form an &quot;optimised&quot; copy.</p>

<p>In order to complete the implementation, what we need now is a
version of copy, that calls <code>copier&lt;true&gt;::do_copy</code>
if it is safe to use <font size="2" face="Courier New">memcpy</font>,
and otherwise calls <code>copier&lt;false&gt;::do_copy</code> to
do a &quot;generic&quot; copy. This is what the version in
listing 1 does. To understand how the code works look at the code
for <font size="2" face="Courier New">copy</font> and consider
first the two