epending on the compression method.

            bits 0 to 3  CM     Compression method
            bits 4 to 7  CINFO  Compression info

      CM (Compression method)
         This identifies the compression method used in the file. CM = 8
         denotes the "deflate" compression method with a window size up
         to 32K.  This is the method used by gzip and PNG (see
         references [<a href="#ref-1" title="&quot;GZIP Compressed Data Format Specification&quot;">1</a>] and [<a href="#ref-2" title="