Tree builder not crashing, need to check functional correctness.

espReader/Reader.c

@@ -117,8 +117,12 @@ void asserts(void)
         assert(sizeof(Bytef) == sizeof(char));
 }
 
-void espr_walk(char *data, size_t size, struct walker_callbacks cb)
-{
+void espr_walk(
+        char *data, 
+        size_t size, 
+        struct walker_callbacks cb, 
+        void *from_parent
+) {
         // check assertions that cannot be checked at compile time
         asserts();
 
@@ -128,7 +132,7 @@ void espr_walk(char *data, size_t size, struct walker_callbacks cb)
         const Type4 type = *(const Type4 *)data;
         assert(type.uint == rt[TES4]);
 
-        data = walk_concat(data, size, cb, NULL);
+        data = walk_concat(data, size, cb, from_parent);
         assert(data == data_start + size);
 }
 
@@ -236,7 +240,7 @@ char *walk_record(char *data, struct walker_callbacks cb, void *from_parent)
 void espr_print(char *data, size_t size)
 {
         struct walker_callbacks cb = { .pre = print_cb };
-        espr_walk(data, size, cb);
+        espr_walk(data, size, cb, NULL);
 }
 
 void print_cb(
@@ -266,7 +270,7 @@ struct esp_stats espr_stats(char *data, size_t size)
 {
         struct esp_stats stats = { 0 };
         struct walker_callbacks cb = { .pre = stats_cb, .data = &stats };
-        espr_walk(data, size, cb);
+        espr_walk(data, size, cb, NULL);
         return stats;
 }
 
@@ -320,7 +324,7 @@ void espr_decompress(char *data, size_t size, char *buf, size_t buf_size)
                 .post = decompress_post, 
                 .data = &s 
         };
-        espr_walk(data, size, cb);
+        espr_walk(data, size, cb, NULL);
 }
 
 /* Handles the copying of groups and records, and the decompression of
@@ -639,10 +643,18 @@ Timestamp convert_ts(uint16_t ts)
 
 MetaNode *espr_create_tree(struct sized_buf in, struct sized_buf tree)
 {
-        const struct sized_buf tree_pre = tree;
+        // create root node
+        MetaNode *root = (MetaNode *)tree.data;
+        *root = (MetaNode){ 0 };
+
+        // update tree
+        sized_buf_update(&tree, sizeof(MetaNode));
+
+        // walk
         struct walker_callbacks cb = { .pre = create_tree_cb, .data = &tree };
-        espr_walk(in.data, in.size, cb);
-        return (MetaNode *)tree_pre.data;
+        espr_walk(in.data, in.size, cb, root);
+
+        return root;
 }
 
 void create_tree_cb(
@@ -656,18 +668,22 @@ void create_tree_cb(
 
         // add new metanode to tree
         struct sized_buf *tree = data;
-        assert(tree->size >= sizeof(MetaNode));
         MetaNode *m = (MetaNode *)tree->data;
-        tree->data += sizeof(MetaNode);
-        tree->size -= sizeof(MetaNode);
+        sized_buf_update(tree, sizeof(MetaNode));
 
+        // parent passes their MetaNode to children
         MetaNode *p = from_parent;
 
         // construct new node
+        *m = (MetaNode){ 0 }; // zero/null unused
         m->n = n;
         m->parent = p;
         m->prev = p->last_child;
-        p->last_child->next = m;
+        // the linked list of children may not already exist
+        if (p->last_child)
+                p->last_child->next = m;
+        else
+                p->first_child = m;
         p->last_child = m;
 
         // send self to children