diff -r 3f324ea53152 -r 21840975d541 src/tree.c
--- a/src/tree.c	Wed Feb 14 22:32:13 2024 +0100
+++ b/src/tree.c	Thu Feb 15 21:54:43 2024 +0100
@@ -28,6 +28,8 @@
 
 #include "cx/tree.h"
 
+#include "cx/array_list.h"
+
 #include <assert.h>
 
 #define CX_TREE_PTR(cur, off) (*(void**)(((char*)(cur))+(off)))
@@ -85,3 +87,85 @@
     tree_prev(node) = NULL;
     tree_next(node) = NULL;
 }
+
+int cx_tree_search(
+        void const *root,
+        void const *data,
+        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, data);
+    if (ret < 0) {
+        return ret;
+    } else if (ret == 0 || tree_children(root) == NULL) {
+        *result = (void*)root;
+        return ret;
+    }
+
+    // create a working stack
+    size_t work_cap = 32;
+    size_t work_size = 0;
+    void const **work = malloc(sizeof(void*) * work_cap);
+    #define work_add(node) cx_array_add(&work, &work_size, &work_cap, \
+        sizeof(void*), &(node), cx_array_default_reallocator)
+
+    // add the children of root to the working stack
+    {
+        void *c = tree_children(root);
+        while (c != NULL) {
+            work_add(c);
+            c = tree_next(c);
+        }
+    }
+
+    // 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);
+
+        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) {
+                work_add(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
+    #undef workq_add
+    free(work);
+    return ret;
+}