A GUID getter for assembly language

[sinsi]

How about this: let's take a completely empirical approach:

• Use UuidCreate() to get a GUID
• Look at the data in the GUID structure, byte by byte
• Use UuidToString() to create the string
• Compare the data layout to the byte order in the string

That should show us the correct order of things.

Already did that.

Code Select Expand

e4 4c 54 8a 70 77 18 4d-83 70 0a e4 8a 29 78 52
8a544ce4-7770-4d18-8370-0ae48a297852The top line is the buffer from UuidCreate
The next line is from UuidToString

[TimoVJL]

What is a GUID?
A Universally Unique IDentifier (UUID) URN Namespace

[TimoVJL]

Also a string for register would be useful, as it might be needed for later usage.

You mean for the registry? I thought that was the XXXXXXXX-XXXX-XXXX ... form. What format exactly is it?

string like "{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}"

[NoCforMe]

So all I need to do is enclose it in {}. Easy peasy.

[NoCforMe]

How about this: let's take a completely empirical approach:

• Use UuidCreate() to get a GUID
• Look at the data in the GUID structure, byte by byte
• Use UuidToString() to create the string
• Compare the data layout to the byte order in the string

That should show us the correct order of things.

Already did that.

Code Select Expand

e4 4c 54 8a 70 77 18 4d-83 70 0a e4 8a 29 78 52
8a544ce4-7770-4d18-8370-0ae48a297852The top line is the buffer from UuidCreate
The next line is from UuidToString

This is my guide, then, to fixing my utility so it shows the value properly. Probably be done later today ...

[TimoVJL]

So all I need to do is enclose it in {}. Easy peasy.

Windows API function StringFromGUID2() make it in UNICODE form for reference.

[NoCforMe]

So all I need to do is enclose it in {}. Easy peasy.

Windows API function StringFromGUID2() make it in UNICODE form for reference.

Unicode, schmunicode; all that's needed are plain ASCII characters here.

[NoCforMe]

OK, new version attached. It puts the GUID in the same format (byte-order wise) as UuidToString(), as shown in the status bar).

Timo, I added "{}" to the GUID string shown at the top: happy? It ain't Unicode, but you can certainly copy and paste into anything.

So it turns out that the GUID format is:

• First 4 bytes (8 hex chars.) in DWORD order (little-endian)
• Next 2 sets of 2 bytes each (4 hex chars.) in WORD order
• Next set of 2 bytes in non-byte-swapped order (?????)
• Last set of 6 bytes (12 hex chars.) in non-byte-swapped order

Weird.

Last question: I'm using uppercase hex characters here, but UuidToString() renders them in lowercase. Probly doesn't matter, but I could put in an option for case here; anyone think that would be a good thing?

[TimoVJL]

In windows register GUIDs are mostly uppercase, like CLSIDs, but not necessarily.

[NoCforMe]

In windows register registry GUIDs are mostly uppercase, like CLSIDs, but not necessarily.

[NoCforMe]

New version gives you the choice of uppercase or not.