static void set_root_node(qrb_tree *tree_p, qrb_node *np)
{
tree_p->root = np;
if( np != NULL ){
np->parent = NULL;
MAKE_BLACK(np);
}
}
static
rbtree_node_t *
__tree_insert (rbtree_t *T, PyObject *k, PyObject *v)
{
rbtree_node_t *x = T->root;
rbtree_node_t *y = T->nil;
int rc = 0;
// Use the optimized function until we can't
if (!PyString_CheckExact(k)) {
T->cmp_func = rbtree_node_compare;
}
while (x != T->nil)
{
rc = COMPARE(T, k, x->key);
y = x;
if (rc == 0)
{
// force a value update
// XXX: (later) validate this?
Py_XDECREF(x->value);
x->value = v;
Py_INCREF(v);
return NULL;
}
if (rc < 0) x = x->l;
else x = x->r;
}
NEW(x, rbtree_node_t);
x->key = k;
x->value = v;
x->p = y;
x->l = T->nil;
x->r = T->nil;
MAKE_BLACK(x);
T->ct++;
if (y == T->nil)
{
T->root = x;
return x;
}
if (rc < 0)
{
y->l = x;
return x;
}
{
y->r = x;
return x;
}
}
int
rbtree_init (rbtree_t *T)
{
NEW(T->nil, rbtree_node_t);
memset(T->nil, 0, sizeof(rbtree_node_t));
MAKE_BLACK(T->nil);
T->nil->l = T->nil;
T->nil->r = T->nil;
T->nil->p = T->nil;
T->root = T->nil;
T->ct = 0;
T->cmp_func = rbtree_node_compare_string;
T->compare = Py_None;
Py_INCREF(Py_None);
return 0;
}
static
void
__rb_del_fix(rbtree_t *T, rbtree_node_t *x)
{
rbtree_node_t *w;
while ((x != T->root) && (COLOR(x) == BLACK))
{
if (x == x->p->l)
{
w = x->p->r;
if (COLOR(w) == RED)
{
MAKE_BLACK(w);
MAKE_RED (x->p);
__rotate_left(T, x->p);
w = x->p->r;
}
if ((COLOR(w->l) == BLACK) && (COLOR(w->r) == BLACK))
{
MAKE_RED(w);
x = x->p;
}
else
{
if (COLOR(w->r) == BLACK)
{
MAKE_BLACK(w->l);
MAKE_RED (w);
__rotate_right(T, w);
w = x->p->r;
}
w->color = COLOR(x->p);
MAKE_BLACK(x->p);
MAKE_BLACK(w->r);
__rotate_left(T, x->p);
x = T->root;
break;
}
}
else
{
w = x->p->l;
if (COLOR(w) == RED)
{
MAKE_BLACK(w);
MAKE_RED (x->p);
__rotate_right(T, x->p);
w = x->p->l;
}
if ((COLOR(w->l) == BLACK) && (COLOR(w->r) == BLACK))
{
MAKE_RED(w);
x = x->p;
}
else
{
if (COLOR(w->l) == BLACK)
{
MAKE_BLACK(w->r);
MAKE_RED (w);
__rotate_left(T, w);
w = x->p->l;
}
w->color = COLOR(x->p);
MAKE_BLACK(x->p);
MAKE_BLACK(w->l);
__rotate_right(T, x->p);
x = T->root;
break;
}
}
}
MAKE_BLACK(x);
}
static
void
__rb_insert (rbtree_t *T, PyObject *k, PyObject *v)
{
rbtree_node_t *x, *y;
Py_INCREF(k);
Py_INCREF(v);
x = __tree_insert(T, k, v);
if (x == NULL) {
return;
}
MAKE_RED (x);
while ((x != T->root) && (COLOR(x->p) == RED))
{
if (x->p == x->p->p->l)
{
y = x->p->p->r;
if (COLOR(y) == RED)
{
MAKE_BLACK(x->p);
MAKE_BLACK(y);
MAKE_RED (x->p->p);
x = x->p->p;
}
else
{
if (x == x->p->r)
{
x = x->p;
__rotate_left(T, x);
}
MAKE_BLACK(x->p);
MAKE_RED (x->p->p);
__rotate_right(T, x->p->p);
break;
}
}
else
{
y = x->p->p->l;
if (COLOR(y) == RED)
{
MAKE_BLACK(x->p);
MAKE_BLACK(y);
MAKE_RED (x->p->p);
x = x->p->p;
}
else
{
if (x == x->p->l)
{
x = x->p;
__rotate_right(T, x);
}
MAKE_BLACK(x->p);
MAKE_RED (x->p->p);
__rotate_left(T, x->p->p);
break;
}
}
}
MAKE_BLACK(T->root);
}
static void rb_delete(qrb_tree *tree_p, qrb_node *n_p )
{
qrb_node *c_p; // the single non-leaf child
qrb_node *parent;
tree_p->node_count --;
if( tree_p->node_count == 0 ){
assert( IS_ROOT_NODE(n_p) );
givbuf(n_p);
tree_p->root = NULL;
return;
}
if( n_p->left != NULL && n_p->right != NULL ){
//fprintf(stderr,"before calling binary_tree_delete:\n");
//dump_rb_node(n_p);
n_p = binary_tree_delete(n_p);
//fprintf(stderr,"after calling binary_tree_delete:\n");
//dump_rb_node(n_p);
} else if( IS_ROOT_NODE(n_p) ){
// we are deleting a root node with only one child
if( n_p->left != NULL ){
set_root_node(tree_p,n_p->left);
} else {
set_root_node(tree_p,n_p->right);
}
givbuf(n_p);
return;
}
assert( n_p->left == NULL || n_p->right == NULL );
if( n_p->left != NULL )
c_p = n_p->left;
else c_p = n_p->right; // may be NULL
// if c_p is null, then we need to keep a reference to the parent...
parent=n_p->parent;
replace_node(tree_p,n_p,c_p);
if( IS_RED(n_p) ){
givbuf(n_p);
return;
}
// Now we can free n_p
givbuf(n_p);
if( IS_RED(c_p) ){
MAKE_BLACK(c_p);
return;
}
// Now we know the node in question is black and has no red child
//assert( n_p->left != NULL && n_p->right != NULL );
// Now we know that both n_p and c_p are black
rebalance(tree_p,c_p,parent);
}
static void rebalance(qrb_tree *tree_p, qrb_node *n_p, qrb_node *parent)
{
qrb_node *s_p; // sibling
int c;
if( n_p != NULL && IS_ROOT_NODE(n_p) ) return; // wikipedia case 1
assert(parent!=NULL);
assert( IS_BLACK(n_p) );
s_p = sibling(n_p,parent); // we have to pass the parent because n_p may be NULL
if( IS_RED(s_p) ){ // wikipedia case 2 : sibling is red
MAKE_RED(/*n_p->*/parent);
MAKE_BLACK(s_p);
if( n_p == /*n_p->*/parent->left ){
rotate_left(tree_p,s_p);
} else {
rotate_right(tree_p,s_p);
}
//assert(n_p!=NULL);
s_p = sibling(n_p,parent); // has changed
}
if( IS_BLACK(s_p) ){
if( IS_BLACK(s_p->left) && IS_BLACK(s_p->right) ){
// sibling and its children are black
if( IS_BLACK(/*n_p->*/parent) ){
// wikipedia case 3 - make the sibling red
MAKE_RED(s_p);
rebalance(tree_p,/*n_p->*/parent,parent->parent);
return;
} else {
// wikipedia case 4
MAKE_BLACK(/*n_p->*/parent);
MAKE_RED(s_p);
return;
}
}
// remaining cases depend on which side S is on
if( s_p == /*n_p->*/ parent->right ){
// S on right - the case shown in wikipedia examples
if( IS_RED(s_p->left) && IS_BLACK(s_p->right) ){
// wikipedia case 5
assert( IS_BLACK(s_p->right) );
rotate_right(tree_p,s_p->left);
MAKE_RED(s_p);
MAKE_BLACK(s_p->parent); // used to be s_p->left
// N's sibling has changed
s_p = sibling(n_p,parent);
// goto case 6
}
} else {
// sibling is left child - mirror case
if( IS_RED(s_p->right) && IS_BLACK(s_p->left) ){
// wikipedia case 5
assert( IS_BLACK(s_p->left) );
rotate_left(tree_p,s_p->right);
MAKE_RED(s_p);
MAKE_BLACK(s_p->parent); // used to be s_p->left
// N's sibling has changed
s_p = sibling(n_p,parent);
// goto case 6
}
}
// fall-through to case 6
if( s_p == /*n_p->*/parent->right ){
// case 6 illustrated on wikipedia
assert( IS_RED(s_p->right) );
rotate_left(tree_p,s_p);
// exchange colors - s_p is now the parent and the old parent is now its left child
c = s_p->color;
s_p->color = s_p->left->color;
s_p->left->color = c;
MAKE_BLACK(s_p->right);
} else {
// case 6, mirror condition
assert( IS_RED(s_p->left) );
rotate_right(tree_p,s_p);
// exchange colors - s_p is now the parent and the old parent is now its left child
c = s_p->color;
s_p->color = s_p->right->color;
s_p->right->color = c;
MAKE_BLACK(s_p->left);
}
}
}
qrb_node * _rb_insert_item(QSP_ARG_DECL qrb_tree* tree_p, Item *ip )
{
qrb_node * x_p;
qrb_node * new_node_p;
qrb_node * gp_p; // grandparent
qrb_node * u_p; // uncle
new_node_p = (qrb_node*) getbuf(sizeof(qrb_node));
// new_node_p->key = key;
new_node_p->data = ip;
new_node_p->left = NULL;
new_node_p->right = NULL;
MAKE_RED(new_node_p);
binary_tree_insert(tree_p,new_node_p);
x_p = new_node_p;
while( 1 ){
if( IS_ROOT_NODE(x_p) ){ // wikipedia case 1
MAKE_BLACK(x_p);
return new_node_p;
}
if( IS_BLACK(x_p->parent) ){ // wikipedia case 2
return new_node_p;
}
gp_p = grandparent(x_p);
assert( gp_p != NULL );
u_p = uncle(x_p);
// We know the parent is red
if( IS_RED(u_p) ){ // wikipedia case 3
MAKE_BLACK(x_p->parent);
MAKE_BLACK(u_p);
MAKE_RED(gp_p);
x_p = gp_p; // loop on grandparent
} else {
// uncle is black
if( x_p == x_p->parent->left && x_p->parent == gp_p->left ){
// wikipedia case 5, left child of a left child
rotate_right(tree_p,x_p->parent);
MAKE_BLACK(x_p->parent);
// new uncle is old grandparent
MAKE_RED(gp_p);
return new_node_p;
} else if( x_p == x_p->parent->right && x_p->parent == gp_p->right ){
// wikipedia case 5 mirror image
rotate_left(tree_p,x_p->parent);
MAKE_BLACK(x_p->parent);
// new uncle is old grandparent
MAKE_RED(gp_p);
return new_node_p;
} else {
// wikipedia case 4
if( x_p == x_p->parent->right ){
// right child of left child
rotate_left(tree_p,x_p);
x_p = x_p->left;
} else {
// left child of right child
rotate_right(tree_p,x_p);
x_p = x_p->right;
}
}
}
} // end tail recursion loop
//MAKE_BLACK( RB_TREE_ROOT(tree) );
// NOTREACHED ???
/*
tree_p->node_count ++;
return new_node_p;
*/
} // rb_insert
