fix(zip): handle ZIP64 files missing indicators of ZIP64 (fix).

We should still raise an exception if offset is not bound, otherwise we
have an unhandled 'UnboundLocalError'.

Author: qkaiser

unblob/handlers/archive/zip.py

@@ -188,7 +188,9 @@ def calculate_chunk(self, file: File, start_offset: int) -> Optional[ValidChunk]
             if offset == end_of_central_directory_offset:
                 break
         else:
-            # if we can't find 32bit ZIP EOCD, we fall back to ZIP64
+            if offset is None:
+                raise InvalidInputFormat("Missing EOCD record header in ZIP chunk.")
+            # if we can't find a valid 32bit ZIP EOCD, we fall back to ZIP64
             end_of_central_directory = self._parse_zip64(file, start_offset, offset)
 
         has_encrypted_files = self.has_encrypted_files(