[Swan-commit] Changes to ref refs/heads/master

[Andrew Cagney]

New commits:
commit d7eea0edd5cede40ec412fa34c5c2757c169b59c
Author: Andrew Cagney <cagney at gnu.org>
Date:   Fri Oct 11 00:24:09 2019 -0400

    address pool: reduce complexity from O(#LEASES) to O(1)
    
    Leases were being stored as a linked list.  In the case of reusable
    (nee sharable) leases that list could grow until there was an entry
    for every possible address.  Think about 10.0.0.0/8.
    
    This patch replaces the list with an array that grows on demand:
    
    - the operation LEASE.ADDRESS->LEASE is O(1)
    
    - the array grows simply doubling it size (0 1 2 4 ...): no
      preallocation magic to test
    
    - lists et.al. get implemented using offsets (array moves): there are
      some pretty ugly macros dealing with this :-(
    
    - the free list is double linked: single-use leases are prepended;
      reusable leases are appended (so they get recovered in FIFO order);
      only when the free list is totally exhausted will the lease array
      grow
    
    - the operation ID->LEASE uses an O(1) hash table implemented on top
      of the leases array: when the array grows the hash table is rebuilt
    
    - the reusable leases unique IDs are stored as strings
    
    - the code that tried to mix in the xauth e-mail address isn't enabled
      as, seamingly, it wasn't doing anything other than changing a log