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
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
/*
* Tests for Basic Tree Operations
* This test does some basic tree operations and verifies their correctness. It
* validates the RB-Tree invariants after each operation, to guarantee the
* stability of the tree.
*
* For testing purposes, we use the memory address of a node as its key, and
* order nodes in ascending order.
*/
#undef NDEBUG
#include <assert.h>
#include <c-stdaux.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "c-rbtree.h"
#include "c-rbtree-private.h"
static size_t validate(CRBTree *t) {
unsigned int i_black, n_black;
CRBNode *n, *p, *o;
size_t count = 0;
c_assert(t);
c_assert(!t->root || c_rbnode_is_black(t->root));
/* traverse to left-most child, count black nodes */
i_black = 0;
n = t->root;
while (n && n->left) {
if (c_rbnode_is_black(n))
++i_black;
n = n->left;
}
n_black = i_black;
/*
* Traverse tree and verify correctness:
* 1) A node is either red or black
* 2) The root is black
* 3) All leaves are black
* 4) Every red node must have two black child nodes
* 5) Every path to a leaf contains the same number of black nodes
*
* Note that NULL nodes are considered black, which is why we don't
* check for 3).
*/
o = NULL;
while (n) {
++count;
/* verify natural order */
c_assert(n > o);
o = n;
/* verify consistency */
c_assert(!n->right || c_rbnode_parent(n->right) == n);
c_assert(!n->left || c_rbnode_parent(n->left) == n);
/* verify 2) */
if (!c_rbnode_parent(n))
c_assert(c_rbnode_is_black(n));
if (c_rbnode_is_red(n)) {
/* verify 4) */
c_assert(!n->left || c_rbnode_is_black(n->left));
c_assert(!n->right || c_rbnode_is_black(n->right));
} else {
/* verify 1) */
c_assert(c_rbnode_is_black(n));
}
/* verify 5) */
if (!n->left && !n->right)
c_assert(i_black == n_black);
/* get next node */
if (n->right) {
n = n->right;
if (c_rbnode_is_black(n))
++i_black;
while (n->left) {
n = n->left;
if (c_rbnode_is_black(n))
++i_black;
}
} else {
while ((p = c_rbnode_parent(n)) && n == p->right) {
n = p;
if (c_rbnode_is_black(p->right))
--i_black;
}
n = p;
if (p && c_rbnode_is_black(p->left))
--i_black;
}
}
return count;
}
static void insert(CRBTree *t, CRBNode *n) {
CRBNode **i, *p;
c_assert(t);
c_assert(n);
c_assert(!c_rbnode_is_linked(n));
i = &t->root;
p = NULL;
while (*i) {
p = *i;
if (n < *i) {
i = &(*i)->left;
} else {
c_assert(n > *i);
i = &(*i)->right;
}
}
c_rbtree_add(t, p, i, n);
}
static void shuffle(CRBNode **nodes, size_t n_memb) {
unsigned int i, j;
CRBNode *t;
for (i = 0; i < n_memb; ++i) {
j = rand() % n_memb;
t = nodes[j];
nodes[j] = nodes[i];
nodes[i] = t;
}
}
static void test_shuffle(void) {
CRBNode *nodes[512];
CRBTree t = {};
unsigned int i, j;
size_t n;
/* allocate and initialize all nodes */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
nodes[i] = malloc(sizeof(*nodes[i]));
c_assert(nodes[i]);
c_rbnode_init(nodes[i]);
}
/* shuffle nodes and validate *empty* tree */
shuffle(nodes, sizeof(nodes) / sizeof(*nodes));
n = validate(&t);
c_assert(n == 0);
/* add all nodes and validate after each insertion */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
insert(&t, nodes[i]);
n = validate(&t);
c_assert(n == i + 1);
}
/* shuffle nodes again */
shuffle(nodes, sizeof(nodes) / sizeof(*nodes));
/* remove all nodes (in different order) and validate on each round */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
c_rbnode_unlink(nodes[i]);
n = validate(&t);
c_assert(n == sizeof(nodes) / sizeof(*nodes) - i - 1);
}
/* shuffle nodes and validate *empty* tree again */
shuffle(nodes, sizeof(nodes) / sizeof(*nodes));
n = validate(&t);
c_assert(n == 0);
/* add all nodes again */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
insert(&t, nodes[i]);
n = validate(&t);
c_assert(n == i + 1);
}
/* 4 times, remove half of the nodes and add them again */
for (j = 0; j < 4; ++j) {
/* shuffle nodes again */
shuffle(nodes, sizeof(nodes) / sizeof(*nodes));
/* remove half of the nodes */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes) / 2; ++i) {
c_rbnode_unlink(nodes[i]);
n = validate(&t);
c_assert(n == sizeof(nodes) / sizeof(*nodes) - i - 1);
}
/* shuffle the removed half */
shuffle(nodes, sizeof(nodes) / sizeof(*nodes) / 2);
/* add the removed half again */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes) / 2; ++i) {
insert(&t, nodes[i]);
n = validate(&t);
c_assert(n == sizeof(nodes) / sizeof(*nodes) / 2 + i + 1);
}
}
/* shuffle nodes again */
shuffle(nodes, sizeof(nodes) / sizeof(*nodes));
/* remove all */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
c_rbnode_unlink(nodes[i]);
n = validate(&t);
c_assert(n == sizeof(nodes) / sizeof(*nodes) - i - 1);
}
/* free nodes again */
for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i)
free(nodes[i]);
}
int main(int argc, char **argv) {
unsigned int i;
/* we want stable tests, so use fixed seed */
srand(0xdeadbeef);
/*
* The tests are pseudo random; run them multiple times, each run will
* have different orders and thus different results.
*/
for (i = 0; i < 4; ++i)
test_shuffle();
return 0;
}
|
