int vertexNumForDirection()

in h3_vertex.c [128:152]

• 20 lines of code
• 7 McCabe index (conditional complexity)

int vertexNumForDirection(const H3Index origin, const Direction direction) {
    int isPent = H3_EXPORT(isPentagon)(origin);
    // Check for invalid directions
    if (direction == CENTER_DIGIT || direction >= INVALID_DIGIT ||
        (isPent && direction == K_AXES_DIGIT))
        return INVALID_VERTEX_NUM;

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

    // Find the appropriate vertex, rotating CCW if necessary
    if (isPent) {
        return (directionToVertexNumPent[direction] + NUM_PENT_VERTS -
                rotations) %
               NUM_PENT_VERTS;
    } else {
        return (directionToVertexNumHex[direction] + NUM_HEX_VERTS -
                rotations) %
               NUM_HEX_VERTS;
    }
}