def decodeMask(R):
        """
        Decode binary mask M encoded via run-length encoding.
        :param   R (object RLE)    : run-length encoding of binary mask
        :return: M (bool 2D array) : decoded binary mask
        """
        N = len(R['counts'])
        M = np.zeros( (R['size'][0]*R['size'][1], ))
        n = 0
        val = 1
        for pos in range(N):
            val = not val
            for c in range(R['counts'][pos]):
                R['counts'][pos]
                M[n] = val
                n += 1
        return M.reshape((R['size']), order='F')

        Decode binary mask M encoded via run-length encoding.
        :param   R (object RLE)    : run-length encoding of binary mask
        :return: M (bool 2D array) : decoded binary mask
        
lib/dataset/pycocotools/coco.py