Re: [Boost-users] Serialization and raw pointer arrays

From: Jeff Flinn (TriumphSprint2000_at_[hidden])
Date: 2007-10-30 08:18:55

Hi Eric,

See inline below, which compiles for me.

Eric wrote:
> Hi,
> I've inherited some complex math code that makes large usage of Matrices 
> based on raw pointer arrays.  I need to serialize/deserialize these arrays 
> as is and am looking to use boost::serialization package.  My attempt at 
> doing so results in the following errors (mostly about non integral array 
> size).  As I do not know the array size when it is created (and lots of code 
> accesses the pointer directly as a chunk of memory that has been allocated, 
> what are my options to get this to work?

I'm not sure what you're saying here, but to get your code to compile 
see the inline addition/changes below

> Errors:
> /usr/include/boost/archive/detail/oserializer.hpp: In function `void 
> boost::archive::save(Archive&, T&) [with Archive = 
> boost::archive::text_oarchive, T = Dummy]':
> /usr/include/boost/archive/basic_text_oarchive.hpp:78:   instantiated from 
> `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) 
> [with T = Dummy, Archive = boost::archive::text_oarchive]'
> /usr/include/boost/archive/detail/interface_oarchive.hpp:78:   instantiated 
> from `Archive& 
> boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T 
> = Dummy, Archive = boost::archive::text_oarchive]'
> serialize_array.cpp:56:   instantiated from here
> /usr/include/boost/archive/detail/oserializer.hpp:567: error: incomplete 
> type `boost::STATIC_ASSERTION_FAILURE< false>' used in nested name specifier
> /usr/include/boost/archive/detail/oserializer.hpp:567: error: size of array 
> has non-integral type `<type error>'
> 
> 
> Code:
> #include <boost/serialization/split_member.hpp>
> #include <fstream>
> #include <iostream>
> 
> #include <boost/archive/text_oarchive.hpp>
> #include <boost/archive/text_iarchive.hpp>
> using namespace std;
> 
> class Dummy
> {

    BOOST_SERIALIZATION_SPLIT_MEMBER()

> public:
>     friend class boost::serialization::access;
> 
>     Dummy() {pVal=NULL;size=0;}
>     ~Dummy() {delete [] pVal;}
> 
>     template<class Archive>
>     void save(Archive & ar, const unsigned int version) const
>     {
>         ar & size;
>         for (int i=0; i<size; i++)
>         {
>             ar & pVal[i];
>         }
>     }
> 
>     template<class Archive>
>     void load(Archive & ar, const unsigned int version)
>     {
>         ar & size;
>         pVal = new int[size];
>         for (int i=0; i<size; i++)
>         {
>             ar & pVal[i];
>         }
>     }
> 
>     int* pVal;
>     int size;
> };
> BOOST_CLASS_VERSION(Dummy, 1)
> 
> int main(int argc, char** argv)
> {
>     Dummy d;
>     d.size = 5;
>     d.pVal = new int[d.size];
>     for (int i=0; i< d.size; i++)
>     {
>         d.pVal[i] = i+10;
>     }
> 
>     ofstream ofOut("testSer.txt");
>     {
>         boost::archive::text_oarchive oa(ofOut);
>         oa << d;

This is the 'const' problem many run into. Robert should really add this 
as a FAQ entry! I've found two options available:

        oa & d;

or

        oa << const_cast<const Dummy&>(d);

>     }
> 
>     Dummy load;
>     {
>         ifstream ifIn("testSer.txt");
>         boost::archive::text_iarchive ia(ifIn);
>         ia >> load;
>     }
>     cout << "size="<<load.size<<endl;
> 
>     for (int i=0; i< load.size; i++)
>     {
>         cout << load.pVal[i] <<endl;
>     }
> 
>     return -1;
> }
> 
> Thanks,
> Eric 

Jeff Flinn