[英]Passing C++ abstract class as argument to Cython
If I have an abstract base class and a derived class that inherits from it but I have another class that takes the abstract base class object as an argument, how should I go about wrapping it? 如果我有一个抽象基类和一个继承自它的派生类,但是我还有另一个类将抽象基类对象作为参数,那么我应该如何包装它呢?
class A {
public:
A(int x, int y);
virtual int FooA(int x, int y) = 0;
virtual void FooB() = 0;
}
class B : public A{
B(int x, int y, int z, int w);
int FooA(int x, int y);
void FooB();
void FooC(int z, int w);
}
class C {
public:
C(A* ptr, int p);
}
How should I go about wrapping this as a whole? 我应该如何将其整体包装? I know that I am not supposed to wrap the abstract class A but I am having difficulties wrapping C since I do not have the python object for A 我知道我不应该包装抽象类A,但是包装C时遇到了困难,因为我没有A的python对象
EDIT: Actually I managed to wrap the class but I am still getting errors which I will illustrate further. 编辑:实际上我设法包装了类,但是我仍然收到错误,我将进一步说明。
source.pyx source.pyx
cdef extern from "A.h"
cdef cppclass A:
A(int x, int y)
int FooA(int x, int y)
void FooB()
cdef extern from "B.h"
cdef cppclass B(A):
B(int x, int y, int z, int w)
int FooA(int x, int y)
void FooB()
void FooC(int z, int w)
cdef extern from "C.h"
cdef cppclass C:
C(A* ptr, int p)
cdef class pyA:
cdef A* baseptr
def __cinit__(self, int x, int y):
if type(self) is A:
self.baseptr = new A(int x, int y)
def __dealloc__(self):
if type(self) is A:
del self.baseptr
def FooA(self, int x, int y):
pass
def FooB(self):
pass
cdef class pyB(pyA):
def __cinit__(self, int x, int y, int z, int w):
if type(self) is pyB:
self.derivedptr = self.baseptr = new B(int x, int y, int z, int w)
def __dealloc__(self):
del self.derivedptr
def FooC(self, int z, int w):
self.derivedptr.FooC(int z, int w)
cdef class pyC:
cdef C *thisptr
def __cinit__(self, pyA ptr, int p):
self.thisptr(<A *> ptr.thisptr, int p)
def __dealloc__(self):
del self.thisptr
This compiled by when I was testing pyC and passing pyB as the first argument, I got: 这是在我测试pyC并将pyB作为第一个参数传递时编译的,我得到了:
TypeError: "Expected pyA, got pyB".
Shouldn't pyB be able to be passed as the first argument as well since it is a subclass of pyA? 由于pyB是pyA的子类,因此不应该也可以将其作为第一个参数传递吗? Or am I way off? 还是我要离开?
My answer is late. 我的答案来晚了。 But for those who might be interested, here is the working code. 但是对于那些可能感兴趣的人,这里是有效的代码。
Ah 啊
#ifndef A_H_
#define A_H_
class A {
public:
virtual int FooA(int x, int y) = 0;
virtual void FooB() = 0;
};
#endif /* A_H_ */
Bh BH
#ifndef B_H_
#define B_H_
#include "A.h"
class B : public A{
public:
B(int x, int y, int z, int w);
int FooA(int x, int y);
void FooB();
void FooC(int z, int w);
};
#endif /* B_H_ */
Ch 章
#ifndef C_H_
#define C_H_
#include "A.h"
class C {
public:
C(A* ptr, int p);
};
#endif /* C_H_ */
B.cpp B.cpp
#include "B.h"
#include <iostream>
using namespace std;
B::B(int x, int y, int z, int w)
{
cout << "B::B" << endl;
cout << x << " " << y << " "
<< z << " " << w << endl;
}
int B::FooA(int x, int y)
{
cout << "B::FooA" << endl;
cout << x << " " << y << endl;
return 0;
}
void B::FooB()
{
cout << "B::FooB" << endl;
}
void B::FooC(int z, int w)
{
cout << "B::FooC" << endl;
cout << z << " " << w << endl;
}
C.cpp C.cpp
#include "C.h"
#include <iostream>
using namespace std;
C::C(A* ptr, int p)
{
cout << "C::C" << endl;
cout << ptr->FooA(0,1) << endl;
ptr->FooB();
}
source.pyx source.pyx
# distutils: language = c++
# distutils: sources = [B.cpp, C.cpp]
cdef extern from "A.h":
cdef cppclass A:
A(int x, int y) except +
int FooA(int x, int y)
void FooB()
cdef extern from "B.h":
cdef cppclass B(A):
B(int x, int y, int z, int w) except +
int FooA(int x, int y)
void FooB()
void FooC(int z, int w)
cdef extern from "C.h":
cdef cppclass C:
C(A *ptr, int p) except +
cdef class pyA:
cdef A *baseptr
def __cinit__(self):
pass
def FooA(self, int x, int y):
pass
def FooB(self):
pass
cdef class pyB(pyA):
cdef B *derivedptr
def __cinit__(self, int x, int y, int z, int w):
self.derivedptr = new B(x, y, z, w)
self.baseptr = self.derivedptr
def __dealloc__(self):
del self.derivedptr
def FooC(self, int z, int w):
self.derivedptr.FooC(z, w)
cdef class pyC:
cdef C *thisptr
def __cinit__(self, pyA ptr, int p):
self.thisptr = new C(ptr.baseptr, p)
def __dealloc__(self):
del self.thisptr
setup.py setup.py
from distutils.core import setup
from Cython.Build import cythonize
setup(
name = 'testapp',
ext_modules = cythonize('*.pyx'),
)
Finally, compile 最后编译
$python setup.py build_ext --inplace
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