WikiSysop: imported from WiKit id 1370

2004-10-08T13:55:17Z

imported from WiKit id 1370

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'''Universally Unique IDentifiers (UUIDs)'''

[[John Havard]] implemented [http://www.havpyro.com/nsuuid.tar.gz nsuuid], a C module which uses libuuid1 (part of e2fsprogs). It may be possible to link against OSSP's uuid implementation. http://www.ossp.org/pkg/lib/uuid/

[[Dossy]] provides a simple pure-Tcl solution here with [[RHS]]'s help:

#
# ns_uuid_v4 --
#
# This generates Version 4 "random" UUIDs.
#
# http://www.ietf.org/internet-drafts/draft-mealling-uuid-urn-03.txt
#
# The algorithm is as follows:
# o Set the two most significant bits (bits six and seven) of the
# clock_seq_hi_and_reserved to zero and one, respectively.
# o Set the four most significant bits (bits 12 through 15) of the
# time_hi_and_version field to the four-bit version number from
# Section 4.1.3.
# o Set all the other bits to randomly (or pseudo-randomly) chosen
# values.
#

proc ns_uuid_v4 {} {
ns_uuid_gen [[binary format "IIII" \
[expr {wide(0x0ffffffff*rand())}]] \
[[expr {wide(0x0ffffffff*rand()) & 0xffff4fff}]] \
[[expr {wide(0x0ffffffff*rand()) & 0x7fffffff}]] \
[[expr {wide(0x0ffffffff*rand())}]]]
}

proc ns_uuid_gen {bits} {
binary scan $bits "H8 H4 H4 H4 H12" a b c d e
return "$a-$b-$c-$d-$e"
}

Nsuuid - Revision history

WikiSysop: imported from WiKit id 1370