/**
* This creates a new node in the AVL then returns the created node
* so that you might populate it with data. If the key already
* exists, then the existing node is returned.
*
* @param avl the AVL to add a property to.
* @param key the key to add to the AVL.
*
* @return the newly created AVL node.
*/
PropPtr
new_prop(PropPtr *avl, char *key)
{
PropPtr ret;
register PropPtr p = *avl;
register int cmp;
static short balancep;
if (p) {
cmp = strcasecmp(key, PropName(p));
if (cmp > 0) {
ret = new_prop(&(p->right), key);
} else if (cmp < 0) {
ret = new_prop(&(p->left), key);
} else {
balancep = 0;
return (p);
}
if (balancep) {
*avl = balance_node(p);
}
return ret;
} else {
p = *avl = alloc_propnode(key);
balancep = 1;
return (p);
}
}
static PropPtr
remove_propnode(char *key, PropPtr * root)
{
PropPtr save;
PropPtr tmp;
PropPtr avl = *root;
int cmpval;
save = avl;
if (avl) {
cmpval = Comparator(key, PropName(avl));
if (cmpval < 0) {
save = remove_propnode(key, &AVL_LF(avl));
} else if (cmpval > 0) {
save = remove_propnode(key, &AVL_RT(avl));
} else if (!(AVL_LF(avl))) {
avl = AVL_RT(avl);
} else if (!(AVL_RT(avl))) {
avl = AVL_LF(avl);
} else {
tmp = remove_propnode(PropName(getmax(AVL_LF(avl))), &AVL_LF(avl));
if (!tmp)
abort(); /* this shouldn't be possible. */
AVL_LF(tmp) = AVL_LF(avl);
AVL_RT(tmp) = AVL_RT(avl);
avl = tmp;
}
if (save) {
AVL_LF(save) = NULL;
AVL_RT(save) = NULL;
}
*root = balance_node(avl);
}
return save;
}
static PropPtr
insert(char *key, PropPtr * avl)
{
PropPtr ret;
register PropPtr p = *avl;
register int cmp;
static short balancep;
if (p) {
cmp = Comparator(key, PropName(p));
if (cmp > 0) {
ret = insert(key, &(AVL_RT(p)));
} else if (cmp < 0) {
ret = insert(key, &(AVL_LF(p)));
} else {
balancep = 0;
return (p);
}
if (balancep) {
*avl = balance_node(p);
}
return ret;
} else {
p = *avl = alloc_propnode(key);
balancep = 1;
return (p);
}
}
/**
* Remove a propnode named 'key' from the AVL root 'root'. This function
* is recursive.
*
* The node (removed from the AVL structure) is returned, or NULL if it
* was not found.
*
* @private
* @param key the prop name to remove
* @param root the root node to start the removal process from
*
* @return the removed node - you should probably free it with free_propnode
*/
static PropPtr
remove_propnode(char *key, PropPtr * root)
{
PropPtr save;
PropPtr tmp;
PropPtr avl = *root;
int cmpval;
save = avl;
if (avl) {
cmpval = strcasecmp(key, PropName(avl));
if (cmpval < 0) {
save = remove_propnode(key, &(avl->left));
} else if (cmpval > 0) {
save = remove_propnode(key, &(avl->right));
} else if (!(avl->left)) {
avl = avl->right;
} else if (!(avl->right)) {
avl = avl->left;
} else {
tmp = remove_propnode(PropName(getmax(avl->left)), &(avl->left));
if (!tmp) { /* this shouldn't be possible. */
panic("remove_propnode() returned NULL !");
}
tmp->left = avl->left;
tmp->right = avl->right;
avl = tmp;
}
if (save) {
save->left = NULL;
save->right = NULL;
}
*root = balance_node(avl);
}
return save;
}
