static void recolor(JRB n)
{
JRB p, gp, s;
int done = 0;
while (!done) {
if (isroot(n)) {
setblack(n);
return;
}
p = n->parent;
if (isblack(p))
return;
if (isroot(p)) {
setblack(p);
return;
}
gp = p->parent;
s = sibling(p);
if (isred(s)) {
setblack(p);
setred(gp);
setblack(s);
n = gp;
}
else {
done = 1;
}
}
/* p's sibling is black, p is red, gp is black */
if ((isleft(n) == 0) == (isleft(p) == 0)) {
single_rotate(gp, isleft(n));
setblack(p);
setred(gp);
}
else {
single_rotate(p, isleft(n));
single_rotate(gp, isleft(n));
setblack(n);
setred(gp);
}
}
void jrb_delete_node(JRB n)
{
JRB s, p, gp;
char ir;
if (isint(n)) {
fprintf(stderr, "Cannot delete an internal node: 0x%p\n", (void *)n);
exit(1);
}
if (ishead(n)) {
fprintf(stderr, "Cannot delete the head of an jrb_tree: 0x%p\n", (void *)n);
exit(1);
}
delete_item(n); /* Delete it from the list */
p = n->parent; /* The only node */
if (isroot(n)) {
p->parent = p;
free(n);
return;
}
s = sibling(n); /* The only node after deletion */
if (isroot(p)) {
s->parent = p->parent;
s->parent->parent = s;
setroot(s);
free(p);
free(n);
return;
}
gp = p->parent; /* Set parent to sibling */
s->parent = gp;
if (isleft(p)) {
gp->flink = s;
setleft(s);
} else {
gp->blink = s;
setright(s);
}
ir = isred(p);
free(p);
free(n);
if (isext(s)) { /* Update proper rext and lext values */
p = lprev(s);
if (!ishead(p)) setrext(p, s);
p = rprev(s);
if (!ishead(p)) setlext(p, s);
} else if (isblack(s)) {
fprintf(stderr, "DELETION PROB -- sib is black, internal\n");
exit(1);
} else {
p = lprev(s);
if (!ishead(p)) setrext(p, s->flink);
p = rprev(s);
if (!ishead(p)) setlext(p, s->blink);
setblack(s);
return;
}
if (ir) return;
/* Recolor */
n = s;
p = n->parent;
s = sibling(n);
while(isblack(p) && isblack(s) && isint(s) &&
isblack(s->flink) && isblack(s->blink)) {
setred(s);
n = p;
if (isroot(n)) return;
p = n->parent;
s = sibling(n);
}
if (isblack(p) && isred(s)) { /* Rotation 2.3b */
single_rotate(p, isright(n));
setred(p);
setblack(s);
s = sibling(n);
}
{ JRB x, z; char il;
if (isext(s)) {
fprintf(stderr, "DELETION ERROR: sibling not internal\n");
exit(1);
}
il = isleft(n);
x = il ? s->flink : s->blink ;
z = sibling(x);
if (isred(z)) { /* Rotation 2.3f */
single_rotate(p, !il);
setblack(z);
if (isred(p)) setred(s); else setblack(s);
setblack(p);
} else if (isblack(x)) { /* Recoloring only (2.3c) */
if (isred(s) || isblack(p)) {
fprintf(stderr, "DELETION ERROR: 2.3c not quite right\n");
exit(1);
}
setblack(p);
setred(s);
return;
} else if (isred(p)) { /* 2.3d */
single_rotate(s, il);
single_rotate(p, !il);
setblack(x);
setred(s);
return;
} else { /* 2.3e */
single_rotate(s, il);
single_rotate(p, !il);
setblack(x);
return;
}
}
}
