aboutsummaryrefslogtreecommitdiff
path: root/src/bstree.c
blob: f0312a800624233839229beec5593ee8f4d89cef (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
/*
 * Copyright 2021 Yaroslav de la Peña Smirnov
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include "bstree.h"

#include <stdlib.h>

struct bstree *
bstree_new(bst_cmp_fn bstcmp, bst_free_fn bstfree)
{
	struct bstree *tree = malloc(sizeof *tree);
	tree->root = NULL;
	tree->cmp = bstcmp;
	tree->free = bstfree;

	return tree;
}

struct bstnode *
bstree_add(struct bstree *tree, void *val)
{
	struct bstnode **cur;
	struct bstnode *prev = NULL;
	cur = &tree->root;
	while (*cur != NULL) {
		prev = *cur;
		if (tree->cmp(val, prev->value) < 0) {
			cur = &prev->left;
		} else {
			cur = &prev->right;
		}
	}
	*cur = calloc(1, sizeof **cur);
	(*cur)->value = val;
	(*cur)->parent = prev;

	return *cur;
}

struct bstnode *
bstree_search(struct bstree *tree, void *val)
{
	struct bstnode *node = tree->root;
	while (node != NULL) {
		int res;
		if ((res = tree->cmp(val, node->value)) == 0) {
			break;
		}
		if (res < 0) {
			node = node->left;
		} else {
			node = node->right;
		}
	}

	return node;
}

#define bstree_extreme(node, d) \
	while (node != NULL && node->d != NULL) { \
		node = node->d; \
	}

struct bstnode *
bstree_max(struct bstnode *node)
{
	bstree_extreme(node, right)
	return node;
}

struct bstnode *
bstree_min(struct bstnode *node)
{
	bstree_extreme(node, left)
	return node;
}

#define bstree_xcessor(na, d, m) \
	if (na->d != NULL) { \
		return bstree_##m(na->d); \
	} \
	struct bstnode *nb = na->parent; \
	while (nb != NULL && nb->d == na) { \
		na = nb; \
		nb = nb->parent; \
	} \
	return nb

struct bstnode *
bstree_successor(struct bstnode *na)
{
	bstree_xcessor(na, right, max);
}

struct bstnode *
bstree_predecessor(struct bstnode *na)
{
	bstree_xcessor(na, left, min);
}

bool
bstree_inorder_walk(struct bstnode *node, bst_walk_cb cb, void *data)
{
	if (node->left != NULL) {
		if (!bstree_inorder_walk(node->left, cb, data)) return false;
	}
	if (!cb(node, data)) return false;
	if (node->right != NULL) {
		if (!bstree_inorder_walk(node->right, cb, data)) return false;
	}
	return true;
}

static void
bstree_transplant(struct bstree *tree, struct bstnode *a, struct bstnode *b)
{
	if (a->parent == NULL) {
		tree->root = b;
	} else if (a == a->parent->left) {
		a->parent->left = b;
	} else {
		a->parent->right = b;
	}
	if (b != NULL) {
		b->parent = a->parent;
	}
}

void
bstree_remove(struct bstree *tree, struct bstnode *na)
{
	if (na->left == NULL) {
		bstree_transplant(tree, na, na->right);
	} else if (na->right == NULL) {
		bstree_transplant(tree, na, na->left);
	} else {
		struct bstnode *nb = bstree_min(na->right);
		if (nb->parent != na) {
			bstree_transplant(tree, nb, nb->right);
			nb->right = na->right;
			nb->right->parent = nb;
		}
		bstree_transplant(tree, na, nb);
		nb->left = na->left;
		nb->left->parent = nb;
	}
	tree->free(na->value);
	free(na);
}

static void
bstree_subdestroy(struct bstree *tree, struct bstnode *node)
{
	if (node->right) bstree_subdestroy(tree, node->right);
	if (node->left) bstree_subdestroy(tree, node->left);
	tree->free(node->value);
	free(node);
}

void
bstree_destroy(struct bstree *tree)
{
	if (tree->root) bstree_subdestroy(tree, tree->root);
	free(tree);
}