code: public static long block_unsafe(GrayS64 integral , int x0 , int y0 , int x1 , int y1 )
  	{
  		return ImplIntegralImageOps.block_unsafe(integral, x0, y0, x1, y1);
  	}
docs: <p>
  Computes the value of a block inside an integral image without bounds checking.  The block is
  defined as follows: x0 &lt; x &le; x1 and y0 &lt; y &le; y1.
  </p>
  
  @param integral Integral image.
  @param x0 Lower bound of the block.  Exclusive.
  @param y0 Lower bound of the block.  Exclusive.
  @param x1 Upper bound of the block.  Inclusive.
  @param y1 Upper bound of the block.  Inclusive.
  @return Value inside the block.