bool cellBoundaryCrossesGeoLoop()

in h3_polygon.c [180:232]
47 lines of code
14 McCabe index (conditional complexity)

bool cellBoundaryCrossesGeoLoop(const GeoLoop *geoloop, const BBox *loopBBox,
                                const CellBoundary *boundary,
                                const BBox *boundaryBBox) {
    if (!bboxOverlapsBBox(loopBBox, boundaryBBox)) {
        return false;
    }
    LongitudeNormalization loopNormalization;
    LongitudeNormalization boundaryNormalization;
    bboxNormalization(loopBBox, boundaryBBox, &loopNormalization,
                      &boundaryNormalization);

    CellBoundary normalBoundary = *boundary;
    for (int i = 0; i < boundary->numVerts; i++) {
        normalBoundary.verts[i].lng =
            normalizeLng(normalBoundary.verts[i].lng, boundaryNormalization);
    }

    BBox normalBoundaryBBox = {
        .north = boundaryBBox->north,
        .south = boundaryBBox->south,
        .east = normalizeLng(boundaryBBox->east, boundaryNormalization),
        .west = normalizeLng(boundaryBBox->west, boundaryNormalization)};

    LatLng loop1;
    LatLng loop2;
    for (int i = 0; i < geoloop->numVerts; i++) {
        loop1 = geoloop->verts[i];
        loop1.lng = normalizeLng(loop1.lng, loopNormalization);
        loop2 = geoloop->verts[(i + 1) % geoloop->numVerts];
        loop2.lng = normalizeLng(loop2.lng, loopNormalization);

        // Quick check if the line segment overlaps our bbox
        if ((loop1.lat >= normalBoundaryBBox.north &&
             loop2.lat >= normalBoundaryBBox.north) ||
            (loop1.lat <= normalBoundaryBBox.south &&
             loop2.lat <= normalBoundaryBBox.south) ||
            (loop1.lng <= normalBoundaryBBox.west &&
             loop2.lng <= normalBoundaryBBox.west) ||
            (loop1.lng >= normalBoundaryBBox.east &&
             loop2.lng >= normalBoundaryBBox.east)) {
            continue;
        }

        for (int j = 0; j < normalBoundary.numVerts; j++) {
            if (lineCrossesLine(
                    &loop1, &loop2, &normalBoundary.verts[j],
                    &normalBoundary.verts[(j + 1) % normalBoundary.numVerts])) {
                return true;
            }
        }
    }
    return false;
}