From 76ca84f72e10ec572318b26bf78aae177e57c1b0 Mon Sep 17 00:00:00 2001
From: Gregory Lirent <opensource@lirent.ru>
Date: Thu, 25 Aug 2022 21:43:31 +0300
Subject: [PATCH] Fix rbtree inorder iter

---
 src/rbtree.c | 61 ++++++++++++++++++----------------------------------
 1 file changed, 21 insertions(+), 40 deletions(-)

diff --git a/src/rbtree.c b/src/rbtree.c
index bd8c6b1..d93466b 100644
--- a/src/rbtree.c
+++ b/src/rbtree.c
@@ -196,60 +196,41 @@ void* libcdsb_builtin_rbtree_node_create(void* v, rbnode_t* p, int c, int n) {
 
 
 stack_t libcdsb_builtin_rbtree_iter_inorder(rbnode_t** root, bool reverse) {
-    rbnode_t *n, hack;
-    stack_t   z, *bot;
+    stack_t z, *cur;
+    rbnode_t     *n;
 
     memset(&z, 0, sizeof(z));
 
-    if (rbnode_is_empty(*root))
+    if (rbnode_is_empty(n = *root))
         return z;
 
-    hack.right = *root;
-    n          = &hack;
+    while (!rbnode_is_empty(n)) {
+        stack_insert(&z, n);
+        n = n->left;
+    }
 
-    for (bot = &z;;) {
-        for (;;) {
-            if (rbnode_is_empty(n->right)) {
+    cur     = z.prev;
+    z.value = z.prev->value;
+    z.prev  = z.prev->prev;
 
-                if (rbnode_is_root(n->parent) || n->parent->left == n) {
-                    n = n->parent;
-                    break;
-                } else n = n->parent;
+    free(cur);
 
-                if (rbnode_is_root(n->parent) || n->parent->left == n) {
-                    n = n->parent;
-                    break;
-                }
+    cur = &z;
 
-                do {
-                    n = n->parent;
-                } while (n->parent->right == n);
+    while ((cur = cur->prev)) {
+        n = cur->value;
 
-                n = n->parent;
-            } else {
-                n = n->right;
+        if (!rbnode_is_empty(n->right)) {
+            n = n->right;
 
-                while (!rbnode_is_empty(n->left))
-                    n = n->left;
-
-                break;
-            }
-
-            if (rbnode_is_root(n)) {
-                bot = z.prev;
-                z   = *bot;
-
-                free(bot);
-
-                if (reverse)
-                    stack_reverse(&z);
-
-                return z;
+            while (!rbnode_is_empty(n)) {
+                stack_insert(cur, n);
+                n = n->left;
             }
         }
-
-        bot = stack_insert(bot, n);
     }
+
+    return z;
 }