--- a/ucx/tree.c Thu Nov 28 17:53:13 2024 +0100
+++ b/ucx/tree.c Mon Jan 06 21:18:36 2025 +0100
@@ -33,146 +33,248 @@
#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)
-void cx_tree_link(
- void *restrict parent,
- void *restrict node,
+#define cx_tree_ptr_locations \
+ loc_parent, loc_children, loc_last_child, loc_prev, loc_next
+
+#define cx_tree_node_layout(tree) \
+ (tree)->loc_parent,\
+ (tree)->loc_children,\
+ (tree)->loc_last_child,\
+ (tree)->loc_prev, \
+ (tree)->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;
+ if (loc_prev >= 0) {
+ 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 *parent,
+ void *node,
+ ptrdiff_t loc_parent,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ assert(loc_parent >= 0);
+ assert(loc_children >= 0);
+ assert(loc_next >= 0);
+
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;
+ void *child;
+ if (loc_last_child >= 0) {
+ child = tree_last_child(parent);
+ tree_last_child(parent) = node;
+ } else {
+ child = tree_children(parent);
+ void *next;
+ while ((next = tree_next(child)) != NULL) {
+ child = next;
+ }
+ }
+ if (loc_prev >= 0) {
+ tree_prev(node) = child;
+ }
+ tree_next(child) = node;
}
tree_parent(node) = parent;
}
+static void *cx_tree_node_prev(
+ ptrdiff_t loc_parent,
+ ptrdiff_t loc_children,
+ ptrdiff_t loc_next,
+ const void *node
+) {
+ void *parent = tree_parent(node);
+ void *begin = tree_children(parent);
+ if (begin == node) return NULL;
+ const void *cur = begin;
+ const void *next;
+ while (1) {
+ next = tree_next(cur);
+ if (next == node) return (void *) cur;
+ cur = next;
+ }
+}
+
void cx_tree_unlink(
void *node,
ptrdiff_t loc_parent,
ptrdiff_t loc_children,
+ ptrdiff_t loc_last_child,
ptrdiff_t loc_prev,
ptrdiff_t loc_next
) {
if (tree_parent(node) == NULL) return;
- void *left = tree_prev(node);
+ assert(loc_children >= 0);
+ assert(loc_next >= 0);
+ assert(loc_parent >= 0);
+ void *left;
+ if (loc_prev >= 0) {
+ left = tree_prev(node);
+ } else {
+ left = cx_tree_node_prev(loc_parent, loc_children, loc_next, 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 {
+ if (loc_prev >= 0) {
+ tree_prev(right) = left;
+ }
+ }
+
tree_parent(node) = NULL;
- tree_prev(node) = NULL;
tree_next(node) = NULL;
+ if (loc_prev >= 0) {
+ tree_prev(node) = NULL;
+ }
}
int cx_tree_search(
- void const *root,
- void const *data,
+ const void *root,
+ size_t depth,
+ const void *node,
cx_tree_search_func sfunc,
void **result,
ptrdiff_t loc_children,
ptrdiff_t loc_next
) {
- int ret;
+ // help avoiding bugs due to uninitialized memory
+ assert(result != NULL);
*result = NULL;
- // shortcut: compare root before doing anything else
- ret = sfunc(root, data);
+ // remember return value for best match
+ int ret = sfunc(root, node);
if (ret < 0) {
- return ret;
- } else if (ret == 0 || tree_children(root) == NULL) {
- *result = (void*)root;
+ // not contained, exit
+ return -1;
+ }
+ *result = (void*) root;
+ // if root is already exact match, exit
+ if (ret == 0) {
+ return 0;
+ }
+
+ // when depth is one, we are already done
+ if (depth == 1) {
return ret;
}
- // create a working stack
- CX_ARRAY_DECLARE(void const*, work);
- cx_array_initialize(work, 32);
+ // special case: indefinite depth
+ if (depth == 0) {
+ depth = SIZE_MAX;
+ }
+
+ // create an iterator
+ CxTreeIterator iter = cx_tree_iterator(
+ (void*) root, false, loc_children, loc_next
+ );
+
+ // skip root, we already handled it
+ cxIteratorNext(iter);
- // 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);
+ // loop through the remaining tree
+ cx_foreach(void *, elem, iter) {
+ // investigate the current node
+ int ret_elem = sfunc(elem, node);
+ if (ret_elem == 0) {
+ // if found, exit the search
+ *result = (void *) elem;
+ ret = 0;
+ break;
+ } else if (ret_elem > 0 && ret_elem < ret) {
+ // new distance is better
+ *result = elem;
+ ret = ret_elem;
+ } else {
+ // not contained or distance is worse, skip entire subtree
+ cxTreeIteratorContinue(iter);
+ }
+
+ // when we reached the max depth, skip the subtree
+ if (iter.depth == depth) {
+ cxTreeIteratorContinue(iter);
}
}
- // remember a candidate for adding the data
- // also remember the exact return code from sfunc
- void *candidate = NULL;
- int ret_candidate = -1;
-
- // process the working stack
- while (work_size > 0) {
- // pop element
- void const *node = work[--work_size];
-
- // apply the search function
- ret = sfunc(node, data);
+ // dispose the iterator as we might have exited the loop early
+ cxTreeIteratorDispose(&iter);
- if (ret == 0) {
- // if found, exit the search
- *result = (void*) node;
- work_size = 0;
- break;
- } else if (ret > 0) {
- // if children might contain the data, add them to the stack
- void *c = tree_children(node);
- while (c != NULL) {
- cx_array_simple_add(work, c);
- c = tree_next(c);
- }
-
- // remember this node in case no child is suitable
- if (ret_candidate < 0 || ret < ret_candidate) {
- candidate = (void *) node;
- 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);
+ assert(ret < 0 || *result != NULL);
return ret;
}
-static bool cx_tree_iter_valid(void const *it) {
- struct cx_tree_iterator_s const *iter = it;
+int cx_tree_search_data(
+ const void *root,
+ size_t depth,
+ 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, depth, 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(void const *it) {
- struct cx_tree_iterator_s const *iter = it;
+static void *cx_tree_iter_current(const void *it) {
+ const struct cx_tree_iterator_s *iter = it;
return iter->node;
}
@@ -180,6 +282,8 @@
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;
@@ -265,17 +369,8 @@
iter.loc_next = loc_next;
iter.visit_on_exit = visit_on_exit;
- // allocate stack
- iter.stack_capacity = 16;
- iter.stack = malloc(sizeof(void *) * 16);
- iter.depth = 0;
-
- // visit the root node
- iter.node = root;
+ // initialize members
iter.node_next = NULL;
- iter.counter = 1;
- iter.depth = 1;
- iter.stack[0] = root;
iter.exiting = false;
iter.skip = false;
@@ -287,20 +382,35 @@
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(void const *it) {
- struct cx_tree_visitor_s const *iter = it;
+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(void const *it) {
- struct cx_tree_visitor_s const *iter = it;
+static void *cx_tree_visitor_current(const void *it) {
+ const struct cx_tree_visitor_s *iter = it;
return iter->node;
}
-__attribute__((__nonnull__))
+cx_attr_nonnull
static void cx_tree_visitor_enqueue_siblings(
struct cx_tree_visitor_s *iter, void *node, ptrdiff_t loc_next) {
node = tree_next(node);
@@ -318,6 +428,9 @@
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;
@@ -377,13 +490,7 @@
iter.loc_children = loc_children;
iter.loc_next = loc_next;
- // allocate stack
- iter.depth = 0;
-
- // visit the root node
- iter.node = root;
- iter.counter = 1;
- iter.depth = 1;
+ // initialize members
iter.skip = false;
iter.queue_next = NULL;
iter.queue_last = NULL;
@@ -396,6 +503,552 @@
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,
+ 0,
+ *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,
+ 0,
+ 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 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,
+ size_t depth
+) {
+ if (tree->root == NULL) return NULL;
+
+ void *found;
+ if (0 == cx_tree_search_data(
+ subtree,
+ depth,
+ 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_insert_element,
+ cx_tree_default_insert_many,
+ cx_tree_default_find
+};
+
+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
+) {
+ if (allocator == NULL) {
+ allocator = cxDefaultAllocator;
+ }
+ assert(create_func != NULL);
+ assert(search_func != NULL);
+ assert(search_data_func != NULL);
+
+ 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->simple_destructor = NULL;
+ 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;
+}
+
+void cxTreeFree(CxTree *tree) {
+ if (tree == NULL) return;
+ if (tree->root != NULL) {
+ cxTreeClear(tree);
+ }
+ cxFree(tree->allocator, 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
+) {
+ if (allocator == NULL) {
+ allocator = cxDefaultAllocator;
+ }
+ assert(root != NULL);
+
+ 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;
+}
+
+void cxTreeSetParent(
+ CxTree *tree,
+ void *parent,
+ void *child
+) {
+ size_t loc_parent = tree->loc_parent;
+ if (tree_parent(child) == NULL) {
+ tree->size++;
+ }
+ cx_tree_link(parent, child, cx_tree_node_layout(tree));
+}
+
+void cxTreeAddChildNode(
+ CxTree *tree,
+ void *parent,
+ void *child
+) {
+ cx_tree_link(parent, child, cx_tree_node_layout(tree));
+ tree->size++;
+}
+
+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 = cx_tree_visitor(
+ tree->root, tree->loc_children, tree->loc_next
+ );
+ while (cxIteratorValid(visitor)) {
+ cxIteratorNext(visitor);
+ }
+ return visitor.depth;
+}
+
+int cxTreeRemoveNode(
+ 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;
+}
+
+int cxTreeDestroyNode(
+ CxTree *tree,
+ void *node,
+ cx_tree_relink_func relink_func
+) {
+ int result = cxTreeRemoveNode(tree, node, relink_func);
+ if (result == 0) {
+ if (tree->simple_destructor) {
+ tree->simple_destructor(node);
+ }
+ if (tree->advanced_destructor) {
+ tree->advanced_destructor(tree->destructor_data, node);
+ }
+ return 0;
+ } else {
+ return result;
+ }
+}
+
+void cxTreeDestroySubtree(CxTree *tree, void *node) {
+ cx_tree_unlink(node, cx_tree_node_layout(tree));
+ CxTreeIterator iter = cx_tree_iterator(
+ node, true,
+ tree->loc_children, tree->loc_next
+ );
+ cx_foreach(void *, child, iter) {
+ if (iter.exiting) {
+ if (tree->simple_destructor) {
+ tree->simple_destructor(child);
+ }
+ if (tree->advanced_destructor) {
+ tree->advanced_destructor(tree->destructor_data, child);
+ }
+ }
+ }
+ tree->size -= iter.counter;
+ if (node == tree->root) {
+ tree->root = NULL;
+ }
+}