/*
splay_tree.c -- splay tree and linked list convenience
- Copyright (C) 2004-2006 Guus Sliepen <guus@tinc-vpn.org>
+ Copyright (C) 2014-2017 Guus Sliepen <guus@meshlink.io>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
/* Splay operation */
static splay_node_t *splay_top_down(splay_tree_t *tree, const void *data, int *result) {
- splay_node_t left = {NULL}, right = {NULL};
+ splay_node_t left, right;
splay_node_t *leftbottom = &left, *rightbottom = &right, *child, *grandchild;
splay_node_t *root = tree->root;
int c;
+ memset(&left, 0, sizeof(left));
+ memset(&right, 0, sizeof(right));
+
if(!root) {
- if(result)
+ if(result) {
*result = 0;
+ }
+
return NULL;
}
child->parent = rightbottom;
rightbottom = child;
- if((root->left = child->right))
+ if((root->left = child->right)) {
child->right->parent = root;
+ }
child->right = root;
root->parent = child;
grandchild->parent = NULL;
root = grandchild;
- } else if (c > 0 && (grandchild = child->right)) {
+ } else if(c > 0 && (grandchild = child->right)) {
leftbottom->right = child;
child->parent = leftbottom;
leftbottom = child;
child->parent = leftbottom;
leftbottom = child;
- if((root->right = child->left))
+ if((root->right = child->left)) {
child->left->parent = root;
+ }
child->left = root;
root->parent = child;
grandchild->parent = NULL;
root = grandchild;
- } else if (c < 0 && (grandchild = child->left)) {
+ } else if(c < 0 && (grandchild = child->left)) {
rightbottom->left = child;
child->parent = rightbottom;
rightbottom = child;
leftbottom->right = root->left;
root->left->parent = leftbottom;
}
+
root->left = left.right;
left.right->parent = root;
}
rightbottom->left = root->right;
root->right->parent = rightbottom;
}
+
root->right = right.left;
right.left->parent = root;
}
/* Return result */
tree->root = root;
- if(result)
+
+ if(result) {
*result = c;
+ }
return tree->root;
}
while((parent = node->parent)) {
if(!(grandparent = parent->parent)) { /* zig */
if(node == parent->left) {
- if((parent->left = node->right))
+ if((parent->left = node->right)) {
parent->left->parent = parent;
+ }
+
node->right = parent;
} else {
- if((parent->right = node->left))
+ if((parent->right = node->left)) {
parent->right->parent = parent;
+ }
+
node->left = parent;
}
greatgrandparent = grandparent->parent;
if(node == parent->left && parent == grandparent->left) { /* left zig-zig */
- if((grandparent->left = parent->right))
+ if((grandparent->left = parent->right)) {
grandparent->left->parent = grandparent;
+ }
+
parent->right = grandparent;
grandparent->parent = parent;
- if((parent->left = node->right))
+ if((parent->left = node->right)) {
parent->left->parent = parent;
+ }
+
node->right = parent;
parent->parent = node;
} else if(node == parent->right && parent == grandparent->right) { /* right zig-zig */
- if((grandparent->right = parent->left))
+ if((grandparent->right = parent->left)) {
grandparent->right->parent = grandparent;
+ }
+
parent->left = grandparent;
grandparent->parent = parent;
- if((parent->right = node->left))
+ if((parent->right = node->left)) {
parent->right->parent = parent;
+ }
+
node->left = parent;
parent->parent = node;
} else if(node == parent->right && parent == grandparent->left) { /* left-right zig-zag */
- if((parent->right = node->left))
+ if((parent->right = node->left)) {
parent->right->parent = parent;
+ }
+
node->left = parent;
parent->parent = node;
- if((grandparent->left = node->right))
+ if((grandparent->left = node->right)) {
grandparent->left->parent = grandparent;
+ }
+
node->right = grandparent;
grandparent->parent = node;
} else { /* right-left zig-zag */
- if((parent->left = node->right))
+ if((parent->left = node->right)) {
parent->left->parent = parent;
+ }
+
node->right = parent;
parent->parent = node;
- if((grandparent->right = node->left))
+ if((grandparent->right = node->left)) {
grandparent->right->parent = grandparent;
+ }
+
node->left = grandparent;
grandparent->parent = node;
}
if((node->parent = greatgrandparent)) {
- if(grandparent == greatgrandparent->left)
+ if(grandparent == greatgrandparent->left) {
greatgrandparent->left = node;
- else
+ } else {
greatgrandparent->right = node;
+ }
}
}
}
splay_tree_t *splay_alloc_tree(splay_compare_t compare, splay_action_t delete) {
splay_tree_t *tree;
- tree = xmalloc_and_zero(sizeof(splay_tree_t));
+ tree = xzalloc(sizeof(splay_tree_t));
tree->compare = compare;
tree->delete = delete;
return tree;
}
-void splay_free_tree(splay_tree_t *tree) {
- free(tree);
-}
-
splay_node_t *splay_alloc_node(void) {
- return xmalloc_and_zero(sizeof(splay_node_t));
+ return xzalloc(sizeof(splay_node_t));
}
void splay_free_node(splay_tree_t *tree, splay_node_t *node) {
- if(node->data && tree->delete)
+ if(node->data && tree->delete) {
tree->delete(node->data);
+ }
free(node);
}
node = tree->root;
if(!node) {
- if(result)
+ if(result) {
*result = 0;
+ }
+
return NULL;
}
c = tree->compare(data, node->data);
if(c < 0) {
- if(node->left)
+ if(node->left) {
node = node->left;
- else
+ } else {
break;
+ }
} else if(c > 0) {
- if(node->right)
+ if(node->right) {
node = node->right;
- else
+ } else {
break;
+ }
} else {
break;
}
}
- if(result)
+ if(result) {
*result = c;
+ }
+
return node;
}
node = splay_search_closest_node(tree, data, &result);
- if(result < 0)
+ if(result < 0) {
node = node->prev;
+ }
return node;
}
node = splay_search_closest_node(tree, data, &result);
- if(result > 0)
+ if(result > 0) {
node = node->next;
+ }
return node;
}
/* Insertion and deletion */
-splay_node_t *splay_insert(splay_tree_t *tree, void *data) {
- splay_node_t *closest, *new;
- int result;
-
- if(!tree->root) {
- new = splay_alloc_node();
- new->data = data;
- splay_insert_top(tree, new);
- } else {
- closest = splay_search_closest_node(tree, data, &result);
-
- if(!result)
- return NULL;
-
- new = splay_alloc_node();
- new->data = data;
-
- if(result < 0)
- splay_insert_before(tree, closest, new);
- else
- splay_insert_after(tree, closest, new);
- }
-
- return new;
-}
-
-splay_node_t *splay_insert_node(splay_tree_t *tree, splay_node_t *node) {
- splay_node_t *closest;
- int result;
-
- if(!tree->root)
- splay_insert_top(tree, node);
- else {
- closest = splay_search_closest_node(tree, node->data, &result);
-
- if(!result)
- return NULL;
-
- if(result < 0)
- splay_insert_before(tree, closest, node);
- else
- splay_insert_after(tree, closest, node);
- }
-
- return node;
-}
-
-void splay_insert_top(splay_tree_t *tree, splay_node_t *node) {
+static void splay_insert_top(splay_tree_t *tree, splay_node_t *node) {
node->prev = node->next = node->left = node->right = node->parent = NULL;
tree->head = tree->tail = tree->root = node;
+ tree->count++;
}
-void splay_insert_before(splay_tree_t *tree, splay_node_t *before, splay_node_t *node) {
+static void splay_insert_after(splay_tree_t *tree, splay_node_t *after, splay_node_t *node);
+
+static void splay_insert_before(splay_tree_t *tree, splay_node_t *before, splay_node_t *node) {
if(!before) {
- if(tree->tail)
+ if(tree->tail) {
splay_insert_after(tree, tree->tail, node);
- else
+ } else {
splay_insert_top(tree, node);
+ }
+
return;
}
node->next = before;
- if((node->prev = before->prev))
+
+ if((node->prev = before->prev)) {
before->prev->next = node;
- else
+ } else {
tree->head = node;
+ }
+
before->prev = node;
splay_bottom_up(tree, before);
node->right = before;
before->parent = node;
- if((node->left = before->left))
+
+ if((node->left = before->left)) {
before->left->parent = node;
+ }
+
before->left = NULL;
node->parent = NULL;
tree->root = node;
+ tree->count++;
}
-void splay_insert_after(splay_tree_t *tree, splay_node_t *after, splay_node_t *node) {
+static void splay_insert_after(splay_tree_t *tree, splay_node_t *after, splay_node_t *node) {
if(!after) {
- if(tree->head)
+ if(tree->head) {
splay_insert_before(tree, tree->head, node);
- else
+ } else {
splay_insert_top(tree, node);
+ }
+
return;
}
node->prev = after;
- if((node->next = after->next))
+
+ if((node->next = after->next)) {
after->next->prev = node;
- else
+ } else {
tree->tail = node;
+ }
+
after->next = node;
splay_bottom_up(tree, after);
node->left = after;
after->parent = node;
- if((node->right = after->right))
+
+ if((node->right = after->right)) {
after->right->parent = node;
+ }
+
after->right = NULL;
node->parent = NULL;
tree->root = node;
+ tree->count++;
+}
+
+splay_node_t *splay_insert(splay_tree_t *tree, void *data) {
+ splay_node_t *closest, *new;
+ int result;
+
+ if(!tree->root) {
+ new = splay_alloc_node();
+ new->data = data;
+ splay_insert_top(tree, new);
+ } else {
+ closest = splay_search_closest_node(tree, data, &result);
+
+ if(!result) {
+ return NULL;
+ }
+
+ new = splay_alloc_node();
+ new->data = data;
+
+ if(result < 0) {
+ splay_insert_before(tree, closest, new);
+ } else {
+ splay_insert_after(tree, closest, new);
+ }
+ }
+
+ return new;
+}
+
+splay_node_t *splay_insert_node(splay_tree_t *tree, splay_node_t *node) {
+ splay_node_t *closest;
+ int result;
+
+ node->left = node->right = node->parent = node->next = node->prev = NULL;
+
+ if(!tree->root) {
+ splay_insert_top(tree, node);
+ } else {
+ closest = splay_search_closest_node(tree, node->data, &result);
+
+ if(!result) {
+ return NULL;
+ }
+
+ if(result < 0) {
+ splay_insert_before(tree, closest, node);
+ } else {
+ splay_insert_after(tree, closest, node);
+ }
+ }
+
+ return node;
}
splay_node_t *splay_unlink(splay_tree_t *tree, void *data) {
node = splay_search_node(tree, data);
- if(node)
+ if(node) {
splay_unlink_node(tree, node);
+ }
return node;
}
void splay_unlink_node(splay_tree_t *tree, splay_node_t *node) {
- if(node->prev)
+ assert(tree->count);
+ assert(node->prev || tree->head == node);
+ assert(node->next || tree->tail == node);
+
+ if(node->prev) {
node->prev->next = node->next;
- else
+ } else {
tree->head = node->next;
+ }
- if(node->next)
+ if(node->next) {
node->next->prev = node->prev;
- else
+ } else {
tree->tail = node->prev;
+ }
splay_bottom_up(tree, node);
if(node->prev) {
node->left->parent = NULL;
tree->root = node->left;
- if((node->prev->right = node->right))
+
+ if((node->prev->right = node->right)) {
node->right->parent = node->prev;
+ }
} else if(node->next) {
tree->root = node->right;
node->right->parent = NULL;
} else {
tree->root = NULL;
}
+
+ tree->count--;
}
void splay_delete_node(splay_tree_t *tree, splay_node_t *node) {
node = splay_search_node(tree, data);
- if(node)
+ if(node) {
splay_delete_node(tree, node);
+ }
}
/* Fast tree cleanup */
for(splay_node_t *node = tree->head, *next; node; node = next) {
next = node->next;
splay_free_node(tree, node);
+ tree->count--;
}
- splay_free_tree(tree);
+ assert(!tree->count);
+ free(tree);
}
/* Tree walking */
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