UUIDs - five groups of hex numbers

[Domitan Redenblack]

UUIDs - are five groups of hex numbers. Does each of these numbers have a particular source or meaning?

 

What can you tell just by looking at a UUID ?

 

[Imnotgoing Sideways]

They're pseudo random, as far as I know.  Their main purpose is to be sure that no two assets have the same reference designator. ()y

 

[Rolig Loon]

You can tell that it's a UUID, or at least in the form of a UUID.  That's about it.

[Void Singer]

a few of them follow some conventions... like (current) avatar keys (older ones may not though) having certian bits that are set, and some that are not, others do not appear to have any obvious patern (texture keys for example). in general there isn't much useful that can be detected from a group key (some may be date encoded, but I can't remember which ones)

[Domitan Redenblack]

So the first group of hex digits (8 of them, 32 bits) would be a number 2^32-1

As a unique marker, this would be a good bet?

 

[Rolig Loon]

Not as unique as the whole thing, but I have no worries about using those first few characters to build, say, a private chat channel:

integer gChan = (integer)("0xF" + llGetSubString(llGetOwner(),0,8) );

 

[Void Singer]

it might help to know what you are wanting to do.... stripping out, or creating a few numbers from the effective 128bits of a key won't be entirely unique, but has differing levels of chance of collision depending on how much is used in the final format. collision is when two different keys generate the same result.

[Domitan Redenblack]

My one prim vendor reports to my database when it gets rezzed in world, and in case of multiple vendors in a single region+parcel, I save the full UUID key to the prim.

But when I report sales and check in regularly, just giving the first 8 hex digits of the vendor UUID seems plenty.

[Domitan Redenblack]

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Rolig Loon wrote: 

integer gChan = (integer)("0xF" + llGetSubString(llGetOwner(),0,8) );

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Will that get the "-" at the end of the 8 hex digits?

e.g. 2771b5f2-2c8c-34a0-aed8-3ed939bb36fe

-->  llGetSubString( str, start_index, end_index);

and I think you want 32-bits negative number: integer gChan = (integer)("0xF" + llGetSubString(llGetOwner(),0,6) );

 

[Void Singer]

I believe that was a think-o, I've done it too... 0x + 0,7 is the basic format.... 0xF + 08 will parse, but may give unexpected results

[Rolig Loon]

 I had eights on the brain while I was typing.  I shouldn't work late at night.

[Domitan Redenblack]

Related question:

If I copy a  texture into an object, it has a certain UUID key.

If I then makes multiple copies of that object and give them away, will the texture be duplicated (have different UUIDs in each object copy) ?

 

[Void Singer]

no... items only get a new uuid when saved after changes. animations, textures, and sounds NEVER change uuids. Objects that are modified do, but you can't access the system uuid (only the rezzed uuid which stays the same while it its rezzed). scripts and notecards that are saved (even if they have no changes) will get a new uuid