openldap/doc/drafts/draft-ietf-ldapbis-strprep-xx.txt

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2003-06-01 06:47:07 +08:00
Internet-Draft Kurt D. Zeilenga
Intended Category: Standard Track OpenLDAP Foundation
Expires in six months 26 May 2003
LDAP: Internationalized String Preparation
<draft-ietf-ldapbis-strprep-00.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.
Distribution of this memo is unlimited. Technical discussion of this
document will take place on the IETF LDAP Revision Working Group
mailing list <ietf-ldapbis@openldap.org>. Please send editorial
comments directly to the author <Kurt@OpenLDAP.org>.
Internet-Drafts are working documents of the Internet Engineering Task
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Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as ``work in progress.''
The list of current Internet-Drafts can be accessed at
<http://www.ietf.org/ietf/1id-abstracts.txt>. The list of
Internet-Draft Shadow Directories can be accessed at
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Copyright (C) The Internet Society (2003). All Rights Reserved.
Please see the Full Copyright section near the end of this document
for more information.
Abstract
The previous Lightweight Directory Access Protocol (LDAP) technical
specifications did not precisely define how string matching is to be
performed. This lead to a number of usability and interoperability
problems. This document defines string preparation algorithms for
matching rules defined for use in LDAP.
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Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14 [RFC2119].
Character names in this document use the notation for code points and
names from the Unicode Standard [Unicode]. For example, the letter
"a" may be represented as either <U+0061> or <LATIN SMALL LETTER A>.
In the lists of mappings and the prohibited characters, the "U+" is
left off to make the lists easier to read. The comments for character
ranges are shown in square brackets (such as "[CONTROL CHARACTERS]")
and do not come from the standard.
Note: a glossary of terms used in Unicode can be found in [Glossary].
Information on the Unicode character encoding model can be found in
[CharModel].
1. Introduction
1.1. Background
A Lightweight Directory Access Protocol (LDAP) [Roadmap] matching rule
[Syntaxes] defines an algorithm for determining whether a presented
value matches an attribute value in accordance with the criteria
defined for the rule. The proposition may be evaluated to True,
False, or Undefined.
True - the attribute contains a matching value,
False - the attribute contains no matching value,
Undefined - it cannot be determined whether the attribute contains
a matching value or not.
For instance, the caseIgnoreMatch matching rule may be used to compare
whether the commonName attribute contains a particular value without
regard for case and insignificant spaces.
1.2. X.500 String Matching Rules
"X.520: Selected attribute types" [X.520] provides (amongst other
things) value syntaxes and matching rules for comparing values
commonly used in the Directory. These specifications are inadequate
for strings composed of characters from the Universal Character Set
(UCS) [ISO10646], a superset of Unicode [Unicode].
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The caseIgnoreMatch matching rule [X.520], for example, is simply
defined as being a case insensitive comparison where insignificant
spaces are ignored. For printableString, there is only one space
character and case mapping is bijective, hence this definition is
sufficient. However, for UCS-based string types such as
universalString, this is not sufficient. For example, a case
insensitive matching implementation which folded lower case characters
to upper case would yield different different results than an
implementation which used upper case to lower case folding. Or one
implementation may view space as referring to only SPACE (U+0020), a
second implementation may view any character with the space separator
(Zs) property as a space, and another implementation may view any
character with the whitespace (WS) category as a space.
The lack of precise specification for string matching has led to
significant interoperability problems. When used in certificate chain
validation, security vulnerabilities can arise. To address these
problems, this document defines precise algorithms for preparing
strings for matching.
1.3. Relationship to "stringprep"
The string preparation algorithms described in this document are based
upon the "stringprep" approach [RFC3454]. In "stringprep", presented
and stored values are first prepared for comparison and so that a
character-by-character comparison yields the "correct" result.
The approach used here is a refinement of the "stringprep" [RFC3454]
approach. Each algorithm involves two additional preparation steps.
a) prior to applying the Unicode string preparation steps outlined in
"stringprep", the string is transcoded to Unicode;
b) after applying the Unicode string preparation steps outlined in
"stringprep", characters insignificant to the matching rules are
removed.
Hence, preparation of strings for X.500 matching involves the
following steps:
1) Transcode
2) Map
3) Normalize
4) Prohibit
5) Check Bidi (Bidirectional)
6) Insignificant Character Removal
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These steps are described in Section 2.
1.4. Relationship to the LDAP Technical Specification
This document is a integral part of the LDAP technical specification
[Roadmap] which obsoletes the previously defined LDAP technical
specification [RFC3377] in its entirety.
This document details new LDAP internationalized string preparation
algorithms used by [Syntaxes] and possible other technical
specifications defining LDAP syntaxes and/or matching rules.
1.5. Relationship to X.500
LDAP is defined [Roadmap] in X.500 terms as an X.500 access mechanism.
As such, there is a strong desire for alignment between LDAP and X.500
syntax and semantics. The string preparation algorithms described in
this document are based upon "Internationalized String Matching Rules
for X.500" [XMATCH] proposal to ITU/ISO Joint Study Group 2.
2. String Preparation
The following six-step process SHALL be applied to each presented and
attribute value in preparation for string match rule evaluation.
1) Transcode
2) Map
3) Normalize
4) Prohibit
5) Check bidi
6) Insignificant Character Removal
Failure in any step is be cause the assertion to be Undefined.
The character repertoire of this process is Unicode 3.2 [Unicode].
2.1. Transcode
Each non-Unicode string value is transcoded to Unicode.
TeletexString [X.680][T.61] values are transcoded to Unicode as
described in Appendix A.
PrintableString [X.680] value are transcoded directly to Unicode.
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UniversalString, UTF8String, and bmpString [X.680] values need not be
transcoded as they are Unicode-based strings (in the case of
bmpString, a subset of Unicode).
If the implementation is unable or unwilling to perform the
transcoding as described above, or the transcoding fails, this step
fails and the assertion is evaluated to Undefined.
The transcoded string is the output string.
2.2. Map
SOFT HYPHEN (U+00AD) and MONGOLIAN TODO SOFT HYPHEN (U+1806) code
points are mapped to nothing. COMBINING GRAPHEME JOINER (U+034F) and
VARIATION SELECTORs (U+180B-180D,FF00-FE0F) code points are also
mapped to nothing. The OBJECT REPLACEMENT CHARACTER (U+FFFC) is
mapped to nothing.
CHARACTER TABULATION (U+0009), LINE FEED (LF) (U+000A), LINE
TABULATION (U+000B), FORM FEED (FF) (U+000C), CARRIAGE RETURN (CR)
(U+000D), and NEXT LINE (NEL) (U+0085) are mapped to SPACE (U+0020).
All other control code points (e.g., Cc) or code points with a control
function (e.g., Cf) are mapped to nothing.
ZERO WIDTH SPACE (U+200B) is mapped to nothing. All other code points
with Separator (space, line, or paragraph) property (e.g, Zs, Zl, or
Zp) are mapped to SPACE (U+0020).
For case ignore, numeric, and stored prefix string matching rules,
characters are case folded per B.2 of [RFC3454].
2.3. Normalize
The input string is be normalized to Unicode Form KC (compatibility
composed) as described in [UAX15].
2.4. Prohibit
All Unassigned, Private Use, and non-character code points are
prohibited. Surrogate codes (U+D800-DFFFF) are prohibited.
The REPLACEMENT CHARACTER (U+FFFD) code point is prohibited.
The first code point of a string is prohibited from being a combining
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character.
Empty strings are prohibited.
The step fails and the assertion is evaluated to Undefined if the
input string contains any prohibited code point. The output string is
the input string.
2.5. Check bidi
There are no bidirectional restrictions. The output string is the
input string.
2.5. Insignificant Character Removal
In this step, characters insignificant to the matching rule are to be
removed. The characters to be removed differ from matching rule to
matching rule.
Section 2.6.1 applies to case ignore and exact string matching.
Section 2.6.2 applies to numericString matching.
Section 2.6.3 applies to telephoneNumber matching
2.6.1. Insignificant Space Removal
For the purposes of this section, a space is defined to be the SPACE
(U+0020) code point followed by no combining marks.
NOTE - The previous steps ensure that the string cannot contain any
code points in the separator class, other than SPACE (U+0020).
The following spaces are regarded as not significant and are to be
removed:
- leading spaces (i.e. those preceding the first character that is
not a space);
- trailing spaces (i.e. those following the last character that is
not a space);
- multiple consecutive spaces (these are taken as equivalent to a
single space character).
A string consisting entirely of spaces is equivalent to a string
containing exactly one space.
For example, removal of spaces from the Form KC string:
"<SPACE><SPACE>foo<SPACE><SPACE>bar<SPACE><SPACE>"
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would result in the output string:
"foo<SPACE>bar"
and the Form KC string:
"<SPACE><SPACE><SPACE>"
would result in the output string:
"<SPACE>".
2.6.2. numericString Insignificant Character Removal
For the purposes of this section, a space is defined to be the SPACE
(U+0020) code point followed by no combining marks.
All spaces are regarded as not significant and are to be removed.
For example, removal of spaces from the Form KC string:
"<SPACE><SPACE>123<SPACE><SPACE>456<SPACE><SPACE>" would result in
the output string:
"123456"
and the Form KC string:
"<SPACE><SPACE><SPACE>"
would result in an empty output string.
2.6.3. telephoneNumber Insignificant Character Removal
For the purposes of this section, a hyphen is defined to be
HYPHEN-MINUS (U+002D), ARMENIAN HYPHEN (U+058A), HYPHEN (U+2010),
NON-BREAKING HYPHEN (U+2011), MINUS SIGN (U+2212), SMALL HYPHEN-MINUS
(U+FE63), or FULLWIDTH HYPHEN-MINUS (U+FF0D) code point followed by no
combining marks and a space is defined to be the SPACE (U+0020) code
point followed by no combining marks.
All hyphens and spaces are regarded as not significant and are to be
removed.
3. Security Considerations
"Preparation for International Strings ('stringprep')" [RFC3454]
security considerations generally apply to the algorithms described
here.
4. Contributors
Appendix A and B of this document were authored by Howard Chu
<hyc@symas.com> of Symas Corporation (based upon information provided
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in RFC 1345).
5. Acknowledgments
The approach used in this document is based upon design principles and
algorithms described in "Preparation of Internationalized Strings
('stringprep')" [RFC3454] by Paul Hoffman and Marc Blanchet. Some
additional guidance was drawn from Unicode Technical Standards,
Technical Reports, and Notes.
6. Author's Address
Kurt Zeilenga
E-mail: <kurt@openldap.org>
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14 (also RFC 2119), March 1997.
[RFC3454] Hoffman, P. and M. Blanchet, "Preparation of
Internationalized Strings ('stringprep')", RFC 3454,
December 2002.
[Roadmap] Zeilenga, K. (editor), "LDAP: Technical Specification
Road Map", draft-ietf-ldapbis-roadmap-xx.txt, a work in
progress.
[Syntaxes] Legg, S. (editor), "LDAP: Syntaxes and Matching Rules",
draft-ietf-ldapbis-syntaxes-xx.txt, a work in progress.
[ISO10646] International Organization for Standardization,
"Universal Multiple-Octet Coded Character Set (UCS) -
Architecture and Basic Multilingual Plane", ISO/IEC
10646-1 : 1993.
[Unicode] The Unicode Consortium, "The Unicode Standard, Version
3.2.0" is defined by "The Unicode Standard, Version 3.0"
(Reading, MA, Addison-Wesley, 2000. ISBN 0-201-61633-5),
as amended by the "Unicode Standard Annex #27: Unicode
3.1" (http://www.unicode.org/reports/tr27/) and by the
"Unicode Standard Annex #28: Unicode 3.2"
(http://www.unicode.org/reports/tr28/).
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[UAX15] Davis, M. and M. Duerst, "Unicode Standard Annex #15:
Unicode Normalization Forms, Version 3.2.0".
<http://www.unicode.org/unicode/reports/tr15/tr15-22.html>,
March 2002.
[X.680] International Telecommunication Union -
Telecommunication Standardization Sector, "Abstract
Syntax Notation One (ASN.1) - Specification of Basic
Notation", X.680(1997) (also ISO/IEC 8824-1:1998).
[T.61] CCITT (now ITU), "Character Repertoire and Coded
Character Sets for the International Teletex Service",
T.61, 1988.
7.2. Informative References
[X.500] International Telecommunication Union -
Telecommunication Standardization Sector, "The Directory
-- Overview of concepts, models and services,"
X.500(1993) (also ISO/IEC 9594-1:1994).
[X.501] International Telecommunication Union -
Telecommunication Standardization Sector, "The Directory
-- Models," X.501(1993) (also ISO/IEC 9594-2:1994).
[X.520] International Telecommunication Union -
Telecommunication Standardization Sector, "The
Directory: Selected Attribute Types", X.520(1993) (also
ISO/IEC 9594-6:1994).
[Glossary] The Unicode Consortium, "Unicode Glossary",
<http://www.unicode.org/glossary/>.
[CharModel] Whistler, K. and M. Davis, "Unicode Technical Report
#17, Character Encoding Model", UTR17,
<http://www.unicode.org/unicode/reports/tr17/>, August
2000.
[XMATCH] Zeilenga, K., "Internationalized String Matching Rules
for X.500", draft-zeilenga-ldapbis-strmatch-xx.txt a
work in progress.
[RFC1345] Simonsen, K., "Character Mnemonics & Character Sets",
RFC 1345, June 1992.
Appendix A. Teletex (T.61) to Unicode
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This appendix defines an algorithm for transcoding [T.61] characters
to [Unicode] characters for use in string preparation for LDAP
matching rules. This appendix is a normative.
The transcoding algorithm is derived from the T.61-8bit definition
provided in [RFC1345]. With a few exceptions, the T.61 character
codes from x00 to x7f are equivalent to the corresponding [Unicode]
code points, and their values are left unchanged by this algorithm.
E.g. the T.61 code x20 is identical to (U+0020). The exceptions are
for these T.61 codes that are undefined: x23, x24, x5c, x5e, x60, x7b,
x7d, and x7e.
The codes from x80 to x9f are also equivalent to the corresponding
Unicode code points. This is specified for completeness only, as
these codes are control characters, and will be mapped to nothing in
the LDAP String Preparation Mapping step.
The remaining T.61 codes are mapped below in Table A.1. Table
positions marked "??" are undefined.
Input strings containing undefined T.61 codes SHALL produce an
Undefined matching result. For diagnostic purposes, this algorithm
does not fail for undefined input codes. Instead, undefined codes in
the input are mapped to the Unicode REPLACEMENT CHARACTER (U+FFFD).
As the LDAP String Preparation Probhibit step disallows the
REPLACEMENT CHARACTER from appearing in its output, this transcoding
yields the desired effect.
Note: RFC 1345 listed the non-spacing accent codepoints as residing in
the range starting at (U+E000). In the current Unicode
standard, the (U+E000) range is reserved for Private Use, and
the non-spacing accents are in the range starting at (U+0300).
The tables here use the (U+0300) range for these accents.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
a0| 00a0 | 00a1 | 00a2 | 00a3 | 0024 | 00a5 | 0023 | 00a7 |
a8| 00a8 | ?? | ?? | 00ab | ?? | ?? | ?? | ?? |
b0| 00b0 | 00b1 | 00b2 | 00b3 | 00d7 | 00b5 | 00b6 | 00b7 |
b8| 00f7 | ?? | ?? | 00bb | 00bc | 00bd | 00be | 00bf |
c0| ?? | 0300 | 0301 | 0302 | 0303 | 0304 | 0306 | 0307 |
c8| 0308 | ?? | 030a | 0327 | 0332 | 030b | 0328 | 030c |
d0| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
d8| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
e0| 2126 | 00c6 | 00d0 | 00aa | ?? | 0126 | 0132 | 013f |
e8| 0141 | 00d8 | 0152 | 00ba | 00de | 0166 | 014a | 0149 |
f0| 0138 | 00e6 | 0111 | 00f0 | 0127 | 0131 | 0133 | 0140 |
f8| 0142 | 00f8 | 0153 | 00df | 00fe | 0167 | 014b | ?? |
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--+------+------+------+------+------+------+------+------+
Table A.1: Mapping of 8-bit T.61 codes to Unicode
T.61 also defines a number of accented characters that are formed by
combining an accent prefix followed by a base character. These
prefixes are in the code range xc1 to xcf. If a prefix character
appears at the end of a string, the result is undefined. Otherwise
these sequences are mapped to Unicode by substituting the
corresponding non-spacing accent code (as listed in Table A.1) for the
accent prefix, and exchanging the order so that the base character
precedes the accent.
Appendix B. Additional Teletex (T.61) to Unicode Tables
All of the accented characters in T.61 have a corresponding code point
in Unicode. For the sake of completeness, the combined character
codes are presented in the following tables. This is informational
only; for matching purposes it is sufficient to map the non-spacing
accent and exchange the order of the character pair as specified in
Appendix A.
B.1. Combinations with SPACE
Accents may be combined with a <SPACE> to generate the accent by
itself. For each accent code, the result of combining with <SPACE> is
listed in Table B.1.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
c0| ?? | 0060 | 00b4 | 005e | 007e | 00af | 02d8 | 02d9 |
c8| 00a8 | ?? | 02da | 00b8 | ?? | 02dd | 02db | 02c7 |
--+------+------+------+------+------+------+------+------+
Table B.1: Mapping of T.61 Accents with <SPACE> to Unicode
B.2. Combinations for xc1: (Grave accent)
T.61 has predefined characters for combinations with A, E, I, O, and
U. Unicode also defines combinations for N, W, and Y. All of these
combinations are present in Table B.2.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 00c0 | ?? | ?? | ?? | 00c8 | ?? | ?? |
48| ?? | 00cc | ?? | ?? | ?? | ?? | 01f8 | 00d2 |
50| ?? | ?? | ?? | ?? | ?? | 00d9 | ?? | 1e80 |
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58| ?? | 1ef2 | ?? | ?? | ?? | ?? | ?? | ?? |
60| ?? | 00e0 | ?? | ?? | ?? | 00e8 | ?? | ?? |
68| ?? | 00ec | ?? | ?? | ?? | ?? | 01f9 | 00f2 |
70| ?? | ?? | ?? | ?? | ?? | 00f9 | ?? | 1e81 |
78| ?? | 1ef3 | ?? | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.2: Mapping of T.61 Grave Accent Combinations
B.3. Combinations for xc2: (Acute accent)
T.61 has predefined characters for combinations with A, E, I, O, U, Y,
C, L, N, R, S, and Z. Unicode also defines G, K, M, P, and W. All of
these combinations are present in Table B.3.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 00c1 | ?? | 0106 | ?? | 00c9 | ?? | 01f4 |
48| ?? | 00cd | ?? | 1e30 | 0139 | 1e3e | 0143 | 00d3 |
50| 1e54 | ?? | 0154 | 015a | ?? | 00da | ?? | 1e82 |
58| ?? | 00dd | 0179 | ?? | ?? | ?? | ?? | ?? |
60| ?? | 00e1 | ?? | 0107 | ?? | 00e9 | ?? | 01f5 |
68| ?? | 00ed | ?? | 1e31 | 013a | 1e3f | 0144 | 00f3 |
70| 1e55 | ?? | 0155 | 015b | ?? | 00fa | ?? | 1e83 |
78| ?? | 00fd | 017a | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.3: Mapping of T.61 Acute Accent Combinations
B.4. Combinations for xc3: (Circumflex)
T.61 has predefined characters for combinations with A, E, I, O, U, Y,
C, G, H, J, S, and W. Unicode also defines the combination for Z.
All of these combinations are present in Table B.4.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 00c2 | ?? | 0108 | ?? | 00ca | ?? | 011c |
48| 0124 | 00ce | 0134 | ?? | ?? | ?? | ?? | 00d4 |
50| ?? | ?? | ?? | 015c | ?? | 00db | ?? | 0174 |
58| ?? | 0176 | 1e90 | ?? | ?? | ?? | ?? | ?? |
60| ?? | 00e2 | ?? | 0109 | ?? | 00ea | ?? | 011d |
68| 0125 | 00ee | 0135 | ?? | ?? | ?? | ?? | 00f4 |
70| ?? | ?? | ?? | 015d | ?? | 00fb | ?? | 0175 |
78| ?? | 0177 | 1e91 | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.4: Mapping of T.61 Circumflex Accent Combinations
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B.5. Combinations for xc4: (Tilde)
T.61 has predefined characters for combinations with A, I, O, U, and
N. Unicode also defines E, V, and Y. All of these combinations are
present in Table B.5.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 00c3 | ?? | ?? | ?? | 1ebc | ?? | ?? |
48| ?? | 0128 | ?? | ?? | ?? | ?? | 00d1 | 00d5 |
50| ?? | ?? | ?? | ?? | ?? | 0168 | 1e7c | ?? |
58| ?? | 1ef8 | ?? | ?? | ?? | ?? | ?? | ?? |
60| ?? | 00e3 | ?? | ?? | ?? | 1ebd | ?? | ?? |
68| ?? | 0129 | ?? | ?? | ?? | ?? | 00f1 | 00f5 |
70| ?? | ?? | ?? | ?? | ?? | 0169 | 1e7d | ?? |
78| ?? | 1ef9 | ?? | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.5: Mapping of T.61 Tilde Accent Combinations
B.6. Combinations for xc5: (Macron)
T.61 has predefined characters for combinations with A, E, I, O, and
U. Unicode also defines Y, G, and AE. All of these combinations are
present in Table B.6.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 0100 | ?? | ?? | ?? | 0112 | ?? | 1e20 |
48| ?? | 012a | ?? | ?? | ?? | ?? | ?? | 014c |
50| ?? | ?? | ?? | ?? | ?? | 016a | ?? | ?? |
58| ?? | 0232 | ?? | ?? | ?? | ?? | ?? | ?? |
60| ?? | 0101 | ?? | ?? | ?? | 0113 | ?? | 1e21 |
68| ?? | 012b | ?? | ?? | ?? | ?? | ?? | 014d |
70| ?? | ?? | ?? | ?? | ?? | 016b | ?? | ?? |
78| ?? | 0233 | ?? | ?? | ?? | ?? | ?? | ?? |
e0| ?? | 01e2 | ?? | ?? | ?? | ?? | ?? | ?? |
f0| ?? | 01e3 | ?? | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.6: Mapping of T.61 Macron Accent Combinations
B.7. Combinations for xc6: (Breve)
T.61 has predefined characters for combinations with A, U, and G.
Unicode also defines E, I, and O. All of these combinations are
present in Table B.7.
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| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 0102 | ?? | ?? | ?? | 0114 | ?? | 011e |
48| ?? | 012c | ?? | ?? | ?? | ?? | ?? | 014e |
50| ?? | ?? | ?? | ?? | ?? | 016c | ?? | ?? |
58| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
60| ?? | 0103 | ?? | ?? | ?? | 0115 | ?? | 011f |
68| ?? | 012d | ?? | ?? | ?? | ?? | 00f1 | 014f |
70| ?? | ?? | ?? | ?? | ?? | 016d | ?? | ?? |
78| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.7: Mapping of T.61 Breve Accent Combinations
B.8. Combinations for xc7: (Dot Above)
T.61 has predefined characters for C, E, G, I, and Z. Unicode also
defines A, O, B, D, F, H, M, N, P, R, S, T, W, X, and Y. All of these
combinations are present in Table B.8.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 0226 | 1e02 | 010a | 1e0a | 0116 | 1e1e | 0120 |
48| 1e22 | 0130 | ?? | ?? | ?? | 1e40 | 1e44 | 022e |
50| 1e56 | ?? | 1e58 | 1e60 | 1e6a | ?? | ?? | 1e86 |
58| 1e8a | 1e8e | 017b | ?? | ?? | ?? | ?? | ?? |
60| ?? | 0227 | 1e03 | 010b | 1e0b | 0117 | 1e1f | 0121 |
68| 1e23 | ?? | ?? | ?? | ?? | 1e41 | 1e45 | 022f |
70| 1e57 | ?? | 1e59 | 1e61 | 1e6b | ?? | ?? | 1e87 |
78| 1e8b | 1e8f | 017c | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.8: Mapping of T.61 Dot Above Accent Combinations
B.9. Combinations for xc8: (Diaeresis)
T.61 has predefined characters for A, E, I, O, U, and Y. Unicode also
defines H, W, X, and t. All of these combinations are present in
Table B.9.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 00c4 | ?? | ?? | ?? | 00cb | ?? | ?? |
48| 1e26 | 00cf | ?? | ?? | ?? | ?? | ?? | 00d6 |
50| ?? | ?? | ?? | ?? | ?? | 00dc | ?? | 1e84 |
58| 1e8c | 0178 | ?? | ?? | ?? | ?? | ?? | ?? |
60| ?? | 00e4 | ?? | ?? | ?? | 00eb | ?? | ?? |
68| 1e27 | 00ef | ?? | ?? | ?? | ?? | ?? | 00f6 |
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70| ?? | ?? | ?? | ?? | 1e97 | 00fc | ?? | 1e85 |
78| 1e8d | 00ff | ?? | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.8: Mapping of T.61 Diaeresis Accent Combinations
B.10. Combinations for xca: (Ring Above)
T.61 has predefined characters for A, and U. Unicode also defines w
and y. All of these combinations are present in Table B.10.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 00c5 | ?? | ?? | ?? | ?? | ?? | ?? |
48| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
50| ?? | ?? | ?? | ?? | ?? | 016e | ?? | ?? |
58| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
60| ?? | 00e5 | ?? | ?? | ?? | ?? | ?? | ?? |
68| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
70| ?? | ?? | ?? | ?? | ?? | 016f | ?? | 1e98 |
78| ?? | 1e99 | ?? | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.10: Mapping of T.61 Ring Above Accent Combinations
B.11. Combinations for xcb: (Cedilla)
T.61 has predefined characters for C, G, K, L, N, R, S, and T.
Unicode also defines E, D, and H. All of these combinations are
present in Table B.11.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | ?? | ?? | 00c7 | 1e10 | 0228 | ?? | 0122 |
48| 1e28 | ?? | ?? | 0136 | 013b | ?? | 0145 | ?? |
50| ?? | ?? | 0156 | 015e | 0162 | ?? | ?? | ?? |
58| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
60| ?? | ?? | ?? | 00e7 | 1e11 | 0229 | ?? | 0123 |
68| 1e29 | ?? | ?? | 0137 | 013c | ?? | 0146 | ?? |
70| ?? | ?? | 0157 | 015f | 0163 | ?? | ?? | ?? |
78| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.11: Mapping of T.61 Cedilla Accent Combinations
B.12. Combinations for xcd: (Double Acute Accent)
T.61 has predefined characters for O, and U. These combinations are
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present in Table B.12.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
48| ?? | ?? | ?? | ?? | ?? | ?? | ?? | 0150 |
50| ?? | ?? | ?? | ?? | ?? | 0170 | ?? | ?? |
68| ?? | ?? | ?? | ?? | ?? | ?? | ?? | 0151 |
70| ?? | ?? | ?? | ?? | ?? | 0171 | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.12: Mapping of T.61 Double Acute Accent Combinations
B.13. Combinations for xce: (Ogonek)
T.61 has predefined characters for A, E, I, and U. Unicode also
defines the combination for O. All of these combinations are present
in Table B.13.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 0104 | ?? | ?? | ?? | 0118 | ?? | ?? |
48| ?? | 012e | ?? | ?? | ?? | ?? | ?? | 01ea |
50| ?? | ?? | ?? | ?? | ?? | 0172 | ?? | ?? |
58| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
60| ?? | 0105 | ?? | ?? | ?? | 0119 | ?? | ?? |
68| ?? | 012f | ?? | ?? | ?? | ?? | ?? | 01eb |
70| ?? | ?? | ?? | ?? | ?? | 0173 | ?? | ?? |
78| ?? | ?? | ?? | ?? | ?? | ?? | ?? | ?? |
--+------+------+------+------+------+------+------+------+
Table B.13: Mapping of T.61 Ogonek Accent Combinations
B.14. Combinations for xcf: (Caron)
T.61 has predefined characters for C, D, E, L, N, R, S, T, and Z.
Unicode also defines A, I, O, U, G, H, j,and K. All of these
combinations are present in Table B.14.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
--+------+------+------+------+------+------+------+------+
40| ?? | 01cd | ?? | 010c | 010e | 011a | ?? | 01e6 |
48| 021e | 01cf | ?? | 01e8 | 013d | ?? | 0147 | 01d1 |
50| ?? | ?? | 0158 | 0160 | 0164 | 01d3 | ?? | ?? |
58| ?? | ?? | 017d | ?? | ?? | ?? | ?? | ?? |
60| ?? | 01ce | ?? | 010d | 010f | 011b | ?? | 01e7 |
68| 021f | 01d0 | 01f0 | 01e9 | 013e | ?? | 0148 | 01d2 |
70| ?? | ?? | 0159 | 0161 | 0165 | 01d4 | ?? | ?? |
78| ?? | ?? | 017e | ?? | ?? | ?? | ?? | ?? |
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--+------+------+------+------+------+------+------+------+
Table B.14: Mapping of T.61 Caron Accent Combinations
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