--- a/ucx/tree.c Thu Oct 03 18:54:19 2024 +0200
+++ b/ucx/tree.c Sun Oct 06 12:00:31 2024 +0200
@@ -28,37 +28,72 @@
#include "cx/tree.h"
+#include "cx/array_list.h"
+
#include <assert.h>
#define CX_TREE_PTR(cur, off) (*(void**)(((char*)(cur))+(off)))
-#define CX_TREE_PTR(cur, off) (*(void**)(((char*)(cur))+(off)))
#define tree_parent(node) CX_TREE_PTR(node, loc_parent)
#define tree_children(node) CX_TREE_PTR(node, loc_children)
+#define tree_last_child(node) CX_TREE_PTR(node, loc_last_child)
#define tree_prev(node) CX_TREE_PTR(node, loc_prev)
#define tree_next(node) CX_TREE_PTR(node, loc_next)
+#define cx_tree_ptr_locations \
+ loc_parent, loc_children, loc_last_child, loc_prev, loc_next
+
+static void cx_tree_zero_pointers(
+ void *node,
+ ptrdiff_t loc_parent,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ tree_parent(node) = NULL;
+ tree_prev(node) = NULL;
+ tree_next(node) = NULL;
+ tree_children(node) = NULL;
+ if (loc_last_child >= 0) {
+ tree_last_child(node) = NULL;
+ }
+}
+
void cx_tree_link(
void *restrict parent,
void *restrict node,
ptrdiff_t loc_parent,
ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
ptrdiff_t loc_prev,
ptrdiff_t loc_next
) {
void *current_parent = tree_parent(node);
if (current_parent == parent) return;
if (current_parent != NULL) {
- cx_tree_unlink(node, loc_parent, loc_children,
- loc_prev, loc_next);
+ cx_tree_unlink(node, cx_tree_ptr_locations);
}
if (tree_children(parent) == NULL) {
tree_children(parent) = node;
+ if (loc_last_child >= 0) {
+ tree_last_child(parent) = node;
+ }
} else {
- void *children = tree_children(parent);
- tree_prev(children) = node;
- tree_next(node) = children;
- tree_children(parent) = node;
+ if (loc_last_child >= 0) {
+ void *child = tree_last_child(parent);
+ tree_prev(node) = child;
+ tree_next(child) = node;
+ tree_last_child(parent) = node;
+ } else {
+ void *child = tree_children(parent);
+ void *next;
+ while ((next = tree_next(child)) != NULL) {
+ child = next;
+ }
+ tree_prev(node) = child;
+ tree_next(child) = node;
+ }
}
tree_parent(node) = parent;
}
@@ -67,6 +102,7 @@
void *node,
ptrdiff_t loc_parent,
ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
ptrdiff_t loc_prev,
ptrdiff_t loc_next
) {
@@ -74,14 +110,849 @@
void *left = tree_prev(node);
void *right = tree_next(node);
- assert(left == NULL || tree_children(tree_parent(node)) != node);
+ void *parent = tree_parent(node);
+ assert(left == NULL || tree_children(parent) != node);
+ assert(right == NULL || loc_last_child < 0 ||
+ tree_last_child(parent) != node);
+
if (left == NULL) {
- tree_children(tree_parent(node)) = right;
+ tree_children(parent) = right;
} else {
tree_next(left) = right;
}
- if (right != NULL) tree_prev(right) = left;
+ if (right == NULL) {
+ if (loc_last_child >= 0) {
+ tree_last_child(parent) = left;
+ }
+ } else {
+ tree_prev(right) = left;
+ }
+
tree_parent(node) = NULL;
tree_prev(node) = NULL;
tree_next(node) = NULL;
}
+
+int cx_tree_search(
+ const void *root,
+ const void *node,
+ cx_tree_search_func sfunc,
+ void **result,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_next
+) {
+ int ret;
+ *result = NULL;
+
+ // shortcut: compare root before doing anything else
+ ret = sfunc(root, node);
+ if (ret < 0) {
+ return ret;
+ } else if (ret == 0 || tree_children(root) == NULL) {
+ *result = (void*)root;
+ return ret;
+ }
+
+ // create a working stack
+ CX_ARRAY_DECLARE(const void *, work);
+ cx_array_initialize(work, 32);
+
+ // add the children of root to the working stack
+ {
+ void *c = tree_children(root);
+ while (c != NULL) {
+ cx_array_simple_add(work, c);
+ c = tree_next(c);
+ }
+ }
+
+ // remember a candidate for adding the data
+ // also remember the exact return code from sfunc
+ void *candidate = (void *) root;
+ int ret_candidate = ret;
+
+ // process the working stack
+ while (work_size > 0) {
+ // pop element
+ const void *elem = work[--work_size];
+
+ // apply the search function
+ ret = sfunc(elem, node);
+
+ if (ret == 0) {
+ // if found, exit the search
+ *result = (void *) elem;
+ work_size = 0;
+ break;
+ } else if (ret > 0) {
+ // if children might contain the data, add them to the stack
+ void *c = tree_children(elem);
+ while (c != NULL) {
+ cx_array_simple_add(work, c);
+ c = tree_next(c);
+ }
+
+ // remember this node in case no child is suitable
+ if (ret < ret_candidate) {
+ candidate = (void *) elem;
+ ret_candidate = ret;
+ }
+ }
+ }
+
+ // not found, but was there a candidate?
+ if (ret != 0 && candidate != NULL) {
+ ret = ret_candidate;
+ *result = candidate;
+ }
+
+ // free the working queue and return
+ free(work);
+ return ret;
+}
+
+int cx_tree_search_data(
+ const void *root,
+ const void *data,
+ cx_tree_search_data_func sfunc,
+ void **result,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_next
+) {
+ // it is basically the same implementation
+ return cx_tree_search(
+ root, data,
+ (cx_tree_search_func) sfunc,
+ result,
+ loc_children, loc_next);
+}
+
+static bool cx_tree_iter_valid(const void *it) {
+ const struct cx_tree_iterator_s *iter = it;
+ return iter->node != NULL;
+}
+
+static void *cx_tree_iter_current(const void *it) {
+ const struct cx_tree_iterator_s *iter = it;
+ return iter->node;
+}
+
+static void cx_tree_iter_next(void *it) {
+ struct cx_tree_iterator_s *iter = it;
+ ptrdiff_t const loc_next = iter->loc_next;
+ ptrdiff_t const loc_children = iter->loc_children;
+ // protect us from misuse
+ if (!iter->base.valid(iter)) return;
+
+ void *children;
+
+ // check if we are currently exiting or entering nodes
+ if (iter->exiting) {
+ children = NULL;
+ // skipping on exit is pointless, just clear the flag
+ iter->skip = false;
+ } else {
+ if (iter->skip) {
+ // skip flag is set, pretend that there are no children
+ iter->skip = false;
+ children = NULL;
+ } else {
+ // try to enter the children (if any)
+ children = tree_children(iter->node);
+ }
+ }
+
+ if (children == NULL) {
+ // search for the next node
+ void *next;
+ cx_tree_iter_search_next:
+ // check if there is a sibling
+ if (iter->exiting) {
+ next = iter->node_next;
+ } else {
+ next = tree_next(iter->node);
+ iter->node_next = next;
+ }
+ if (next == NULL) {
+ // no sibling, we are done with this node and exit
+ if (iter->visit_on_exit && !iter->exiting) {
+ // iter is supposed to visit the node again
+ iter->exiting = true;
+ } else {
+ iter->exiting = false;
+ if (iter->depth == 1) {
+ // there is no parent - we have iterated the entire tree
+ // invalidate the iterator and free the node stack
+ iter->node = iter->node_next = NULL;
+ iter->stack_capacity = iter->depth = 0;
+ free(iter->stack);
+ iter->stack = NULL;
+ } else {
+ // the parent node can be obtained from the top of stack
+ // this way we can avoid the loc_parent in the iterator
+ iter->depth--;
+ iter->node = iter->stack[iter->depth - 1];
+ // retry with the parent node to find a sibling
+ goto cx_tree_iter_search_next;
+ }
+ }
+ } else {
+ if (iter->visit_on_exit && !iter->exiting) {
+ // iter is supposed to visit the node again
+ iter->exiting = true;
+ } else {
+ iter->exiting = false;
+ // move to the sibling
+ iter->counter++;
+ iter->node = next;
+ // new top of stack is the sibling
+ iter->stack[iter->depth - 1] = next;
+ }
+ }
+ } else {
+ // node has children, push the first child onto the stack and enter it
+ cx_array_simple_add(iter->stack, children);
+ iter->node = children;
+ iter->counter++;
+ }
+}
+
+CxTreeIterator cx_tree_iterator(
+ void *root,
+ bool visit_on_exit,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_next
+) {
+ CxTreeIterator iter;
+ iter.loc_children = loc_children;
+ iter.loc_next = loc_next;
+ iter.visit_on_exit = visit_on_exit;
+
+ // initialize members
+ iter.node_next = NULL;
+ iter.exiting = false;
+ iter.skip = false;
+
+ // assign base iterator functions
+ iter.base.mutating = false;
+ iter.base.remove = false;
+ iter.base.current_impl = NULL;
+ iter.base.valid = cx_tree_iter_valid;
+ iter.base.next = cx_tree_iter_next;
+ iter.base.current = cx_tree_iter_current;
+
+ // visit the root node
+ iter.node = root;
+ if (root != NULL) {
+ iter.stack_capacity = 16;
+ iter.stack = malloc(sizeof(void *) * 16);
+ iter.stack[0] = root;
+ iter.counter = 1;
+ iter.depth = 1;
+ } else {
+ iter.stack_capacity = 0;
+ iter.stack = NULL;
+ iter.counter = 0;
+ iter.depth = 0;
+ }
+
+ return iter;
+}
+
+static bool cx_tree_visitor_valid(const void *it) {
+ const struct cx_tree_visitor_s *iter = it;
+ return iter->node != NULL;
+}
+
+static void *cx_tree_visitor_current(const void *it) {
+ const struct cx_tree_visitor_s *iter = it;
+ return iter->node;
+}
+
+__attribute__((__nonnull__))
+static void cx_tree_visitor_enqueue_siblings(
+ struct cx_tree_visitor_s *iter, void *node, ptrdiff_t loc_next) {
+ node = tree_next(node);
+ while (node != NULL) {
+ struct cx_tree_visitor_queue_s *q;
+ q = malloc(sizeof(struct cx_tree_visitor_queue_s));
+ q->depth = iter->queue_last->depth;
+ q->node = node;
+ iter->queue_last->next = q;
+ iter->queue_last = q;
+ node = tree_next(node);
+ }
+ iter->queue_last->next = NULL;
+}
+
+static void cx_tree_visitor_next(void *it) {
+ struct cx_tree_visitor_s *iter = it;
+ // protect us from misuse
+ if (!iter->base.valid(iter)) return;
+
+ ptrdiff_t const loc_next = iter->loc_next;
+ ptrdiff_t const loc_children = iter->loc_children;
+
+ // add the children of the current node to the queue
+ // unless the skip flag is set
+ void *children;
+ if (iter->skip) {
+ iter->skip = false;
+ children = NULL;
+ } else {
+ children = tree_children(iter->node);
+ }
+ if (children != NULL) {
+ struct cx_tree_visitor_queue_s *q;
+ q = malloc(sizeof(struct cx_tree_visitor_queue_s));
+ q->depth = iter->depth + 1;
+ q->node = children;
+ if (iter->queue_last == NULL) {
+ assert(iter->queue_next == NULL);
+ iter->queue_next = q;
+ } else {
+ iter->queue_last->next = q;
+ }
+ iter->queue_last = q;
+ cx_tree_visitor_enqueue_siblings(iter, children, loc_next);
+ }
+
+ // check if there is a next node
+ if (iter->queue_next == NULL) {
+ iter->node = NULL;
+ return;
+ }
+
+ // dequeue the next node
+ iter->node = iter->queue_next->node;
+ iter->depth = iter->queue_next->depth;
+ {
+ struct cx_tree_visitor_queue_s *q = iter->queue_next;
+ iter->queue_next = q->next;
+ if (iter->queue_next == NULL) {
+ assert(iter->queue_last == q);
+ iter->queue_last = NULL;
+ }
+ free(q);
+ }
+
+ // increment the node counter
+ iter->counter++;
+}
+
+CxTreeVisitor cx_tree_visitor(
+ void *root,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_next
+) {
+ CxTreeVisitor iter;
+ iter.loc_children = loc_children;
+ iter.loc_next = loc_next;
+
+ // initialize members
+ iter.skip = false;
+ iter.queue_next = NULL;
+ iter.queue_last = NULL;
+
+ // assign base iterator functions
+ iter.base.mutating = false;
+ iter.base.remove = false;
+ iter.base.current_impl = NULL;
+ iter.base.valid = cx_tree_visitor_valid;
+ iter.base.next = cx_tree_visitor_next;
+ iter.base.current = cx_tree_visitor_current;
+
+ // visit the root node
+ iter.node = root;
+ if (root != NULL) {
+ iter.counter = 1;
+ iter.depth = 1;
+ } else {
+ iter.counter = 0;
+ iter.depth = 0;
+ }
+
+ return iter;
+}
+
+static void cx_tree_add_link_duplicate(
+ void *original, void *duplicate,
+ ptrdiff_t loc_parent, ptrdiff_t loc_children, ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev, ptrdiff_t loc_next
+) {
+ void *shared_parent = tree_parent(original);
+ if (shared_parent == NULL) {
+ cx_tree_link(original, duplicate, cx_tree_ptr_locations);
+ } else {
+ cx_tree_link(shared_parent, duplicate, cx_tree_ptr_locations);
+ }
+}
+
+static void cx_tree_add_link_new(
+ void *parent, void *node, cx_tree_search_func sfunc,
+ ptrdiff_t loc_parent, ptrdiff_t loc_children, ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev, ptrdiff_t loc_next
+) {
+ // check the current children one by one,
+ // if they could be children of the new node
+ void *child = tree_children(parent);
+ while (child != NULL) {
+ void *next = tree_next(child);
+
+ if (sfunc(node, child) > 0) {
+ // the sibling could be a child -> re-link
+ cx_tree_link(node, child, cx_tree_ptr_locations);
+ }
+
+ child = next;
+ }
+
+ // add new node as new child
+ cx_tree_link(parent, node, cx_tree_ptr_locations);
+}
+
+int cx_tree_add(
+ const void *src,
+ cx_tree_search_func sfunc,
+ cx_tree_node_create_func cfunc,
+ void *cdata,
+ void **cnode,
+ void *root,
+ ptrdiff_t loc_parent,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ *cnode = cfunc(src, cdata);
+ if (*cnode == NULL) return 1;
+ cx_tree_zero_pointers(*cnode, cx_tree_ptr_locations);
+
+ void *match = NULL;
+ int result = cx_tree_search(
+ root,
+ *cnode,
+ sfunc,
+ &match,
+ loc_children,
+ loc_next
+ );
+
+ if (result < 0) {
+ // node does not fit into the tree - return non-zero value
+ return 1;
+ } else if (result == 0) {
+ // data already found in the tree, link duplicate
+ cx_tree_add_link_duplicate(match, *cnode, cx_tree_ptr_locations);
+ } else {
+ // closest match found, add new node
+ cx_tree_add_link_new(match, *cnode, sfunc, cx_tree_ptr_locations);
+ }
+
+ return 0;
+}
+
+unsigned int cx_tree_add_look_around_depth = 3;
+
+size_t cx_tree_add_iter(
+ struct cx_iterator_base_s *iter,
+ size_t num,
+ cx_tree_search_func sfunc,
+ cx_tree_node_create_func cfunc,
+ void *cdata,
+ void **failed,
+ void *root,
+ ptrdiff_t loc_parent,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ // erase the failed pointer
+ *failed = NULL;
+
+ // iter not valid? cancel...
+ if (!iter->valid(iter)) return 0;
+
+ size_t processed = 0;
+ void *current_node = root;
+ const void *elem;
+
+ for (void **eptr; processed < num &&
+ iter->valid(iter) && (eptr = iter->current(iter)) != NULL;
+ iter->next(iter)) {
+ elem = *eptr;
+
+ // create the new node
+ void *new_node = cfunc(elem, cdata);
+ if (new_node == NULL) return processed;
+ cx_tree_zero_pointers(new_node, cx_tree_ptr_locations);
+
+ // start searching from current node
+ void *match;
+ int result;
+ unsigned int look_around_retries = cx_tree_add_look_around_depth;
+ cx_tree_add_look_around_retry:
+ result = cx_tree_search(
+ current_node,
+ new_node,
+ sfunc,
+ &match,
+ loc_children,
+ loc_next
+ );
+
+ if (result < 0) {
+ // traverse upwards and try to find better parents
+ void *parent = tree_parent(current_node);
+ if (parent != NULL) {
+ if (look_around_retries > 0) {
+ look_around_retries--;
+ current_node = parent;
+ } else {
+ // look around retries exhausted, start from the root
+ current_node = root;
+ }
+ goto cx_tree_add_look_around_retry;
+ } else {
+ // no parents. so we failed
+ *failed = new_node;
+ return processed;
+ }
+ } else if (result == 0) {
+ // data already found in the tree, link duplicate
+ cx_tree_add_link_duplicate(match, new_node, cx_tree_ptr_locations);
+ // but stick with the original match, in case we needed a new root
+ current_node = match;
+ } else {
+ // closest match found, add new node as child
+ cx_tree_add_link_new(match, new_node, sfunc,
+ cx_tree_ptr_locations);
+ current_node = match;
+ }
+
+ processed++;
+ }
+ return processed;
+}
+
+size_t cx_tree_add_array(
+ const void *src,
+ size_t num,
+ size_t elem_size,
+ cx_tree_search_func sfunc,
+ cx_tree_node_create_func cfunc,
+ void *cdata,
+ void **failed,
+ void *root,
+ ptrdiff_t loc_parent,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ // erase failed pointer
+ *failed = NULL;
+
+ // super special case: zero elements
+ if (num == 0) {
+ return 0;
+ }
+
+ // special case: one element does not need an iterator
+ if (num == 1) {
+ void *node;
+ if (0 == cx_tree_add(
+ src, sfunc, cfunc, cdata, &node, root,
+ loc_parent, loc_children, loc_last_child,
+ loc_prev, loc_next)) {
+ return 1;
+ } else {
+ *failed = node;
+ return 0;
+ }
+ }
+
+ // otherwise, create iterator and hand over to other function
+ CxIterator iter = cxIterator(src, elem_size, num);
+ return cx_tree_add_iter(cxIteratorRef(iter), num, sfunc,
+ cfunc, cdata, failed, root,
+ loc_parent, loc_children, loc_last_child,
+ loc_prev, loc_next);
+}
+
+static void cx_tree_default_destructor(CxTree *tree) {
+ if (tree->simple_destructor != NULL || tree->advanced_destructor != NULL) {
+ CxTreeIterator iter = tree->cl->iterator(tree, true);
+ cx_foreach(void *, node, iter) {
+ if (iter.exiting) {
+ if (tree->simple_destructor) {
+ tree->simple_destructor(node);
+ }
+ if (tree->advanced_destructor) {
+ tree->advanced_destructor(tree->destructor_data, node);
+ }
+ }
+ }
+ }
+ cxFree(tree->allocator, tree);
+}
+
+static CxTreeIterator cx_tree_default_iterator(
+ CxTree *tree,
+ bool visit_on_exit
+) {
+ return cx_tree_iterator(
+ tree->root, visit_on_exit,
+ tree->loc_children, tree->loc_next
+ );
+}
+
+static CxTreeVisitor cx_tree_default_visitor(CxTree *tree) {
+ return cx_tree_visitor(tree->root, tree->loc_children, tree->loc_next);
+}
+
+static int cx_tree_default_insert_element(
+ CxTree *tree,
+ const void *data
+) {
+ void *node;
+ if (tree->root == NULL) {
+ node = tree->node_create(data, tree);
+ if (node == NULL) return 1;
+ cx_tree_zero_pointers(node, cx_tree_node_layout(tree));
+ tree->root = node;
+ tree->size = 1;
+ return 0;
+ }
+ int result = cx_tree_add(data, tree->search, tree->node_create,
+ tree, &node, tree->root, cx_tree_node_layout(tree));
+ if (0 == result) {
+ tree->size++;
+ } else {
+ cxFree(tree->allocator, node);
+ }
+ return result;
+}
+
+static size_t cx_tree_default_insert_many(
+ CxTree *tree,
+ struct cx_iterator_base_s *iter,
+ size_t n
+) {
+ size_t ins = 0;
+ if (!iter->valid(iter)) return 0;
+ if (tree->root == NULL) {
+ // use the first element from the iter to create the root node
+ void **eptr = iter->current(iter);
+ void *node = tree->node_create(*eptr, tree);
+ if (node == NULL) return 0;
+ cx_tree_zero_pointers(node, cx_tree_node_layout(tree));
+ tree->root = node;
+ ins = 1;
+ iter->next(iter);
+ }
+ void *failed;
+ ins += cx_tree_add_iter(iter, n, tree->search, tree->node_create,
+ tree, &failed, tree->root, cx_tree_node_layout(tree));
+ tree->size += ins;
+ if (ins < n) {
+ cxFree(tree->allocator, failed);
+ }
+ return ins;
+}
+
+static void *cx_tree_default_find(
+ CxTree *tree,
+ const void *subtree,
+ const void *data
+) {
+ if (tree->root == NULL) return NULL;
+
+ void *found;
+ if (0 == cx_tree_search_data(
+ subtree,
+ data,
+ tree->search_data,
+ &found,
+ tree->loc_children,
+ tree->loc_next
+ )) {
+ return found;
+ } else {
+ return NULL;
+ }
+}
+
+static cx_tree_class cx_tree_default_class = {
+ cx_tree_default_destructor,
+ cx_tree_default_insert_element,
+ cx_tree_default_insert_many,
+ cx_tree_default_find,
+ cx_tree_default_iterator,
+ cx_tree_default_visitor
+};
+
+CxTree *cxTreeCreate(
+ const CxAllocator *allocator,
+ cx_tree_node_create_func create_func,
+ cx_tree_search_func search_func,
+ cx_tree_search_data_func search_data_func,
+ ptrdiff_t loc_parent,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ CxTree *tree = cxMalloc(allocator, sizeof(CxTree));
+ if (tree == NULL) return NULL;
+
+ tree->cl = &cx_tree_default_class;
+ tree->allocator = allocator;
+ tree->node_create = create_func;
+ tree->search = search_func;
+ tree->search_data = search_data_func;
+ tree->advanced_destructor = (cx_destructor_func2) cxFree;
+ tree->destructor_data = (void *) allocator;
+ tree->loc_parent = loc_parent;
+ tree->loc_children = loc_children;
+ tree->loc_last_child = loc_last_child;
+ tree->loc_prev = loc_prev;
+ tree->loc_next = loc_next;
+ tree->root = NULL;
+ tree->size = 0;
+
+ return tree;
+}
+
+CxTree *cxTreeCreateWrapped(
+ const CxAllocator *allocator,
+ void *root,
+ ptrdiff_t loc_parent,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ CxTree *tree = cxMalloc(allocator, sizeof(CxTree));
+ if (tree == NULL) return NULL;
+
+ tree->cl = &cx_tree_default_class;
+ // set the allocator anyway, just in case...
+ tree->allocator = allocator;
+ tree->node_create = NULL;
+ tree->search = NULL;
+ tree->search_data = NULL;
+ tree->simple_destructor = NULL;
+ tree->advanced_destructor = NULL;
+ tree->destructor_data = NULL;
+ tree->loc_parent = loc_parent;
+ tree->loc_children = loc_children;
+ tree->loc_last_child = loc_last_child;
+ tree->loc_prev = loc_prev;
+ tree->loc_next = loc_next;
+ tree->root = root;
+ tree->size = cxTreeSubtreeSize(tree, root);
+ return tree;
+}
+
+int cxTreeAddChild(
+ CxTree *tree,
+ void *parent,
+ const void *data) {
+ void *node = tree->node_create(data, tree);
+ if (node == NULL) return 1;
+ cx_tree_zero_pointers(node, cx_tree_node_layout(tree));
+ cx_tree_link(parent, node, cx_tree_node_layout(tree));
+ tree->size++;
+ return 0;
+}
+
+size_t cxTreeSubtreeSize(CxTree *tree, void *subtree_root) {
+ CxTreeVisitor visitor = cx_tree_visitor(
+ subtree_root,
+ tree->loc_children,
+ tree->loc_next
+ );
+ while (cxIteratorValid(visitor)) {
+ cxIteratorNext(visitor);
+ }
+ return visitor.counter;
+}
+
+size_t cxTreeSubtreeDepth(CxTree *tree, void *subtree_root) {
+ CxTreeVisitor visitor = cx_tree_visitor(
+ subtree_root,
+ tree->loc_children,
+ tree->loc_next
+ );
+ while (cxIteratorValid(visitor)) {
+ cxIteratorNext(visitor);
+ }
+ return visitor.depth;
+}
+
+size_t cxTreeDepth(CxTree *tree) {
+ CxTreeVisitor visitor = tree->cl->visitor(tree);
+ while (cxIteratorValid(visitor)) {
+ cxIteratorNext(visitor);
+ }
+ return visitor.depth;
+}
+
+int cxTreeRemove(
+ CxTree *tree,
+ void *node,
+ cx_tree_relink_func relink_func
+) {
+ if (node == tree->root) return 1;
+
+ // determine the new parent
+ ptrdiff_t loc_parent = tree->loc_parent;
+ void *new_parent = tree_parent(node);
+
+ // first, unlink from the parent
+ cx_tree_unlink(node, cx_tree_node_layout(tree));
+
+ // then relink each child
+ ptrdiff_t loc_children = tree->loc_children;
+ ptrdiff_t loc_next = tree->loc_next;
+ void *child = tree_children(node);
+ while (child != NULL) {
+ // forcibly set the parent to NULL - we do not use the unlink function
+ // because that would unnecessarily modify the children linked list
+ tree_parent(child) = NULL;
+
+ // update contents, if required
+ if (relink_func != NULL) {
+ relink_func(child, node, new_parent);
+ }
+
+ // link to new parent
+ cx_tree_link(new_parent, child, cx_tree_node_layout(tree));
+
+ // proceed to next child
+ child = tree_next(child);
+ }
+
+ // clear the linked list of the removed node
+ tree_children(node) = NULL;
+ ptrdiff_t loc_last_child = tree->loc_last_child;
+ if (loc_last_child >= 0) tree_last_child(node) = NULL;
+
+ // the tree now has one member less
+ tree->size--;
+
+ return 0;
+}
+
+void cxTreeRemoveSubtree(CxTree *tree, void *node) {
+ if (node == tree->root) {
+ tree->root = NULL;
+ tree->size = 0;
+ return;
+ }
+ size_t subtree_size = cxTreeSubtreeSize(tree, node);
+ cx_tree_unlink(node, cx_tree_node_layout(tree));
+ tree->size -= subtree_size;
+}