static void copy(
this_type const & from,
this_type & to,
uint64_t const blockid,
uint64_t const numblocks
)
{
uint64_t const blocksize = (from.H.size()+numblocks-1) / numblocks;
uint64_t const idlow = blockid*blocksize;
uint64_t const idhigh = std::min(idlow+blocksize,from.H.size());
for ( uint64_t i = idlow; i < idhigh; ++i )
if ( from.H[i].first != base_type::unused() )
to.insert(from.H[i].first,from.H[i].second);
}
