[Rpm-maint] Reserve ALT RPM tags range

[Panu Matilainen]

On 03/06/2018 06:29 PM, Vladimir D. Seleznev wrote:
> On Wed, Feb 28, 2018 at 05:54:27AM -0500, Jeff Johnson wrote:
>>> You might try the convention of assigning tags in the 1Gb space from 0x40000000 to 0x4fffffff as you wish.
>>>
>>> (aside)
>>> RPM5 has something called "arbitrary tags" in the 0x40000000 -> 0x4fffffff range.
>>>
>>> Short answer:
>>> Choose any tagno in that range and do what you wish.
>>>
>>> Longer answer:
>>>
>>> Choose a tag name string.
>>>
>>> The  tagno is computed from a (configurable) tag name string as follows:
>>>
>>> 1) the tag name plain text is canonicalized (leading alphabetic, alphanumeric characters, 1st letter uppercase, rest lowercase). E.g. "Mynewtag42"
>>>
>>> 2) the  4 binary bytes of the SHA1 of the canonical string are copied into a uint32 (which needs to be swabbed on big endian platforms).
>>>
>>> 3) the tagno is assigned by then masking on the 0x40000000 arbitrary tag identifier onto the least significant 30 bits of the uint32.
> 
> Thank you for the suggestion, I think we shall follow this!
> 

Sigh. What's so secret about that work that you can't at least briefly 
explain the actual use for those tags here?

	- Panu -