caddr_t
avl_delete( Avlnode **root, void *data, IFP fcmp )
{
int shorter;
return ravl_delete( root, (caddr_t)data, fcmp, &shorter );
}
/*
* container_ravl_delete -- (internal) deletes the container
*/
static void
container_ravl_destroy(struct block_container *bc)
{
struct block_container_ravl *c =
(struct block_container_ravl *)bc;
ravl_delete(c->tree);
Free(bc);
}
static caddr_t
ravl_delete(
Avlnode **root,
caddr_t data,
IFP fcmp,
int *shorter
)
{
int shortersubtree = 0;
int cmp;
caddr_t savedata;
Avlnode *minnode, *savenode;
if ( *root == NULLAVL )
return( 0 );
cmp = (*fcmp)( data, (*root)->avl_data );
/* found it! */
if ( cmp == 0 ) {
savenode = *root;
savedata = savenode->avl_data;
/* simple cases: no left child */
if ( (*root)->avl_left == 0 ) {
*root = (*root)->avl_right;
*shorter = 1;
free( (char *) savenode );
return( savedata );
/* no right child */
} else if ( (*root)->avl_right == 0 ) {
*root = (*root)->avl_left;
*shorter = 1;
free( (char *) savenode );
return( savedata );
}
/*
* avl_getmin will return to us the smallest node greater
* than the one we are trying to delete. deleting this node
* from the right subtree is guaranteed to end in one of the
* simple cases above.
*/
minnode = (*root)->avl_right;
while ( minnode->avl_left != NULLAVL )
minnode = minnode->avl_left;
/* swap the data */
(*root)->avl_data = minnode->avl_data;
minnode->avl_data = savedata;
savedata = ravl_delete( &(*root)->avl_right, data, fcmp,
&shortersubtree );
if ( shortersubtree )
*shorter = right_balance( root );
else
*shorter = 0;
/* go left */
} else if ( cmp < 0 ) {
if ( (savedata = ravl_delete( &(*root)->avl_left, data, fcmp,
&shortersubtree )) == 0 ) {
*shorter = 0;
return( 0 );
}
/* left subtree shorter? */
if ( shortersubtree )
*shorter = left_balance( root );
else
*shorter = 0;
/* go right */
} else {
if ( (savedata = ravl_delete( &(*root)->avl_right, data, fcmp,
&shortersubtree )) == 0 ) {
*shorter = 0;
return( 0 );
}
if ( shortersubtree )
*shorter = right_balance( root );
else
*shorter = 0;
}
return( savedata );
}
