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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* rbtree.c
*
* Copyright (C) 2020 David Oberhollenzer <goliath@infraroot.at>
*/
#include "config.h"
#include "rbtree.h"
#include "../test.h"
static int key_compare(const void *a, const void *b)
{
return *((sqfs_s32 *)a) - *((sqfs_s32 *)b);
}
static size_t count_nodes_dfs(rbtree_node_t *n)
{
return 1 + (n->left == NULL ? 0 : count_nodes_dfs(n->left))
+ (n->right == NULL ? 0 : count_nodes_dfs(n->right));
}
static size_t min_depth(rbtree_node_t *n)
{
size_t lhs, rhs;
if (n == NULL)
return 0;
lhs = min_depth(n->left) + 1;
rhs = min_depth(n->right) + 1;
return lhs < rhs ? lhs : rhs;
}
static size_t max_depth(rbtree_node_t *n)
{
size_t lhs, rhs;
if (n == NULL)
return 0;
lhs = min_depth(n->left) + 1;
rhs = min_depth(n->right) + 1;
return lhs > rhs ? lhs : rhs;
}
static size_t get_ref_black_depth(rbtree_t *rb)
{
rbtree_node_t *n;
size_t count = 0;
for (n = rb->root; n != NULL; n = n->left) {
if (!n->is_red)
count += 1;
}
return count;
}
static void check_binary_tree_dfs(rbtree_node_t *n)
{
const void *key = rbtree_node_key(n);
const void *cmp;
if (n->left != NULL) {
cmp = rbtree_node_key(n->left);
TEST_ASSERT(key_compare(cmp, key) < 0);
check_binary_tree_dfs(n->left);
}
if (n->right != NULL) {
cmp = rbtree_node_key(n->right);
TEST_ASSERT(key_compare(cmp, key) > 0);
check_binary_tree_dfs(n->right);
}
}
static void check_colors_dfs(rbtree_node_t *n)
{
if (n->is_red) {
TEST_ASSERT(n->left == NULL || !n->left->is_red);
TEST_ASSERT(n->right == NULL || !n->right->is_red);
}
if (n->left != NULL)
check_colors_dfs(n->left);
if (n->right != NULL)
check_colors_dfs(n->right);
}
static void check_black_depth_dfs(rbtree_node_t *n, size_t ref,
size_t counter)
{
if (!n->is_red)
counter += 1;
if (n->left == NULL || n->right == NULL)
TEST_EQUAL_UI(counter, ref);
if (n->left != NULL)
check_black_depth_dfs(n->left, ref, counter);
if (n->right != NULL)
check_black_depth_dfs(n->right, ref, counter);
}
int main(void)
{
size_t count, blkdepth, mind, maxd;
sqfs_s32 key, key2;
rbtree_node_t *n;
sqfs_u64 value;
rbtree_t rb;
TEST_ASSERT(rbtree_init(&rb, sizeof(sqfs_s32),
sizeof(sqfs_u64), key_compare) == 0);
count = 0;
for (key = -1000; key < 1000; ++key) {
/* lookup of current key must fail prior to insert */
TEST_NULL(rbtree_lookup(&rb, &key));
/* previous key/value pairs must still be there */
for (key2 = -1000; key2 < key; ++key2) {
n = rbtree_lookup(&rb, &key2);
TEST_NOT_NULL(n);
value = *((sqfs_u64 *)rbtree_node_value(n));
TEST_EQUAL_UI((sqfs_u64)(key2 + 10000), value);
}
/* insert key value pair */
value = key + 10000;
TEST_ASSERT(rbtree_insert(&rb, &key, &value) == 0);
count += 1;
/* check if the tree has the right number of nodes */
TEST_EQUAL_UI(count_nodes_dfs(rb.root), count);
/* check if it is still a binary tree */
check_binary_tree_dfs(rb.root);
/* root node must be black. Every red node
must have black children. */
TEST_ASSERT(!rb.root->is_red);
check_colors_dfs(rb.root);
/* every path from the root to a leave must have
the same number of black nodes. */
blkdepth = get_ref_black_depth(&rb);
check_black_depth_dfs(rb.root, blkdepth, 0);
/* longest root to leaf path must be at most
twice as long as the shortest. */
mind = min_depth(rb.root);
maxd = max_depth(rb.root);
TEST_ASSERT(maxd <= mind * 2);
/* lookup of current key must work after insert */
n = rbtree_lookup(&rb, &key);
TEST_NOT_NULL(n);
value = *((sqfs_u64 *)rbtree_node_value(n));
TEST_EQUAL_UI((sqfs_u64)(key + 10000), value);
}
rbtree_cleanup(&rb);
return EXIT_SUCCESS;
}
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