stringprep(3)

stringprep(3tcl) Preparation of Internationalized Strings stringprep(3tcl)

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NAME
stringprep - Implementation of stringprep

SYNOPSIS
package require Tcl 8.3

package require stringprep 1.0.1

::stringprep::register profile ?-mapping list? ?-normalization form?
?-prohibited list? ?-prohibitedList list? ?-prohibitedCommand command?
?-prohibitedBidi boolean?

::stringprep::stringprep profile string

::stringprep::compare profile string1 string2

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DESCRIPTION
This is an implementation in Tcl of the Preparation of International-
ized Strings ("stringprep"). It allows to define stringprep profiles
and use them to prepare Unicode strings for comparison as defined in
RFC-3454.

COMMANDS
::stringprep::register profile ?-mapping list? ?-normalization form?
?-prohibited list? ?-prohibitedList list? ?-prohibitedCommand command?
?-prohibitedBidi boolean?
Register the stringprep profile named profile. Options are the
following.

Option -mapping specifies stringprep mapping tables. This pa-
rameter takes list of tables from appendix B of RFC-3454. The
usual list values are {B.1 B.2} or {B.1 B.3} where B.1 contains
characters which commonly map to nothing, B.3 specifies case
folding, and B.2 is used in profiles with unicode normalization
form KC. Defult value is {} which means no mapping.

Option -normalization takes a string and if it is nonempty then
it uses as a name of Unicode normalization form. Any value of
"D", "C", "KD" or "KC" may be used, though RFC-3454 defines only
two options: no normalization or normalization using form KC.

Option -prohibited takes a list of RFC-3454 tables with prohib-
ited characters. Current version does allow to prohibit either
all tables from C.3 to C.9 or neither of them. An example of
this list for RFC-3491 is {A.1 C.1.2 C.2.2 C.3 C.4 C.5 C.6 C.7
C.8 C.9}.

Option -prohibitedList specifies a list of additional prohibited
characters. The list contains not characters themselves but
their Unicode numbers. For example, Nodeprep specification from
RFC-3920 forbids the following codes: {0x22 0x26 0x27 0x2f 0x3a
0x3c 0x3e 0x40} (\" \& \' / : < > @).

Option -prohibitedCommand specifies a command which is called
for every character code in mapped and normalized string. If the
command returns true then the character is considered prohib-
ited. This option is useful when a list for -prohibitedList is
too large.

Option -prohibitedBidi takes boolean value and if it is true
then the bidirectional character processing rules defined in
section 6 of RFC-3454 are used.

::stringprep::stringprep profile string
Performs stringprep operations defined in profile profile to
string string. Result is a prepared string or one of the follow-
ing errors: invalid_profile (profile profile is not defined),
prohibited_character (string string contains a prohibited char-
acter) or prohibited_bidi (string string contains a prohibited
bidirectional sequence).

::stringprep::compare profile string1 string2
Compares two unicode strings prepared accordingly to stringprep
profile profile. The command returns 0 if prepared strings are
equal, -1 if string1 is lexicographically less than string2, or
1 if string1 is lexicographically greater than string2.

EXAMPLES
Nameprep profile definition (see RFC-3491):

::stringprep::register nameprep -mapping {B.1 B.2} -normalization KC -prohibited {A.1 C.1.2 C.2.2 C.3 C.4 C.5 C.6 C.7 C.8 C.9} -prohibitedBidi 1

Nodeprep and resourceprep profile definitions (see RFC-3920):

::stringprep::register nodeprep -mapping {B.1 B.2} -normalization KC -prohibited {A.1 C.1.1 C.1.2 C.2.1 C.2.2 C.3 C.4 C.5 C.6 C.7 C.8 C.9} -prohibitedList {0x22 0x26 0x27 0x2f 0x3a 0x3c 0x3e 0x40} -prohibitedBidi 1

::stringprep::register resourceprep -mapping {B.1} -normalization KC -prohibited {A.1 C.1.2 C.2.1 C.2.2 C.3 C.4 C.5 C.6 C.7 C.8 C.9} -prohibitedBidi 1

REFERENCES
[1] "Preparation of Internationalized Strings ('stringprep')",
(http://www.ietf.org/rfc/rfc3454.txt)

[2] "Nameprep: A Stringprep Profile for Internationalized Domain
Names (IDN)", (http://www.ietf.org/rfc/rfc3491.txt)

[3] "Extensible Messaging and Presence Protocol (XMPP): Core",
(http://www.ietf.org/rfc/rfc3920.txt)

AUTHORS
Sergei Golovan

BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain
bugs and other problems. Please report such in the category stringprep
of the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please
also report any ideas for enhancements you may have for either package
and/or documentation.

When proposing code changes, please provide unified diffs, i.e the out-
put of diff -u.

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