Direction directionForVertexNum()

in h3_vertex.c [173:192]

• 15 lines of code
• 6 McCabe index (conditional complexity)

Direction directionForVertexNum(const H3Index origin, const int vertexNum) {
    int isPent = H3_EXPORT(isPentagon)(origin);
    // Check for invalid vertexes
    if (vertexNum < 0 ||
        vertexNum > (isPent ? NUM_PENT_VERTS : NUM_HEX_VERTS) - 1)
        return INVALID_DIGIT;

    // Determine the vertex rotations for this cell
    int rotations;
    H3Error err = vertexRotations(origin, &rotations);
    if (err) {
        return INVALID_DIGIT;
    }

    // Find the appropriate direction, rotating CW if necessary
    return isPent ? vertexNumToDirectionPent[(vertexNum + rotations) %
                                             NUM_PENT_VERTS]
                  : vertexNumToDirectionHex[(vertexNum + rotations) %
                                            NUM_HEX_VERTS];
}