/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 2016 Olaf Wintermann. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "avl.h"
#define ptrcast(ptr) ((void*)(ptr))
#define alloc_tree(al) (UcxAVLTree*) almalloc((al), sizeof(UcxAVLTree))
#define alloc_node(al) (UcxAVLNode*) almalloc((al), sizeof(UcxAVLNode))
static void ucx_avl_connect(UcxAVLTree *tree,
UcxAVLNode *node, UcxAVLNode *child, intptr_t nullkey) {
if (child) {
child->parent = node;
}
// if child is NULL, nullkey decides if left or right pointer is cleared
if (tree->cmpfunc(
ptrcast(child ? child->key : nullkey),
ptrcast(node->key), tree->userdata) > 0) {
node->right = child;
} else {
node->left = child;
}
size_t lh = node->left ? node->left->height : 0;
size_t rh = node->right ? node->right->height : 0;
node->height = 1 + (lh > rh ? lh : rh);
}
#define avlheight(node) ((node) ? (node)->height : 0)
static UcxAVLNode* avl_rotright(UcxAVLTree *tree, UcxAVLNode *l0) {
UcxAVLNode *p = l0->parent;
UcxAVLNode *l1 = l0->left;
if (p) {
ucx_avl_connect(tree, p, l1, 0);
} else {
l1->parent = NULL;
}
ucx_avl_connect(tree, l0, l1->right, l1->key);
ucx_avl_connect(tree, l1, l0, 0);
return l1;
}
static UcxAVLNode* avl_rotleft(UcxAVLTree *tree, UcxAVLNode *l0) {
UcxAVLNode *p = l0->parent;
UcxAVLNode *l1 = l0->right;
if (p) {
ucx_avl_connect(tree, p, l1, 0);
} else {
l1->parent = NULL;
}
ucx_avl_connect(tree, l0, l1->left, l1->key);
ucx_avl_connect(tree, l1, l0, 0);
return l1;
}
static void ucx_avl_balance(UcxAVLTree *tree, UcxAVLNode *n) {
int lh = avlheight(n->left);
int rh = avlheight(n->right);
n->height = 1 + (lh > rh ? lh : rh);
if (lh - rh == 2) {
UcxAVLNode *c = n->left;
if (avlheight(c->right) - avlheight(c->left) == 1) {
avl_rotleft(tree, c);
}
n = avl_rotright(tree, n);
} else if (rh - lh == 2) {
UcxAVLNode *c = n->right;
if (avlheight(c->left) - avlheight(c->right) == 1) {
avl_rotright(tree, c);
}
n = avl_rotleft(tree, n);
}
if (n->parent) {
ucx_avl_balance(tree, n->parent);
} else {
tree->root = n;
}
}
UcxAVLTree *ucx_avl_new(cmp_func cmpfunc) {
return ucx_avl_new_a(cmpfunc, ucx_default_allocator());
}
UcxAVLTree *ucx_avl_new_a(cmp_func cmpfunc, UcxAllocator *allocator) {
UcxAVLTree* tree = alloc_tree(allocator);
if (tree) {
tree->allocator = allocator;
tree->cmpfunc = cmpfunc;
tree->root = NULL;
tree->userdata = NULL;
}
return tree;
}
static void ucx_avl_free_node(UcxAllocator *al, UcxAVLNode *node) {
if (node) {
ucx_avl_free_node(al, node->left);
ucx_avl_free_node(al, node->right);
alfree(al, node);
}
}
void ucx_avl_free(UcxAVLTree *tree) {
UcxAllocator *al = tree->allocator;
ucx_avl_free_node(al, tree->root);
alfree(al, tree);
}
UcxAVLNode *ucx_avl_get_node(UcxAVLTree *tree, intptr_t key) {
UcxAVLNode *n = tree->root;
int cmpresult;
while (n && (cmpresult = tree->cmpfunc(
ptrcast(key), ptrcast(n->key), tree->userdata))) {
n = cmpresult > 0 ? n->right : n->left;
}
return n;
}
void *ucx_avl_get(UcxAVLTree *tree, intptr_t key) {
UcxAVLNode *n = ucx_avl_get_node(tree, key);
return n ? n->value : NULL;
}
int ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value) {
return ucx_avl_put_s(tree, key, value, NULL);
}
int ucx_avl_put_s(UcxAVLTree *tree, intptr_t key, void *value,
void **oldvalue) {
if (tree->root) {
UcxAVLNode *n = tree->root;
int cmpresult;
while ((cmpresult = tree->cmpfunc(
ptrcast(key), ptrcast(n->key), tree->userdata))) {
UcxAVLNode *m = cmpresult > 0 ? n->right : n->left;
if (m) {
n = m;
} else {
break;
}
}
if (cmpresult) {
UcxAVLNode* e = alloc_node(tree->allocator);
if (e) {
e->key = key; e->value = value; e->height = 1;
e->parent = e->left = e->right = NULL;
ucx_avl_connect(tree, n, e, 0);
ucx_avl_balance(tree, n);
return 0;
} else {
return 1;
}
} else {
if (oldvalue) {
*oldvalue = n->value;
}
n->value = value;
return 0;
}
} else {
tree->root = alloc_node(tree->allocator);
if (tree->root) {
tree->root->key = key; tree->root->value = value;
tree->root->height = 1;
tree->root->parent = tree->root->left = tree->root->right = NULL;
if (oldvalue) {
*oldvalue = NULL;
}
return 0;
} else {
return 1;
}
}
}
int ucx_avl_remove(UcxAVLTree *tree, intptr_t key) {
return ucx_avl_remove_s(tree, key, NULL, NULL);
}
int ucx_avl_remove_node(UcxAVLTree *tree, UcxAVLNode *node) {
return ucx_avl_remove_s(tree, node->key, NULL, NULL);
}
int ucx_avl_remove_s(UcxAVLTree *tree, intptr_t key,
intptr_t *oldkey, void **oldvalue) {
UcxAVLNode *n = tree->root;
int cmpresult;
while (n && (cmpresult = tree->cmpfunc(
ptrcast(key), ptrcast(n->key), tree->userdata))) {
n = cmpresult > 0 ? n->right : n->left;
}
if (n) {
if (oldkey) {
*oldkey = n->key;
}
if (oldvalue) {
*oldvalue = n->value;
}
UcxAVLNode *p = n->parent;
if (n->left && n->right) {
UcxAVLNode *s = n->right;
while (s->left) {
s = s->left;
}
ucx_avl_connect(tree, s->parent, s->right, s->key);
n->key = s->key; n->value = s->value;
p = s->parent;
alfree(tree->allocator, s);
} else {
if (p) {
ucx_avl_connect(tree, p, n->right ? n->right:n->left, n->key);
} else {
tree->root = n->right ? n->right : n->left;
if (tree->root) {
tree->root->parent = NULL;
}
}
alfree(tree->allocator, n);
}
if (p) {
ucx_avl_balance(tree, p);
}
return 0;
} else {
return 1;
}
}
static size_t ucx_avl_countn(UcxAVLNode *node) {
if (node) {
return 1 + ucx_avl_countn(node->left) + ucx_avl_countn(node->right);
} else {
return 0;
}
}
size_t ucx_avl_count(UcxAVLTree *tree) {
return ucx_avl_countn(tree->root);
}