a0e4cae820
This adds an self-standing RB-Tree implementation to src/basic/. This will be needed for NSEC RR lookups, since we need "close lookups", which hashmaps (not even ordered-hashmaps) can give us in reasonable time.
363 lines
11 KiB
C
363 lines
11 KiB
C
/***
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This file is part of systemd. See COPYING for details.
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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/*
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* Tests for RB-Tree
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*/
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#undef NDEBUG
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#include <assert.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include "c-rbtree.h"
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/* verify that all API calls are exported */
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static void test_api(void) {
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CRBTree t = {};
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CRBNode n = C_RBNODE_INIT(n);
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assert(!c_rbnode_is_linked(&n));
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/* init, is_linked, add, remove, remove_init */
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c_rbtree_add(&t, NULL, &t.root, &n);
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assert(c_rbnode_is_linked(&n));
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c_rbtree_remove_init(&t, &n);
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assert(!c_rbnode_is_linked(&n));
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c_rbtree_add(&t, NULL, &t.root, &n);
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assert(c_rbnode_is_linked(&n));
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c_rbtree_remove(&t, &n);
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assert(c_rbnode_is_linked(&n)); /* @n wasn't touched */
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c_rbnode_init(&n);
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assert(!c_rbnode_is_linked(&n));
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/* first, last, leftmost, rightmost, next, prev */
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assert(!c_rbtree_first(&t));
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assert(!c_rbtree_last(&t));
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assert(&n == c_rbnode_leftmost(&n));
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assert(&n == c_rbnode_rightmost(&n));
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assert(!c_rbnode_next(&n));
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assert(!c_rbnode_prev(&n));
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}
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/* copied from c-rbtree.c, relies on internal representation */
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static inline _Bool c_rbnode_is_red(CRBNode *n) {
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return !((unsigned long)n->__parent_and_color & 1UL);
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}
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/* copied from c-rbtree.c, relies on internal representation */
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static inline _Bool c_rbnode_is_black(CRBNode *n) {
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return !!((unsigned long)n->__parent_and_color & 1UL);
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}
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static size_t validate(CRBTree *t) {
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unsigned int i_black, n_black;
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CRBNode *n, *p, *o;
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size_t count = 0;
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assert(t);
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assert(!t->root || c_rbnode_is_black(t->root));
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/* traverse to left-most child, count black nodes */
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i_black = 0;
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n = t->root;
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while (n && n->left) {
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if (c_rbnode_is_black(n))
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++i_black;
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n = n->left;
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}
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n_black = i_black;
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/*
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* Traverse tree and verify correctness:
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* 1) A node is either red or black
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* 2) The root is black
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* 3) All leaves are black
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* 4) Every red node must have two black child nodes
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* 5) Every path to a leaf contains the same number of black nodes
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*
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* Note that NULL nodes are considered black, which is why we don't
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* check for 3).
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*/
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o = NULL;
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while (n) {
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++count;
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/* verify natural order */
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assert(n > o);
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o = n;
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/* verify consistency */
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assert(!n->right || c_rbnode_parent(n->right) == n);
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assert(!n->left || c_rbnode_parent(n->left) == n);
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/* verify 2) */
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if (!c_rbnode_parent(n))
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assert(c_rbnode_is_black(n));
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if (c_rbnode_is_red(n)) {
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/* verify 4) */
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assert(!n->left || c_rbnode_is_black(n->left));
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assert(!n->right || c_rbnode_is_black(n->right));
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} else {
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/* verify 1) */
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assert(c_rbnode_is_black(n));
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}
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/* verify 5) */
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if (!n->left && !n->right)
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assert(i_black == n_black);
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/* get next node */
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if (n->right) {
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n = n->right;
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if (c_rbnode_is_black(n))
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++i_black;
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while (n->left) {
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n = n->left;
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if (c_rbnode_is_black(n))
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++i_black;
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}
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} else {
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while ((p = c_rbnode_parent(n)) && n == p->right) {
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n = p;
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if (c_rbnode_is_black(p->right))
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--i_black;
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}
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n = p;
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if (p && c_rbnode_is_black(p->left))
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--i_black;
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}
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}
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return count;
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}
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static void insert(CRBTree *t, CRBNode *n) {
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CRBNode **i, *p;
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assert(t);
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assert(n);
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assert(!c_rbnode_is_linked(n));
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i = &t->root;
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p = NULL;
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while (*i) {
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p = *i;
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if (n < *i) {
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i = &(*i)->left;
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} else {
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assert(n > *i);
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i = &(*i)->right;
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}
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}
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c_rbtree_add(t, p, i, n);
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}
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static void shuffle(void **nodes, size_t n_memb) {
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unsigned int i, j;
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void *t;
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for (i = 0; i < n_memb; ++i) {
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j = rand() % n_memb;
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t = nodes[j];
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nodes[j] = nodes[i];
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nodes[i] = t;
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}
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}
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/* run some pseudo-random tests on the tree */
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static void test_shuffle(void) {
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CRBNode *nodes[256];
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CRBTree t = {};
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unsigned int i, j;
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size_t n;
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/* allocate and initialize all nodes */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
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nodes[i] = malloc(sizeof(*nodes[i]));
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assert(nodes[i]);
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c_rbnode_init(nodes[i]);
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}
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/* shuffle nodes and validate *empty* tree */
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shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
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n = validate(&t);
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assert(n == 0);
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/* add all nodes and validate after each insertion */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
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insert(&t, nodes[i]);
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n = validate(&t);
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assert(n == i + 1);
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}
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/* shuffle nodes again */
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shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
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/* remove all nodes (in different order) and validate on each round */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
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c_rbtree_remove(&t, nodes[i]);
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n = validate(&t);
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assert(n == sizeof(nodes) / sizeof(*nodes) - i - 1);
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c_rbnode_init(nodes[i]);
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}
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/* shuffle nodes and validate *empty* tree again */
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shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
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n = validate(&t);
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assert(n == 0);
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/* add all nodes again */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
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insert(&t, nodes[i]);
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n = validate(&t);
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assert(n == i + 1);
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}
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/* 4 times, remove half of the nodes and add them again */
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for (j = 0; j < 4; ++j) {
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/* shuffle nodes again */
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shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
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/* remove half of the nodes */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes) / 2; ++i) {
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c_rbtree_remove(&t, nodes[i]);
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n = validate(&t);
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assert(n == sizeof(nodes) / sizeof(*nodes) - i - 1);
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c_rbnode_init(nodes[i]);
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}
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/* shuffle the removed half */
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shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes) / 2);
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/* add the removed half again */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes) / 2; ++i) {
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insert(&t, nodes[i]);
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n = validate(&t);
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assert(n == sizeof(nodes) / sizeof(*nodes) / 2 + i + 1);
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}
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}
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/* shuffle nodes again */
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shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
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/* remove all */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
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c_rbtree_remove(&t, nodes[i]);
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n = validate(&t);
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assert(n == sizeof(nodes) / sizeof(*nodes) - i - 1);
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c_rbnode_init(nodes[i]);
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}
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/* free nodes again */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i)
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free(nodes[i]);
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}
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typedef struct {
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unsigned long key;
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CRBNode rb;
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} Node;
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#define node_from_rb(_rb) ((Node *)((char *)(_rb) - offsetof(Node, rb)))
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static int compare(CRBTree *t, void *k, CRBNode *n) {
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unsigned long key = (unsigned long)k;
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Node *node = node_from_rb(n);
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return (key < node->key) ? -1 : (key > node->key) ? 1 : 0;
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}
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/* run tests against the c_rbtree_find*() helpers */
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static void test_map(void) {
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CRBNode **slot, *p;
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CRBTree t = {};
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Node *nodes[2048];
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unsigned long i;
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/* allocate and initialize all nodes */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
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nodes[i] = malloc(sizeof(*nodes[i]));
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assert(nodes[i]);
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nodes[i]->key = i;
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c_rbnode_init(&nodes[i]->rb);
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}
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/* shuffle nodes */
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shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
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/* add all nodes, and verify that each node is linked */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
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assert(!c_rbnode_is_linked(&nodes[i]->rb));
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assert(!c_rbtree_find_entry(&t, compare, (void *)nodes[i]->key, Node, rb));
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slot = c_rbtree_find_slot(&t, compare, (void *)nodes[i]->key, &p);
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assert(slot);
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c_rbtree_add(&t, p, slot, &nodes[i]->rb);
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assert(c_rbnode_is_linked(&nodes[i]->rb));
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assert(nodes[i] == c_rbtree_find_entry(&t, compare, (void *)nodes[i]->key, Node, rb));
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}
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/* shuffle nodes again */
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shuffle((void **)nodes, sizeof(nodes) / sizeof(*nodes));
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/* remove all nodes (in different order) */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
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assert(c_rbnode_is_linked(&nodes[i]->rb));
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assert(nodes[i] == c_rbtree_find_entry(&t, compare, (void *)nodes[i]->key, Node, rb));
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c_rbtree_remove_init(&t, &nodes[i]->rb);
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assert(!c_rbnode_is_linked(&nodes[i]->rb));
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assert(!c_rbtree_find_entry(&t, compare, (void *)nodes[i]->key, Node, rb));
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}
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/* free nodes again */
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for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i)
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free(nodes[i]);
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}
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int main(int argc, char **argv) {
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unsigned int i;
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/* we want stable tests, so use fixed seed */
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srand(0xdeadbeef);
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test_api();
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/*
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* The tests are pseudo random; run them multiple times, each run will
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* have different orders and thus different results.
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*/
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for (i = 0; i < 4; ++i) {
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test_shuffle();
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test_map();
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}
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return 0;
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}
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