237     VertexList() : fHead(nullptr), fTail(nullptr) {}  in VertexList()
238     VertexList(Vertex* head, Vertex* tail) : fHead(head), fTail(tail) {}  in VertexList()
240     Vertex* fTail;  member
242         list_insert<Vertex, &Vertex::fPrev, &Vertex::fNext>(v, prev, next, &fHead, &fTail);  in insert()
245         insert(v, fTail, nullptr);  in append()
251         if (fTail) {  in append()
252             fTail->fNext = list.fHead;  in append()
253             list.fHead->fPrev = fTail;  in append()
257         fTail = list.fTail;  in append()
263         list_remove<Vertex, &Vertex::fPrev, &Vertex::fNext>(v, &fHead, &fTail);  in remove()
266         if (fHead && fTail) {  in close()
267             fTail->fNext = fHead;  in close()
268             fHead->fPrev = fTail;  in close()
424     EdgeList() : fHead(nullptr), fTail(nullptr) {}  in EdgeList()
426     Edge* fTail;  member
428         list_insert<Edge, &Edge::fLeft, &Edge::fRight>(edge, prev, next, &fHead, &fTail);  in insert()
431         insert(e, fTail, nullptr);  in append()
434         list_remove<Edge, &Edge::fLeft, &Edge::fRight>(edge, &fHead, &fTail);  in remove()
442         if (fHead && fTail) {  in close()
443             fTail->fRight = fHead;  in close()
444             fHead->fLeft = fTail;  in close()
459         , fTail(nullptr)  in Poly()
516             while (v != vertices.fTail) {  in emit()
562         if (!fTail) {  in addEdge()
563             fHead = fTail = alloc.make<MonotonePoly>(e, side);  in addEdge()
565         } else if (e->fBottom == fTail->fLastEdge->fBottom) {  in addEdge()
567         } else if (side == fTail->fSide) {  in addEdge()
568             fTail->addEdge(e);  in addEdge()
571             e = alloc.make<Edge>(fTail->fLastEdge->fBottom, e->fBottom, 1, Edge::Type::kInner);  in addEdge()
572             fTail->addEdge(e);  in addEdge()
579                 m->fPrev = fTail;  in addEdge()
580                 fTail->fNext = m;  in addEdge()
581                 fTail = m;  in addEdge()
596     Vertex* lastVertex() const { return fTail ? fTail->fLastEdge->fBottom : fFirstVertex; }  in lastVertex()
600     MonotonePoly* fTail;  member
798     for (prev = edges->fTail; prev != nullptr; prev = prev->fLeft) {  in find_enclosing_edges()
1132         Vertex* prev = contour->fTail;  in sanitize_contours()
1170         Vertex* prev = contour->fTail;  in build_edges()
1239     VertexList back(slow->fNext, vertices->fTail);  in merge_sort()
1240     front.fTail->fNext = back.fHead->fPrev = nullptr;  in merge_sort()
1245     vertices->fHead = vertices->fTail = nullptr;  in merge_sort()
1417                         if (leftPoly->fTail && leftPoly->fTail->fSide == Poly::kLeft_Side) {  in tessellate()
1504     Edge* prevEdge = boundary->fTail;  in simplify_boundary()
1523                 prevEdge = boundary->fTail;  in simplify_boundary()
1559     Edge* prevEdge = boundary->fTail;  in stroke_boundary()
1581             fix_inversions(innerVertices.fTail, innerVertex, prevBisector, bisector, prevEdge, c);  in stroke_boundary()
1582             fix_inversions(outerVertices.fTail, outerVertex, prevBisector, bisector, prevEdge, c);  in stroke_boundary()
1601     fix_inversions(innerVertices.fTail, innerVertices.fHead, prevBisector, bisector, prevEdge, c);  in stroke_boundary()
1602     fix_inversions(outerVertices.fTail, outerVertices.fHead, prevBisector, bisector, prevEdge, c);  in stroke_boundary()
1603     Vertex* prevInnerVertex = innerVertices.fTail;  in stroke_boundary()
1604     Vertex* prevOuterVertex = outerVertices.fTail;  in stroke_boundary()
1725             outerMesh->fHead = outerMesh->fTail = nullptr;  in contours_to_polys()