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"""
Support for typing ctypes function pointers.
"""
import ctypes
import sys
from numba.core import types
from numba.core.typing import templates
from .typeof import typeof_impl
_FROM_CTYPES = {
ctypes.c_bool: types.boolean,
ctypes.c_int8: types.int8,
ctypes.c_int16: types.int16,
ctypes.c_int32: types.int32,
ctypes.c_int64: types.int64,
ctypes.c_uint8: types.uint8,
ctypes.c_uint16: types.uint16,
ctypes.c_uint32: types.uint32,
ctypes.c_uint64: types.uint64,
ctypes.c_float: types.float32,
ctypes.c_double: types.float64,
ctypes.c_void_p: types.voidptr,
ctypes.py_object: types.ffi_forced_object,
}
_TO_CTYPES = {v: k for (k, v) in _FROM_CTYPES.items()}
def from_ctypes(ctypeobj):
"""
Convert the given ctypes type to a Numba type.
"""
if ctypeobj is None:
# Special case for the restype of void-returning functions
return types.none
assert isinstance(ctypeobj, type), ctypeobj
def _convert_internal(ctypeobj):
# Recursive helper
if issubclass(ctypeobj, ctypes._Pointer):
valuety = _convert_internal(ctypeobj._type_)
if valuety is not None:
return types.CPointer(valuety)
else:
return _FROM_CTYPES.get(ctypeobj)
ty = _convert_internal(ctypeobj)
if ty is None:
raise TypeError("Unsupported ctypes type: %s" % ctypeobj)
return ty
def to_ctypes(ty):
"""
Convert the given Numba type to a ctypes type.
"""
assert isinstance(ty, types.Type), ty
if ty is types.none:
# Special case for the restype of void-returning functions
return None
def _convert_internal(ty):
if isinstance(ty, types.CPointer):
return ctypes.POINTER(_convert_internal(ty.dtype))
else:
return _TO_CTYPES.get(ty)
ctypeobj = _convert_internal(ty)
if ctypeobj is None:
raise TypeError("Cannot convert Numba type '%s' to ctypes type"
% (ty,))
return ctypeobj
def is_ctypes_funcptr(obj):
try:
# Is it something of which we can get the address
ctypes.cast(obj, ctypes.c_void_p)
except ctypes.ArgumentError:
return False
else:
# Does it define argtypes and restype
return hasattr(obj, 'argtypes') and hasattr(obj, 'restype')
def get_pointer(ctypes_func):
"""
Get a pointer to the underlying function for a ctypes function as an
integer.
"""
return ctypes.cast(ctypes_func, ctypes.c_void_p).value
def make_function_type(cfnptr):
"""
Return a Numba type for the given ctypes function pointer.
"""
if cfnptr.argtypes is None:
raise TypeError("ctypes function %r doesn't define its argument types; "
"consider setting the `argtypes` attribute"
% (cfnptr.__name__,))
cargs = [from_ctypes(a)
for a in cfnptr.argtypes]
cret = from_ctypes(cfnptr.restype)
# void* return type is a int/long on 32 bit platforms and an int on 64 bit
# platforms, explicit conversion to a int64 should match.
if cret == types.voidptr:
cret = types.uintp
if sys.platform == 'win32' and not cfnptr._flags_ & ctypes._FUNCFLAG_CDECL:
# 'stdcall' calling convention under Windows
cconv = 'x86_stdcallcc'
else:
# Default C calling convention
cconv = None
sig = templates.signature(cret, *cargs)
return types.ExternalFunctionPointer(sig, cconv=cconv,
get_pointer=get_pointer)
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