Commit Graph

2 Commits (d02f1be46ac384aa1937971092394562533e9456)

Author SHA1 Message Date
James Tucker 24bac27632 util/rands: add Shuffle and Perm functions with on-stack RNG state
The new math/rand/v2 package includes an m-local global random number
generator that can not be reseeded by the user, which is suitable for
most uses without the RNG pools we have in a number of areas of the code
base.

The new API still does not have an allocation-free way of performing a
seeded operations, due to the long term compiler bug around interface
parameter escapes, and the Source interface.

This change introduces the two APIs that math/rand/v2 can not yet
replace efficiently: seeded Perm() and Shuffle() operations. This
implementation chooses to use the PCG random source from math/rand/v2,
as with sufficient compiler optimization, this source should boil down
to only two on-stack registers for random state under ideal conditions.

Updates #17243

Signed-off-by: James Tucker <james@tailscale.com>
9 months ago
Brad Fitzpatrick 7175f06e62 util/rands: add package with HexString func
We use it a number of places in different repos. Might as well make
one. Another use is coming.

Updates #cleanup

Change-Id: Ib7ce38de0db35af998171edee81ca875102349a4
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago