def new_array_type()

in functions/source/KeyGen/cffi/backend_ctypes.py [0:0]

• 106 lines of code
• 29 McCabe index (conditional complexity)

    def new_array_type(self, CTypesPtr, length):
        if length is None:
            brackets = ' &[]'
        else:
            brackets = ' &[%d]' % length
        BItem = CTypesPtr._BItem
        getbtype = self.ffi._get_cached_btype
        if BItem is getbtype(model.PrimitiveType('char')):
            kind = 'char'
        elif BItem in (getbtype(model.PrimitiveType('signed char')),
                       getbtype(model.PrimitiveType('unsigned char'))):
            kind = 'byte'
        else:
            kind = 'generic'
        #
        class CTypesArray(CTypesGenericArray):
            __slots__ = ['_blob', '_own']
            if length is not None:
                _ctype = BItem._ctype * length
            else:
                __slots__.append('_ctype')
            _reftypename = BItem._get_c_name(brackets)
            _declared_length = length
            _CTPtr = CTypesPtr

            def __init__(self, init):
                if length is None:
                    if isinstance(init, (int, long)):
                        len1 = init
                        init = None
                    elif kind == 'char' and isinstance(init, bytes):
                        len1 = len(init) + 1    # extra null
                    else:
                        init = tuple(init)
                        len1 = len(init)
                    self._ctype = BItem._ctype * len1
                self._blob = self._ctype()
                self._own = True
                if init is not None:
                    self._initialize(self._blob, init)

            @staticmethod
            def _initialize(blob, init):
                if isinstance(init, bytes):
                    init = [init[i:i+1] for i in range(len(init))]
                else:
                    if isinstance(init, CTypesGenericArray):
                        if (len(init) != len(blob) or
                            not isinstance(init, CTypesArray)):
                            raise TypeError("length/type mismatch: %s" % (init,))
                    init = tuple(init)
                if len(init) > len(blob):
                    raise IndexError("too many initializers")
                addr = ctypes.cast(blob, ctypes.c_void_p).value
                PTR = ctypes.POINTER(BItem._ctype)
                itemsize = ctypes.sizeof(BItem._ctype)
                for i, value in enumerate(init):
                    p = ctypes.cast(addr + i * itemsize, PTR)
                    BItem._initialize(p.contents, value)

            def __len__(self):
                return len(self._blob)

            def __getitem__(self, index):
                if not (0 <= index < len(self._blob)):
                    raise IndexError
                return BItem._from_ctypes(self._blob[index])

            def __setitem__(self, index, value):
                if not (0 <= index < len(self._blob)):
                    raise IndexError
                self._blob[index] = BItem._to_ctypes(value)

            if kind == 'char' or kind == 'byte':
                def _to_string(self, maxlen):
                    if maxlen < 0:
                        maxlen = len(self._blob)
                    p = ctypes.cast(self._blob,
                                    ctypes.POINTER(ctypes.c_char))
                    n = 0
                    while n < maxlen and p[n] != b'\x00':
                        n += 1
                    return b''.join([p[i] for i in range(n)])

            def _get_own_repr(self):
                if getattr(self, '_own', False):
                    return 'owning %d bytes' % (ctypes.sizeof(self._blob),)
                return super(CTypesArray, self)._get_own_repr()

            def _convert_to_address(self, BClass):
                if BClass in (CTypesPtr, None) or BClass._automatic_casts:
                    return ctypes.addressof(self._blob)
                else:
                    return CTypesData._convert_to_address(self, BClass)

            @staticmethod
            def _from_ctypes(ctypes_array):
                self = CTypesArray.__new__(CTypesArray)
                self._blob = ctypes_array
                return self

            @staticmethod
            def _arg_to_ctypes(value):
                return CTypesPtr._arg_to_ctypes(value)

            def __add__(self, other):
                if isinstance(other, (int, long)):
                    return CTypesPtr._new_pointer_at(
                        ctypes.addressof(self._blob) +
                        other * ctypes.sizeof(BItem._ctype))
                else:
                    return NotImplemented

            @classmethod
            def _cast_from(cls, source):
                raise NotImplementedError("casting to %r" % (
                    cls._get_c_name(),))
        #
        CTypesArray._fix_class()
        return CTypesArray