| 1 | n/a | import sys |
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| 2 | n/a | from ctypes import * |
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| 3 | n/a | |
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| 4 | n/a | _array_type = type(Array) |
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| 5 | n/a | |
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| 6 | n/a | def _other_endian(typ): |
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| 7 | n/a | """Return the type with the 'other' byte order. Simple types like |
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| 8 | n/a | c_int and so on already have __ctype_be__ and __ctype_le__ |
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| 9 | n/a | attributes which contain the types, for more complicated types |
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| 10 | n/a | arrays and structures are supported. |
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| 11 | n/a | """ |
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| 12 | n/a | # check _OTHER_ENDIAN attribute (present if typ is primitive type) |
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| 13 | n/a | if hasattr(typ, _OTHER_ENDIAN): |
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| 14 | n/a | return getattr(typ, _OTHER_ENDIAN) |
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| 15 | n/a | # if typ is array |
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| 16 | n/a | if isinstance(typ, _array_type): |
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| 17 | n/a | return _other_endian(typ._type_) * typ._length_ |
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| 18 | n/a | # if typ is structure |
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| 19 | n/a | if issubclass(typ, Structure): |
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| 20 | n/a | return typ |
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| 21 | n/a | raise TypeError("This type does not support other endian: %s" % typ) |
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| 22 | n/a | |
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| 23 | n/a | class _swapped_meta(type(Structure)): |
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| 24 | n/a | def __setattr__(self, attrname, value): |
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| 25 | n/a | if attrname == "_fields_": |
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| 26 | n/a | fields = [] |
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| 27 | n/a | for desc in value: |
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| 28 | n/a | name = desc[0] |
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| 29 | n/a | typ = desc[1] |
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| 30 | n/a | rest = desc[2:] |
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| 31 | n/a | fields.append((name, _other_endian(typ)) + rest) |
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| 32 | n/a | value = fields |
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| 33 | n/a | super().__setattr__(attrname, value) |
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| 34 | n/a | |
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| 35 | n/a | ################################################################ |
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| 36 | n/a | |
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| 37 | n/a | # Note: The Structure metaclass checks for the *presence* (not the |
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| 38 | n/a | # value!) of a _swapped_bytes_ attribute to determine the bit order in |
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| 39 | n/a | # structures containing bit fields. |
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| 40 | n/a | |
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| 41 | n/a | if sys.byteorder == "little": |
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| 42 | n/a | _OTHER_ENDIAN = "__ctype_be__" |
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| 43 | n/a | |
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| 44 | n/a | LittleEndianStructure = Structure |
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| 45 | n/a | |
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| 46 | n/a | class BigEndianStructure(Structure, metaclass=_swapped_meta): |
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| 47 | n/a | """Structure with big endian byte order""" |
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| 48 | n/a | __slots__ = () |
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| 49 | n/a | _swappedbytes_ = None |
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| 50 | n/a | |
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| 51 | n/a | elif sys.byteorder == "big": |
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| 52 | n/a | _OTHER_ENDIAN = "__ctype_le__" |
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| 53 | n/a | |
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| 54 | n/a | BigEndianStructure = Structure |
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| 55 | n/a | class LittleEndianStructure(Structure, metaclass=_swapped_meta): |
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| 56 | n/a | """Structure with little endian byte order""" |
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| 57 | n/a | __slots__ = () |
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| 58 | n/a | _swappedbytes_ = None |
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| 59 | n/a | |
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| 60 | n/a | else: |
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| 61 | n/a | raise RuntimeError("Invalid byteorder") |
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