From ea578b348f63939bb07bd669ad86d3fe1b6d5f65 Mon Sep 17 00:00:00 2001
From: "marcel.braun" <marcel.braun@ost.ch>
Date: Sun, 29 Mar 2026 21:30:32 +0200
Subject: Save WIP add some definitions and helper functions

---
 kernel/src/filesystem/ext2/ext2_filesystem.cpp | 33 ++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

(limited to 'kernel/src')

diff --git a/kernel/src/filesystem/ext2/ext2_filesystem.cpp b/kernel/src/filesystem/ext2/ext2_filesystem.cpp
index 19f1014..e176ade 100644
--- a/kernel/src/filesystem/ext2/ext2_filesystem.cpp
+++ b/kernel/src/filesystem/ext2/ext2_filesystem.cpp
@@ -3,15 +3,48 @@
 #include "kernel/devices/block_device_utils.hpp"
 #include "kernel/devices/device.hpp"
 #include "kernel/filesystem/ext2/ext2_inode.hpp"
+#include "kernel/filesystem/ext2/ext2_superblock.hpp"
 #include "kernel/filesystem/filesystem.hpp"
 #include "kernel/filesystem/inode.hpp"
 
 #include <kstd/memory>
 
+#include <cstddef>
+#include <cstdint>
 #include <string_view>
 
 namespace filesystem::ext2
 {
+  namespace
+  {
+    constexpr size_t SUPERBLOCK_OFFSET = 1024;
+    constexpr uint16_t EXT2_MAGIC = 0xEF53;
+
+    // Mode bits
+    constexpr uint16_t S_IFMT = 0xF000;
+    constexpr uint16_t S_IFREG = 0x8000;
+    constexpr uint16_t S_IFDIR = 0x4000;
+
+    auto S_ISREG(uint16_t mode) -> bool
+    {
+      return (mode & S_IFMT) == S_IFREG;
+    }
+    auto S_ISDIR(uint16_t mode) -> bool
+    {
+      return (mode & S_IFMT) == S_IFDIR;
+    }
+
+    auto get_block_size(ext2_superblock const & superblock) -> size_t
+    {
+      return 1024U << superblock.log_block_size;
+    }
+
+    auto get_inode_size(ext2_superblock const & superblock) -> size_t
+    {
+      return superblock.rev_level == 0 ? 128 : superblock.inode_size;
+    }
+  }  // namespace
+
   auto ext2_filesystem::mount(kstd::shared_ptr<devices::device> const & device) -> int
   {
     filesystem::mount(device);  // TODO BA-FS26 error handling?
-- 
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