/**Function********************************************************************
Synopsis [Computes the ITE of three ZDDs.]
Description [Computes the ITE of three ZDDs. Returns a pointer to the
result if successful; NULL otherwise.]
SideEffects [None]
SeeAlso []
******************************************************************************/
DdNode *
Cudd_zddIte(
DdManager * dd,
DdNode * f,
DdNode * g,
DdNode * h)
{
DdNode *res;
do {
dd->reordered = 0;
res = cuddZddIte(dd, f, g, h);
} while (dd->reordered == 1);
return(res);
} /* end of Cudd_zddIte */
/**
@brief Computes the ITE of three ZDDs.
@return a pointer to the result if successful; NULL otherwise.
@sideeffect None
*/
DdNode *
Cudd_zddIte(
DdManager * dd,
DdNode * f,
DdNode * g,
DdNode * h)
{
DdNode *res;
do {
dd->reordered = 0;
res = cuddZddIte(dd, f, g, h);
} while (dd->reordered == 1);
if (dd->errorCode == CUDD_TIMEOUT_EXPIRED && dd->timeoutHandler) {
dd->timeoutHandler(dd, dd->tohArg);
}
return(res);
} /* end of Cudd_zddIte */
/**Function********************************************************************
Synopsis [Performs the recursive step of Cudd_zddIte.]
Description []
SideEffects [None]
SeeAlso []
******************************************************************************/
DdNode *
cuddZddIte(
DdManager * dd,
DdNode * f,
DdNode * g,
DdNode * h)
{
DdNode *tautology, *empty;
DdNode *r,*Gv,*Gvn,*Hv,*Hvn,*t,*e;
unsigned int topf,topg,toph,v,top;
int index;
statLine(dd);
/* Trivial cases. */
/* One variable cases. */
if (f == (empty = DD_ZERO(dd))) { /* ITE(0,G,H) = H */
return(h);
}
topf = cuddIZ(dd,f->index);
topg = cuddIZ(dd,g->index);
toph = cuddIZ(dd,h->index);
v = ddMin(topg,toph);
top = ddMin(topf,v);
tautology = (top == CUDD_MAXINDEX) ? DD_ONE(dd) : dd->univ[top];
if (f == tautology) { /* ITE(1,G,H) = G */
return(g);
}
/* From now on, f is known to not be a constant. */
zddVarToConst(f,&g,&h,tautology,empty);
/* Check remaining one variable cases. */
if (g == h) { /* ITE(F,G,G) = G */
return(g);
}
if (g == tautology) { /* ITE(F,1,0) = F */
if (h == empty) return(f);
}
/* Check cache. */
r = cuddCacheLookupZdd(dd,DD_ZDD_ITE_TAG,f,g,h);
if (r != NULL) {
return(r);
}
/* Recompute these because they may have changed in zddVarToConst. */
topg = cuddIZ(dd,g->index);
toph = cuddIZ(dd,h->index);
v = ddMin(topg,toph);
if (topf < v) {
r = cuddZddIte(dd,cuddE(f),g,h);
if (r == NULL) return(NULL);
} else if (topf > v) {
if (topg > v) {
Gvn = g;
index = h->index;
} else {
Gvn = cuddE(g);
index = g->index;
}
if (toph > v) {
Hv = empty; Hvn = h;
} else {
Hv = cuddT(h); Hvn = cuddE(h);
}
e = cuddZddIte(dd,f,Gvn,Hvn);
if (e == NULL) return(NULL);
cuddRef(e);
r = cuddZddGetNode(dd,index,Hv,e);
if (r == NULL) {
Cudd_RecursiveDerefZdd(dd,e);
return(NULL);
}
cuddDeref(e);
} else {
index = f->index;
if (topg > v) {
Gv = empty; Gvn = g;
} else {
Gv = cuddT(g); Gvn = cuddE(g);
}
if (toph > v) {
Hv = empty; Hvn = h;
} else {
Hv = cuddT(h); Hvn = cuddE(h);
}
e = cuddZddIte(dd,cuddE(f),Gvn,Hvn);
if (e == NULL) return(NULL);
cuddRef(e);
t = cuddZddIte(dd,cuddT(f),Gv,Hv);
if (t == NULL) {
Cudd_RecursiveDerefZdd(dd,e);
return(NULL);
}
cuddRef(t);
r = cuddZddGetNode(dd,index,t,e);
if (r == NULL) {
Cudd_RecursiveDerefZdd(dd,e);
Cudd_RecursiveDerefZdd(dd,t);
return(NULL);
}
cuddDeref(t);
cuddDeref(e);
}
cuddCacheInsert(dd,DD_ZDD_ITE_TAG,f,g,h,r);
return(r);
} /* end of cuddZddIte */
