python-can/can/ctypesutil.py at develop · feuerball/python-can · GitHub

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# type: ignore

"""

This module contains common `ctypes` utils.

"""

import ctypes

import logging

import sys

from typing import Any, Callable, Optional, Tuple, Union

log = logging.getLogger("can.ctypesutil")

__all__ = ["CLibrary", "HANDLE", "PHANDLE", "HRESULT"]

try:

_LibBase = ctypes.WinDLL

_FUNCTION_TYPE = ctypes.WINFUNCTYPE

except AttributeError:

_LibBase = ctypes.CDLL

_FUNCTION_TYPE = ctypes.CFUNCTYPE

class CLibrary(_LibBase):

def __init__(self, library_or_path: Union[str, ctypes.CDLL]) -> None:

self.func_name: Any

if isinstance(library_or_path, str):

super().__init__(library_or_path)

else:

super().__init__(library_or_path._name, library_or_path._handle)

def map_symbol(

self,

func_name: str,

restype: Any = None,

argtypes: Tuple[Any, ...] = (),

errcheck: Optional[Callable[..., Any]] = None,

) -> Any:

"""

Map and return a symbol (function) from a C library. A reference to the

mapped symbol is also held in the instance

:param func_name:

symbol_name

:param ctypes.c_* restype:

function result type (i.e. ctypes.c_ulong...), defaults to void

:param tuple(ctypes.c_* ... ) argtypes:

argument types, defaults to no args

:param callable errcheck:

optional error checking function, see ctypes docs for _FuncPtr

"""

if argtypes:

prototype = _FUNCTION_TYPE(restype, *argtypes)

else:

prototype = _FUNCTION_TYPE(restype)

try:

func = prototype((func_name, self))

except AttributeError:

raise ImportError(

f'Could not map function "{func_name}" from library {self._name}'

) from None

func._name = func_name # pylint: disable=protected-access

log.debug(

'Wrapped function "%s", result type: %s, error_check %s',

func_name,

type(restype),

errcheck,

)

if errcheck is not None:

func.errcheck = errcheck

setattr(self, func_name, func)

return func

if sys.platform == "win32":

HRESULT = ctypes.HRESULT

elif sys.platform == "cygwin":

class HRESULT(ctypes.c_long):

pass

# Common win32 definitions

class HANDLE(ctypes.c_void_p):

pass

PHANDLE = ctypes.POINTER(HANDLE)

python-can/can/ctypesutil.py at develop · feuerball/python-can · GitHub

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