Review

14

sos/mrtd/PassportFileService.java

readFile(short)

class PassportFileService {
   /**
    * Reads the file with id <code>fid</code>.
    *
    * @param fid the file to read.
    *
    * @return the contents of the file.
    */
   public byte[] readFile(short fid) throws IOException {
      /* Was this file read previously? */
      Short fidKey = new Short(fid);
      if (files.containsKey(fidKey)) {
         return (byte[])files.get(fidKey);
      }
      /* No? Read it from document... */
      SecureMessagingWrapper wrapper = getWrapper();
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      service.sendSelectFile(wrapper, fid);
      int offset = 0;
      while (true) {
         byte[] data = service.sendReadBinary(wrapper, (short)offset, 255);
         if (data.length == 0) {
            // TODO: also break out of loop if SW indicates EOF
            break;
         }
         out.write(data, 0, data.length);
         offset += data.length;
      }
      byte[] file = out.toByteArray();
      files.put(fidKey, file);
      return file;
   }

}