From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Custom Storage Pool questions
Date: Tue, 14 Sep 2021 08:23:08 +0200 [thread overview]
Message-ID: <shpf4d$1a6s$1@gioia.aioe.org> (raw)
In-Reply-To: bec26cfe-a7c3-49b9-8272-9f08be93d7fdn@googlegroups.com
On 2021-09-14 02:48, Jere wrote:
> Yes, but if you look at that blog, they are allocating space for the /user/ data
> and for the Next/Prev for controlled types and First/Last for unconstrained
> arrays in addition to the size specified by allocate.
I do not understand your concern. The blog discusses how to add service
data to the objects allocated in the pool.
I use such pools extensively in Simple Components. E.g. linked lists are
implemented this way. The list links are allocated in front of list
elements which can be of any type, unconstrained arrays included.
The problem with unconstrained arrays is not that the bounds are not
allocated, they are, but the semantics of X'Address when applied to arrays.
A'Address is the address of the first array element, not of the array
object. For a pool designer it constitutes a problem of getting the
array object by address. This is what Emmanuel discusses in the blog.
[ The motivation behind Ada choice was probably to keep the semantics
implementation-independent. ]
Consider for example a list of String elements. When Allocate is called
with String, it returns the address of all String. But that is not the
address you would get if you applied 'Address. You have to add/subtract
some offset in order to get one from another.
In Simple Components this offset is determined at run-time for each
generic instance.
Of course, a proper solution would be fixing Ada by adding another
address attribute:
X'Object_Address
returning the first address of the object as allocated.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2021-09-14 6:23 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 0:53 Custom Storage Pool questions Jere
2021-09-13 5:29 ` Randy Brukardt
2021-09-14 1:04 ` Jere
2021-09-21 0:06 ` Randy Brukardt
2021-09-18 11:32 ` Simon Wright
2021-09-20 0:31 ` Jere
2021-09-20 6:34 ` Niklas Holsti
2021-09-20 6:48 ` Emmanuel Briot
2021-09-20 7:35 ` Dmitry A. Kazakov
2021-09-20 16:59 ` Shark8
2021-09-21 0:50 ` Randy Brukardt
2021-09-21 23:08 ` Jere
2021-09-28 4:42 ` Randy Brukardt
2021-10-02 23:19 ` Jere
2021-10-03 8:52 ` Dmitry A. Kazakov
2021-10-14 1:26 ` Randy Brukardt
2021-09-13 11:12 ` J-P. Rosen
2021-09-14 0:48 ` Jere
2021-09-14 6:08 ` J-P. Rosen
2021-09-15 0:39 ` Jere
2021-09-15 7:01 ` Simon Wright
2021-09-16 23:32 ` Jere
2021-09-20 23:51 ` Randy Brukardt
2021-09-21 22:40 ` Jere
2021-09-14 6:23 ` Dmitry A. Kazakov [this message]
2021-09-14 6:42 ` J-P. Rosen
2021-09-14 7:00 ` Dmitry A. Kazakov
2021-09-20 23:58 ` Randy Brukardt
2021-09-15 0:21 ` Jere
2021-09-15 6:54 ` Dmitry A. Kazakov
2021-09-20 23:48 ` Randy Brukardt
2021-09-14 10:54 ` Egil H H
2021-09-15 0:11 ` Jere
2021-09-15 16:43 ` Simon Wright
2021-09-15 17:03 ` Simon Wright
2021-09-15 19:07 ` Dmitry A. Kazakov
2021-09-15 20:40 ` Simon Wright
2021-09-16 7:12 ` Emmanuel Briot
2021-09-16 23:21 ` Jere
2021-09-17 7:08 ` Emmanuel Briot
2021-09-17 7:18 ` Simon Wright
2021-09-17 13:56 ` Dmitry A. Kazakov
2021-09-17 19:46 ` Simon Wright
2021-09-17 20:39 ` Dmitry A. Kazakov
2021-09-17 21:17 ` Niklas Holsti
2021-09-18 7:49 ` Dmitry A. Kazakov
2021-09-18 9:03 ` Niklas Holsti
2021-09-18 10:22 ` Dmitry A. Kazakov
2021-09-18 15:59 ` Niklas Holsti
2021-09-18 16:19 ` Dmitry A. Kazakov
2021-09-19 10:36 ` Niklas Holsti
2021-09-19 11:41 ` Dmitry A. Kazakov
2021-09-20 7:05 ` Niklas Holsti
2021-09-20 7:35 ` Dmitry A. Kazakov
2021-09-20 8:08 ` Niklas Holsti
2021-09-20 8:28 ` Dmitry A. Kazakov
2021-09-21 0:45 ` Randy Brukardt
2021-09-21 0:40 ` Randy Brukardt
2021-09-21 0:30 ` Randy Brukardt
2021-09-21 0:37 ` Randy Brukardt
2021-09-21 6:28 ` Dmitry A. Kazakov
2021-09-28 4:38 ` Randy Brukardt
2021-09-28 7:00 ` Dmitry A. Kazakov
2021-09-21 0:26 ` Randy Brukardt
2021-09-21 6:51 ` Dmitry A. Kazakov
2021-09-28 4:31 ` Randy Brukardt
2021-09-28 6:56 ` Dmitry A. Kazakov
2021-09-28 7:52 ` Simon Wright
2021-09-28 8:07 ` Dmitry A. Kazakov
2021-09-28 22:04 ` Randy Brukardt
2021-09-29 7:57 ` Dmitry A. Kazakov
2021-09-29 14:41 ` Shark8
2021-09-29 15:16 ` Dmitry A. Kazakov
2021-09-30 0:16 ` Randy Brukardt
2021-09-30 8:08 ` Dmitry A. Kazakov
2021-10-01 0:04 ` Randy Brukardt
2021-10-01 8:25 ` Dmitry A. Kazakov
2021-10-02 9:06 ` Randy Brukardt
2021-10-02 10:18 ` Dmitry A. Kazakov
2021-10-03 4:33 ` Randy Brukardt
2021-10-03 8:40 ` Dmitry A. Kazakov
2021-10-14 1:21 ` Randy Brukardt
2021-10-14 3:12 ` philip...@gmail.com
2021-10-14 7:31 ` Dmitry A. Kazakov
2021-10-15 0:36 ` Randy Brukardt
2021-10-15 8:08 ` Stephen Leake
2021-10-15 8:18 ` Dmitry A. Kazakov
2021-10-15 22:22 ` Randy Brukardt
2021-10-15 8:15 ` Dmitry A. Kazakov
2021-10-15 22:44 ` Randy Brukardt
2021-10-16 9:00 ` Dmitry A. Kazakov
2021-10-16 14:32 ` Simon Wright
2021-10-16 15:06 ` Dmitry A. Kazakov
2021-10-18 14:23 ` Shark8
2021-09-21 0:19 ` Randy Brukardt
2021-09-21 0:18 ` Randy Brukardt
2021-09-16 8:41 ` Dmitry A. Kazakov
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