/*
An implementation of top-down splaying
D. Sleator <sleator@cs.cmu.edu>
- March 1992
+ March 1992
"Splay trees", or "self-adjusting search trees" are a simple and
efficient data structure for storing an ordered set. The data
The following code was written by Daniel Sleator, and is released
in the public domain. It has been heavily modified by Carmelo Piccione,
- (cep@andrew.cmu.edu), to suit personal needs,
+ (cep@andrew.cmu.edu), to suit personal needs,
*/
#include <stdlib.h>
splaytree->compare = compare;
splaytree->copy_key = copy_key;
splaytree->free_key = free_key;
-
+
/* Return instantiated splay tree */
return splaytree;
}
/* Free the splaytree struct itself */
free(splaytree);
-
+
/* Done, return success */
return SUCCESS;
/* Free left node */
free_splaynode(splaynode->left, free_key);
-
+
/* Free right node */
free_splaynode(splaynode->right, free_key);
-
+
/* Free this node's key */
free_key(splaynode->key);
-
+
/* Note that the data pointers are not freed here.
Should be freed with a splay traversal function */
-
+
/* Free the splaynode structure itself */
free(splaynode);
/* Null argument check */
if (splaytree == NULL)
- return;
+ return;
if (func_ptr == NULL)
- return;
-
+ return;
+
/* Call recursive helper function */
splay_traverse_helper(func_ptr, splaytree->root);
}
/* Helper function to traverse the entire splaytree */
-static inline void splay_traverse_helper (void (*func_ptr)(), splaynode_t * splaynode) {
+static inline void splay_traverse_helper (void (*func_ptr)(), splaynode_t * splaynode) {
/* Normal if this happens, its a base case of recursion */
if (splaynode == NULL)
/* Recursively traverse to the left */
splay_traverse_helper(func_ptr, splaynode->left);
-
-
+
+
/* Node is a of regular type, so its ok to perform the function on it */
if (splaynode->type == REGULAR_NODE_TYPE)
- func_ptr(splaynode->data);
-
+ func_ptr(splaynode->data);
+
/* Node is of symbolic link type, do nothing */
else if (splaynode->type == SYMBOLIC_NODE_TYPE)
- ;
-
+ ;
+
/* Unknown node type */
else
;
-
+
/* Recursively traverse to the right */
splay_traverse_helper(func_ptr, splaynode->right);
int match_type;
if (key == NULL)
- return NULL;
-
+ return NULL;
+
if (splaytree == NULL)
- return NULL;
-
+ return NULL;
+
splaynode = splaytree->root;
-
+
/* Bring the targeted splay node to the top of the splaytree */
splaynode = splay(key, splaynode, &match_type, splaytree->compare);
splaytree->root = splaynode;
-
-
+
+
/* We only want perfect matches, so return null when match isn't perfect */
- if (match_type == CLOSEST_MATCH)
+ if (match_type == CLOSEST_MATCH)
return NULL;
/* This shouldn't happen because of the match type check, but whatever */
if (splaytree->root == NULL)
- return NULL;
-
+ return NULL;
+
/* Node is a regular type, return its data pointer */
if (splaytree->root->type == REGULAR_NODE_TYPE) /* regular node */
- return splaytree->root->data;
-
+ return splaytree->root->data;
+
/* If the node is a symlink, pursue one link */
if (splaytree->root->type == SYMBOLIC_NODE_TYPE) /* symbolic node */
- return ((splaynode_t*)splaytree->root->data)->data;
-
-
+ return ((splaynode_t*)splaytree->root->data)->data;
+
+
/* Unknown type */
return NULL;
}
splaynode_t * splaynode;
int match_type;
-
- /* Null argument checks */
+
+ /* Null argument checks */
if (splaytree == NULL)
- return NULL;
-
+ return NULL;
+
if (key == NULL)
- return NULL;
-
+ return NULL;
+
splaynode = splaytree->root;
/* Find the splaynode */
/* Finds the desired node, and changes the tree such that it is the root */
static inline splaynode_t * splay (void * key, splaynode_t * t, int * match_type, int (*compare)()) {
-
-/* Simple top down splay, not requiring key to be in the tree t.
+
+/* Simple top down splay, not requiring key to be in the tree t.
What it does is described above. */
splaynode_t N, *l, *r, *y;
*match_type = CLOSEST_MATCH;
-
- if (t == NULL) return t;
+
+ if (t == NULL) return t;
N.left = N.right = NULL;
l = r = &N;
-
+
for (;;) {
- if (compare(key, t->key) < 0) {
- if (t->left == NULL) break;
- if (compare(key, t->left->key) < 0) {
- y = t->left; /* rotate right */
- t->left = y->right;
- y->right = t;
- t = y;
- if (t->left == NULL) break;
- }
- r->left = t; /* link right */
- r = t;
- t = t->left;
- } else if (compare(key, t->key) > 0) {
- if (t->right == NULL) break;
- if (compare(key, t->right->key) > 0) {
- y = t->right; /* rotate left */
- t->right = y->left;
- y->left = t;
- t = y;
- if (t->right == NULL) break;
- }
- l->right = t; /* link left */
- l = t;
- t = t->right;
- } else {
- *match_type = PERFECT_MATCH;
- break;
- }
+ if (compare(key, t->key) < 0) {
+ if (t->left == NULL) break;
+ if (compare(key, t->left->key) < 0) {
+ y = t->left; /* rotate right */
+ t->left = y->right;
+ y->right = t;
+ t = y;
+ if (t->left == NULL) break;
+ }
+ r->left = t; /* link right */
+ r = t;
+ t = t->left;
+ } else if (compare(key, t->key) > 0) {
+ if (t->right == NULL) break;
+ if (compare(key, t->right->key) > 0) {
+ y = t->right; /* rotate left */
+ t->right = y->left;
+ y->left = t;
+ t = y;
+ if (t->right == NULL) break;
+ }
+ l->right = t; /* link left */
+ l = t;
+ t = t->right;
+ } else {
+ *match_type = PERFECT_MATCH;
+ break;
+ }
}
l->right = t->left; /* assemble */
r->left = t->right;
t->left = N.right;
t->right = N.left;
-
+
return t;
//return NULL;
/* Deletes a splay node from a splay tree. If the node doesn't exist
then nothing happens */
inline int splay_delete(void * key, splaytree_t * splaytree) {
-
+
splaynode_t * splaynode;
/* Use helper function to delete the node and return the resulting tree */
if ((splaynode = splay_delete_helper(key, splaytree->root, splaytree->compare, splaytree->free_key)) == NULL)
- return FAILURE;
-
+ return FAILURE;
+
/* Set new splaytree root equal to the returned splaynode after deletion */
splaytree->root = splaynode;
-
+
/* Finished, no errors */
return SUCCESS;
}
/* Deletes a splay node */
static inline splaynode_t * splay_delete_helper(void * key, splaynode_t * splaynode, int (*compare)(), void (*free_key)()) {
-
+
splaynode_t * new_root;
int match_type;
-
- /* Argument check */
- if (splaynode == NULL)
- return NULL;
-
+
+ /* Argument check */
+ if (splaynode == NULL)
+ return NULL;
+
splaynode = splay(key, splaynode, &match_type, compare);
-
- /* If entry wasn't found, quit here */
- if (match_type == CLOSEST_MATCH)
- return NULL;
-
- /* If the targeted node's left pointer is null, then set the new root
- equal to the splaynode's right child */
- if (splaynode->left == NULL) {
- new_root = splaynode->right;
- }
-
- /* Otherwise, do something I don't currently understand */
- else {
- new_root = splay(key, splaynode->left, &match_type, compare);
- new_root->right = splaynode->right;
- }
-
- /* Set splay nodes children pointers to null */
- splaynode->left = splaynode->right = NULL;
-
- /* Free the splaynode (and only this node since its children are now empty */
- free_splaynode(splaynode, free_key);
-
- /* Return the resulting tree */
- return new_root;
-
+
+ /* If entry wasn't found, quit here */
+ if (match_type == CLOSEST_MATCH)
+ return NULL;
+
+ /* If the targeted node's left pointer is null, then set the new root
+ equal to the splaynode's right child */
+ if (splaynode->left == NULL) {
+ new_root = splaynode->right;
+ }
+
+ /* Otherwise, do something I don't currently understand */
+ else {
+ new_root = splay(key, splaynode->left, &match_type, compare);
+ new_root->right = splaynode->right;
+ }
+
+ /* Set splay nodes children pointers to null */
+ splaynode->left = splaynode->right = NULL;
+
+ /* Free the splaynode (and only this node since its children are now empty */
+ free_splaynode(splaynode, free_key);
+
+ /* Return the resulting tree */
+ return new_root;
+
}
/* Create a new splay node type */
static inline splaynode_t * new_splaynode(int type, void * key, void * data) {
- splaynode_t * splaynode;
- /* Argument checks */
- if (data == NULL)
- return NULL;
-
- if (key == NULL)
- return NULL;
-
- /* Creates the new splay node struct */
- if ((splaynode = (splaynode_t*)malloc(sizeof(splaynode_t))) == NULL)
- return NULL;
-
- splaynode->data = data;
- splaynode->type = type;
- splaynode->key = key;
-
- /* Return the new splay node */
- return splaynode;
+ splaynode_t * splaynode;
+ /* Argument checks */
+ if (data == NULL)
+ return NULL;
+
+ if (key == NULL)
+ return NULL;
+
+ /* Creates the new splay node struct */
+ if ((splaynode = (splaynode_t*)malloc(sizeof(splaynode_t))) == NULL)
+ return NULL;
+
+ splaynode->data = data;
+ splaynode->type = type;
+ splaynode->key = key;
+
+ /* Return the new splay node */
+ return splaynode;
}
/* Inserts a link into the splay tree */
splaynode_t * splaynode, * data_node;
void * key_clone;
- /* Null arguments */
+ /* Null arguments */
if (splaytree == NULL)
- return FAILURE;
-
+ return FAILURE;
+
if (alias_key == NULL)
- return FAILURE;
+ return FAILURE;
if (orig_key == NULL)
- return FAILURE;
-
+ return FAILURE;
+
/* Find the splaynode corresponding to the original key */
if ((data_node = get_splaynode_of(orig_key, splaytree)) == NULL)
- return FAILURE;
-
+ return FAILURE;
+
/* Create a new splay node of symbolic link type */
if ((splaynode = new_splaynode(SYMBOLIC_NODE_TYPE, (key_clone = splaytree->copy_key(alias_key)), data_node)) == NULL) {
- splaytree->free_key(key_clone);
- return OUTOFMEM_ERROR;
+ splaytree->free_key(key_clone);
+ return OUTOFMEM_ERROR;
}
/* Insert the splaynode into the given splaytree */
splaynode->left=splaynode->right = NULL;
free_splaynode(splaynode, splaytree->free_key);
return FAILURE;
- }
-
+ }
+
/* Done, return success */
return SUCCESS;
-}
+}
/* Inserts 'data' into the 'splaytree' paired with the passed 'key' */
inline int splay_insert(void * data, void * key, splaytree_t * splaytree) {
- splaynode_t * splaynode;
- void * key_clone;
-
- /* Null argument checks */
- if (splaytree == NULL) {
- return FAILURE;
- }
-
- if (key == NULL)
- return FAILURE;
-
- /* Clone the key argument */
- key_clone = splaytree->copy_key(key);
-
- /* Create a new splaynode (of regular type) */
- if ((splaynode = new_splaynode(REGULAR_NODE_TYPE, key_clone, data)) == NULL) {
- splaytree->free_key(key_clone);
- return OUTOFMEM_ERROR;
- }
-
-
- /* Inserts the splaynode into the splaytree */
- if (splay_insert_node(splaynode, splaytree) < 0) {
- splaynode->left=splaynode->right=NULL;
- free_splaynode(splaynode, splaytree->free_key);
- return FAILURE;
- }
-
-
- return SUCCESS;
+ splaynode_t * splaynode;
+ void * key_clone;
+
+ /* Null argument checks */
+ if (splaytree == NULL) {
+ return FAILURE;
+ }
+
+ if (key == NULL)
+ return FAILURE;
+
+ /* Clone the key argument */
+ key_clone = splaytree->copy_key(key);
+
+ /* Create a new splaynode (of regular type) */
+ if ((splaynode = new_splaynode(REGULAR_NODE_TYPE, key_clone, data)) == NULL) {
+ splaytree->free_key(key_clone);
+ return OUTOFMEM_ERROR;
+ }
+
+
+ /* Inserts the splaynode into the splaytree */
+ if (splay_insert_node(splaynode, splaytree) < 0) {
+ splaynode->left=splaynode->right=NULL;
+ free_splaynode(splaynode, splaytree->free_key);
+ return FAILURE;
+ }
+
+
+ return SUCCESS;
}
/* Helper function to insert splaynodes into the splaytree */
int cmpval;
void * key;
splaynode_t * t;
-
+
/* Null argument checks */
if (splaytree == NULL)
return FAILURE;
if (splaynode == NULL)
- return FAILURE;
-
+ return FAILURE;
+
key = splaynode->key;
-
- t = splaytree->root;
+
+ t = splaytree->root;
/* Root is null, insert splaynode here */
if (t == NULL) {
- splaynode->left = splaynode->right = NULL;
- splaytree->root = splaynode;
- return SUCCESS;
+ splaynode->left = splaynode->right = NULL;
+ splaytree->root = splaynode;
+ return SUCCESS;
}
-
+
t = splay(key, t, &match_type, splaytree->compare);
-
+
if ((cmpval = splaytree->compare(key,t->key)) < 0) {
- splaynode->left = t->left;
- splaynode->right = t;
- t->left = NULL;
- splaytree->root = splaynode;
- return SUCCESS;
+ splaynode->left = t->left;
+ splaynode->right = t;
+ t->left = NULL;
+ splaytree->root = splaynode;
+ return SUCCESS;
- }
+ }
else if (cmpval > 0) {
- splaynode->right = t->right;
- splaynode->left = t;
- t->right = NULL;
- splaytree->root = splaynode;
- return SUCCESS;
- }
-
+ splaynode->right = t->right;
+ splaynode->left = t;
+ t->right = NULL;
+ splaytree->root = splaynode;
+ return SUCCESS;
+ }
+
/* Item already exists in tree, don't reinsert */
else {
-
+
return FAILURE;
}
}
/* Returns the 'maximum' key that is less than the given key in the splaytree */
inline void * splay_find_below_max(void * key, splaytree_t * splaytree) {
-
- void * closest_key;
-
- if (splaytree == NULL)
- return NULL;
- if (splaytree->root == NULL)
- return NULL;
- if (key == NULL)
- return NULL;
-
- closest_key = NULL;
-
- splay_find_below_max_helper(key, &closest_key, splaytree->root, splaytree->compare);
-
- if (closest_key == NULL) return NULL;
- return splay_find(closest_key, splaytree);
+
+ void * closest_key;
+
+ if (splaytree == NULL)
+ return NULL;
+ if (splaytree->root == NULL)
+ return NULL;
+ if (key == NULL)
+ return NULL;
+
+ closest_key = NULL;
+
+ splay_find_below_max_helper(key, &closest_key, splaytree->root, splaytree->compare);
+
+ if (closest_key == NULL) return NULL;
+ return splay_find(closest_key, splaytree);
}
/* Returns the 'minimum' key that is greater than the given key in the splaytree */
inline void * splay_find_above_min(void * key, splaytree_t * splaytree) {
-
- void * closest_key;
-
- if (splaytree == NULL)
- return NULL;
- if (splaytree->root == NULL)
- return NULL;
- if (key == NULL)
- return NULL;
- closest_key = NULL;
-
- splay_find_above_min_helper(key, &closest_key, splaytree->root, splaytree->compare);
-
- if (closest_key == NULL) {
- return NULL;
- }
-
- return splay_find(closest_key, splaytree);
+
+ void * closest_key;
+
+ if (splaytree == NULL)
+ return NULL;
+ if (splaytree->root == NULL)
+ return NULL;
+ if (key == NULL)
+ return NULL;
+ closest_key = NULL;
+
+ splay_find_above_min_helper(key, &closest_key, splaytree->root, splaytree->compare);
+
+ if (closest_key == NULL) {
+ return NULL;
+ }
+
+ return splay_find(closest_key, splaytree);
}
/* Helper function */
static inline void splay_find_below_max_helper(void * min_key, void ** closest_key, splaynode_t * root, int (*compare)()) {
- /* Empty root, return*/
- if (root == NULL)
- return;
-
- /* The root key is less than the previously found closest key.
- Also try to make the key non null if the value is less than the max key */
-
- if ((*closest_key == NULL) || (compare(root->key, *closest_key) < 0)) {
-
- /* The root key is less than the given max key, so this is the
- smallest change from the given max key */
- if (compare(root->key, min_key) > 0) {
-
- *closest_key = root->key;
-
- /* Look right again in case even a greater key exists that is
- still less than the given max key */
- splay_find_below_max_helper(min_key, closest_key, root->left, compare);
- }
-
- /* The root key is greater than the given max key, and greater than
- the closest key, so search left */
- else {
- splay_find_below_max_helper(min_key, closest_key, root->right, compare);
- }
- }
-
- /* The root key is less than the found closest key, search right */
- else {
- splay_find_below_max_helper(min_key, closest_key, root->left, compare);
- }
-
+ /* Empty root, return*/
+ if (root == NULL)
+ return;
+
+ /* The root key is less than the previously found closest key.
+ Also try to make the key non null if the value is less than the max key */
+
+ if ((*closest_key == NULL) || (compare(root->key, *closest_key) < 0)) {
+
+ /* The root key is less than the given max key, so this is the
+ smallest change from the given max key */
+ if (compare(root->key, min_key) > 0) {
+
+ *closest_key = root->key;
+
+ /* Look right again in case even a greater key exists that is
+ still less than the given max key */
+ splay_find_below_max_helper(min_key, closest_key, root->left, compare);
+ }
+
+ /* The root key is greater than the given max key, and greater than
+ the closest key, so search left */
+ else {
+ splay_find_below_max_helper(min_key, closest_key, root->right, compare);
+ }
+ }
+
+ /* The root key is less than the found closest key, search right */
+ else {
+ splay_find_below_max_helper(min_key, closest_key, root->left, compare);
+ }
+
}
/* Helper function */
static inline void splay_find_above_min_helper(void * max_key, void ** closest_key, splaynode_t * root, int (*compare)()) {
- /* Empty root, stop */
- if (root == NULL)
- return;
-
- /* The root key is greater than the previously found closest key.
- Also try to make the key non null if the value is less than the min key */
-
- if ((*closest_key == NULL) || (compare(root->key, *closest_key) > 0)) {
-
- /* The root key is greater than the given min key, so this is the
- smallest change from the given min key */
- if (compare(root->key, max_key) < 0) {
-
- *closest_key = root->key;
-
- /* Look left again in case even a smaller key exists that is
- still greater than the given min key */
- splay_find_above_min_helper(max_key, closest_key, root->right, compare);
- }
-
- /* The root key is less than the given min key, and less than
- the closest key, so search right */
- else {
- splay_find_above_min_helper(max_key, closest_key, root->left, compare);
- }
- }
-
- /* The root key is greater than the found closest key, search left */
- else {
- splay_find_above_min_helper(max_key, closest_key, root->right, compare);
- }
-}
+ /* Empty root, stop */
+ if (root == NULL)
+ return;
+
+ /* The root key is greater than the previously found closest key.
+ Also try to make the key non null if the value is less than the min key */
+
+ if ((*closest_key == NULL) || (compare(root->key, *closest_key) > 0)) {
+
+ /* The root key is greater than the given min key, so this is the
+ smallest change from the given min key */
+ if (compare(root->key, max_key) < 0) {
+
+ *closest_key = root->key;
+
+ /* Look left again in case even a smaller key exists that is
+ still greater than the given min key */
+ splay_find_above_min_helper(max_key, closest_key, root->right, compare);
+ }
+
+ /* The root key is less than the given min key, and less than
+ the closest key, so search right */
+ else {
+ splay_find_above_min_helper(max_key, closest_key, root->left, compare);
+ }
+ }
+
+ /* The root key is greater than the found closest key, search left */
+ else {
+ splay_find_above_min_helper(max_key, closest_key, root->right, compare);
+ }
+}
/* Find the minimum entry of the splay tree */
inline void * splay_find_min(splaytree_t * t) {
- splaynode_t * splaynode;
-
- if (t == NULL)
- return NULL;
- if (t->root == NULL)
- return NULL;
-
- splaynode = t->root;
-
- while (splaynode->left != NULL)
- splaynode= splaynode->left;
-
- return splaynode->data;
+ splaynode_t * splaynode;
+
+ if (t == NULL)
+ return NULL;
+ if (t->root == NULL)
+ return NULL;
+
+ splaynode = t->root;
+
+ while (splaynode->left != NULL)
+ splaynode= splaynode->left;
+
+ return splaynode->data;
}
/* Find the maximum entry of the splay tree */
inline void * splay_find_max(splaytree_t * t) {
- splaynode_t * splaynode;
-
- if (t == NULL)
- return NULL;
- if (t->root == NULL)
- return NULL;
-
- splaynode = t->root;
-
- while (splaynode->right != NULL) {
- printf("data:%d\n", *(int*)splaynode->key);
- splaynode = splaynode->right;
- }
- return splaynode->data;
+ splaynode_t * splaynode;
+
+ if (t == NULL)
+ return NULL;
+ if (t->root == NULL)
+ return NULL;
+
+ splaynode = t->root;
+
+ while (splaynode->right != NULL) {
+ printf("data:%d\n", *(int*)splaynode->key);
+ splaynode = splaynode->right;
+ }
+ return splaynode->data;
}
inline int splay_size(splaytree_t * t) {
- if (t == NULL)
- return 0;
- if (t->root == NULL)
- return 0;
-
- return splay_rec_size(t->root);
-
+ if (t == NULL)
+ return 0;
+ if (t->root == NULL)
+ return 0;
+
+ return splay_rec_size(t->root);
+
}
static inline int splay_rec_size(splaynode_t * splaynode) {
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