From 8a61744dc0ce9a7e181124ebb31638bfd1edadf9 Mon Sep 17 00:00:00 2001
From: DualFroz <me@dualfroz.com>
Date: Sun, 6 Sep 2026 19:53:02 +0200
Subject: [PATCH] feat: add rbtInsert and rbtRemove to rbt

---
 src/rbt.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)

diff --git a/src/rbt.c b/src/rbt.c
index 8afc949..81fb69d 100644
--- a/src/rbt.c
+++ b/src/rbt.c
@@ -155,3 +155,159 @@ void rbtInit(RbTree* t)
     t->count = 0;
 }
 
+bool rbtInsert(RbTree* t, RbtNode* node, RbtCompareFn compare)
+{
+    RbtNode* parent = nullptr;
+    RbtNode* cur = t->root;
+    bool goLeft = false;
+
+    while (cur != nullptr) {
+        int c = compare(node, cur);
+        if (c == 0)
+            return false;
+        parent = cur;
+        goLeft = c < 0;
+        cur = goLeft ? cur->left : cur->right;
+    }
+
+    node->left = nullptr;
+    node->right = nullptr;
+    node->parent = parent;
+    node->red = true;
+
+    if (parent == nullptr)
+        t->root = node;
+    else if (goLeft)
+        parent->left = node;
+    else
+        parent->right = node;
+
+    t->count++;
+    insertFixup(t, node);
+    return true;
+}
+
+void rbtRemove(RbTree* t, RbtNode* z)
+{
+    RbtNode* y = z;
+    bool yOriginalRed = y->red;
+    RbtNode* x;
+    RbtNode* xParent;
+
+    if (z->left == nullptr) {
+        x = z->right;
+        xParent = z->parent;
+        setChild(t, z->parent, z, z->right);
+        if (z->right != nullptr)
+            z->right->parent = z->parent;
+    } else if (z->right == nullptr) {
+        x = z->left;
+        xParent = z->parent;
+        setChild(t, z->parent, z, z->left);
+        if (z->left != nullptr)
+            z->left->parent = z->parent;
+    } else {
+        y = z->right;
+        while (y->left != nullptr)
+            y = y->left;
+        yOriginalRed = y->red;
+        x = y->right;
+
+        if (y->parent == z) {
+            xParent = y;
+        } else {
+            xParent = y->parent;
+            setChild(t, y->parent, y, y->right);
+            if (y->right != nullptr)
+                y->right->parent = y->parent;
+            y->right = z->right;
+            y->right->parent = y;
+        }
+
+        setChild(t, z->parent, z, y);
+        y->parent = z->parent;
+        y->left = z->left;
+        y->left->parent = y;
+        y->red = z->red;
+    }
+
+    t->count--;
+    if (!yOriginalRed)
+        removeFixup(t, x, xParent);
+}
+
+RbtNode* rbtFind(const RbTree* t, const void* key, RbtLookupFn lookup)
+{
+    RbtNode* cur = t->root;
+    while (cur != nullptr) {
+        int c = lookup(key, cur);
+        if (c == 0)
+            return cur;
+        cur = c < 0 ? cur->left : cur->right;
+    }
+    return nullptr;
+}
+
+RbtNode* rbtFirst(const RbTree* t)
+{
+    RbtNode* n = t->root;
+    if (n == nullptr)
+        return nullptr;
+    while (n->left != nullptr)
+        n = n->left;
+    return n;
+}
+
+RbtNode* rbtLast(const RbTree* t)
+{
+    RbtNode* n = t->root;
+    if (n == nullptr)
+        return nullptr;
+    while (n->right != nullptr)
+        n = n->right;
+    return n;
+}
+
+RbtNode* rbtNext(const RbtNode* node)
+{
+    if (node->right != nullptr) {
+        RbtNode* n = node->right;
+        while (n->left != nullptr)
+            n = n->left;
+        return n;
+    }
+    RbtNode* n = (RbtNode*)node;
+    RbtNode* parent = n->parent;
+    while (parent != nullptr && n == parent->right) {
+        n = parent;
+        parent = parent->parent;
+    }
+    return parent;
+}
+
+RbtNode* rbtPrev(const RbtNode* node)
+{
+    if (node->left != nullptr) {
+        RbtNode* n = node->left;
+        while (n->right != nullptr)
+            n = n->right;
+        return n;
+    }
+    RbtNode* n = (RbtNode*)node;
+    RbtNode* parent = n->parent;
+    while (parent != nullptr && n == parent->left) {
+        n = parent;
+        parent = parent->parent;
+    }
+    return parent;
+}
+
+usize rbtCount(const RbTree* t)
+{
+    return t->count;
+}
+
+bool rbtIsEmpty(const RbTree* t)
+{
+    return t->root == nullptr;
+}