelson Chin
Lu Chin Ding ZyKaan
Chen Shuyi Mao Yonggang
Mao Yonggang Ken Lunde
Lua Kim Teng Victor Cheng
Stephen G. Simpson Yuan Jiang
Liu HuiFang Harald T. Alvestrand
Feng Hui
Security Considerations
Security issues are not discussed in this memo.
Authors' Addresses
Zhu,Hai-feng (HF. Zhu)
Dept. of Computer Science & Technology
Tsinghua University
Beijing, 100084
China
Tel: +86-1-2561144 ext. 3492
Fax: +86-1-2564173
Email: zhf@net.edu.cn, zhf@net.tsinghua.edu.cn
Hu,Dao-yuan (DY. Hu)
Tsinghua Networking Center
Tsinghua University
Beijing, 100084
China
Tel: +86-1-2594016
Fax: +86-1-2564173
Email: hdy@tsinghua.edu.cn
Wang,Zhi-guan (ZG. Wang)
SubCommitte 2 (SC2)
China Information Technology Standardization Technical Committee
(CITS)
Beijing, 100083
China
Tel: +86-1-4012392
Fax: +86-1-4010601
Kao,Tien-cheu (TC. Kao)
I.T. Promotion Division
Institute for Information Industry(III)
Taipei
Taiwan
Tel: +886-2-5631688
Fax: +886-2-563-4209
Email: tckao@iiidns.iii.org.tw
Chang,Wen-chung (WC. Chang)
Institute for Information Industry(III)
Taipei
Taiwan
Tel: +886-2-7327771
Fax: +886-2-7370188
Email: chung@iiidns.iii.org.tw
Mark R. Crispin
Networks and Distributed Computing
University of Washington
4545 15th Avenue NE
Seattle, WA 98105-4527
USA
Tel: +1 (206) 543-5762
Fax: +1 (206) 685-4045
Email: MRC@CAC.Washington.EDU
Appendix -- Conversion Table for CNS-11643 and Big5
This is a conversion table for the Chinese characters in Big5 and
CNS-11643, including some specific characters in Eten variant of Big5.
Noted that this list only contains Chinese characters, symbols are
not provided. For more complete table, please refer to [CJK] or
the ftp sites listed in section 1.4, where conversion programs are
available.
1. Big5 Level 1 correspondence to CNS 11643-1992 Plane 1:
0xA440-0xACFD <-> 0x4421-0x5322 # Level 1 Chinese start
0xACFE <-> 0x5753
0xAD40-0xAFCF <-> 0x5323-0x5752
0xAFD0-0xBBC7 <-> 0x5754-0x6B4F
0xBBC8-0xBE51 <-> 0x6B51-0x6F5B
0xBE52 <-> 0x6B50
0xBE53-0xC1AA <-> 0x6F5C-0x7534
0xC1AB-0xC2CA <-> 0x7536-0x7736
0xC2CB <-> 0x7535
0xC2CC-0xC360 <-> 0x7737-0x782C
0xC361-0xC3B8 <-> 0x782E-0x7863
0xC3B9 <-> 0x7865
0xC3BA <-> 0x7864
0xC3BB-0xC455 <-> 0x7866-0x7961
0xC456 <-> 0x782D
0xC457-0xC67E <-> 0x7962-0x7D4B # Level 1 Chinese end
2. Big5 Level 2 correspondence to CNS 11643-1992 Plane 2:
0xC940-0xC949 <-> 0x2121-0x212A
0xC94A -> 0x4442 # duplicate of 0xA461
0xC94B-0xC96B <-> 0x212B-0x214B
0xC96C-0xC9BD <-> 0x214D-0x217C
0xC9BE <-> 0x214C
0xC9BF-0xC9EC <-> 0x217D-0x224C
0xC9ED-0xCAF6 <-> 0x224E-0x2438
0xCAF7 <-> 0x224D
0xCAF8-0xD6CB <-> 0x2439-0x376E
0xD6CC <-> 0x3E63
0xD6CD-0xD779 <-> 0x3770-0x387D
0xD77A <-> 0x3F6A
0xD77B-0xDADE <-> 0x387E-0x3E62
0xDADF <-> 0x376F
0xDAE0-0xDBA6 <-> 0x3E64-0x3F69
0xDBA7-0xDDFB <-> 0x3F6B-0x4423
0xDDFC -> 0x4176 # duplicate of 0xDCD1
0xDDFD-0xE8A2 <-> 0x4424-0x554A
0xE8A3-0xE975 <-> 0x554C-0x5721
0xE976-0xEB5A <-> 0x5723-0x5A27
0xEB5B-0xEBF0 <-> 0x5A29-0x5B3E
0xEBF1 <-> 0x554B
0xEBF2-0xECDD <-> 0x5B3F-0x5C69
0xECDE <-> 0x5722
0xECDF-0xEDA9 <-> 0x5C6A-0x5D73
0xEDAA-0xEEEA <-> 0x5D75-0x6038
0xEEEB <-> 0x642F
0xEEEC-0xF055 <-> 0x6039-0x6242
0xF056 <-> 0x5D74
0xF057-0xF0CA <-> 0x6243-0x6336
0xF0CB <-> 0x5A28
0xF0CC-0xF162 <-> 0x6337-0x642E
0xF163-0xF16A <-> 0x6430-0x6437
0xF16B <-> 0x6761
0xF16C-0xF267 <-> 0x6438-0x6572
0xF268 <-> 0x6934
0xF269-0xF2C2 <-> 0x6573-0x664C
0xF2C3-0xF374 <-> 0x664E-0x6760
0xF375-0xF465 <-> 0x6762-0x6933
0xF466-0xF4B4 <-> 0x6935-0x6961
0xF4B5 <-> 0x664D
0xF4B6-0xF4FC <-> 0x6962-0x6A4A
0xF4FD-0xF662 <-> 0x6A4C-0x6C51
0xF663 <-> 0x6A4B
0xF664-0xF976 <-> 0x6C52-0x7165
0xF977-0xF9C3 <-> 0x7167-0x7233
0xF9C4 <-> 0x7166
0xF9C5 <-> 0x7234
0xF9C6 <-> 0x7240
0xF9C7-0xF9D1 <-> 0x7235-0x723F
0xF9D2-0xF9D5 <-> 0x7241-0x7244
3. Big5 Level 2 correspondence to CNS 11643-1992 Plane 3:
0xF9D6 <-> 0x4337 # ETen-specific Chinese
0xF9D7 <-> 0x4F50 # ETen-specific Chinese
0xF9D8 <-> 0x444E # ETen-specific Chinese
0xF9D9 <-> 0x504A # ETen-specific Chinese
0xF9DA <-> 0x2C5D # ETen-specific Chinese
0xF9DB <-> 0x3D7E # ETen-specific Chinese
0xF9DC <-> 0x4B5C # ETen-specific Chinese
References
[ASCII] American National Standards Institute, "Coded character set
-- 7-bit American National Standard Code for Information
Interchange", ANSI X3.4-1986.
[BIG5] Institute for Information Industry, "Chinese Coded
Character Set in Computer ", March, 1984
[CJK] Ken Lunde, On-line documentation of Chinese/Japanese/Korean
Information Processing, 1995, available at:
ftp://ftp.ora.com/pub/examples/nutshell/ujip/doc/cjk.inf
[CNS-5205] "Information processing -- 7-Bit Coded Character Set For
Information Interchange", CNS-5205.
[CNS-11643] "Chinese Standard Interchange Code", CNS-11643 version
1992; "Standard Interchange Code for Generally-Used Chinese
Characters", CNS 11643 version 1986.
[GB-1988] "7-bit Coding Character Set for Information Interchange",
GB 1988-80.
[GB-2312] "Coding of Chinese Ideogram Set for Information Interchange
Basic Set", GB 2312-80.
[GB-7589] "Code of Chinese Ideograms Set for Information Interchange,
the 2nd Supplementary Set", UDC 681.3.048, GB 7589-87.
[GB-7590] "Code of Chinese Ideogram Set for Information Interchange,
the 4th Supplementary Set",UDC 681.3.048, GB 7590-87.
[GB-8565] "Information Processing Coded Character Sets for Text
Communication", UDC 681.3, GB 8565-88.
[GB-12345] "Code of Chinese Ideogram Set for Information Interchange
Supplementary Set", GB/T 12345-90.
[GB-13000] "Information technology--Universal Multiple-Octet Coded
Character Set(UCS)---Part 1: Architecture and Basic Multilingual Plane",
GB13000.1
[GB-13131] "Code of Chinese Ideogram Set for Information Interchange,
the 3rd Supplementary Set", GB 13131-91.
[GB-13132] "Code of Chinese Ideogram Set for Information Interchange,
the 5th Supplementary Set", GB 13132-91.
[ISO-646] International Organization for Standardization (ISO),
"Information technology -- ISO 7-bit coded character set for
information interchange", International Standard, Ref. No. ISO/IEC
646:1991.
[ISO-2022] International Organization for Standardization (ISO),
"Information processing -- ISO 7-bit and 8-bit coded character sets
-- Code extension techniques", International Standard, Ref. No. ISO
2022-1986 (E).
[ISO-10021] Information Technology - Text communication -
Message-Oriented Text Interchange Systems (MOTIS), ISO 10021,
October 1988.
[ISO-10646] ISO/IEC 10646-1:1993(E) Information Technology--Universal
Multiple-octet Coded Character Set (UCS)---Part 1: Architecture and
Basic Multilingual Plane"
[ISOREG] International Organization for Standardization (ISO),
"International Register of Coded Character Sets To Be Used With
Escape Sequences".
[MIME-1] Borenstein, N., and Freed, N., "MIME (Multipurpose Internet
Mail Extensions) Part One: Mechanisms for Specifying and Describing
the Format of Internet Message Bodies", RFC 1521, Bellcore, Innosoft,
September 1993.
[MIME-2] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Two: Message Header Extensions for Non-ASCII Text", RFC 1522,
University of Tennessee, September 1993.
[RFC-822] Crocker, D., "Standard for the Format of ARPA Internet Text
Messages", STD 11, RFC 822, University of Delaware, August 1982.
[RFC-1036] Horton M., and Adams, R., "Standard for Interchange of
USENET Messages", RFC 1036, AT&T Bell Laboratories, Center for
Seismic Studies, December 1987.
[RFC-1468] Murai J., Crispin M. and E. van der Poel, Japanese
Character Encoding for Internet Messages, June 1993.
[RFC-1557] Choi U., Chon K. and Park H., Korean Character Encoding
for Internet Messages, December 1993.
[RFC-1641] Goldsmith D., and Davis M., "Using Unicode with MIME", RFC
1641, Taligent Inc., July 1994
[RFC-1642] Goldsmith D., and Davis M.," UTF-7, A Mail-Safe Transformation
Format of Unicode", July 1994
[RFC-1700] Reynolds J., and Postel J., "Assigned Numbers",RFC 1700,
STD 2, ISI, October 1994
[SMTP] Postel, Jonathan B. "Simple Mail Transfer Protocol", STD 10,
RFC 821, USC/Information Sciences Institute, August 1982.
[SMTPEXT] Klensin, J.; Freed, N.; Rose, M.; Stefferud, E.; and
Crocker, D., "SMTP Service Extensions", RFC 1651, July 1994.
[Unicode 1.1] "The Unicode Standard, Version 1.1",
Addison-Wesley, Reading, MA (to be published; the contents
of this standard is currently available by combining
[Unicode92], [Unicode93], and [Unicode4]).
[Unicode92] The Unicode Consortium, "The Unicode Standard -
Worldwide Character Encoding - Version 1.0", Volume 1,
Addison-Wesley, Reading, MA, 1992 (ISBN 0-201-56788-1).
[Unicode93] The Unicode Consortium, "The Unicode Standard -
Worldwide Character Encoding - Version 1.0", Volume 2,
Addison-Wesley, Reading, MA, 1992 (ISBN 0-201-60845-6).
[Unicode4] The Unicode Consortium, "The Unicode Standard -
Version 1.1 (Prepublication Edition)", Unicode Technical
Report #4 (avaliable from the Unicode Consortium).