public static byte[] swapInts(byte b[], int off, int len) {
        checkLength(len, 4);
        for (int i = off, n = off + len; i < n; i += 4) {
            swap(b, i, i+3);
            swap(b, i+1, i+2);
        }
        return b;
    }
@Test
    public void testSwapInts() {
        assertArrayEquals(FLOAT_PI_LE ,
                ByteUtils.swapInts(FLOAT_PI_BE.clone(), 0,
                        FLOAT_PI_BE.length));
    }