From 98bea5b32aa14b5f79120798ef4f6753dbf0138c Mon Sep 17 00:00:00 2001
From: Phireh <phireh@fukurokuju.dev>
Date: Mon, 17 Feb 2025 21:03:09 +0100
Subject: [PATCH] Initial implementation of Btree

---
 Makefile |   2 +-
 list.h   |   2 +-
 tree.h   | 128 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 122 insertions(+), 10 deletions(-)

diff --git a/Makefile b/Makefile
index 3ff2d8e..d7edac6 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 IHCT_CFLAGS=-Wall -Wextra -Wpedantic -Wfatal-errors -std=gnu99 -fPIC -shared
 TEST_CFLAGS=-Wall -Wextra -Wpedantic -Wfatal-errors -DIHCT_SHORT -L./ -Wl,-rpath ./
 
-tests: tests.c list.h libihct.so
+tests: tests.c list.h tree.h libihct.so
 	gcc $(TEST_CFLAGS) tests.c -lihct -o tests
 
 libihct.so: ihct/vector.c ihct/ihct.c
diff --git a/list.h b/list.h
index 677bebc..b0b9ed6 100644
--- a/list.h
+++ b/list.h
@@ -139,7 +139,7 @@ typedef struct dnode_ {
         void *vptr;
     };
     dnode_ptr next;
-	dnode_ptr prev;
+    dnode_ptr prev;
 } dnode_t;
 
 void dlist_append(dnode_t *start, dnode_t *tail)
diff --git a/tree.h b/tree.h
index ae72a08..192e0f7 100644
--- a/tree.h
+++ b/tree.h
@@ -1,5 +1,7 @@
 #ifndef TREE_H
 #define TREE_H
+#include <string.h>
+#include <stdbool.h>
 typedef struct tnode_ tnode_t;
 typedef struct tnode_* tnode_ptr;
 typedef enum { INT, UINT, CHAR, FLOAT, DOUBLE, CHAR_PTR, VOID_PTR } tnode_value_t;
@@ -12,21 +14,131 @@ typedef struct tnode_ {
         char vc;
         float vf;
         double vd;
-        char* vcp;
+        char *vcp;
         void *vptr;
     };
     tnode_ptr parent;
-    tnode_ptr left_leaf;
-    tnode_ptr right_leaf;
+    tnode_ptr left_child;
+    tnode_ptr right_child;
 } tnode_t;
 
-
-tnode_t* tree_root(tnode_t* leaf)
+int compare(int type, void *left, void *right)
 {
-	tnode_t* current = leaf;
+    switch (type)
+    {
+    case INT:
+        return *((int*)left) - *((int*)right);
+    case UINT:
+        return *((unsigned int*)left) - *((unsigned int*)right);
+    case FLOAT:
+        return *((float*)left) - *((float*)right);
+    case DOUBLE:
+        return *((float*)left) - *((float*)right);
+    case CHAR_PTR:
+        return strcmp((char*)left, (char*)right);
+    default:
+        return 0;
+    }
+}
 
-	while(current = current->parent && current->parent);
-	return current;
+tnode_t* btree_root(tnode_t *node)
+{
+    tnode_t* current = node;
+    while((current = current->parent) && current->parent);
+    return current;
+}
+
+void btree_insert(tnode_t *root, tnode_t *new_node)
+{
+    tnode_t *current = root;
+    int rootdiff = compare(current->type, &current->vi, &new_node->vi);
+    bool left = current->left_child != NULL;
+    bool right = current->right_child != NULL;
+
+    if (!rootdiff) return;
+
+    if (left)
+    {
+        if (rootdiff < 0)
+            btree_insert(current->left_child, new_node);
+    }
+    else
+    {
+        if (rootdiff < 0)
+        {
+            current->left_child = new_node;
+            new_node->parent = current;
+        }
+    }
+    if (right)
+    {
+        if (rootdiff > 0)
+            btree_insert(current->right_child, new_node);
+    }
+    else
+    {
+        if (rootdiff > 0)
+        {
+            current->right_child = new_node;
+            new_node->parent = current;
+        }
+    }
+}
+
+void btree_delete(tnode_t *root, void *data)
+{
+    int rootdiff = compare(root->type, &root->vi, data);
+    bool left = root->left_child;
+    bool right = root->right_child;
+    tnode_t **position_in_parent_ptr = NULL;
+    if (root->parent && root->parent->left_child == root)
+        position_in_parent_ptr = &root->parent->left_child;
+    if (root->parent && root->parent->right_child == root)
+        position_in_parent_ptr = &root->parent->right_child;
+
+    if (rootdiff < 0 && left)
+    {
+        btree_delete(root->left_child, data);
+    }
+    if (rootdiff > 0 && right)
+    {
+        btree_delete(root->right_child, data);
+    }
+    if (!rootdiff)
+    {
+        if (left && !right)
+        {
+            root->left_child->parent = root->parent;
+            if (position_in_parent_ptr)
+                *position_in_parent_ptr = root->left_child;
+        }
+        if (!left && right)
+        {
+            root->right_child->parent = root->parent;
+            if (position_in_parent_ptr)
+                *position_in_parent_ptr = root->right_child;
+        }
+        if (left && right)
+        {
+            tnode_t *walker = root->right_child;
+            while (walker->left_child) walker = walker->left_child;
+            if (position_in_parent_ptr)
+                *position_in_parent_ptr = walker;
+            walker->parent = root->parent;
+        }
+    }
+}
+
+tnode_t* btree_find(tnode_t *current, void *data)
+{
+    int currentdiff = compare(current->type, &current->vi, data);
+    if (!currentdiff) return current;
+    if (currentdiff < 0)
+        if (current->left_child) btree_find(current->left_child, data);
+        else return NULL;
+    else
+        if (current->right_child) btree_find(current->right_child, data);
+        else return NULL;
 }
 
 #endif //TREE_H