[New-bugs-announce] [issue12945] ctypes works incorrectly with _swappedbytes_ = 1

[Pavel Boldin]

New submission from Pavel Boldin <boldin.pavel at gmail.com>:

ctypes seems to work incorrectly with _swappedbytes_ specified.

I.e. it misses some values from buffer:

class X(ctypes.Structure):
    _swappedbytes_ = 1
    _pack_ = 1
    _fields_ = [
        ('a', ctypes.c_ubyte, 4),
        ('b', ctypes.c_ubyte, 4),
        ('c', ctypes.c_ushort, 8),
        ('d', ctypes.c_ushort, 8),
    ]

buf = '\x12\x34\x56\x78'
x = X.from_buffer_copy(buf)

print x.a == 1
print x.b == 2
print x.c == 3
print x.d == 4

This prints
True
True
False
False

Where as four 'True' are expected.

----------
components: ctypes
files: test_ctypes.py
messages: 143761
nosy: Pavel.Boldin
priority: normal
severity: normal
status: open
title: ctypes works incorrectly with _swappedbytes_ = 1
versions: Python 2.7, Python 3.1
Added file: http://bugs.python.org/file23122/test_ctypes.py

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue12945>
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