protected void readHeader(){
  String id="";
  for (int i=0; i < 6; i++) {
    id+=(char)read();
  }
  if (!id.startsWith("GIF")) {
    status=STATUS_FORMAT_ERROR;
    return;
  }
  readLSD();
  if (gctFlag && !err()) {
    gct=readColorTable(gctSize);
    bgColor=gct[bgIndex];
  }
}

protected void readHeader ( ) { String id = "" ; for ( int i = 0 ; i < 6 ; i ++ ) { id += ( char ) read ( ) ; } if ( ! id . startsWith ( "GIF" ) ) { status = STATUS_FORMAT_ERROR ; return ; } readLSD ( ) ; if ( gctFlag && ! err ( ) ) { gct = readColorTable ( gctSize ) ; bgColor = gct [ bgIndex ] ; } }
reads gif file header information .
