def new_pointer_type(self, BItem):
        getbtype = self.ffi._get_cached_btype
        if BItem is getbtype(model.PrimitiveType('char')):
            kind = 'charp'
        elif BItem in (getbtype(model.PrimitiveType('signed char')),
                       getbtype(model.PrimitiveType('unsigned char'))):
            kind = 'bytep'
        elif BItem is getbtype(model.void_type):
            kind = 'voidp'
        else:
            kind = 'generic'
        #
        class CTypesPtr(CTypesGenericPtr):
            __slots__ = ['_own']
            if kind == 'charp':
                __slots__ += ['__as_strbuf']
            _BItem = BItem
            if hasattr(BItem, '_ctype'):
                _ctype = ctypes.POINTER(BItem._ctype)
                _bitem_size = ctypes.sizeof(BItem._ctype)
            else:
                _ctype = ctypes.c_void_p
            if issubclass(BItem, CTypesGenericArray):
                _reftypename = BItem._get_c_name('(* &)')
            else:
                _reftypename = BItem._get_c_name(' * &')

            def __init__(self, init):
                ctypeobj = BItem._create_ctype_obj(init)
                if kind == 'charp':
                    self.__as_strbuf = ctypes.create_string_buffer(
                        ctypeobj.value + b'\x00')
                    self._as_ctype_ptr = ctypes.cast(
                        self.__as_strbuf, self._ctype)
                else:
                    self._as_ctype_ptr = ctypes.pointer(ctypeobj)
                self._address = ctypes.cast(self._as_ctype_ptr,
                                            ctypes.c_void_p).value
                self._own = True

            def __add__(self, other):
                if isinstance(other, (int, long)):
                    return self._new_pointer_at(self._address +
                                                other * self._bitem_size)
                else:
                    return NotImplemented

            def __sub__(self, other):
                if isinstance(other, (int, long)):
                    return self._new_pointer_at(self._address -
                                                other * self._bitem_size)
                elif type(self) is type(other):
                    return (self._address - other._address) // self._bitem_size
                else:
                    return NotImplemented

            def __getitem__(self, index):
                if getattr(self, '_own', False) and index != 0:
                    raise IndexError
                return BItem._from_ctypes(self._as_ctype_ptr[index])

            def __setitem__(self, index, value):
                self._as_ctype_ptr[index] = BItem._to_ctypes(value)

            if kind == 'charp' or kind == 'voidp':
                @classmethod
                def _arg_to_ctypes(cls, *value):
                    if value and isinstance(value[0], bytes):
                        return ctypes.c_char_p(value[0])
                    else:
                        return super(CTypesPtr, cls)._arg_to_ctypes(*value)

            if kind == 'charp' or kind == 'bytep':
                def _to_string(self, maxlen):
                    if maxlen < 0:
                        maxlen = sys.maxsize
                    p = ctypes.cast(self._as_ctype_ptr,
                                    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._as_ctype_ptr.contents),)
                return super(CTypesPtr, self)._get_own_repr()
        #
        if (BItem is self.ffi._get_cached_btype(model.void_type) or
            BItem is self.ffi._get_cached_btype(model.PrimitiveType('char'))):
            CTypesPtr._automatic_casts = True
        #
        CTypesPtr._fix_class()
        return CTypesPtr
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/cffi-1.5.2/cffi/backend_ctypes.py/CTypesBackend.new_pointer_type/original