/* Finds and deletes the best-fit node from the tree. Return a pointer to the
resulting tree. best-fit means the node with the given or lower key */
struct Curl_tree *Curl_splaygetbest(struct timeval i,
struct Curl_tree *t,
struct Curl_tree **removed)
{
struct Curl_tree *x;
if(!t) {
*removed = NULL; /* none removed since there was no root */
return NULL;
}
t = Curl_splay(i, t);
if(compare(i, t->key) < 0) {
/* too big node, try the smaller chain */
if(t->smaller)
t=Curl_splay(t->smaller->key, t);
else {
/* fail */
*removed = NULL;
return t;
}
}
if(compare(i, t->key) >= 0) { /* found it */
/* FIRST! Check if there is a list with identical keys */
x = t->same;
if(x) {
/* there is, pick one from the list */
/* 'x' is the new root node */
x->key = t->key;
x->larger = t->larger;
x->smaller = t->smaller;
*removed = t;
return x; /* new root */
}
if(t->smaller == NULL) {
x = t->larger;
}
else {
x = Curl_splay(i, t->smaller);
x->larger = t->larger;
}
*removed = t;
return x;
}
else {
*removed = NULL; /* no match */
return t; /* It wasn't there */
}
}
/* Deletes the very node we point out from the tree if it's there. Stores a
pointer to the new resulting tree in 'newroot'.
Returns zero on success and non-zero on errors! TODO: document error codes.
When returning error, it does not touch the 'newroot' pointer.
NOTE: when the last node of the tree is removed, there's no tree left so
'newroot' will be made to point to NULL.
*/
int Curl_splayremovebyaddr(struct Curl_tree *t,
struct Curl_tree *remove,
struct Curl_tree **newroot)
{
struct Curl_tree *x;
if (!t || !remove)
return 1;
if(KEY_NOTUSED == remove->key) {
/* Key set to NOTUSED means it is a subnode within a 'same' linked list
and thus we can unlink it easily. The 'smaller' link of a subnode
links to the parent node. */
remove->smaller->same = remove->same;
if(remove->same)
remove->same->smaller = remove->smaller;
/* voila, we're done! */
*newroot = t; /* return the same root */
return 0;
}
t = Curl_splay(remove->key, t);
/* First make sure that we got a root node witht he same key as the one we
want to remove, as otherwise we might be trying to remove a node that
isn't actually in the tree. */
if(t->key != remove->key)
return 2;
/* Check if there is a list with identical sizes, as then we're trying to
remove the root node of a list of nodes with identical keys. */
x = t->same;
if(x) {
/* 'x' is the new root node, we just make it use the root node's
smaller/larger links */
x->key = t->key;
x->larger = t->larger;
x->smaller = t->smaller;
}
else {
/* Remove the root node */
if (t->smaller == NULL)
x = t->larger;
else {
x = Curl_splay(remove->key, t->smaller);
x->larger = t->larger;
}
}
*newroot = x; /* store new root pointer */
return 0;
}
/* Deletes 'i' from the tree if it's there (with an exact match). Returns a
pointer to the resulting tree.
Function not used in libcurl.
*/
struct Curl_tree *Curl_splayremove(struct timeval i,
struct Curl_tree *t,
struct Curl_tree **removed)
{
struct Curl_tree *x;
*removed = NULL; /* default to no removed */
if(t==NULL)
return NULL;
t = Curl_splay(i,t);
if(compare(i, t->key) == 0) { /* found it */
/* FIRST! Check if there is a list with identical sizes */
if((x = t->same) != NULL) {
/* there is, pick one from the list */
/* 'x' is the new root node */
x->key = t->key;
x->larger = t->larger;
x->smaller = t->smaller;
*removed = t;
return x; /* new root */
}
if(t->smaller == NULL) {
x = t->larger;
}
else {
x = Curl_splay(i, t->smaller);
x->larger = t->larger;
}
*removed = t;
return x;
}
else
return t; /* It wasn't there */
}
/* Insert key i into the tree t. Return a pointer to the resulting tree or
* NULL if something went wrong.
*
* @unittest: 1309
*/
struct Curl_tree *Curl_splayinsert(struct timeval i,
struct Curl_tree *t,
struct Curl_tree *node)
{
static const struct timeval KEY_NOTUSED = {-1, -1}; /* will *NEVER* appear */
if(node == NULL)
return t;
if(t != NULL) {
t = Curl_splay(i, t);
if(compare(i, t->key)==0) {
/* There already exists a node in the tree with the very same key. Build
a linked list of nodes. We make the new 'node' struct the new master
node and make the previous node the first one in the 'same' list. */
node->same = t;
node->key = i;
node->smaller = t->smaller;
node->larger = t->larger;
t->smaller = node; /* in the sub node for this same key, we use the
smaller pointer to point back to the master
node */
t->key = KEY_NOTUSED; /* and we set the key in the sub node to NOTUSED
to quickly identify this node as a subnode */
return node; /* new root node */
}
}
if(t == NULL) {
node->smaller = node->larger = NULL;
}
else if(compare(i, t->key) < 0) {
node->smaller = t->smaller;
node->larger = t;
t->smaller = NULL;
}
else {
node->larger = t->larger;
node->smaller = t;
t->larger = NULL;
}
node->key = i;
node->same = NULL; /* no identical node (yet) */
return node;
}
/* Insert key i into the tree t. Return a pointer to the resulting tree or
* NULL if something went wrong.
*
* @unittest: 1309
*/
struct Curl_tree *Curl_splayinsert(struct curltime i,
struct Curl_tree *t,
struct Curl_tree *node)
{
static const struct curltime KEY_NOTUSED = {
(time_t)-1, (unsigned int)-1
}; /* will *NEVER* appear */
if(node == NULL)
return t;
if(t != NULL) {
t = Curl_splay(i, t);
if(compare(i, t->key) == 0) {
/* There already exists a node in the tree with the very same key. Build
a doubly-linked circular list of nodes. We add the new 'node' struct
to the end of this list. */
node->key = KEY_NOTUSED; /* we set the key in the sub node to NOTUSED
to quickly identify this node as a subnode */
node->samen = t;
node->samep = t->samep;
t->samep->samen = node;
t->samep = node;
return t; /* the root node always stays the same */
}
}
if(t == NULL) {
node->smaller = node->larger = NULL;
}
else if(compare(i, t->key) < 0) {
node->smaller = t->smaller;
node->larger = t;
t->smaller = NULL;
}
else {
node->larger = t->larger;
node->smaller = t;
t->larger = NULL;
}
node->key = i;
/* no identical nodes (yet), we are the only one in the list of nodes */
node->samen = node;
node->samep = node;
return node;
}
/* Finds and deletes the best-fit node from the tree. Return a pointer to the
resulting tree. best-fit means the smallest node if it is not larger than
the key */
struct Curl_tree *Curl_splaygetbest(struct curltime i,
struct Curl_tree *t,
struct Curl_tree **removed)
{
static struct curltime tv_zero = {0, 0};
struct Curl_tree *x;
if(!t) {
*removed = NULL; /* none removed since there was no root */
return NULL;
}
/* find smallest */
t = Curl_splay(tv_zero, t);
if(compare(i, t->key) < 0) {
/* even the smallest is too big */
*removed = NULL;
return t;
}
/* FIRST! Check if there is a list with identical keys */
x = t->samen;
if(x != t) {
/* there is, pick one from the list */
/* 'x' is the new root node */
x->key = t->key;
x->larger = t->larger;
x->smaller = t->smaller;
x->samep = t->samep;
t->samep->samen = x;
*removed = t;
return x; /* new root */
}
/* we splayed the tree to the smallest element, there is no smaller */
x = t->larger;
*removed = t;
return x;
}
/* Deletes the very node we point out from the tree if it's there. Stores a
* pointer to the new resulting tree in 'newroot'.
*
* Returns zero on success and non-zero on errors! TODO: document error codes.
* When returning error, it does not touch the 'newroot' pointer.
*
* NOTE: when the last node of the tree is removed, there's no tree left so
* 'newroot' will be made to point to NULL.
*
* @unittest: 1309
*/
int Curl_splayremovebyaddr(struct Curl_tree *t,
struct Curl_tree *removenode,
struct Curl_tree **newroot)
{
static const struct timeval KEY_NOTUSED = {-1, -1}; /* will *NEVER* appear */
struct Curl_tree *x;
if(!t || !removenode)
return 1;
if(compare(KEY_NOTUSED, removenode->key) == 0) {
/* Key set to NOTUSED means it is a subnode within a 'same' linked list
and thus we can unlink it easily. The 'smaller' link of a subnode
links to the parent node. */
if(removenode->smaller == NULL)
return 3;
removenode->smaller->same = removenode->same;
if(removenode->same)
removenode->same->smaller = removenode->smaller;
/* Ensures that double-remove gets caught. */
removenode->smaller = NULL;
/* voila, we're done! */
*newroot = t; /* return the same root */
return 0;
}
t = Curl_splay(removenode->key, t);
/* First make sure that we got the same root node as the one we want
to remove, as otherwise we might be trying to remove a node that
isn't actually in the tree.
We cannot just compare the keys here as a double remove in quick
succession of a node with key != KEY_NOTUSED && same != NULL
could return the same key but a different node. */
if(t != removenode)
return 2;
/* Check if there is a list with identical sizes, as then we're trying to
remove the root node of a list of nodes with identical keys. */
x = t->same;
if(x) {
/* 'x' is the new root node, we just make it use the root node's
smaller/larger links */
x->key = t->key;
x->larger = t->larger;
x->smaller = t->smaller;
}
else {
/* Remove the root node */
if(t->smaller == NULL)
x = t->larger;
else {
x = Curl_splay(removenode->key, t->smaller);
x->larger = t->larger;
}
}
*newroot = x; /* store new root pointer */
return 0;
}
