python调用c++ ctype list传数组或者返回数组的方法

2019-11-25 13:18:22

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示例1：

pycallclass.cpp：

#include <iostream>using namespace std;typedef unsigned char BYTE;#define MAX_COUNT 20 struct tagOutCardResult_py{	BYTE							cbCardCount;						BYTE							cbResultCard1;	BYTE							cbResultCard2;	BYTE							cbResultCard3;	BYTE							cbResultCard4;	BYTE							cbResultCard5;	BYTE							cbResultCard6;	BYTE							cbResultCard7;	BYTE							cbResultCard8;	BYTE							cbResultCard9;	BYTE							cbResultCard10;	BYTE							cbResultCard11;	BYTE							cbResultCard12;	BYTE							cbResultCard13;	BYTE							cbResultCard14;	BYTE							cbResultCard15;	BYTE							cbResultCard16;	BYTE							cbResultCard17;	BYTE							cbResultCard18;	BYTE							cbResultCard19;	BYTE							cbResultCard20;}; struct tagOutCardResult{	BYTE							cbCardCount;						BYTE							cbResultCard[MAX_COUNT];			void clear()	{		cbCardCount = 0;		for (int nIdx = 0;nIdx < MAX_COUNT;++nIdx)		{			cbResultCard[nIdx] = 0;		}	}		void topy(tagOutCardResult_py* ppy)	{		cout<<"topy function begin"<<endl;		ppy->cbCardCount = cbCardCount;		cout<<"topy function 1"<<endl;		ppy->cbResultCard1 = cbResultCard[1 - 1];		cout<<"topy function 2"<<endl;		ppy->cbResultCard2 = cbResultCard[2 - 1];		ppy->cbResultCard3 = cbResultCard[3 - 1];		ppy->cbResultCard4 = cbResultCard[4 - 1];		ppy->cbResultCard5 = cbResultCard[5 - 1];		ppy->cbResultCard6 = cbResultCard[6 - 1];		ppy->cbResultCard7 = cbResultCard[7 - 1];		ppy->cbResultCard8 = cbResultCard[8 - 1];		ppy->cbResultCard9 = cbResultCard[9 - 1];		ppy->cbResultCard10 = cbResultCard[10 - 1];		ppy->cbResultCard11 = cbResultCard[11 - 1];		ppy->cbResultCard12 = cbResultCard[12 - 1];		ppy->cbResultCard13 = cbResultCard[13 - 1];		ppy->cbResultCard14 = cbResultCard[14 - 1];		ppy->cbResultCard15 = cbResultCard[15 - 1];		ppy->cbResultCard16 = cbResultCard[16 - 1];		ppy->cbResultCard17 = cbResultCard[17 - 1];		ppy->cbResultCard18 = cbResultCard[18 - 1];		ppy->cbResultCard19 = cbResultCard[19 - 1];		ppy->cbResultCard20 = cbResultCard[20 - 1];		cout<<"topy function end"<<endl;	}}; class TestLib{	public:		void display(tagOutCardResult& ret);};void TestLib::display(tagOutCardResult& ret) {	ret.cbCardCount = 3;	ret.cbResultCard[0] = 1;	ret.cbResultCard[1] = 50;	ret.cbResultCard[2] = 100; 	cout<<"First display aaa ";	cout<<"hello ";	cout<<"world ";} extern "C" {	TestLib oGameLogic;	void display(tagOutCardResult_py* ret_py) {		tagOutCardResult oRet;		oGameLogic.display(oRet);		cout<<"before topy"<<endl;		oRet.topy(ret_py);		cout<<"after topy"<<endl;		cout<<"in cpp:ret_py->cbCardCount:"<<ret_py->cbCardCount<<endl;		cout<<"in cpp:ret_py->cbResultCard1:"<<ret_py->cbResultCard1<<endl;		cout<<" this:" << ret_py << endl;	}}

编译脚本：

g++ -o libpycallclass.so -shared -fPIC pycallclass.cpp -I/usr/include/python2.6 -L/usr/lib64/python2.6/config

Game.py调用部分。类声明：

import ctypes class tagOutCardResult_py(ctypes.Structure): _fields_ = [("cbCardCount", ctypes.c_ubyte), /("cbResultCard1", ctypes.c_ubyte), /("cbResultCard2", ctypes.c_ubyte), /("cbResultCard3", ctypes.c_ubyte), /("cbResultCard4", ctypes.c_ubyte), /("cbResultCard5", ctypes.c_ubyte), /("cbResultCard6", ctypes.c_ubyte), /("cbResultCard7", ctypes.c_ubyte), /("cbResultCard8", ctypes.c_ubyte), /("cbResultCard9", ctypes.c_ubyte), /("cbResultCard10", ctypes.c_ubyte), /("cbResultCard11", ctypes.c_ubyte), /("cbResultCard12", ctypes.c_ubyte), /("cbResultCard13", ctypes.c_ubyte), /("cbResultCard14", ctypes.c_ubyte), /("cbResultCard15", ctypes.c_ubyte), /("cbResultCard16", ctypes.c_ubyte), /("cbResultCard17", ctypes.c_ubyte), /("cbResultCard18", ctypes.c_ubyte), /("cbResultCard19", ctypes.c_ubyte), /("cbResultCard20", ctypes.c_ubyte)]

Game.py调用部分。具体调用：

  import ctypes  so = ctypes.cdll.LoadLibrary  lib = so("./libpycallclass.so")  ERROR_MSG('display(/)')  ret = tagOutCardResult_py(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)  ERROR_MSG("before lib.display(ctypes.byref(ret))")  lib.display(ctypes.byref(ret))  ERROR_MSG("after lib.display(ctypes.byref(ret))")  ERROR_MSG('#######################################################################################')  ERROR_MSG(ret)  ERROR_MSG(ret.cbCardCount)  ERROR_MSG(ret.cbResultCard1)  ERROR_MSG(ret.cbResultCard2)  ERROR_MSG(ret.cbResultCard3)  ERROR_MSG(type(ret))

传入一个结构体，使用引用返回，回到python中打印出来结果是对的。

这样就可以传入，可以传出了。

示例1end#########################################################################

示例2：

pycallclass.cpp:

#include <iostream>using namespace std;typedef unsigned char BYTE;#define MAX_COUNT 20 #if defined(WIN32)||defined(WINDOWS)#define DLL_EXPORT __declspec(dllexport)#else#define DLL_EXPORT#endif struct ByteArray_20{	BYTE e1;	BYTE e2;	BYTE e3;	BYTE e4;	BYTE e5;	BYTE e6;	BYTE e7;	BYTE e8;	BYTE e9;	BYTE e10;	BYTE e11;	BYTE e12;	BYTE e13;	BYTE e14;	BYTE e15;	BYTE e16;	BYTE e17;	BYTE e18;	BYTE e19;	BYTE e20;};struct ByteArray_20_3{	ByteArray_20 e1;	ByteArray_20 e2;	ByteArray_20 e3;}; struct ByteArrayNew_20_3{	BYTE e[3][20];}; class TestLib{	public:		void LogicFunc(ByteArray_20_3& ret);		void LogicFuncNew(ByteArrayNew_20_3& ret);};void TestLib::LogicFunc(ByteArray_20_3& ret) {	ret.e1.e1 = 3;	ret.e1.e2 = 1;	ret.e1.e3 = 50;	ret.e2.e1 = 100;	ret.e2.e2 = 200;	ret.e2.e3 = 20; 	cout<<"TestLib::LogicFunc"<<endl;}void TestLib::LogicFuncNew(ByteArrayNew_20_3& ret) {	ret.e[0][0] = 31;	ret.e[0][1] = 11;	ret.e[0][2] = 51;	ret.e[1][0] = 101;	ret.e[1][1] = 201;	ret.e[1][2] = 21; 	cout << "TestLib::LogicFuncNew" << endl;} extern "C" {	TestLib oGameLogic;	void DLL_EXPORT display(ByteArray_20_3* pret) {		cout<<"cpp display func begin"<<endl;		oGameLogic.LogicFunc(*pret);		cout<<"cpp display func end"<<endl;	}	void DLL_EXPORT display2(ByteArrayNew_20_3* pret) {		cout << "cpp display2 func begin" << endl;		oGameLogic.LogicFuncNew(*pret);		cout << "cpp display2 func end" << endl;	}}

pycallclass.py:

import ctypes def ERROR_MSG(str): print str class ByteArray_20(ctypes.Structure): _fields_ = [/("e1", ctypes.c_ubyte), /("e2", ctypes.c_ubyte), /("e3", ctypes.c_ubyte), /("e4", ctypes.c_ubyte), /("e5", ctypes.c_ubyte), /("e6", ctypes.c_ubyte), /("e7", ctypes.c_ubyte), /("e8", ctypes.c_ubyte), /("e9", ctypes.c_ubyte), /("e10", ctypes.c_ubyte), /("e11", ctypes.c_ubyte), /("e12", ctypes.c_ubyte), /("e13", ctypes.c_ubyte), /("e14", ctypes.c_ubyte), /("e15", ctypes.c_ubyte), /("e16", ctypes.c_ubyte), /("e17", ctypes.c_ubyte), /("e18", ctypes.c_ubyte), /("e19", ctypes.c_ubyte), /("e20", ctypes.c_ubyte)]  class ByteArray_20_3(ctypes.Structure): _fields_ = [/("e1", ByteArray_20), /("e2", ByteArray_20), /("e3", ByteArray_20)] def __init__(self):  self.aaa = 123  self.bbb = [1, 2, 3, 4, 5]  self.ccc = "alksdfjlasdfjk" def test(self):  self.aaa = 123  self.bbb = [1, 2, 3, 4, 5]  self.ccc = "alksdfjlasdfjk"  self.e1.e1 = 5  self.e1.e2 = 20  so = ctypes.cdll.LoadLibrarylib = so("./libpycallclass.dll")print('display()')ret = ByteArray_20_3()ret.test()ERROR_MSG(ret.e1.e1)ERROR_MSG(ret.e1.e2)print("before lib.display(ctypes.byref(ret))")lib.display(ctypes.byref(ret))print("after lib.display(ctypes.byref(ret))")print('#######################################################################################')print(ret)ERROR_MSG(ret.e1)ERROR_MSG(ret.e2)ERROR_MSG(ret.e3)ERROR_MSG(ret.e1.e1)ERROR_MSG(ret.e1.e2)ERROR_MSG(ret.e1.e3)ERROR_MSG(ret.e2.e1)ERROR_MSG(ret.e2.e2)ERROR_MSG(ret.e2.e3)ERROR_MSG(type(ret)) print("before lib.display2(ctypes.byref(ret))")lib.display2(ctypes.byref(ret))print("after lib.display2(ctypes.byref(ret))")print('#######################################################################################')print(ret)ERROR_MSG(ret.e1)ERROR_MSG(ret.e2)ERROR_MSG(ret.e3)ERROR_MSG(ret.e1.e1)ERROR_MSG(ret.e1.e2)ERROR_MSG(ret.e1.e3)ERROR_MSG(ret.e2.e1)ERROR_MSG(ret.e2.e2)ERROR_MSG(ret.e2.e3)ERROR_MSG(type(ret)) ret.test()ERROR_MSG(ret.e1.e1)ERROR_MSG(ret.e1.e2)

g++:

g++ -o libpycallclass.so -shared -fPIC pycallclass.cpp -I/usr/include/python2.6 -L/usr/lib64/python2.6/config

windows:

新建一个DLL工程，把pycallclass.cpp加进去，编译成DLL就OK了。

千万注意python的运行时是32位的还是64位的，DLL或者SO必须和它对应。

python类可以嵌套使用，继承ctypes.Structure，部分成员是_fields_里定义的，部分成员在__init__里定义，这样的类也可以ctypes.byref(self)传进c++去，传的是指针，传入传出就都OK了。

注意示例2中ByteArrayNew_20_3的用法，python中是定义了20个变量，c++中是直接一个二维数组。内存结构是一致的，所以可以直接这样使用。注意类型和长度必须一致，否则可能会内存访问越界。

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