// InputStream you can cut off at a certain byte
// (to test streaming input)
sclass SimulatedPartialInputStream {
  InputStream in;
  long position, cutOffPoint;
  
  *(InputStream *in) {}
  
  public int read() {
    if (position >= cutOffPoint) ret -1;
    in b = in.read();
    if (b >= 0) ++position;
    ret b;
  }
}