From 9c602f2cf8fd87f55adc31c085e469e72b7cbbfa Mon Sep 17 00:00:00 2001
From: "marcel.braun" <marcel.braun@ost.ch>
Date: Sun, 29 Mar 2026 20:49:03 +0200
Subject: Move block device offset and size-to-blocks calculation to
 block_device_utils

---
 kernel/src/filesystem/device_inode.cpp         | 76 +-------------------------
 kernel/src/filesystem/ext2/ext2_filesystem.cpp |  2 +
 2 files changed, 5 insertions(+), 73 deletions(-)

(limited to 'kernel/src/filesystem')

diff --git a/kernel/src/filesystem/device_inode.cpp b/kernel/src/filesystem/device_inode.cpp
index 64cd6e9..da062fc 100644
--- a/kernel/src/filesystem/device_inode.cpp
+++ b/kernel/src/filesystem/device_inode.cpp
@@ -2,7 +2,7 @@
 
 #include "kapi/system.hpp"
 
-#include "kernel/devices/block_device.hpp"
+#include "kernel/devices/block_device_utils.hpp"
 #include "kernel/devices/device.hpp"
 #include "kernel/filesystem/inode.hpp"
 
@@ -10,7 +10,6 @@
 #include <kstd/memory>
 #include <kstd/vector>
 
-#include <algorithm>
 #include <cstddef>
 
 namespace filesystem
@@ -29,20 +28,7 @@ namespace filesystem
   {
     if (m_device->is_block_device())
     {
-      return process_blocks(offset, size, buffer,
-                            [](size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
-                               std::byte * scratch, void * buffer) {
-                              auto * out = static_cast<std::byte *>(buffer);
-                              if (off == 0 && len == device->block_size())
-                              {
-                                device->read_block(idx, out + done);
-                              }
-                              else
-                              {
-                                device->read_block(idx, scratch);
-                                kstd::libc::memcpy(out + done, scratch + off, len);
-                              }
-                            });
+      return devices::block_device_utils::read(m_device, buffer, offset, size);
     }
     else
     {
@@ -54,21 +40,7 @@ namespace filesystem
   {
     if (m_device->is_block_device())
     {
-      return process_blocks(offset, size, const_cast<void *>(buffer),
-                            [](size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
-                               std::byte * scratch, void * buffer) {
-                              auto const * in = static_cast<std::byte const *>(buffer);
-                              if (off == 0 && len == device->block_size())
-                              {
-                                device->write_block(idx, in + done);
-                              }
-                              else
-                              {
-                                device->read_block(idx, scratch);
-                                kstd::libc::memcpy(scratch + off, in + done, len);
-                                device->write_block(idx, scratch);
-                              }
-                            });
+      return devices::block_device_utils::write(m_device, buffer, offset, size);
     }
     else
     {
@@ -81,46 +53,4 @@ namespace filesystem
     return m_device;
   }
 
-  auto device_inode::process_blocks(size_t offset, size_t size, void * buffer, block_op op) const -> size_t
-  {
-    if (buffer == nullptr)
-    {
-      kapi::system::panic("[FILESYSTEM] device_file::process_blocks called with null buffer.");
-    }
-
-    if (size == 0)
-    {
-      return 0;
-    }
-
-    auto * block_dev = static_cast<devices::block_device *>(m_device.get());
-    if (block_dev == nullptr)
-    {
-      kapi::system::panic("[FILESYSTEM] device_file: expected block_device.");
-    }
-
-    size_t const block_size = block_dev->block_size();
-    size_t const capacity = block_dev->capacity();
-
-    if (offset >= capacity)
-      return 0;
-    size_t const total_to_process = std::min(size, capacity - offset);
-
-    kstd::vector<std::byte> scratch_buffer{block_size};
-    auto processed = 0uz;
-
-    while (processed < total_to_process)
-    {
-      size_t const absolute_offset = offset + processed;
-      size_t const block_index = absolute_offset / block_size;
-      size_t const in_block_offset = absolute_offset % block_size;
-      size_t const chunk_size = std::min(total_to_process - processed, block_size - in_block_offset);
-
-      op(block_index, in_block_offset, chunk_size, processed, block_dev, scratch_buffer.data(), buffer);
-
-      processed += chunk_size;
-    }
-
-    return processed;
-  }
 }  // namespace filesystem
\ No newline at end of file
diff --git a/kernel/src/filesystem/ext2/ext2_filesystem.cpp b/kernel/src/filesystem/ext2/ext2_filesystem.cpp
index 373c6a2..19f1014 100644
--- a/kernel/src/filesystem/ext2/ext2_filesystem.cpp
+++ b/kernel/src/filesystem/ext2/ext2_filesystem.cpp
@@ -1,5 +1,6 @@
 #include "kernel/filesystem/ext2/ext2_filesystem.hpp"
 
+#include "kernel/devices/block_device_utils.hpp"
 #include "kernel/devices/device.hpp"
 #include "kernel/filesystem/ext2/ext2_inode.hpp"
 #include "kernel/filesystem/filesystem.hpp"
@@ -19,6 +20,7 @@ namespace filesystem::ext2
 
     // TODO BA-FS26 implement
     m_root_inode = kstd::make_shared<ext2_inode>();
+    // devices::block_device_utils::read(device, nullptr, 0, 0);  // TODO BA-FS26 just for testing
     return 0;
   }
 
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