gdalgorithms-list

[Algorithms] GUIDs

[Matthew D. <MD...@ac...>]

Hi,
 
Does anyone know the algorithm or have source code describing the way
CoGuidCreate or UuidCreate generates the GUIDs?  Or perhaps there's a cross
platform solution to generating globally unique identifiers?
 
Regards,

Matt J. Davies 
Programmer 
Acclaim Studios Ltd. 
Lansdown Road, 
Cheltenham, 
Gloucestershire, 
United Kingdom, 
GL50 2JA. 

Tel: +44 (0) 1242 533 682 
Fax: +44 (0) 1242 533 700 

 

Re: [Algorithms] GUIDs

[Davide P. <da...@pr...>]

Does anyone know the algorithm or have source code describing the way
CoGuidCreate or UuidCreate generates the GUIDs?  Or perhaps there's a cross
platform solution to generating globally unique identifiers?

MSDN library samples...

VC98\mfc\utility\guidgen

Davide Pirola

www.prograph.it
www.protonic.net

Re: [Algorithms] GUIDs

[Neal T. <ne...@ps...>]

  From: Matthew Davies=20
  Does anyone know the algorithm or have source code describing the way =
CoGuidCreate or UuidCreate generates the GUIDs?  Or perhaps there's a =
cross platform solution to generating globally unique identifiers?


  I believe a GUID is the same as a Free Software Foundation UUID, in =
which case you might want to look at:

  http://www.opennc.org/onlinepubs/9629399/apdxa.htm

  (specification plus algorithms for generating UUIDs)
  =20
  Neal Tringham (Sick Puppies)

  ne...@ps...
  ne...@em...

Re: [Algorithms] GUIDs

[Davide P. <da...@pr...>]

>Does anyone know the algorithm or have source code describing the way
>CoGuidCreate or UuidCreate generates the GUIDs?  Or perhaps there's a =
cross
>platform solution to generating globally unique identifiers?

MSDN library samples...

VC98\mfc\utility\guidgen

Davide Pirola

www.prograph.it
www.protonic.net

Re: [Algorithms] GUIDs

[Kent Q. <ken...@co...>]

I don't have the details, but as I recall, the general idea was to
combine the network MAC address of the machine generating the GUID
(which is a 48-bit unique number) with a version of the date and time
down to the millisecond. No two machines with a network card should ever
be able to generate the same GUIDs that way (as long as you don't
generate more than one per millisecond, anyway!).

For machines that don't have a network card, there was some other way of
getting the 48-bit ID, but I forget what it is.

> Matthew Davies wrote:
> 
> Hi,
> 
> Does anyone know the algorithm or have source code describing the way
> CoGuidCreate or UuidCreate generates the GUIDs?  Or perhaps there's a
> cross platform solution to generating globally unique identifiers?
> 

-- 
-----------------------------------------------------------------------
Kent Quirk                   | CogniToy: Intelligent toys...
Game Designer                |           for intelligent minds.
ken...@co...      | http://www.cognitoy.com/     
_____________________________|_________________________________________

RE: [Algorithms] GUIDs

[Scott B. <sc...@ga...>]

Win32 GUID's are based on the algorithm used by OSF's DCE. Here's a starting
point:

http://msdn.microsoft.com/library/default.asp?URL=/library/books/inole/S10E8
.HTM

Check out the last paragraph...talks about where to find the actual spec for
the algorithm.

Scott

-----Original Message-----
From: gda...@li...
[mailto:gda...@li...]On Behalf Of Matthew
Davies
Sent: Thursday, July 20, 2000 1:59 AM
To: Algorithms List (E-mail)
Subject: [Algorithms] GUIDs


Hi,

Does anyone know the algorithm or have source code describing the way
CoGuidCreate or UuidCreate generates the GUIDs?  Or perhaps there's a cross
platform solution to generating globally unique identifiers?

Regards,
Matt J. Davies
Programmer
Acclaim Studios Ltd.
Lansdown Road,
Cheltenham,
Gloucestershire,
United Kingdom,
GL50 2JA.
Tel: +44 (0) 1242 533 682
Fax: +44 (0) 1242 533 700

[Algorithms] Machine specific optimization

[Kevin L. <lac...@in...>]

What wouild the c++ code look like that polls the cpu ? to see what type
of stucture I want to use? For example using the mmx vector and matrix
classes etc.

Thanks
Kevin

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