to those bytes is put into <tt>next_in</tt>.  We also
check to see if end-of-file on the input has been reached.  If we are at the end of file, then <tt>flush</tt> is set to the
<em>zlib</em> constant <tt>Z_FINISH</tt>, which is later passed to <tt>deflate()</tt> to
indicate that this is the last chunk of input data to compress.  We need to use <tt>feof()</tt>
to check for end-of-file as opposed to seeing if fewer than <tt>CHUNK</tt> bytes have been read.  The
reason is that if the input file length is an e