}
}
+/**
+ * CRBCompareFunc - compare a node to a key
+ * @t: tree where the node is linked to
+ * @k: key to compare
+ * @n: node to compare
+ *
+ * If you use the tree-traversal helpers (which are optional), you need to
+ * provide this callback so they can compare nodes in a tree to the key you
+ * look for.
+ *
+ * The tree @t is provided as optional context to this callback. The key you
+ * look for is provided as @k, the current node that should be compared to is
+ * provided as @n. This function should work like strcmp(), that is, return -1
+ * if @key orders before @n, 0 if both compare equal, and 1 if it orders after
+ * @n.
+ */
+typedef int (*CRBCompareFunc) (CRBTree *t, void *k, CRBNode *n);
+
+/**
+ * c_rbtree_find_node() - find node
+ * @t: tree to search through
+ * @f: comparison function
+ * @k: key to search for
+ *
+ * This searches through @t for a node that compares equal to @k. The function
+ * @f must be provided by the caller, which is used to compare nodes to @k. See
+ * the documentation of CRBCompareFunc for details.
+ *
+ * If there are multiple entries that compare equal to @k, this will return a
+ * pseudo-randomly picked node. If you need stable lookup functions for trees
+ * where duplicate entries are allowed, you better code your own lookup.
+ *
+ * Return: Pointer to matching node, or NULL.
+ */
+static inline CRBNode *c_rbtree_find_node(CRBTree *t, CRBCompareFunc f, const void *k) {
+ CRBNode *i;
+
+ assert(t);
+ assert(f);
+
+ i = t->root;
+ while (i) {
+ int v = f(t, (void *)k, i);
+ if (v < 0)
+ i = i->left;
+ else if (v > 0)
+ i = i->right;
+ else
+ return i;
+ }
+
+ return NULL;
+}
+
+/**
+ * c_rbtree_find_entry() - find entry
+ * @_t: tree to search through
+ * @_f: comparison function
+ * @_k: key to search for
+ * @_t: type of the structure that embeds the nodes
+ * @_o: name of the node-member in type @_t
+ *
+ * This is very similar to c_rbtree_find_node(), but instead of returning a
+ * pointer to the CRBNode, it returns a pointer to the surrounding object. This
+ * object must embed the CRBNode object. The type of the surrounding object
+ * must be given as @_t, and the name of the embedded CRBNode member as @_o.
+ *
+ * See c_rbtree_find_node() for more details.
+ *
+ * Return: Pointer to found entry, NULL if not found.
+ */
+#define c_rbtree_find_entry(_m, _f, _k, _t, _o) \
+ ((_t *)(((char *)c_rbtree_find_node((_m), (_f), (_k)) ?: \
+ (char *)NULL + offsetof(_t, _o)) - offsetof(_t, _o)))
+
+/**
+ * c_rbtree_find_slot() - find slot to insert new node
+ * @t: tree to search through
+ * @f: comparison function
+ * @k: key to search for
+ * @p: output storage for parent pointer
+ *
+ * This searches through @t just like c_rbtree_find_node() does. However,
+ * instead of returning a pointer to a node that compares equal to @k, this
+ * searches for a slot to insert a node with key @k. A pointer to the slot is
+ * returned, and a pointer to the parent of the slot is stored in @p. Both
+ * can be passed directly to c_rbtree_add(), together with your node to insert.
+ *
+ * If there already is a node in the tree, that compares equal to @k, this will
+ * return NULL and store the conflicting node in @p. In all other cases,
+ * this will return a pointer (non-NULL) to the empty slot to insert the node
+ * at. @p will point to the parent node of that slot.
+ *
+ * If you want trees that allow duplicate nodes, you better code your own
+ * insertion function.
+ *
+ * Return: Pointer to slot to insert node, or NULL on conflicts.
+ */
+static inline CRBNode **c_rbtree_find_slot(CRBTree *t, CRBCompareFunc f, const void *k, CRBNode **p) {
+ CRBNode **i;
+
+ assert(t);
+ assert(f);
+ assert(p);
+
+ i = &t->root;
+ *p = NULL;
+ while (*i) {
+ int v = f(t, (void *)k, *i);
+ *p = *i;
+ if (v < 0)
+ i = &(*i)->left;
+ else if (v > 0)
+ i = &(*i)->right;
+ else
+ return NULL;
+ }
+
+ return i;
+}
+
#ifdef __cplusplus
}
#endif
--- /dev/null
+/***
+ This file is part of crbtree. See COPYING for details.
+
+ crbtree is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ crbtree is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with crbtree; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+/*
+ * Tests Map API
+ * This contains tests for the CRBMap API, which wraps CRBTree but provides
+ * insertion and lookup helpers. Tests for internal tree consistency are
+ * skipped here, as other tests already do that. This just tests for the
+ * extensions that CRBMap provides over CRBTree.
+ */
+
+#undef NDEBUG
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "crbtree.h"
+#include "crbtree-private.h"
+
+typedef struct {
+ unsigned long key;
+ CRBNode rb;
+} Node;
+
+#define node_from_rb(_rb) ((Node *)((char *)(_rb) - offsetof(Node, rb)))
+
+static int test_compare(CRBTree *t, void *k, CRBNode *n) {
+ unsigned long key = (unsigned long)k;
+ Node *node = node_from_rb(n);
+
+ return (key < node->key) ? -1 : (key > node->key) ? 1 : 0;
+}
+
+static void shuffle(Node **nodes, size_t n_memb) {
+ unsigned int i, j;
+ Node *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_map(void) {
+ CRBNode **slot, *p;
+ CRBTree t = {};
+ Node *nodes[2048];
+ unsigned long i;
+
+ /* allocate and initialize all nodes */
+ for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
+ nodes[i] = malloc(sizeof(*nodes[i]));
+ assert(nodes[i]);
+ nodes[i]->key = i;
+ c_rbnode_init(&nodes[i]->rb);
+ }
+
+ /* shuffle nodes */
+ shuffle(nodes, sizeof(nodes) / sizeof(*nodes));
+
+ /* add all nodes, and verify that each node is linked */
+ for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
+ assert(!c_rbnode_is_linked(&nodes[i]->rb));
+ assert(!c_rbtree_find_entry(&t, test_compare, (void *)nodes[i]->key, Node, rb));
+
+ slot = c_rbtree_find_slot(&t, test_compare, (void *)nodes[i]->key, &p);
+ assert(slot);
+ c_rbtree_add(&t, p, slot, &nodes[i]->rb);
+
+ assert(c_rbnode_is_linked(&nodes[i]->rb));
+ assert(nodes[i] == c_rbtree_find_entry(&t, test_compare, (void *)nodes[i]->key, Node, rb));
+ }
+
+ /* shuffle nodes again */
+ shuffle(nodes, sizeof(nodes) / sizeof(*nodes));
+
+ /* remove all nodes (in different order) */
+ for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i) {
+ assert(c_rbnode_is_linked(&nodes[i]->rb));
+ assert(nodes[i] == c_rbtree_find_entry(&t, test_compare, (void *)nodes[i]->key, Node, rb));
+
+ c_rbtree_remove_init(&t, &nodes[i]->rb);
+
+ assert(!c_rbnode_is_linked(&nodes[i]->rb));
+ assert(!c_rbtree_find_entry(&t, test_compare, (void *)nodes[i]->key, Node, rb));
+ }
+
+ /* free nodes again */
+ for (i = 0; i < sizeof(nodes) / sizeof(*nodes); ++i)
+ free(nodes[i]);
+}
+
+int main(int argc, char **argv) {
+ /* we want stable tests, so use fixed seed */
+ srand(0xdeadbeef);
+
+ test_map();
+ return 0;
+}
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