From a98e51a869955aef29c3057c8c539ad59829b51f Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Mon, 23 Jun 2025 13:11:17 +0100
Subject: [PATCH] b-tree: fix incorrect copy bounds and pointer swaps

---
 src/b-tree.c | 64 +++++++++++++++++++++++++++++++++++++++++-----------
 src/b-tree.h |  1 +
 2 files changed, 52 insertions(+), 13 deletions(-)

diff --git a/src/b-tree.c b/src/b-tree.c
index 3179962..03d2088 100644
--- a/src/b-tree.c
+++ b/src/b-tree.c
@@ -1,5 +1,7 @@
 #include "b-tree.h"
 
+#include "bin.h"
+
 #include <assert.h>
 #include <blue/core/queue.h>
 #include <stdlib.h>
@@ -180,21 +182,33 @@ static void node_shift_entries(
 	unsigned long count = nr_entries - shift_from;
 
 	for (unsigned long i = 0; i < count; i++) {
-		unsigned long from = (src + count - 1) - i;
-		unsigned long to = (dest + count - 1) - i;
+		unsigned long from, to;
+		if (shift_by > 0) {
+			from = (src + count - 1) - i;
+			to = (dest + count - 1) - i;
+		} else {
+			from = src + i;
+			to = dest + i;
+		}
+
 		b_tree_node_entry *entry = node_get_entry(tree, node, from);
 		node_set_entry(tree, node, to, entry);
 	}
 
+#if 0
 	if (shift_by < 0) {
-		dest = nr_entries + shift_by;
+		if (src < dest + count) {
+			src = dest + count;
+		}
 		count = labs(shift_by);
 	} else {
-		dest = src;
 		count = shift_by;
 	}
 
-	node_kill_entry(tree, node, dest);
+	for (size_t i = 0; i < count; i++) {
+		node_kill_entry(tree, node, src + i);
+	}
+#endif
 }
 
 static void node_shift_children(
@@ -221,19 +235,30 @@ static void node_shift_children(
 	}
 
 	for (unsigned long i = 0; i < count; i++) {
-		unsigned long child = node_get_child(tree, node, src + i);
-		node_set_child(tree, node, dest + i, child);
+		unsigned long from, to;
+		if (shift_by > 0) {
+			from = (src + count - 1) - i;
+			to = (dest + count - 1) - i;
+		} else {
+			from = src + i;
+			to = dest + i;
+		}
+
+		unsigned long child = node_get_child(tree, node, from);
+		node_set_child(tree, node, to, child);
 	}
 
 	if (shift_by < 0) {
-		dest = nr_entries + 1 + shift_from;
 		count = labs(shift_by);
 	} else {
-		dest = src;
 		count = shift_by;
 	}
 
-	node_set_child(tree, node, dest, B_TREE_INVALID_PTR);
+#if 0
+	for (size_t i = 0; i < count; i++) {
+		node_set_child(tree, node, src + i, B_TREE_INVALID_PTR);
+	}
+#endif
 }
 
 static void node_move_entries(
@@ -367,12 +392,22 @@ static int node_is_leaf(struct b_tree *tree, b_tree_node *node)
 
 static void node_init(struct b_tree *tree, b_tree_node *out)
 {
+	if (!tree->tree_ops->node_init) {
+		abort();
+	}
+
+	tree->tree_ops->node_init(tree, out);
+
+#if 0
 	memset(out, 0x0, tree->tree_node_size);
 	for (unsigned int i = 0; i < tree->tree_order; i++) {
 		node_set_child(tree, out, i, B_TREE_INVALID_PTR);
 	}
+#endif
 }
 
+extern const struct b_tree_ops chunk_table_ops;
+
 int b_tree_put(struct b_tree *tree, const b_tree_node_entry *to_put)
 {
 	int depth = 0;
@@ -449,7 +484,8 @@ int b_tree_put(struct b_tree *tree, const b_tree_node_entry *to_put)
 		nr_entries = node_get_nr_entries(tree, next);
 		if (nr_entries < tree->tree_order - 1) {
 			/* swap current and next pointers. */
-
+			SWAP(b_tree_node *, current, next);
+			SWAP(long, current_id, next_id);
 			leaf = node_is_leaf(tree, current);
 
 			depth++;
@@ -463,6 +499,7 @@ int b_tree_put(struct b_tree *tree, const b_tree_node_entry *to_put)
 		   be moved to `current`.
 
 		   `n3` will become the right sibling of `next` */
+
 		b_tree_node *n3 = cache_alloc_node(tree);
 		node_init(tree, n3);
 
@@ -511,8 +548,9 @@ int b_tree_put(struct b_tree *tree, const b_tree_node_entry *to_put)
 			current = n3;
 			current_id = n3_id;
 		} else {
+			cache_free_node(tree, n3);
 			SWAP(b_tree_node *, current, next);
-			current_id = next_id;
+			SWAP(long, current_id, next_id);
 		}
 
 		depth++;
@@ -575,7 +613,7 @@ int b_tree_get(struct b_tree *tree, b_tree_node_entry *to_get)
 
 		/* swap current and next pointers. */
 		SWAP(b_tree_node *, current, next);
-		current_id = next_id;
+		SWAP(long, current_id, next_id);
 		nr_entries = node_get_nr_entries(tree, current);
 	}
 
diff --git a/src/b-tree.h b/src/b-tree.h
index a75b3fc..ea826c4 100644
--- a/src/b-tree.h
+++ b/src/b-tree.h
@@ -23,6 +23,7 @@ struct b_tree_ops {
 		const b_tree_node *);
 	long (*tree_alloc_node)(struct b_tree *);
 
+	void (*node_init)(struct b_tree *, b_tree_node *);
 	unsigned long (*node_get_nr_entries)(struct b_tree *, b_tree_node *);
 	void (*node_set_nr_entries)(
 		struct b_tree *,