1 files changed, 82 insertions, 0 deletions
diff --git a/kernel/src/filesystem/file_descriptor_table.cpp b/kernel/src/filesystem/file_descriptor_table.cpp
new file mode 100644
index 0000000..814322e
--- /dev/null
+++ b/kernel/src/filesystem/file_descriptor_table.cpp
@@ -0,0 +1,82 @@
+#include "kernel/filesystem/file_descriptor_table.hpp"
+
+#include "kapi/system.hpp"
+
+#include "kernel/filesystem/open_file_description.hpp"
+
+#include <algorithm>
+#include <cstddef>
+#include <optional>
+
+namespace filesystem
+{
+  namespace
+  {
+    constinit auto static global_file_descriptor_table = std::optional<file_descriptor_table>{};
+  }  // namespace
+
+  auto file_descriptor_table::init() -> void
+  {
+    if (global_file_descriptor_table)
+    {
+      kapi::system::panic("[FILESYSTEM] File descriptor table has already been initialized.");
+    }
+
+    global_file_descriptor_table.emplace(file_descriptor_table{});
+  }
+
+  auto file_descriptor_table::get() -> file_descriptor_table &
+  {
+    if (!global_file_descriptor_table)
+    {
+      kapi::system::panic("[FILESYSTEM] File descriptor table has not been initialized.");
+    }
+
+    return *global_file_descriptor_table;
+  }
+
+  auto file_descriptor_table::add_file(open_file_description & file_description) -> int
+  {
+    auto it = std::ranges::find_if(m_open_files, [](auto & open_file) { return !open_file.has_value(); });
+    if (it != m_open_files.end())
+    {
+      *it = file_description;
+      return static_cast<int>(it - m_open_files.begin());
+    }
+
+    m_open_files.push_back(file_description);
+    return static_cast<int>(m_open_files.size() - 1);
+  }
+
+  auto file_descriptor_table::get_file(int fd) const -> std::optional<open_file_description>
+  {
+    if (fd < 0)
+    {
+      return std::nullopt;
+    }
+
+    auto const index = static_cast<size_t>(fd);
+    if (index >= m_open_files.size() || !m_open_files.at(fd).has_value())
+    {
+      return std::nullopt;
+    }
+
+    return m_open_files.at(fd);
+  }
+
+  auto file_descriptor_table::remove_file(int fd) -> void
+  {
+    if (fd < 0)
+    {
+      return;
+    }
+
+    auto const index = static_cast<size_t>(fd);
+    if (index >= m_open_files.size())
+    {
+      return;
+    }
+
+    m_open_files.at(fd).reset();
+  }
+}  // namespace filesystem
+\ No newline at end of file