efficient way to copy composite types

[mop65715]

I'm perusing code that is structured around - presumably a bridge design. There's performance concerns surround the store functions that store composite types which contains POD types. So consider:

# include <iostream>
# include <iomanip>

struct foo {
 int x ; 
 int y ;
 // more stuff
};

struct bar {
  foo f;
  void store ( const foo& in ) 
  { f = in; }
};

int main() 
{
  foo f ;
  bar b; 
  b.store ( f ) ;
}

For starters, there was a discussion about using std::swap to copy the structs ( though admittedly I'm not following how) or memcpy. While I haven't had a chance to benchmark a memcpy version, I question what this will 'buy' me. Thoughts/suggestions

Thanks in advance