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Subject: Re: [Boost-users] [Q] reading back serialized Collection of shared_ptr
From: V S P (toreason_at_[hidden])
Date: 2009-06-19 20:24:28
Ok,
I got it to work.. I think...
So to serialize a collection (multiset in my case) of shared ptrs
such that the collection inherited from std::multiset
the following steps need to be taken (and may be I have more here than
needed)
1)
Include appropriate header file from
#include <boost/serialization/set.hpp>
#include <boost/serialization/vector.hpp>
#include <boost/serialization/list.hpp>
#include <boost/serialization/deque.hpp>
2) Do NOT make a serialize method within your class (the child fo the
std::multiset)
3) you will need to typecast up to the parent your class object instance
before
calling the serialization/deserialization (otherwise you will get a
compile time error
that your class does not have a serialize method)
Therefore I had to use the make_nvp function directly (and not that NVP
macro)
ia >> boost::serialization::make_nvp("MYTABLE",(tTB::ThisParent&)mytb);
my two major mistakes were not including the header file for collection
and the adding a method called serialize within my child (and that made
the serialize
library use my version which did not make sense)
Vlad
On Fri, 19 Jun 2009 16:18 -0400, "V S P" <toreason_at_[hidden]> wrote:
> I made may be a little more headways since my previous question
>
> and now have an xml archive that appears to 'denote' the shared pointers
> (see below)
>
> To do this I found and used boost template function specifically for
> shared pointers
>
>
> -- a data member of myclass inheritin from std::multiset
> -- TRow is the Value type of the multiset that implements 'serialize'
> method
> --
> --
> struct
> {
> template <typename Archive>
> void serialize (Archive& ar, const unsigned int version)const
> {
> for(tThisClassConstIterator it=this->begin();
> it!=this->end(); ++it)
> {
> boost::serialization::save<Archive,typename
> TRow>(ar,*it,version);
> }
>
> }
>
> tTEST_TB3
>
>
>
>
> now however I do not understand how to 'deserialize this'
>
> The basic call to
>
> void load_table (tTEST_TB3& t, const char * filename)
> {
> // open the archive
> std::ifstream ifs(filename);
> assert(ifs.good());
> boost::archive::xml_iarchive ia(ifs);
>
>
> ia >> BOOST_SERIALIZATION_NVP(t);
> }
>
>
> does not even compile, I suspect it is because
>
> when this 'serialize' function on tTEST_TB3 is called, now
> the
> boost::serialization::save<Archive,typename
> TRow>(ar,*it,version);
>
> is NOT valid, because the ar is of type iarchive, and save function
> on the shared_ptr is not defined for 'iarchive', only for oarchive.
>
> So there is another function in the same boost header file
> ( #include <boost/serialization/shared_ptr.hpp> )
> that defines a 'load' function for the shared ptr
>
> However -- what I do not undestand is how to invoke this function
>
> it seems like I have to iterate through every entry in the archive
> and then call load to read it into a shared ptr?
> That seems to be contrary to all the other mechanism supported by
> the Serialization library.
>
> The basic examples just say that I can take a container and just shift
> it in
> (or out) of Archiver -- but that does not work if the container is of
> shared pointers.
> That's why I went the route of iterating through every element of the
> container to
> serialize, and not do not undestand how to load it back.
>
>
>
> So I need some help
> (I can provide the complete example if needed)
>
>
>
> thank you in advance
>
>
>
>
> ----------
>
> <?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
> <!DOCTYPE boost_serialization>
> <boost_serialization signature="serialization::archive" version="5">
> <t class_id="0" tracking_level="0" version="0">
> <px class_id="1" tracking_level="1" version="0" object_id="_0">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_1">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_2">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_3">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_4">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_5">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_6">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_7">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_8">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> <px class_id_reference="1" object_id="_9">
> <otrq_prov_id>1245439719</otrq_prov_id>
> <clnt_dbid>1245439719</clnt_dbid>
> <mydate>6/19/2009 15:28:39</mydate>
> <amount>33222112121.212000</amount>
> </px>
> </t>
> </boost_serialization>
>
>
>
>
>
>
>
>
>
> --
> V S P
> toreason_at_[hidden]
>
> --
> http://www.fastmail.fm - Send your email first class
>
-- V S P toreason_at_[hidden] -- http://www.fastmail.fm - Does exactly what it says on the tin
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