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#include <apos/sp_tree.h>
static void __sp_turn_left(struct sp_node *n)
{
struct sp_node *l = sp_left(n);
struct sp_node *p = sp_paren(n);
sp_paren(l) = sp_paren(n);
sp_left(n) = sp_right(l);
sp_paren(n) = l;
sp_right(l) = n;
if(p && sp_left(p) == n)
sp_left(p) = l;
else if (p)
sp_right(p) = l;
if(sp_left(n))
sp_lparen(n) = n;
}
static void __sp_turn_right(struct sp_node *n)
{
struct sp_node *r = sp_right(n);
struct sp_node *p = sp_paren(n);
sp_paren(r) = sp_paren(n);
sp_right(n) = sp_left(r);
sp_paren(n) = r;
sp_left(r) = n;
if(p && sp_left(p) == n)
sp_left(p) = r;
else if (p)
sp_right(p) = r;
if(sp_right(n))
sp_rparen(n) = n;
}
static int __sp_balance(struct sp_node *n)
{
int l = 0;
int r = 0;
if(sp_left(n))
l = sp_left(n)->hint + 1;
if(sp_right(n))
r = sp_right(n)->hint + 1;
return l - r;
}
static int __sp_max_hint(struct sp_node *n)
{
int l = 0;
int r = 0;
if(sp_left(n))
l = sp_left(n)->hint + 1;
if(sp_right(n))
r = sp_right(n)->hint + 1;
if(l > r)
return l;
else
return r;
}
static void __sp_update(struct sp_node **root, struct sp_node *n)
{
while(n){
int b = __sp_balance(n);
int prev_hint = n->hint;
struct sp_node *p = sp_paren(n);
if(b < -1) {
/* leaning to the right */
if(n == *root)
*root = sp_right(n);
__sp_turn_right(n);
}
else if(b > 1){
/* leaning to the left */
if(n == *root)
*root = sp_left(n);
__sp_turn_left(n);
}
n->hint = __sp_max_hint(n);
if(n->hint == 0 || n->hint != prev_hint)
n = p;
else
return;
}
}
void sp_insert(struct sp_node **root, struct sp_node *p,
struct sp_node *n, enum sp_dir d)
{
if(!*root){
*root = n;
return;
}
if(d == LEFT)
sp_left(p) = n;
else
sp_right(p) = n;
sp_paren(n) = p;
__sp_update(root, n);
}
static void __sp_replace_right(struct sp_node *n, struct sp_node *r)
{
struct sp_node *p = sp_paren(n);
struct sp_node *rp = sp_paren(r);
if(sp_left(rp) == r){
sp_left(rp) = sp_right(r);
if(sp_right(r))
sp_rparen(r) = rp;
}
if(sp_paren(rp) == n)
sp_paren(rp) = r;
sp_paren(r) = p;
sp_left(r) = sp_left(n);
if(sp_right(n) != r){
sp_right(r) = sp_right(n);
sp_rparen(n) = r;
}
if(p && sp_left(p) == n)
sp_left(p) = r;
else if (p)
sp_right(p) = r;
if(sp_left(n))
sp_lparen(n) = r;
}
static void __sp_replace_left(struct sp_node *n, struct sp_node *l)
{
struct sp_node *p = sp_paren(n);
struct sp_node *lp = sp_paren(l);
if(sp_right(lp) == l){
sp_right(lp) = sp_left(l);
if(sp_left(l))
sp_lparen(l) = lp;
}
if(sp_paren(lp) == n)
sp_paren(lp) = l;
sp_paren(l) = p;
sp_right(l) = sp_right(n);
if(sp_left(n) != l){
sp_left(l) = sp_left(n);
sp_lparen(n) = l;
}
if(p && sp_left(p) == n)
sp_left(p) = l;
else if (p)
sp_right(p) = l;
if(sp_right(n))
sp_rparen(n) = l;
}
/* TODO: handle root better */
void sp_remove(struct sp_node **root, struct sp_node *del)
{
if(sp_right(del)){
struct sp_node *least = sp_first(sp_right(del));
if(del == *root)
*root = least;
__sp_replace_right(del, least);
__sp_update(root, sp_right(least));
return;
}
if(sp_left(del)){
struct sp_node *most = sp_last(sp_left(del));
if(del == *root)
*root = most;
__sp_replace_left(del, most);
__sp_update(root, sp_left(most));
return;
}
if(del == *root){
*root = 0;
return;
}
/* empty node */
struct sp_node *paren = sp_paren(del);
if(sp_left(paren) == del)
sp_left(paren) = 0;
else
sp_right(paren) = 0;
__sp_update(root, paren);
}
struct sp_node *sp_first(struct sp_node *n)
{
if(!sp_left(n)) return n;
return sp_first(sp_left(n));
}
struct sp_node *sp_last(struct sp_node *n)
{
if(!sp_right(n)) return n;
return sp_last(sp_right(n));
}
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