Re: [Boost-users] serialization: pointer reconstruction

Subject: Re: [Boost-users] serialization: pointer reconstruction
From: Robert Ramey (ramey_at_[hidden])
Date: 2010-01-26 13:19:17

I believe that what you want to do is already handled automatically
by the serialization library.  The only requirement is that struct B
be serialized before struct C.  The serialization library handles
all the id management internally.

Robert Ramey

Noah Roberts wrote:
> A while back I asked about saving a pointer to an item in another
> class that is stored as a direct instance variable (no pointer).
> Here's a brief illustration:
>
> struct A
> {
> };
>
> struct B
> {
>  A a;
> };
>
> struct C
> {
>  A * a; // points to a B::a.
> };
>
> I have an idea how to store and restore these relationships but I'd
> like to see if there are any improvement ideas and/or direction to
> existing behavior I'm not seeing in the documentation.
>
> My idea is to first store B::a (which simply makes sense in my problem
> anyway) and when I do this to call some custom support functions to
> generate a unique ID for the object at that address and store it
> first, then the rest of the data in A.  This would appear in
> A::serialize and the unique ID would be stored in the Archive (added
> behavior) as a map from address to uid.
>
> Then when storing C I would request the unique ID for the address the
> pointer stores and store it.
>
> On reading I read B::a first and it sort of reverses the process.  The
> uid is read and then A::serialize stores the uid and 'this' in the
> archive map in a uid->address format.  I then read the uid on reading
> C::a and request the address from the archive using that value.
>
> I've already subclassed the Archive in order to pass around other load
> information needed by classes that didn't have local copies, so that's
> the easy part (though it wasn't a straight forward operation).  The
> question I have though is that since the pointer archiving already
> must use some similar type of API, can I use it instead of rolling my
> own and how would I do that?