From d48eb85d1d8205c8b0dc68f459e72675cc1a656e Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Tue, 6 Dec 2022 19:05:00 +0100
Subject: [PATCH] Heap: Avoid magic numbers

---
 kernel/src/memory/Heap.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/src/memory/Heap.cpp b/kernel/src/memory/Heap.cpp
index d0f65e5d..703b7922 100644
--- a/kernel/src/memory/Heap.cpp
+++ b/kernel/src/memory/Heap.cpp
@@ -29,6 +29,8 @@ struct HeapBlock : DoublyLinkedListNode<HeapBlock>
 
 static_assert(sizeof(HeapBlock) == 48UL);
 
+static const isize HEAP_BLOCK_SIZE = 48;
+
 static DoublyLinkedList<HeapBlock> heap;
 
 static Result<HeapBlock*> allocate_pages(usize count)
@@ -64,14 +66,15 @@ static usize space_available(HeapBlock* block)
     return block->full_size - block->req_size;
 }
 
+// The heap block is stored right behind a memory block.
 static HeapBlock* get_heap_block_for_pointer(void* ptr)
 {
-    return (HeapBlock*)offset_ptr(ptr, -48);
+    return (HeapBlock*)offset_ptr(ptr, -HEAP_BLOCK_SIZE);
 }
 
 static void* get_pointer_from_heap_block(HeapBlock* block)
 {
-    return (void*)offset_ptr(block, 48);
+    return (void*)offset_ptr(block, HEAP_BLOCK_SIZE);
 }
 
 static usize get_fair_offset_to_split_at(HeapBlock* block, usize min)