cpython: 72e73fa03124 (original) (raw)

Mercurial > cpython

changeset 71311:72e73fa03124 3.2

Close #4376: ctypes now supports nested structures in a endian different than the parent structure. Patch by Vlad Riscutia. [#4376]

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--- a/Lib/ctypes/_endian.py +++ b/Lib/ctypes/_endian.py @@ -7,14 +7,18 @@ def _other_endian(typ): """Return the type with the 'other' byte order. Simple types like c_int and so on already have ctype_be and ctype_le attributes which contain the types, for more complicated types

• only arrays are supported.

• arrays and structures are supported. """

• try:

• check _OTHER_ENDIAN attribute (present if typ is primitive type)

• if hasattr(typ, _OTHER_ENDIAN): return getattr(typ, _OTHER_ENDIAN)

• except AttributeError:

•    if type(typ) == _array_type:[](#l1.15)

•        return _other_endian(typ._type_) * typ._length_[](#l1.16)

•    raise TypeError("This type does not support other endian: %s" % typ)[](#l1.17)

• if typ is array

• if isinstance(typ, _array_type):

•    return _other_endian(typ._type_) * typ._length_[](#l1.20)

• if typ is structure

• if issubclass(typ, Structure):

•    return typ[](#l1.23)

• raise TypeError("This type does not support other endian: %s" % typ)

class _swapped_meta(type(Structure)): def setattr(self, attrname, value):

--- a/Lib/ctypes/test/test_byteswap.py +++ b/Lib/ctypes/test/test_byteswap.py @@ -185,18 +185,32 @@ class Test(unittest.TestCase): self.assertRaises(TypeError, setattr, T, "fields", [("x", typ)]) def test_struct_struct(self):

•    # Nested structures with different byte order not (yet) supported[](#l2.7)

•    if sys.byteorder == "little":[](#l2.8)

•        base = BigEndianStructure[](#l2.9)

•    else:[](#l2.10)

•        base = LittleEndianStructure[](#l2.11)

•    # nested structures with different byteorders[](#l2.12)

+

•    # create nested structures with given byteorders and set memory to data[](#l2.14)

•    def set_structures(endianness, nested_endianness, data):[](#l2.15)

•        class NestedStructure(nested_endianness):[](#l2.16)

•            _fields_ = [("x", c_uint32),[](#l2.17)

•                        ("y", c_uint32)][](#l2.18)

+

•        class TestStructure(endianness):[](#l2.20)

•            _fields_ = [("point", NestedStructure)][](#l2.21)

•    class T(Structure):[](#l2.23)

•        _fields_ = [("a", c_int),[](#l2.24)

•                    ("b", c_int)][](#l2.25)

•    class S(base):[](#l2.26)

•        pass[](#l2.27)

•    self.assertRaises(TypeError, setattr, S, "_fields_", [("s", T)])[](#l2.28)

•        self.assertEqual(len(data), sizeof(TestStructure))[](#l2.29)

•        return cast(data, POINTER(TestStructure))[0][](#l2.30)

+

•    for nested, data in ([](#l2.32)

•        (BigEndianStructure, b'\0\0\0\1\0\0\0\2'),[](#l2.33)

•        (LittleEndianStructure, b'\1\0\0\0\2\0\0\0'),[](#l2.34)

•    ):[](#l2.35)

•        for parent in ([](#l2.36)

•            BigEndianStructure,[](#l2.37)

•            LittleEndianStructure,[](#l2.38)

•            Structure,[](#l2.39)

•        ):[](#l2.40)

•            s = set_structures(parent, nested, data)[](#l2.41)

•            self.assertEqual(s.point.x, 1)[](#l2.42)

•            self.assertEqual(s.point.y, 2)[](#l2.43)

def test_struct_fields_2(self): # standard packing in struct uses no alignment.

--- a/Misc/ACKS +++ b/Misc/ACKS @@ -735,6 +735,7 @@ Jan Pieter Riegel Armin Rigo Nicholas Riley Jean-Claude Rimbault +Vlad Riscutia Juan M. Bello Rivas Davide Rizzo Anthony Roach

--- a/Misc/NEWS +++ b/Misc/NEWS @@ -27,6 +27,9 @@ Core and Builtins Library ------- +- Issue #4376: ctypes now supports nested structures in a endian different than

• the parent structure. Patch by Vlad Riscutia. +

• Raise ValueError when attempting to set the _CHUNK_SIZE attribute of a TextIOWrapper to a huge value, not TypeError.