[bug] fix #6, correctly parse big-endian nii file, bump 0.8.2

Author: fangq

README.md

@@ -4,7 +4,7 @@
 
 - Copyright: (C) Qianqian Fang (2019-2025) <q.fang at neu.edu>
 - License: Apache License, Version 2.0
-- Version: 0.8.1
+- Version: 0.8.2
 - URL: https://github.com/NeuroJSON/pyjdata
 - Acknowledgement: This project is supported by US National Institute of Health (NIH)
   grant [U24-NS124027](https://reporter.nih.gov/project-details/10308329)

jdata/__init__.py

@@ -121,7 +121,7 @@
 
 from .neurojson import neuroj, neurojgui
 
-__version__ = "0.8.1"
+__version__ = "0.8.2"
 __all__ = [
     "loadjson",
     "savejson",

jdata/jnifti.py

@@ -84,9 +84,10 @@ def nii2jnii(filename, format="jnii", *varargin, **kwargs):
     dataendian = sys.byteorder
 
     if nii["hdr"]["sizeof_hdr"] not in [348, 540]:
-        nii["hdr"]["sizeof_hdr"] = struct.unpack(
-            ">I", struct.pack("<I", nii["hdr"]["sizeof_hdr"])
-        )[0]
+        value = nii["hdr"]["sizeof_hdr"]
+        if not isinstance(value, np.ndarray):
+            value = np.array(value)
+        nii["hdr"]["sizeof_hdr"] = value.byteswap()
 
     if nii["hdr"]["sizeof_hdr"] == 540:  # NIFTI-2 format
         niftiheader = niiformat("nifti2")
@@ -104,14 +105,15 @@ def nii2jnii(filename, format="jnii", *varargin, **kwargs):
     if nii["hdr"]["dim"][0] > 7:
         names = list(nii["hdr"].keys())
         for name in names:
-            nii["hdr"][name] = struct.unpack(
-                ">" + nii["hdr"][name][1:],
-                struct.pack("<" + nii["hdr"][name][1:], nii["hdr"][name]),
-            )[0]
+            value = nii["hdr"][name]
+            if not isinstance(value, np.ndarray):
+                value = np.array(value)
+
+            # Swap bytes and change dtype
+            nii["hdr"][name] = value.byteswap()
+
         if nii["hdr"]["sizeof_hdr"] > 540:
-            nii["hdr"]["sizeof_hdr"] = struct.unpack(
-                ">I", struct.pack("<I", nii["hdr"]["sizeof_hdr"])
-            )[0]
+            nii["hdr"]["sizeof_hdr"] = nii["hdr"]["sizeof_hdr"].byteswap()
 
     type2byte = np.array(
         [

setup.py

@@ -6,7 +6,7 @@
 setup(
     name="jdata",
     packages=["jdata"],
-    version="0.8.1",
+    version="0.8.2",
     license="Apache license 2.0",
     description="JSON/binary JSON formats for exchanging Python and Numpy data",
     long_description=readme,