static byte[] loadBinaryFileChunk(File f, long start, int l) ctex {
  byte[] buf = new byte[l];
  RandomAccessFile raf = new RandomAccessFile(f, "r");
  try {
    raf.seek(start);
    raf.readFully(buf);
    ret buf;
  } finally {
    raf.close();
  }
}

ifclass LongRange
static byte[] loadBinaryFileChunk(File f, LongRange r) {
  ret loadBinaryFileChunk(f, r.start, toInt_checked(r.length()));
}
endif