cdm/src/main/java/ucar/nc2/iosp/misc/Uspln.java
private boolean checkFormat() throws IOException {

    raf.seek(0);
    boolean extended = false;
    while (true) {
      long offset = raf.getFilePointer();
      String line = raf.readLine();
      if (line == null) {
        break;
      }
      if (pMAGIC.matcher(line).find() || pMAGIC_OLD.matcher(line).find()) {
        extended = pMAGIC_EX.matcher(line).find();
        break;
      }
    }
    return extended;
  }
private boolean checkFormat() throws IOException {

    raf.seek(0);
    boolean extended = false;
    while (true) {
      long offset = raf.getFilePointer();
      String line = raf.readLine();
      if (line == null) {
        break;
      }
      if (pMAGIC.matcher(line).find() || pMAGIC_OLD.matcher(line).find()) {
        extended = pMAGIC_EX.matcher(line).find();
        break;
      }
    }
    return extended;
  }
Read all the data and return the number of strokes

@return true if extended format
@throws IOException if read error