int _IsolateOuterplanarityObstructionE3orE4(graphP theGraph)
{
isolatorContextP IC = &theGraph->IC;
int u, d, XorY;
/* Minor E3 */
if (FUTUREPERTINENT(theGraph, theGraph->IC.x, theGraph->IC.v) ||
FUTUREPERTINENT(theGraph, theGraph->IC.y, theGraph->IC.v))
{
if (_MarkHighestXYPath(theGraph) != TRUE)
return NOTOK;
if (FUTUREPERTINENT(theGraph, theGraph->IC.x, theGraph->IC.v))
XorY = theGraph->IC.x;
else XorY = theGraph->IC.y;
/* The cases of X externally active and Y externally active
are the same except for the bicomp external face marking
(because parameter order is important) */
if (XorY == theGraph->IC.x)
{
if (_MarkPathAlongBicompExtFace(theGraph, IC->x, IC->w) != OK ||
_MarkPathAlongBicompExtFace(theGraph, IC->y, IC->r) != OK)
return NOTOK;
}
else
{
if (_MarkPathAlongBicompExtFace(theGraph, IC->r, IC->x) != OK ||
_MarkPathAlongBicompExtFace(theGraph, IC->w, IC->y) != OK)
return NOTOK;
}
if (_FindUnembeddedEdgeToCurVertex(theGraph, IC->w, &IC->dw) != TRUE)
return NOTOK;
if (_FindUnembeddedEdgeToAncestor(theGraph, XorY, &u, &d) != TRUE)
return NOTOK;
if (theGraph->functions.fpMarkDFSPath(theGraph, u, IC->v) != OK ||
theGraph->functions.fpMarkDFSPath(theGraph, XorY, d) != OK ||
theGraph->functions.fpMarkDFSPath(theGraph, IC->w, IC->dw) != OK ||
_JoinBicomps(theGraph) != OK ||
_AddAndMarkEdge(theGraph, u, d) != OK ||
_AddAndMarkEdge(theGraph, IC->v, IC->dw) != OK)
return NOTOK;
return OK;
}
/* Otherwise, isolate Minor E4 (reduce to minor A) */
if (_FindUnembeddedEdgeToAncestor(theGraph, IC->w, &u, &d) != TRUE)
return NOTOK;
IC->v = u;
IC->dw = d;
return _IsolateOuterplanarityObstructionA(theGraph);
}
int _AddAndMarkUnembeddedEdges(graphP theGraph)
{
isolatorContextP IC = &theGraph->IC;
if (_AddAndMarkEdge(theGraph, IC->ux, IC->dx) != OK ||
_AddAndMarkEdge(theGraph, IC->uy, IC->dy) != OK)
return NOTOK;
if (IC->dw != NIL)
if (_AddAndMarkEdge(theGraph, IC->v, IC->dw) != OK)
return NOTOK;
if (IC->dz != NIL)
if (_AddAndMarkEdge(theGraph, IC->uz, IC->dz) != OK)
return NOTOK;
return OK;
}
int _IsolateOuterplanarityObstructionE(graphP theGraph)
{
isolatorContextP IC = &theGraph->IC;
if (_MarkPathAlongBicompExtFace(theGraph, IC->r, IC->r) != OK ||
theGraph->functions.fpMarkDFSPath(theGraph, IC->w, IC->dw) != OK ||
_JoinBicomps(theGraph) != OK ||
_AddAndMarkEdge(theGraph, IC->v, IC->dw) != OK)
return NOTOK;
return OK;
}
int _IsolateOuterplanarityObstructionE1orE2(graphP theGraph)
{
isolatorContextP IC = &theGraph->IC;
int XPrevLink = 1;
if (_MarkHighestXYPath(theGraph) != TRUE)
return NOTOK;
/* Isolate E1 */
if (theGraph->IC.px != theGraph->IC.x)
{
if (_MarkPathAlongBicompExtFace(theGraph, IC->r, IC->w) != OK ||
_MarkPathAlongBicompExtFace(theGraph, IC->py, IC->r) != OK)
return NOTOK;
}
else if (theGraph->IC.py != theGraph->IC.y)
{
if (_MarkPathAlongBicompExtFace(theGraph, IC->r, IC->x) != OK ||
_MarkPathAlongBicompExtFace(theGraph, IC->w, IC->r) != OK)
return NOTOK;
}
/* Isolate E2 */
else if (IC->w != _GetNextVertexOnExternalFace(theGraph, IC->x, &XPrevLink))
{
if (_MarkPathAlongBicompExtFace(theGraph, IC->r, IC->y) != OK)
return NOTOK;
}
else
{
if (_MarkPathAlongBicompExtFace(theGraph, IC->x, IC->r) != OK)
return NOTOK;
}
/* Final bits are in common */
if (_FindUnembeddedEdgeToCurVertex(theGraph, IC->w, &IC->dw) != TRUE ||
theGraph->functions.fpMarkDFSPath(theGraph, IC->w, IC->dw) != OK ||
_JoinBicomps(theGraph) != OK ||
_AddAndMarkEdge(theGraph, IC->v, IC->dw) != OK)
return NOTOK;
return OK;
}
