code: private static byte[] byteCopy(byte[] source, int offset,
  				   int count, byte[] target) {
  	for (int i = offset, j = 0; i < offset + count; i++, j++) {
  	    target[j] = source[i];
  	}
  	return target;
      }
docs: Copies count elements from source, starting at element with
  index offset, to the given target.
  @param source the source.
  @param offset the offset.
  @param count the number of elements to be copied.
  @param target the target to be returned.
  @return the target being copied to.