Subject: [Boost-users] [serialization] object tracking for shared strings
From: Nils Krumnack (nils_at_[hidden])
Date: 2009-12-16 18:48:22
Hi all,
I hope one of you will be able to help me with this: I am working
with a data structure that contains a large number of (mostly
identical) strings. To save memory I put together a shared memory
string implementation, which ensures that each string is kept in
memory only once (implemented through a global map with all strings).
However, once I write them to disk, I again have n copies of each
string. I would really prefer, if I could avoid the space overhead.
At first glance, object tracking seems to be the way to go. If my
strings were tracked, there would automatically be only one copy of
each string. However I can't quite figure out how. I don't really
want to change the global tracking behavior for std::string, since
that might end up affecting code all over the place.
Serializing pointers would be an option, but then I would have to deal
with the issue of when to deallocate that object. I suppose I could
serialize shared pointers, but then I would have to change my
implementation to use shared pointers internally. Alternatively I
could also wrap a struct around the strings internally and turn on
tracking for that struct, but again I would have to complicate my
implementation for the sake of serialization.
What I was hoping to find was some way of telling the archive at the
point where I am serializing the object, that it should track this one
object. I am thinking of something like
ar & BOOST_SERIALIZATION_TRACK_THIS (mystring);
I was looking for something like that in the documentation, but wasn't
very successful. Any ideas?
Thanks in advance for any help,
Nils