[Python-Dev] Re: [Python-checkins] CVS: python/dist/src/Objects dictobject.c,2.68,2.69

[Greg Stein]

On Tue, Dec 12, 2000 at 05:02:49PM -0800, Tim Peters wrote:
> Update of /cvsroot/python/python/dist/src/Objects
> In directory slayer.i.sourceforge.net:/tmp/cvs-serv31776/python/dist/src/objects
> 
> Modified Files:
> 	dictobject.c 
> Log Message:
> Bring comments up to date (e.g., they still said the table had to be
> a prime size, which is in fact never true anymore ...).
>...
> --- 55,78 ----
>   
>   /*
> ! There are three kinds of slots in the table:
> ! 
> ! 1. Unused.  me_key == me_value == NULL
> !    Does not hold an active (key, value) pair now and never did.  Unused can
> !    transition to Active upon key insertion.  This is the only case in which
> !    me_key is NULL, and is each slot's initial state.
> ! 
> ! 2. Active.  me_key != NULL and me_key != dummy and me_value != NULL
> !    Holds an active (key, value) pair.  Active can transition to Dummy upon
> !    key deletion.  This is the only case in which me_value != NULL.
> ! 
> ! 3. Dummy.  me_key == dummy && me_value == NULL
> !    Previously held an active (key, value) pair, but that was deleted and an
> !    active pair has not yet overwritten the slot.  Dummy can transition to
> !    Active upon key insertion.  Dummy slots cannot be made Unused again
> !    (cannot have me_key set to NULL), else the probe sequence in case of
> !    collision would have no way to know they were once active.

4. The popitem finger.


:-)

Cheers,
-g

-- 
Greg Stein, http://www.lyra.org/