protected void fill() throws IOException {
  checkClosed();
  if ((len=in.read(buf)) > 0) {
    inf.setInput(buf,0,len);
  }
}

protected void fill ( ) throws IOException { checkClosed ( ) ; if ( ( len = in . read ( buf ) ) > 0 ) { inf . setInput ( buf , 0 , len ) ; } }
fills the input buffer with data to be decompressed .
