private void  CheckReadBytes(IndexInput input, int size, int pos)
		{
			// Just to see that "offset" is treated properly in readBytes(), we
			// add an arbitrary offset at the beginning of the array
			int offset = size % 10; // arbitrary
			buffer = ArrayUtil.Grow(buffer, offset + size);
			Assert.AreEqual(pos, input.GetFilePointer());
			long left = TEST_FILE_LENGTH - input.GetFilePointer();
			if (left <= 0)
			{
				return ;
			}
			else if (left < size)
			{
				size = (int) left;
			}
			input.ReadBytes(buffer, offset, size);
			Assert.AreEqual(pos + size, input.GetFilePointer());
			for (int i = 0; i < size; i++)
			{
				Assert.AreEqual(Byten(pos + i), buffer[offset + i], "pos=" + i + " filepos=" + (pos + i));
			}
		}