[Boost-users] [Serialization] Serializing to a void * and a size?

From: Baranowski, Daniel (dbaranowski_at_[hidden])
Date: 2006-10-11 14:05:39

I've been tasked with creating a set of objects that will need to be
passed off to some other function as raw data in the form of a void *
and a size. Eventually, this goes through some networking code and
through the process of magic, shows up on another computer and has to be
reassembled. 

So, to avoid being limited to simple structs where I could just cast it
to a void * and get the sizeof(), I was thinking about using the
serialization library.

The examples are all very good and have helped me understand how to
serialize to a file, and I even saw an example for using serializing
with asio (which I wish I could use). Unfortunately, I don't have
control over the networking and can't use the asio library.

I guess my questions is, what's the best way to serialize to a void *
and a size? I'm pretty illiterate on streams, so I've started to read up
on it, but I haven't figured it out yet, though I feel that's probably
where the answer lies.

Here's a test program that compiles, but obviously doesn't work:
#include <sstream>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>

// A very simple test class with some data in it
class A
{
private:
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & ar, const unsigned int /* file_version */){
        ar & x;
    }
public:
    A::A(){ x = 0; }    // default constructor
    int x;
    virtual A::~A(){}   // default destructor
};

int main(int argc, char *argv[])
{
   // Create an object on the heap
   A * pA = new A;
   pA->x = 1234567890;

   // serialize it
   std::ostringstream sTestBinary1;
   boost::archive::binary_oarchive oa(sTestBinary1);
   oa << *pA;

   // Get the size of the buffer and a pointer to it
   size_t iSize = 0;//sTestBinary1.size(); // ?? How do I get the size
??
   void * pVoid = sTestBinary1.rdbuf(); // ?? Is this the right pointer
??

   // .. Magic occurs here (gets sent across the network as the raw
data)

   // Create a stream to read from
   std::istringstream sTestBinary2;
   sTestBinary2.read((char *)pVoid, iSize);

   // open the archive
   boost::archive::binary_iarchive ia(sTestBinary2);

   // restore the object from the archive
   A * pB = new A;   // pB->x equals 0 now
   ia >> *pB;

   // Make sure the objects contain the same data
   assert(pA->x == pB->x);
   return 0;
}

Thanks for any help,
Daniel
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