Method stepToEdge

czxing/src/main/cpp/zxing/src/BitMatrixCursor.h:114–131

* @brief stepToEdge advances cursor to one step behind the next (or n-th) edge. * @param nth number of edges to pass * @param range max number of steps to take * @param backup whether or not to backup one step so we land in front of the edge * @return number of steps taken or 0 if moved outside of range/image */

	 * @return number of steps taken or 0 if moved outside of range/image
	 */
	int stepToEdge(int nth = 1, int range = 0, bool backup = false)
	{
		int steps = 0;
		auto lv = testAt(p);

		while (nth && (!range || steps < range) && lv.isValid()) {
			++steps;
			auto v = testAt(p + steps * d);
			if (lv != v) {
				lv = v;
				--nth;
			}
		}
		if (backup)
			--steps;
		p += steps * d;
		return steps * (nth == 0);
	}

	bool stepAlongEdge(Direction dir, bool skipCorner = false)
	{