From 1eaefde012ca2457bf7775467eda92b6375e90e5 Mon Sep 17 00:00:00 2001
From: Ivan Morozov <ivan.morozov@onlyoffice.com>
Date: Fri, 16 Sep 2022 22:54:30 +0300
Subject: [PATCH] Added experimental red-black tree output iterator. Fixed
 compoundfile Delete()

---
 Common/cfcpp/RBTree/rbtree.cpp | 40 +++++++++++++++++++++++++++++-----
 Common/cfcpp/RBTree/rbtree.h   | 20 ++++++++---------
 2 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/Common/cfcpp/RBTree/rbtree.cpp b/Common/cfcpp/RBTree/rbtree.cpp
index c3e0047f20..e4c193e05b 100644
--- a/Common/cfcpp/RBTree/rbtree.cpp
+++ b/Common/cfcpp/RBTree/rbtree.cpp
@@ -423,12 +423,40 @@ void RBTree::DoVisitTreeNodes(Action<PIRBNode> action, PIRBNode walker)
     }
 }
 
-RBTree::iterator::iterator(RBTree &tree, bool end)
+RBTree::iterator::iterator(RBTree *tree) : tree(tree)
 {
-    Action<PIRBNode> inserter = [&] (PIRBNode pNode)
+    if (tree == nullptr)
+        return;
+
+    auto walker = tree->getRoot();
+    while (walker != nullptr)
     {
-        heap.push_back(pNode);
-    };
-    tree.VisitTreeNodes(inserter);
-    current = end ? heap.end() : heap.begin();
+        current = walker;
+        walker = walker->getLeft();
+    }
+}
+
+RBTree::iterator &RBTree::iterator::operator++()
+{
+    if (current->getRight())
+    {
+        current = current->getRight();
+        auto walker = tree->getRoot();
+        while (walker != nullptr)
+        {
+            current = walker;
+            walker = walker->getLeft();
+        }
+    }
+    else if (current->getParent())
+    {
+        current = current->getParent();
+        return *this;
+    }
+    else
+    {
+        current.reset();
+    }
+
+    return *this;
 }
diff --git a/Common/cfcpp/RBTree/rbtree.h b/Common/cfcpp/RBTree/rbtree.h
index 7c8fb93f01..60aaf87b3e 100644
--- a/Common/cfcpp/RBTree/rbtree.h
+++ b/Common/cfcpp/RBTree/rbtree.h
@@ -52,23 +52,21 @@ private:
     void DoVisitTreeNodes(Action<PIRBNode> action, PIRBNode walker);
 
 public:
-    // todo this from C# and it's weak realization
-   class iterator : public std::iterator<std::bidirectional_iterator_tag, std::ptrdiff_t, IRBNode, IRBNode*, PIRBNode>
+
+   class iterator : public std::iterator<std::output_iterator_tag, std::ptrdiff_t, IRBNode, IRBNode*, PIRBNode>
    {
-       std::list<WPIRBNode> heap;
-       std::list<WPIRBNode>::iterator current;
+       PIRBNode current;
+       RBTree* tree;
    public:
-       iterator(RBTree &tree, bool end = false);
-       inline iterator& operator++() {++current; return *this;}
-       inline iterator& operator--() {--current; return *this;}
+       iterator(RBTree *tree);
+       iterator& operator++();
        inline bool operator==(const iterator &other) const {return current == other.current;}
        inline bool operator!=(const iterator &other) const {return current != other.current;}
-       inline PIRBNode operator*() {return current->lock();}
-       inline iterator end() {current = heap.end(); return *this;}
+       inline PIRBNode operator*() {return current;}
    };
 
-   iterator&& begin() {return std::move(iterator(*this));}
-   iterator&& end() {return std::move(iterator(*this).end());}
+   iterator begin() {return iterator(this);}
+   iterator end() {return iterator(nullptr);}
 
 private:
     PIRBNode root;