Is the main issue to avoid loss of storage space? That is, access time is
not that important?
Thomas
Den mån 30 dec. 2024 08:28Binyamin Dissen <
00000662573e2c3a-dmarc-requ...@listserv.ua.edu> skrev:
> The issue with playing with pointers is that the storage would be lost.
> Blocks
> have quite variant lengths.
>
> I guess I could create X areas and release an area when all items in the
> area
> have been deleted (perhaps transfer items if the remaining count is low).
>
> On Mon, 30 Dec 2024 06:44:33 +0000 "Farley, Peter"
> <0000031df298a9da-dmarc-requ...@listserv.ua.edu> wrote:
>
> :>Sounds to me like a deque with functions q.popleft() to remove at the
> left side, q.append() to add at the right side. Scan process would be a
> series of popleft calls with append for the ones being left for a later
> time.
> :>
> :>E.G. (pseudocode):
> :>
> :>Scan(q) {
> :> Curlen = len(q)
> :> For qx = 1 to Curlen {
> :> Qitem = q.popleft()
> :> If Qitem is NOT to be removed {
> :> q.append(Qitem)
> :> }
> :> Else { Process removed Qitem }
> :> }
> :>}
> :>
> :>If the “Qitems” are relatively large in size and all at different
> addresses then the deque structure (which can be a dynamically sized array)
> can just store pointers to the actual items, resulting in not a lot of data
> movement at all.
> :>
> :>FWIW, I have done something like this in COBOL, though not for an
> employer.
> :>
> :>HTH
> :>
> :>Peter
> :>
> :>From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On
> Behalf Of Binyamin Dissen
> :>Sent: Sunday, December 29, 2024 3:51 PM
> :>To: IBM-MAIN@LISTSERV.UA.EDU
> :>Subject: Ideas of managing a data structure
> :>
> :>
> :>The data structure consists of various items of different lengths. The
> items
> :>
> :>are added serially and periodically the area is scanned where most items
> are
> :>
> :>removed. The remaining items are likely to be removed in a later scan
> (with
> :>
> :>new items).
> :>
> :>
> :>
> :>My thought was to have two data areas, and during the scan insert the
> :>
> :>undeleted items into the alternate area. It will be a bit of data moves
> but is
> :>
> :>simple.
> :>
> :>
> :>
> :>Does Knuth talk about such a data structure?
>
> --
> Binyamin Dissen <bdis...@dissensoftware.com>
> http://www.dissensoftware.com
>
> Director, Dissen Software, Bar & Grill - Israel
>
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