Bugfix: SubFile.seek for unsignedinteger

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- `SubFile.seek` for some integer-like scalar types (e.g. `numpy.unsignedinteger`)
+
 
 ## [0.6.0] - 2026-02-03
 

jbpy/core.py

@@ -61,8 +61,8 @@ class SubFile:
 
     def __init__(self, file: Any, start: int, length: int):
         self._file = file
-        self._start = start
-        self._length = length
+        self._start = int(start)
+        self._length = int(length)
         self._pos = 0  # position within the subfile
 
     def seek(self, offset: int, whence: int = 0) -> int:
@@ -82,11 +82,11 @@ def seek(self, offset: int, whence: int = 0) -> int:
             Current offset in the SubFile
         """
         if whence == 0:
-            new_pos = offset
+            new_pos = int(offset)
         elif whence == 1:
-            new_pos = self._pos + offset
+            new_pos = self._pos + int(offset)
         elif whence == 2:
-            new_pos = self._length + offset
+            new_pos = self._length + int(offset)
         else:
             raise ValueError(f"whence value {whence} unsupported")
 

test/test_core.py

@@ -9,6 +9,7 @@
 import string
 import tempfile
 
+import numpy as np
 import pytest
 
 import jbpy.core
@@ -784,6 +785,11 @@ def test_subfile(tmp_path):
         subfile.seek(length + 100)
         assert subfile.read() == b""
 
+        # seeking works with int-like
+        subfile.seek(np.uint8(24), os.SEEK_SET)
+        subfile.seek(-8, os.SEEK_CUR)
+        assert subfile.tell() == 16
+
         assert subfile.readable()