用Boost.Python将C++代码封装为Python模块
一. 基础篇
借助Boost.Python库可以将C/C++代码方便、快捷地移植到python模块当中，实现对python模块的扩充。首先，将C++下的代码编译为动态库，并将生成的动态库命名为封装模块的名字，如：用BOOST_PYTHON_MODULE(Module_Name)宏对需要导出的函数、全局变量、类等导入Python的Module_Name模块，此时生成的动态库需要更名为Module_Name.pyd。然后，将Module_Name.pyd放在python的系统搜索目录中（通常是%PYTHON_PATH%\DLLs目录）。最后，在IDLE GUI界面或是python脚本中执行import Module_Name，这样就可以在python复用C++中定义的函数、类等而不必重写。
xuyuan77标注: 如果出现dll无法加载的情况，可以用depends工具查看是否有依赖的dll缺失，比如我在ipython中import BoostPython_Module_Abs 时无法load dll，是因为 DLLS目录下没有依赖的boost_python3-vc140-mt-x64-1_66.dll文件。
我测试的时候用的是boost 1_66版本，python3.5版本。原作者的代码有很多错误，我注释了代码，只试了import BoostPython_Module_Abs 模块。可以成功运行。
二. 实例篇
下面的实例代码主要针对抽象类、带默认实现虚函数的类、类的成员函数及操作符重载、带默认参数的函数(包括构造函数)、派生类、纯虚函数、返回对象及字符串的函数等的封装方法，基本概括了C+扩展到python模块的常见类型。
//boostpython_abs.h
#include <string>
#ifndef BOOSTPYTHON_ABS_H #define BOOSTPYTHON_ABS_H /* *brief: * wrap c/c++ code as dll and export the class/function interfaces * to python as modules with boost-library *author: * hank *history: * created 2012-07-13 */ #ifndef BSTPABS_API #define BSTPABS_API __declspec(dllimport) #else #define BSTPABS_API __declspec(dllexport) #endif /* * 1.export the abstract class into python module * 2.abstract class with member over-load functions|operators */ class BSTPABS_API CPhone { public: enum Mode { CANCONNECTED = , CONNECTED, PAUSE, DISCONNECTED }; public: CPhone(std::string owner = "") {} virtual int make_call(int phone_num) = ; virtual std::string make_call(std::string name) = ; virtual CPhone& operator << (int phone_num) = ; virtual CPhone& operator << (std::string name) = ; }; //here,wrap the CPhone class class CPhoneWrap :public CPhone, public boost::python::wrapper<CPhone> { public: int make_call(int phone_num); std::string make_call(std::string name); CPhone& operator <<(int phone_num); CPhone& operator << (std::string name); }; #endif//BOOSTPYTHON_ABS_H
//boostpython_abs.cpp #include <boost/python.hpp> #include "boostpython_abs.h"
//define function pointers of overload functions int (CPhone::*make_call1)(int) = &CPhone::make_call; std::string(CPhone::*make_call2)(std::string) = &CPhone::make_call; CPhone& (CPhone::*o1)(int) = &CPhone::operator<<; CPhone& (CPhone::*o2)(std::string) = &CPhone::operator<<; int CPhoneWrap::make_call(int phone_num) { return this->get_override("make_call1")(); } std::string CPhoneWrap::make_call(std::string name) { return this->get_override("make_call2")(); } CPhone& CPhoneWrap::operator << (int phone_num) { return boost::python::call<CPhoneWrap&>(this->get_override("o1").ptr()); } CPhone& CPhoneWrap::operator <<(std::string name) { return boost::python::call<CPhoneWrap&>(this->get_override("o2").ptr()); } /* * Boost.Python Module Export Code bellow */ BOOST_PYTHON_MODULE(BoostPython_Module_Abs)
{ using namespace boost::python; class_<CPhoneWrap, boost::noncopyable>("CPhone") .def("<<", pure_virtual(o1), return_internal_reference<>()) .def("<<", pure_virtual(o2), return_internal_reference<>()) .def("make_call", pure_virtual(make_call1)) .def("make_call", pure_virtual(make_call2)) ; enum_<CPhoneWrap::Mode>("Mode") .value("CANCONNECTED", CPhoneWrap::Mode::CANCONNECTED) .value("CONNECTED", CPhoneWrap::Mode::CONNECTED) .value("PAUSE", CPhoneWrap::Mode::PAUSE) .value("DISCONNECTED", CPhoneWrap::Mode::DISCONNECTED) ; }
//boostpython_com.h #ifndef BOOSTPYTHON_COM_H #define BOOSTPYTHON_COM_H #include "boostpython_abs.h" #ifndef BSTPCOM_API #define BSTPCOM_API __declspec(dllimport) #else #define BSTPCOM_API __declspec(dllexport) #endif /* * 1.common class with member over-load functions|operators * 2.with default parameter in constructor function */ class BSTPCOM_API CPerson
{
private:
int phone_num; std::string name; CPhone::Mode mode; public: CPerson() {/*initializtion here*/ } CPerson(int num, CPhone::Mode aMode = CPhone::CANCONNECTED)
{
this->mode = aMode;
} void set(int num)
{
this->phone_num = num;
} void set(std::string aName)
{
this->name = aName;
} void setall(int num, std::string name = "") {/*do something here*/ } CPerson&operator<<(int phone_num) { return *this; } CPerson&operator<<(std::string name) { return *this; } CPerson& write(int phone_num) { return *this; } CPerson& write(std::string name) { return *this; } }; #endif//BOOSTPYTHON_COM_H
//boostpython_com.cpp #include <boost/python.hpp>
#include "boostpython_com.h"
#include "boostpython_abs.h"
/* * the function pointers of overload functions */ //void (CPerson::*set1)(int) = &CPerson::set;
//
//void (CPerson::*set2)(std::string) = &CPerson::set;
//
//CPerson& (CPerson::*write1)(int) = &CPerson::write;
//
//CPerson& (CPerson::*write2)(std::string) = &CPerson::write; /* * Boost.Python Module Export Code bellow */ //BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(setall_overload, setall, 1, 2)
//
//BOOST_PYTHON_MODULE (BoostPython_Module_Com)
//
//{
//
// using namespace boost::python;
//
// class_<CPerson>("CPerson")
//
// .def(init<int, optional<CPhoneWrap::Mode> >())
//
// .def(self << int())
//
// .def(self << std::string())
//
// .def("setall", &CPerson::setall, setall_overload())
//
// .def("set", set1)
//
// .def("set", set2)
//
// .def("write", write1)
//
// .def("write", write2);
//
//}
//boostpython_info.h
#ifndef BOOSTPYTHON_INFO_H
#define BOOSTPYTHON_INFO_H
#include "boostpython_abs.h"
#include "boostpython_com.h"
#include <python.h> //included in dir %PYTHON_PATH%\include
#include <vector>
#ifndef BSTPINFO_API
#define BSTPINFO_API __declspec(dllimport)
#else
#define BSTPINFO_API __declspec(dllexport)
#endif
/*
* 1. virtual functions with default implements
* 2. stl export
* 3. with char* return function,must wrap it
* 4. global function(c-style)
*/
class BSTPINFO_API CInfo
{
public:
virtual std::string get_info() { return "None Info"; }
};
class BSTPINFO_API CMessageInfo :public CInfo
{
public:
virtual std::string get_info() { return "Message Info"; }
};
class BSTPINFO_API CContact
{
std::vector<std::string> m_vec;
public:
std::vector<std::string> get_contact_person()
{
return m_vec;
}
CInfo* get_contact_style() { return new(std::nothrow)CMessageInfo(); }
void set_contact_style(CInfo*) {/*todo:xxx*/ }
char* get_info() { return "return char* in python"; }
//you should wrap char* f(),however,const char* f() this not needed
PyObject* get_info_wrap() { return Py_BuildValue("s", get_info()); }
};
#endif //BOOSTPYTHON_INFO_H
#include <boost/python.hpp>
#include "boostpython_info.h"
class CInfoWrap :public CInfo,
public boost::python::wrapper<CInfo>
{
public:
std::string get_info()
{
if (boost::python::override g = this->get_override("get_info"))
{
return get_info();
}
return CInfo::get_info();
}
};
class CMessageInfoWrap :public CMessageInfo,
public boost::python::wrapper<CMessageInfo>
{
std::string get_info()
{
if (boost::python::override g = this->get_override("get_info"))
{
return get_info();
}
return CMessageInfo::get_info();
}
};
//define export methods of string-vector into python
typedef std::vector<std::string> CStringVector;
void push_back(CStringVector& vec, std::string str)
{
vec.push_back(str);
}
std::string pop_back(CStringVector& vec)
{
std::string ret = vec.back();
vec.pop_back();
return ret;
}
/*
* Boost.Python Module code
*/
//
//BOOST_PYTHON_MODULE(BoostPython_Module_Info)
//
//{
//
// using namespace boost::python;
//
// //export vector in c++ as list in python
//
// class_<CStringVector>("CStringVector")
//
// .def("push_back", push_back)
//
// .def("pop_back", pop_back)
//
// .def("__iter__", boost::python::iterator<CStringVector>())
//
// ;
//
// class_<CInfoWrap, boost::noncopyable>("CInfo")
//
// .def("get_info", &CInfo::get_info)
//
// ;
//
// class_<CMessageInfoWrap, bases<CInfo>, boost::noncopyable>("CMessageInfo")
//
// .def("get_info", &CMessageInfo::get_info)
//
// ;
//
// class_<CContact>("CContact")
//
// .def("get_contact_person", &CContact::get_contact_person)
//
// .def("get_contact_style", &CContact::get_contact_style, return_value_policy<manage_new_object>())
//
// .def("set_contact_style", &CContact::set_contact_style)
//
// .def("get_info", &CContact::get_info_wrap);
//
//}
#!/bin/python #demo.py ''' brief: demonstratione of C/C++ dll export into python modules author: hank/-- ''' import BoostPython_Module_Abs import BoostPython_Module_Com import BoostPython_Module_Info info = BoostPython_Module_Info.CMessageInfo() contact = BoostPython_Module_Info.CContact() contact.set_contact_style(info) getinfo = contact.get_contact_style() print(type(getinfo)) #the type should be CMessageInfo instance chars = contact.get_info() print(chars)
三. 参考文献
1. http://sourceforge.net/projects/boost/files/boost/1.50.0/boost_1_49_0.zip/download压缩包自带文档
2. python-2.7.2自带文档
转自：http://blog.csdn.net/scuhank/article/details/7769342