diff --git a/src/dirmonitor.py b/src/dirmonitor.py
index 926ad50..3b0cce4 100644
--- a/src/dirmonitor.py
+++ b/src/dirmonitor.py
@@ -36,6 +36,73 @@ def walk(self, root: str) -> Iterator[tuple[str, os.stat_result]]:
                         yield from self.walk(path)
 
 class _DirectorySnapshotDiff(DirectorySnapshotDiff):
+    def __init__(
+            self,
+            ref: DirectorySnapshot,
+            snapshot: DirectorySnapshot,
+            *,
+            ignore_device: bool = False,
+    ) -> None:
+        super().__init__(ref, snapshot, ignore_device=ignore_device)
+        created = snapshot.paths - ref.paths
+        deleted = ref.paths - snapshot.paths
+
+        if ignore_device:
+
+            def get_inode(directory: DirectorySnapshot, full_path: bytes | str) -> int | tuple[int, int]:
+                return directory.inode(full_path)[0]
+
+        else:
+
+            def get_inode(directory: DirectorySnapshot, full_path: bytes | str) -> int | tuple[int, int]:
+                return directory.inode(full_path)
+
+        # check that all unchanged paths have the same inode
+        for path in ref.paths & snapshot.paths:
+            if get_inode(ref, path) != get_inode(snapshot, path):
+                created.add(path)
+                deleted.add(path)
+
+        # find moved paths
+        moved: set[tuple[bytes | str, bytes | str]] = set()
+        for path in set(deleted):
+            inode = ref.inode(path)
+            new_path = snapshot.path(inode)
+            if new_path and ref.mtime(path) == snapshot.mtime(new_path):
+                # file is not deleted but moved
+                deleted.remove(path)
+                moved.add((path, new_path))
+
+        for path in set(created):
+            inode = snapshot.inode(path)
+            old_path = ref.path(inode)
+            if old_path and ref.mtime(old_path) == snapshot.mtime(path):
+                created.remove(path)
+                moved.add((old_path, path))
+
+        # find modified paths
+        # first check paths that have not moved
+        modified: set[bytes | str] = set()
+        for path in ref.paths & snapshot.paths:
+            if get_inode(ref, path) == get_inode(snapshot, path) and (
+                ref.mtime(path) != snapshot.mtime(path) or ref.size(path) != snapshot.size(path)
+            ):
+                modified.add(path)
+
+        for old_path, new_path in moved:
+            if ref.mtime(old_path) != snapshot.mtime(new_path) or ref.size(old_path) != snapshot.size(new_path):
+                modified.add(old_path)
+
+        self._dirs_created = [path for path in created if snapshot.isdir(path)]
+        self._dirs_deleted = [path for path in deleted if ref.isdir(path)]
+        self._dirs_modified = [path for path in modified if ref.isdir(path)]
+        self._dirs_moved = [(frm, to) for (frm, to) in moved if ref.isdir(frm)]
+
+        self._files_created = list(created - set(self._dirs_created))
+        self._files_deleted = list(deleted - set(self._dirs_deleted))
+        self._files_modified = list(modified - set(self._dirs_modified))
+        self._files_moved = list(moved - set(self._dirs_moved))
+
     @property
     def files_moved(self) -> list[dict[str, bytes | str]]:
         """重写 files_moved 方法，直接构造moved所需要的字典"""