static
AvlNode* avl_find_node ( AvlNode* t, Word k, Word(*kCmp)(UWord,UWord) )
{
if (kCmp) {
/* Boxed comparisons */
Word cmpresS;
while (True) {
if (t == NULL) return NULL;
cmpresS = kCmp(t->key, k);
if (cmpresS > 0) t = t->child[0]; else
if (cmpresS < 0) t = t->child[1]; else
return t;
}
} else {
/* Unboxed comparisons */
Word cmpresS; /* signed */
UWord cmpresU; /* unsigned */
while (True) {
if (t == NULL) return NULL; /* unlikely ==> predictable */
cmpresS = cmp_unsigned_Words( (UWord)t->key, (UWord)k );
if (cmpresS == 0) return t; /* unlikely ==> predictable */
cmpresU = (UWord)cmpresS;
cmpresU >>=/*unsigned*/ (8 * sizeof(cmpresU) - 1);
t = t->child[cmpresU];
}
}
}
static
AvlNode* avl_find_node ( AvlNode* t, Word k, Word(*kCmp)(Word,Word) )
{
Word cmpres;
while (True) {
if (t == NULL) return NULL;
cmpres = kCmp(t->key, k);
if (cmpres > 0) t = t->left; else
if (cmpres < 0) t = t->right; else
return t;
}
}
static
Bool avl_find_bounds ( AvlNode* t,
/*OUT*/UWord* kMinP, /*OUT*/UWord* vMinP,
/*OUT*/UWord* kMaxP, /*OUT*/UWord* vMaxP,
UWord minKey, UWord minVal,
UWord maxKey, UWord maxVal,
UWord key,
Word(*kCmp)(UWord,UWord) )
{
UWord kLowerBound = minKey;
UWord vLowerBound = minVal;
UWord kUpperBound = maxKey;
UWord vUpperBound = maxVal;
while (t) {
Word cmpresS = kCmp ? kCmp(t->key, key)
: cmp_unsigned_Words(t->key, key);
if (cmpresS < 0) {
kLowerBound = t->key;
vLowerBound = t->val;
t = t->child[1];
continue;
}
if (cmpresS > 0) {
kUpperBound = t->key;
vUpperBound = t->val;
t = t->child[0];
continue;
}
/* We should never get here. If we do, it means the given key
is actually present in the tree, which means the original
call was invalid -- an error on the caller's part, and we
cannot give any meaningful values for the bounds. (Well,
maybe we could, but we're not gonna. Ner!) */
return False;
}
if (kMinP) *kMinP = kLowerBound;
if (vMinP) *vMinP = vLowerBound;
if (kMaxP) *kMaxP = kUpperBound;
if (vMaxP) *vMaxP = vUpperBound;
return True;
}
/* Remove an element a from the AVL tree t. a must be part of
the tree. Returns True if the depth of the tree has shrunk.
*/
static
Bool avl_remove_wrk ( AvlNode** rootp,
AvlNode* a,
Word(*kCmp)(Word,Word) )
{
Bool ch;
Word cmpres = kCmp( (*rootp)->key, a->key );
if (cmpres > 0) {
/* remove from the left subtree */
AvlNode* left_subtree = (*rootp)->left;
assert(left_subtree);
ch = avl_remove_wrk(&left_subtree, a, kCmp);
(*rootp)->left=left_subtree;
if (ch) {
switch ((*rootp)->balance++) {
case -1:
return True;
case 0:
return False;
case 1:
break;
default:
assert(0);
}
switch ((*rootp)->right->balance) {
case 0:
avl_swl( rootp );
(*rootp)->balance = -1;
(*rootp)->left->balance = 1;
return False;
case 1:
avl_swl( rootp );
(*rootp)->balance = 0;
(*rootp)->left->balance = 0;
return -1;
case -1:
break;
default:
assert(0);
}
avl_swr( &((*rootp)->right) );
avl_swl( rootp );
avl_nasty( *rootp );
return True;
}
}
else if (cmpres < 0) {
/* remove from the right subtree */
AvlNode* right_subtree = (*rootp)->right;
assert(right_subtree);
ch = avl_remove_wrk(&right_subtree, a, kCmp);
(*rootp)->right = right_subtree;
if (ch) {
switch ((*rootp)->balance--) {
case 1:
return True;
case 0:
return False;
case -1:
break;
default:
assert(0);
}
switch ((*rootp)->left->balance) {
case 0:
avl_swr( rootp );
(*rootp)->balance = 1;
(*rootp)->right->balance = -1;
return False;
case -1:
avl_swr( rootp );
(*rootp)->balance = 0;
(*rootp)->right->balance = 0;
return True;
case 1:
break;
default:
assert(0);
}
avl_swl( &((*rootp)->left) );
avl_swr( rootp );
avl_nasty( *rootp );
return True;
}
}
else {
assert(cmpres == 0);
assert((*rootp)==a);
return avl_removeroot_wrk(rootp, kCmp);
}
return 0;
}
/* Insert element a into the AVL tree t. Returns True if the depth of
the tree has grown. If element with that key is already present,
just copy a->val to existing node, first returning old ->val field
of existing node in *oldV, so that the caller can finalize it
however it wants.
*/
static
Bool avl_insert_wrk ( AvlNode** rootp,
/*OUT*/MaybeWord* oldV,
AvlNode* a,
Word (*kCmp)(Word,Word) )
{
Word cmpres;
/* initialize */
a->left = 0;
a->right = 0;
a->balance = 0;
oldV->b = False;
/* insert into an empty tree? */
if (!(*rootp)) {
(*rootp) = a;
return True;
}
cmpres = kCmp( (*rootp)->key, a->key );
if (cmpres > 0) {
/* insert into the left subtree */
if ((*rootp)->left) {
AvlNode* left_subtree = (*rootp)->left;
if (avl_insert_wrk(&left_subtree, oldV, a, kCmp)) {
switch ((*rootp)->balance--) {
case 1:
return False;
case 0:
return True;
case -1:
break;
default:
assert(0);
}
if ((*rootp)->left->balance < 0) {
avl_swr( rootp );
(*rootp)->balance = 0;
(*rootp)->right->balance = 0;
} else {
avl_swl( &((*rootp)->left) );
avl_swr( rootp );
avl_nasty( *rootp );
}
} else {
(*rootp)->left = left_subtree;
}
return False;
} else {
(*rootp)->left = a;
if ((*rootp)->balance--)
return False;
return True;
}
assert(0);/*NOTREACHED*/
}
else if (cmpres < 0) {
/* insert into the right subtree */
if ((*rootp)->right) {
AvlNode* right_subtree = (*rootp)->right;
if (avl_insert_wrk(&right_subtree, oldV, a, kCmp)) {
switch((*rootp)->balance++) {
case -1:
return False;
case 0:
return True;
case 1:
break;
default:
assert(0);
}
if ((*rootp)->right->balance > 0) {
avl_swl( rootp );
(*rootp)->balance = 0;
(*rootp)->left->balance = 0;
} else {
avl_swr( &((*rootp)->right) );
avl_swl( rootp );
avl_nasty( *rootp );
}
} else {
(*rootp)->right = right_subtree;
}
return False;
} else {
(*rootp)->right = a;
if ((*rootp)->balance++)
return False;
return True;
}
assert(0);/*NOTREACHED*/
}
else {
/* cmpres == 0, a duplicate - replace the val, but don't
incorporate the node in the tree */
oldV->b = True;
oldV->w = (*rootp)->val;
(*rootp)->val = a->val;
return False;
}
}
/* Remove an element a from the AVL tree t. a must be part of
the tree. Returns True if the depth of the tree has shrunk.
*/
static
Bool avl_remove_wrk ( AvlNode** rootp,
AvlNode* a,
Word(*kCmp)(UWord,UWord) )
{
Bool ch;
Word cmpres;
cmpres = kCmp ? /*boxed*/ kCmp( (*rootp)->key, a->key )
: /*unboxed*/ cmp_unsigned_Words( (UWord)(*rootp)->key,
(UWord)a->key );
if (cmpres > 0){
/* remove from the left subtree */
AvlNode* left_subtree = (*rootp)->child[0];
tl_assert(left_subtree);
ch = avl_remove_wrk(&left_subtree, a, kCmp);
(*rootp)->child[0]=left_subtree;
if (ch) {
switch ((*rootp)->balance++) {
case -1: return True;
case 0: return False;
case 1: break;
default: tl_assert(0);
}
switch ((*rootp)->child[1]->balance) {
case 0:
avl_swl( rootp );
(*rootp)->balance = -1;
(*rootp)->child[0]->balance = 1;
return False;
case 1:
avl_swl( rootp );
(*rootp)->balance = 0;
(*rootp)->child[0]->balance = 0;
return True;
case -1:
break;
default:
tl_assert(0);
}
avl_swr( &((*rootp)->child[1]) );
avl_swl( rootp );
avl_nasty( *rootp );
return True;
}
}
else
if (cmpres < 0) {
/* remove from the right subtree */
AvlNode* right_subtree = (*rootp)->child[1];
tl_assert(right_subtree);
ch = avl_remove_wrk(&right_subtree, a, kCmp);
(*rootp)->child[1] = right_subtree;
if (ch) {
switch ((*rootp)->balance--) {
case 1: return True;
case 0: return False;
case -1: break;
default: tl_assert(0);
}
switch ((*rootp)->child[0]->balance) {
case 0:
avl_swr( rootp );
(*rootp)->balance = 1;
(*rootp)->child[1]->balance = -1;
return False;
case -1:
avl_swr( rootp );
(*rootp)->balance = 0;
(*rootp)->child[1]->balance = 0;
return True;
case 1:
break;
default:
tl_assert(0);
}
avl_swl( &((*rootp)->child[0]) );
avl_swr( rootp );
avl_nasty( *rootp );
return True;
}
}
else {
tl_assert(cmpres == 0);
tl_assert((*rootp)==a);
return avl_removeroot_wrk(rootp, kCmp);
}
return 0;
}