[issue4376] Nested ctypes 'BigEndianStructure' fails
STINNER Victor
report at bugs.python.org
Wed Jul 13 18:05:38 CEST 2011
STINNER Victor <victor.stinner at haypocalc.com> added the comment:
I don't like your test because it depends on system endian:
+ if sys.byteorder == "little":
+ struct.menu.spam = 0x000000FF
+ else:
+ struct.menu.spam = 0xFF000000
I would prefer a test creating a structure from a byte string. Something like:
---------------------------
import ctypes
class Nested(ctypes.BigEndianStructure):
_fields_ = (
('x', ctypes.c_uint32),
('y', ctypes.c_uint32),
)
class TestStruct(ctypes.BigEndianStructure):
_fields_ = (
('point', Nested),
)
data = b'\0\0\0\1\0\0\0\2'
assert len(data) == ctypes.sizeof(TestStruct)
obj = ctypes.cast(data, ctypes.POINTER(TestStruct))[0]
assert obj.point.x == 1
assert obj.point.y == 2
---------------------------
Use b'\1\0\0\0\2\0\0\0' for little endian.
----------
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<http://bugs.python.org/issue4376>
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